Annual/Termination Reports:

[06/28/2009] [09/13/2010] [07/31/2011] [10/23/2012]

Report Information

Participants

" Ahola, Jason jahola@uidaho.edu Idaho
" Hill, Rod rodhill@uidaho.edu Idaho.
" Welch, Cassie welc1710@vandals.uidaho.edu Idaho.
" Berger, Larry llberger@uiuc.edu Illinois.
" Carstens, Gordon g-carstens@tamu.edu Texas.
" Crawford, Grant craw0105@umn.edu Minnesota.
" Crews, Denny Denny.Crews@colostate.edu Colorado.
" Davis, Michael davis.28@osu.edu Ohio.
" Hansen, Gary Gary_Hansen@ncsu.edu North Carolina
" Kriese-Anderson, Lisa Ann kriesla@auburn.edu Alabama
" Maddock, Travis tdmaddock@ufl.edu Florida.
" Oltjen, James jwoltjen@ucdavis.edu California.
" Cruz, Gustavo California.
" Rauw, Wendy wrauw@cabnr.unr.edu Nevada.
" Turzillo, Adele aturzillo@csrees.usda.gov CSREES Adviser.

Brief Summary of Minutes

Members Not Attending: Robert Dailey and Eugene Felton, West Virginia, Robert Herd, Australia, Brett Hess (administrative adviser, Wyoming), Monty Kerley, Missouri, Robert Myer, Florida, Roberto Sainz, California, Thomas Welsh, Texas, Robert Wettemann, Oklahoma, Scott Whisnant, North Carolina.

Guests: Holly Foster, Drovers.

The annual meeting of the W1010 technical committee was held in Davis California on April 28-29, 2009. The meeting was called to order by the inaugural committee chair, Rod Hill.

The group was welcomed to the University of California, Davis by Dr Mary Delaney, Chair of the Department of Animal Science.
Each of the stations prepared a brief written report and presented this information to the group in attendance.

In the business meeting, Dr Adele Turzillo (USDA-CSREES, National Program Leader) provided programmatic updates on personnel and the USDA Strategic Plan. Dr. Turzillo also provided insight into successful grantsmanship and funding opportunities.

It was decided that the next year meeting would be held in Missouri, as for this year, preceding the Beef Improvement Federation meeting. Dr Carstens will serve as Chair in 2009-10. Dr Berger was elected to serve as Secretary.
Following experiment station presentations, the committee explored avenues, mechanisms and future plans for collaborative research and joint grant submissions.

Accomplishments

The Alabama Station reported two experiments. In the first experiment, fifty Simmental-Angus crossbred cows were bred AI to either a bull with a known low feed:gain ratio (FE = 4.8) or to a bull with an unknown feed:gain ratio. Sixteen male progeny resulted (8 low F:G; 8 unknown F:G). Half of the male progeny were left intact as bulls, while the other half was castrated. After weaning, the cattle were fed a total mixed diet (cp = 13%; tdn = 70%) in individual stalls for 84 days. Feed intake was recorded daily and cattle were weighed bi-weekly during the gain test period. At day 44 of the test period, muscle and adipose tissue samples (2 g each) were obtained between the 12th and 13th ribs. They were immediately frozen with liquid nitrogen and remained frozen until ready for elucidation of gene expression (mRNA abundance) using real-time PCR. For this portion of the experiment, the objective was to examine relationships between GE (mRNA abundance) of fatty acid synthase (FAS), PPAR ±, PPAR ³2, carnitine palmitoyl transferase (CPT-1b), leptin, uncoupling protein 2 (UCP-2), ubiquitin conjugating enzyme (E2) and polyubiquitin (PQ) genes in both skeletal muscle (SKM) and adipose tissue (AT) with FE and RFI in finishing cattle. Independent variables of bull type (low feed:gain ratio vs. unknown) and calf sex was used to evaluate ADG, total gain, feed:gain ratio and RFI. Bull type was not a significant source of variation for any trait. Bull calves gained faster (lsmeans 143.5 kg vs. 114.6 kg; P<0.05) with better feed:gain ratios (P<.05). There were no significant differences between feed intake of bulls and steers. Adipose FAS, leptin and PPAR³2 gene expression were unrelated to RFI. Skeletal muscle UCP-2 and E-2 but not CPT-1b, PPAR± and PQ gene expression were correlated with RFI (P<.05). Results indicate that adipose tissue genes for fat deposition are likely minimally related to RFI and FE, while skeletal muscle gene expression associated with mitochondrial metabolism and protein turnover are correlated with RFI. The transcriptomic signature for efficiency in beef cattle appears more related to skeletal than adipose tissue metabolism.<br /> <br /> In a second experiment, in which commercial yearling heifers (n=71, age = 402 days, initial BW = 433.2± 34.5 kg ) were placed on ad libitum feed (DM = 89%, CP = 13.7%) for either 79 (n=16), 100 (n=16), 121 (n=16), 142 (n=16) or 163 (n=7) days. Days on feed (DOF) group assignments were stratified across initial weight and height. Individual birth dates and breed composition were known. Heifers were trained to calan gates and individual daily feed intake and orts recorded. BW was recorded weekly. Thirty five days prior to harvest, half of each DOF group was fed 300 mg/hd/d of Ractopamine-HCL (RAC). Blood samples were taken via venipuncture at d 0, 14, 28, and 34 of the treatment phase. Ultrasound measurements of 12th rib fat, longissimus dorsi area (LMA) and percent intramuscular fat (IMF) were taken at d 0, 35 d prior to harvest and 1 d prior to harvest. Animals were humanely harvested and carcass data collected included: 12th rib fat thickness, USDA marbling score (USDA MS), %KPH, USDA Yield Grade, HCW, and LMA. At harvest, a 2 g sample of adipose, muscle and liver tissue was obtained from each carcass. Samples were immediately frozen in liquid nitrogen to be later evaluated for gene expression using real-time PCR for IGF-1, myostatin and glucose. Plasma samples were assayed for leptin, IGF-1, glucose, non-sterified fatty acids and insulin concentration via RIA. RFI will be calculated over the duration of the feeding period and the last 35 days prior to slaughter. RFI will be correlated with various measures of gene expression and assay concentrations found in the blood and tissue samples.<br /> <br /> The California Station reported that studies were conducted to model the cow-calf production system to allow comparison of management strategy by animal efficiency interactions. For example, this information could be used to improve genetics or to determine the appropriate management system for different genotypes, or animals with varying energetic efficiencies. Useful for this ongoing effort are our previously published analytical results of production and economic relationships between genetics, management, and beef quality.<br /> <br /> The Colorado Station reported that a facility is under construction to that features a 6 × 40 hd capacity feedlot with a 24-node GrowSafe system. The feedlot will also be carbon capture capable. The main research interest will be the genetics of efficient feed utilization, with collaborative projects in ruminant nutrition, physiology, and environmental impact. The new facility is scheduled for completion in August, 2009. We plan to begin conducting feed intake trials in the fall of 2009.<br /> <br /> The Florida Station reported two experiments. In experiment 1, steers (n = 170) were born in 2006 and 2007, progeny of a diallel mating of 33 sires and 143 dams from 6 breed groups (1 = Angus, 2 = ¾ A ¼ B, 3 = Brangus, 4 = ½ A ½ B, 5 = ¼ A ¾ B,and 6 = Brahman). Cows were synchronized with a progesterone-releasing device (CIDR®, Pfizer Animal Health) for 7 d (March), followed by an injection of PGF (5 ml of LUTALYSE® Pfizer Animal Health) artificially injection of PGF2± (5 ml of LUTALYSE®, Pfizer Animal Health), artificially inseminated twice, then placed with a natural service sire for 60 d (6 breeding groups with one sire per breed group). Calves were born in Spring and raised at the University of Florida Beef Research Unit (BRU), Gainesville, until weaning. After weaning, calves were pre-conditioned for 4 wk using concentrate (1.6 kg to 3.6 kg; 488 Pellet, Medicated Weaning Ration, Lakeland Animal Nutrition, Lakeland, Florida; and soy hull pellets), hay, pasture, and free choice mineral (UF University Special Hi-Cu Mineral, University of Florida, Animal Science Department, Gainesville). Calves were transported to the University of Florida feed intake facility (North Florida Research and Education Center, Marianna) in September. Animals were randomly allocated to 10 pens of 20 calves each in 2006, and to 14 pens of 13 to 14 calves each in 2007, by sire group (1 = A, 2 = ¾ A ¼ B, 3 = Brangus, 4 = ½ A ½ B, 5 = ¼ A ¾ B, and 6 = B) and sex (bull, heifer, and steer). The 2006 concentrate diet was composed of whole corn, soybean hulls, corn gluten feed, cottonseed hulls, and a protein, vitamin, and mineral supplement (FRM, Bainbridge, GA). The 2007 diet had greater fiber content (chopped bermudagrass instead of soybean hull pellets). The concentrate had a DM, CP, NEm and NEg of 91.2%, 17.3%, 1.7 mcal/kg DM NEm and 1.2 mcal/kg DM NEg in 2006 and 90.0%,14.1%, 1.5 mcal/kg DM NEm, and 0.9 mcal/kg DM NEg in 2007. The pre-trial adjustment period was of 21 d, and the trial period lasted 70 d. GrowSafe software recorded individual feed intake in real-time. Weights and exit velocity were taken every 2 weeks. Upon completion of the feed efficiency trial, steers were sent to a South Texas feedlot (King Ranch Feedyard, Kingsville, TX), and commercially slaughtered at approximately 14 mm of fat over the longissimus muscle (Sam Kane Beef Processors, Corpus Christy, TX). Residual feed intake was computed as actual minus expected feed intake (Koch et al., 1963; Arthur et al., 2001; Archer et al., 2007). Expected feed intake was a linear function of average daily gain and metabolic mid-weight. Average daily gain was computed as regression of weight on test days. Metabolic mid-weight was estimated mid-weight (estimated initial weight plus average daily gain times 35 d) to the power of 0.75. Temperament was measured as exit velocity (EV) from the chute (m/sec). Carcass traits measured were: hot carcass weight (HCW, kg), dressing percent (DP, %), longissimus muscle area (LMA,cm2), fat thickness between the 12th and 13th rib (FT, cm), kidney, pelvic, and heart fat (KPH,% of carcass weight), and marbling score (MS; USDA scores: 200 = traces, 300 = slight, 400 = small, 500 = modest, 600 = moderate). Meat quality traits were: Warner-Bratzler shear force (SF, kg), tenderness score (TS; 1 = extremely tough, 2 = very tough, 3 = moderately tough, 4 = slightly tough, 5 = slightly tender, 6 = moderately tender, 7 = very tender, 8 = extremely tender), juiciness (JU,1= extremely dry to 8 = extremely juicy), flavor (FL, 1 = extremely bland to 8 = extremely intense), thaw loss (TL, %; 100*(Frozen wt  Thawed wt)/Thawed wt), and cooking loss (CL, %; 100*(Thawed wt  Cooked wt)/Cooked wt). Traits were analyzed using single-trait mixed models (SAS Proc Mixed). Fixed effects were contemporary group (year-pen), RFI group (1 = high = RFI > 0.85 kg, 2 = medium = -0.85 kg d RFI d 0.85 kg, 3=low=-0.85kg; SD = 1.7 kg), age of calf, Brahman fraction of calf within RFI group, heterozygosity of calf, and mean EV. Random effects were sire and residual (zero mean, common variance, uncorrelated). Procedure GPLOT of SAS was used to graph least squares means by RFI group and breed group of calf. (Florida report truncated at 4223 characters, originally 8137 characters).<br /> <br /> The Idaho Station reports that a major study (four years) of the relationship between RFI and Maintenance Energy (ME) EPD in Red Angus sired calves began in 2008. ME EPD is an estimation of energy requirements needed to maintain / sustain animal body condition. When ME EPD is linked to feed efficiency (FE), a highly complementary research strategy results in which a new approach to improve FE is investigated. In addition, a new approach to estimating FE is being embraced by the scientific community largely because it is heritable and independent of many other production traits and is currently known by several different terms: net feed efficiency (NFE), residual feed intake (RFI), and net feed intake. The term RFI will be used throughout this document. RFI measures the variation in feed intake beyond that needed to support maintenance and growth requirements and is calculated as the difference between actual feed intake and the amount of feed an animal is expected to consume based on its body weight and average daily gain. Cattle eating less than expected for their body weight and average daily gain have a negative RFI value, equating to an improved feed efficiency. RFI is an intensely studied, well-developed, new measure of FE that is important to the future profitability and sustainability of the United States beef industry.<br /> <br /> This applied research and outreach project aims to convey results to all sectors of the beef industry - demonstrating the great potential of RFI as a management tool. We are characterizing Red Angus sires for RFI and evaluating the relationship between end-product quality, feed efficiency, and ME. Using the Red Angus breed as a model for others, together we will take an industry leadership role and show that adoption of RFI has advantages directly addressing the following goals: large savings in feed costs, enhancing economic opportunities and increasing profitability, and improving quality of life for beef producers. Furthermore, using less feed for similar production levels also means that this approach will result in reductions in waste products from beef cattle, and thus, reduce the environmental impact of beef production. <br /> <br /> RFI Cohort 1 Study: Prior to this project being funded, four Red Angus bulls with high accuracy ME EPD were selected. Following funding of the project, the research team (University of Idaho and RAAA) worked together to identify additional candidate sires. In May 2007, 120 cross-bred cows at the Nancy M. Cummings Research, Extension and Education Center (NMCREEC), Salmon, ID, were randomly selected for artificial insemination to the four sires initially chosen to generate Cohort 1 progeny. Cows and calves were managed under routine practices. At approximately 9 months of age, progeny of these sires, steers (n = 25) and heifers (n = 17), were transported from NMCREEC to the University of Idaho, Moscow, ID for evaluation of RFI via Calan gate technology (American Calan, Northwood, NH). Prior to the RFI measurement period, animals were allowed an approximate 2 wk adjustment period in which they were adapted to the diet and learned electronic gate operation. Pre- and post- study, animals were weighed on 2 consecutive days (d 0, d 1 and d 84, d 85) before the morning feeding. After initial body weight (BW) measurements and for the subsequent 84-d, animals were fed a growing ration individually using electronic gates. The animals were allowed ad libitum access to fresh feed, which was provided twice daily with orts weighed and recorded daily. During the 84-d test period, animals were weighed every 2 wk. Ultrasound measure for fat thickness (UFT) and LM area (ULMA) were taken on d 85. Hair was removed, and vegetable oil was applied between the 12th and 13th ribs in preparation for measurements of UFT and ULMA. Heifers were returned to NMCREEC upon completion of the test period. After the 84-d test period, the growing ration was modified in 4 stages to the finishing ration. At the time of report submission, steers are being fed the finishing ration until their rib fat depth reaches approximately 0.5 in. Steers will be slaughtered for carcass data collection and objective meat quality determination. (Idaho report truncated at 4240 characters, originally 7789 characters.)<br /> <br /> The Illinois Station reported three experiments. In the first experiment, approximately 400 sire-identified steers were randomly assigned to 50 Grow-Safe units. Six corn and corn-corn co-product based diets were randomly assigned to pen. To estimate diet digestibility, steers were fed in pens where feces could be collected underneath the slats. Bomb calorimetry was done on both the diets and feces to estimate digestible energy intake of each animal. Twenty-seven Angus, Simmental and Angus X Simmental sires were represented in this data set. The 400 head were harvest in three kill groups such that each kill group would average 1.2 cm of back fat. The RFI for the most efficient sire group was -1.59 Mcals of digestible energy per day, and the least efficient sire group was 2.09 Mcals of digestible energy. The correlation of RFI and digestible energy intake above maintenance was 0.873. When RFI was regressed against Mcals of digestible energy intake above maintenance, the R2 =0.75. These data are interpreted to suggest that as intake above maintenance increases, there is a decreasing efficiency of nutrient utilization. These data challenge the dogma that increasing intakes above maintenance should result in more efficient weight gain because a smaller proportion of the total intake is used for maintenance.<br /> <br /> For experiments two and three, sire-identified steers were fed high-concentrate diets and the heifer mates were fed high-forage diets. In year one five high use Angus sires were compared with approximately 20 steer and 20 heifer progeny per sire. The high-concentrate diet was based on corn and distillers grains. The high-forage diet was alfalfa-grass silage. The correlation between sire RFI on the high concentrate and high forage diets was 0.26. In year two steer and heifer progeny from 16 high-use Angus bulls were compared. The steers were fed a typical feedlot diet based on corn and corn co-products. The heifers were fed oatlage and a small amount of wet distillers to increase the crude protein. The correlation between sire RFI on the high concentrate and high forage diet was 0.05. The oatlage for the second year was poorer quality and resulted in gains of 0.7 kg per day compared to approximately 1.0 kg/day in the first year. These data suggest that caution is need in extrapolating RFI data for high concentrate diets to cattle fed high roughage diets.<br /> <br /> The Minnesota Station reported that in February 2009 they conducted the annual Minnesota Cow/Calf Days, with the theme of the program being Impacts of Cow Size. Two of the topics in the program were focused on the effect of cow size on overall beef production (DiCostanzo, 2009; McMurry, 2009). The message from both of these presentations was that cow/calf producers need to focus on producing efficient replacement females. Data were presented (McMurry, 2009) indicating that as cow size increased, offspring weaning weight as a percentage of cow size decreased. Additional data (DiCostanzo, 2009) were presented showing the economic impact of maintaining heavy cows that do not wean calves proportionally heavier to justify the added cost of their maintenance. These presentations took place at ten locations across Minnesota, with a total producer attendance of approximately 750. In addition, the proceedings and presentations from these meetings will be available to beef cattle producers in Minnesota and beyond. Producer evaluations from these meetings were quite positive, with many responses commenting on a renewed commitment among producers to moderate cow size and focus on efficient production in their cow herd. The positive responses will likely lead to a follow-up beef cow efficiency topic on the 2010 Minnesota Beef Cow/Calf Day program.<br /> <br /> The Minnesota station also reported a study to determine effect of feedstuff and feeding device (bunks, hay ring, rolled or ground and delivered on the ground) on dry matter intake of beef cows. Trials 1 and 2 in this experiment consisted of group feeding experiments to determine intake of various feedstuffs presented in different feeding devices. Trial 3 will utilize Calan gates to determine individual feed intakes of cows consuming various feedstuffs, and fits with Objective 3 of the W1010 committee. In Trial 3, 40 cows will be adapted to consume a mixed diet of hay and dry supplement for 14 days through individual Calan doors. Treatments will be arranged in a 2 x 2 factorial, with factors consisting of energy supplement source (corn grain and wet beet pulp) and forage source (alfalfa hay and alfalfa haylage). Cows will be fed for a period of 56 days to establish accurate intake patterns in response to changes in weather. Individual animal weights will be taken on day 1 and day 56. Feed intake will be recorded daily, and samples will be collected weekly to determine nutrient content of feed and feed refusals.<br /> <br /> The Nevada Station reported a study that investigates the molecular bases of feed efficiency by measuring RNA expression in skeletal muscle and liver and by recording feed intake and growth. Feed intake and body weight were measured in 30 animals, in three feeding regimes, during one week. Personnel and time limits did not allow for testing over a longer period of time. In addition, body weight has been recorded during growth. Animals were fed either grain/hay, corn/grain/hay, and corn/alfalfa. For each individual, at slaughter, samples were collected of the muscle, blood, heart, liver, spleen, lung and kidney. A bovine microarray (Affymetrix) would be used to identify sequences up and down regulated in muscle and liver. Sequences differentially expressed would be used in Real Time PCR for all individuals in order to establish the relationship between RNA expression of those sequences and feed efficiency. Feed samples from all treatment groups will be analyzed for energy content. Differences between animals in growth and feed efficiency using feed intake values expressed in metabolizable energy content and use these results in an economical analysis of the three feeding regimes will be analyzed.<br /> <br /> In addition, a model to estimate grazing ability in free-range ruminants based on the model that is used to estimate Residual Feed Intake (Rauw et al., 2006a) is under development. In extensive production systems, animals (seasonally) graze the rangelands, which reduces production costs because animals do not need to be fed. However, grazing animals are subject to recurrent periods of undernutrition during droughts and the winter in which large amounts of body tissue may be catabolized. Preliminary results on a grazing experiment in sheep in the cold Nevada desert showed that 94% of 915 ewes lost body weight during the grazing period, while pregnant animals in particular must gain weight (Rauw et al., 2006). Selection for within-species variation in grazing ability may offer the opportunity to breed for a better adaptation to poor quality rangelands, resulting in healthier animals and improved production. Grazing ability, however, is difficult to record in individual animals under free ranging conditions, since feed intake can not be accurately recorded without time consuming methods. Alternatively, grazing ability may be indirectly inferred from changes in body weight and production characteristics during the grazing period Rauw (2008). RFI is estimated as:<br /> FIi = b0 + (b1 × BWi0.75) + (b2 × BWGi) + ei, (1)<br /> where FIi = feed intake of individual i, BWi0.75 = metabolic body weight, BWGi = body weight gain, b0 = population intercept, b1 and b2 = partial regression coefficients representing maintenance requirements and feed requirements for growth, respectively, and ei = the error term, representing RFI. Rewriting this model gives: <br /> GAi = GIi - b0 - ei = (b1 × BWi0.75) + (b2 × BWGi), (2)<br /> where GAi = grazing ability of individual i, GIi = grazing intake of individual i, and other parameters are as in model (1). The amount of resources ingested is confounded with the efficiency of resources allocated, however, in a resource limiting environment, for the livestock producer it is more important if the animal has been able to ingest a sufficient amount of resources than if the animal is more or less efficient in allocating those. Since feed intakes and partial regression coefficients cannot be estimated in the field, estimates can be derived from the literature or from controlled experiments on a sub-group originating from the animal population of interest. A hatch project addressing this issue is currently being reviewed. Body weights can be estimated before and after animals are allowed to range freely on the rangelands, and metabolic body weight and body weight gain can be calculated.<br /> <br /> Preliminary results indicate that grazing ability is heritable, which would assure a significant response to selection when selected for. In the context of resource allocation, GA presents an estimate of the individual ability to graze at resource limiting rangelands and can be applied to different range species. (Nevada report truncated at 4156 characters, originally 5089 characters).<br /> <br /> The Ohio Station reported that a divergent selection experiment based on feed:gain ratios was conducted in the early 1980s using Angus beef cattle located at the Eastern Agricultural Research Station (EARS), Belle Valley, OH (Bishop et al., 1991a,b). Bulls were selected and individually fed during a 140-d postweaning performance test. At the end of the period, the 3 bulls with the highest feed:gain ratios and 3 three with the lowest feed:gain ratios were selected and randomly mated to 20 cows each. The progeny were then fed to assess postweaning and carcass performance. The purpose of the study was to compare mean responses of the 2 divergently selected lines of Angus beef cattle and to calculate heritability estimates for feed conversion and the phenotypic and genetic correlations between feed conversion and other economically important traits. The heritability estimates (0.46 for FCR adjusted for maintenance requirements; 0.26 for FCR unadjusted for maintenance) indicated that genetic variability for feed conversion existed in this beef cattle population. Bishop et al. (1991a,b) reported that progeny of the low FCR sires had greater subcutaneous fat than progeny of the high FCR sires, but no significant differences in other carcass traits were found. Phenotypic correlations indicated that the progeny with lower feed:gain ratios were fatter, gained weight at a faster rate, and yielded carcasses with higher quality grades, but less desirable yield grades. The selection criterion used in the divergent selection experiment was feed:gain ratio. The main objective of Shannon Smiths Masters thesis was to compare results of the selection experiment obtained using feed:gain ratios with those obtained using RFI. The sub-objectives were to:<br /> 1. Compare rankings of bulls based on feed:gain ratio vs. RFI;<br /> 2. Determine the phenotypic correlations of RFI with weights, gains, feed intake, feed:gain ratio, and backfat thickness of the bulls individually fed in the selection experiment.<br /> <br /> Between 1979 and 1983, 35 bull calves were randomly chosen each year from the purebred Angus herd located at EARS. The bull calves were individually fed in a 140-d postweaning performance test. Numbers of bulls completing the performance test in 1979 through 1983 were 35, 34, 35, 34, and 33, respectively. After weaning at approximately 7 mo of age, bulls were placed in a 3-sided barn where they were group fed for 1 wk. Bulls were then randomly assigned to individual feed bunks, where they were tied for 2 h each morning and 2 h each afternoon, and were allowed to adjust to the tying procedure for 1 wk. On-test weights were taken and recording of individual feed consumption began. Average on-test age and weight were 222 d and 232 kg, respectively. Weights and feed consumption were recorded once every 28 d. Weights were recorded in the morning before feeding. The final weight was calculated as the average of 2 weights taken on consecutive days after the 140-d performance test was completed. On the same day as the second off-test weight was taken, hip height and ultrasound estimates of subcutaneous fat thickness over the longissimus muscle between the 12th and 13th ribs were recorded. Each year, the 3 bulls with the highest feed:gain ratios and the 3 bulls with the lowest feed:gain ratios were selected from the individually fed bulls, and were randomly mated to approximately 20 cows each in a test herd of Angus cows also located at EARS. A different set of bulls was chosen each year; thus, the experiment was a single generation selection experiment replicated 4 times. The Beef Improvement Federation (BIF, 1986) recommends adjusting feed:gain ratios for differences in maintenance requirements, if feed consumption per unit of gain is evaluated over time-constant intervals. The adjustment was accomplished by multiplying the ratio of test group average metabolic midweight (Wi.75) to individual metabolic midweight (Wij.75) as follows: BIF-adjusted feed efficiency = (Wi.75/ Wij.75) (feed/gain), where subscript i refers to ith year of test (1979, 1980, 1981, 1982, or 1983) and subscript j refers to jth bull within the ith year. Midweights were estimated as ½ (initial weight on test + final weight off test). This procedure adjusts the feed conversion of heavier-than-average bulls downward, because the bulls would be expected to have above-average maintenance requirements and above-average metabolic weights (BIF, 1986). Feed:gain ratios of lighter-than-average bulls would be adjusted upward, because their maintenance requirements and metabolic weights would be below average. The bulls used for mating in the selection experiment were chosen based on their adjusted feed:gain ratios. (Ohio report truncated to 4744 characters, originally 14428 characters.)<br /> <br /> The Oklahoma Station reported that Angus nonlactating, spring-calving cows were used to determine variation in maintenance energy requirements (MR), to evaluate the relationships among MR and cow and calf performance, plasma concentrations of IGF-I, T4, glucose, insulin and ruminal temperature, and to describe the longissimus muscle (LM) proteome and evaluate protein abundance in cows with different MR. Cows (4 to 7 yr of age) with a BCS of 5.0 ± 0.2, and BW of 582 ± 37 kg, in the second to third trimester of gestation, were studied in groups. Cows were individually fed a complete diet in amounts to meet predicted MR (Level 1 Model, NRC 1996), and daily FI was adjusted weekly until constant BW was achieved for at least 21 d (maintenance). Cows were classified based on MR as low (> 0.5 SD less than mean, LMR), moderate (± 0.5 SD of mean, MMR) or high (> 0.5 SD more than mean, HMR) MR. Blood samples were taken at maintenance and at 2 mo post partum. Muscle biopsies were taken from LMR and HMR cows at maintenance. Proteins from LM were separated by two-dimensional, difference gel electrophoresis and abundance was quantified and compared. The greatest differences in MR between cows were 29% (n = 23), 24% (n = 32), and 25% (n = 38) in the 3 groups. Daily MR (NEm, Kcal"BW-0.75"d-1) averaged 89.2 ± 6.3, 93.0 ± 4.9, and 90.4 ± 4.6, in groups 1, 2 and 3, respectively.<br /> <br /> Postpartum BW and BCS, calves birth and weaning weights, resumption of luteal activity after calving, plasma concentrations of hormones and ruminal temperature were not influenced by MR of the cows. However, MR was negatively correlated with concentrations of IGF-I in plasma (r = -0.38; P = 0.05) and tended to be positively correlated with T4 in plasma (r = 0.31; P = 0.12) at 2 mo post partum. A total of 103 proteins were isolated from the LM, and 52 gene products were identified, of which many (33%) participated in metabolism. Protein abundance tended (P = 0.11) to be greater in HMR cows for cofilin-2. Greater abundance of cofilin-2 in HMR cows may have application as a biomarker for MR. . Productive cows that require less feed for maintenance will improve efficiency of production and enhance the sustainability of the environment.<br /> <br /> The Texas Station reported on results from four experiments. In the first experiment (Lancaster et al., 2008), Angus bulls and heifers from the Ohio Station that were divergently selected for serum insulin-like growth factor-I (IGF-I) concentration were used to evaluate the effects of IGF-I selection line on feed efficiency traits in 2 studies. In study 1, bulls (low line n = 9; high line n = 8) and heifers (low line n = 9; high line n = 13) were fed a roughage-based diet (ME = 1.95 Mcal/kg DM), and in study 2, bulls (low line n = 15; high line n = 12) and heifers (low line n = 9; high line n = 20) were fed a grain-based diet (ME = 2.85 Mcal/kg DM). Blood samples were collected at weaning and at the start and end of each study and serum IGF-I concentration determined. RFI was calculated, within study, as the residual from the linear regression of DMI on mid-test BW0.75 (MBW), ADG, gender, gender by MBW and gender by ADG. In study 1, calves from the low IGF-I selection line had similar ADG compared to calves from the high IGF-I selection line. DMI and feed conversion ratio (FCR) were also similar between IGF-I selection lines, however, calves from the low IGF-I line tended (P < 0.10) to have lower RFI than calves from the high IGF-I line (-0.26 vs. 0.24 ± 0.31 kg/d). In study 2, IGF-I selection line had no influence on performance or feed efficiency traits. However, there was a tendency (P = 0.15) for an IGF-I line by gender interaction for RFI. Bulls from the low IGF-I line had numerically lower RFI than those from the high IGF-I line, whereas, in heifers IGF-I line had no effect on RFI. In studies 1 and 2, weaning and initial IGF-I concentrations were not correlated with either FCR or RFI. However, regression analysis revealed a gender by IGF-I concentration interaction for initial IGF-I concentration in study 1 and weaning IGF-I concentration in study 2, such that the regression coefficient was positive for bulls and negative for heifers. These data suggest that genetic selection for postweaning serum IGF-I concentration had minimal effect on RFI in beef cattle.<br /> <br /> In the second experiment (Lancaster et al., 2009a), data from 341 Angus bulls was used to characterize feed efficiency traits and to examine phenotypic correlations with feeding behavior and carcass ultrasound traits. Individual DMI and feeding behavior traits were measured in bulls fed a corn silage-based diet (ME = 2.77 Mcal/kg DM) using a GrowSafe feeding system. Ultrasound measures of carcass 12-13th rib fat thickness (BF) and longissimus muscle area (LMA) were obtained at the start and end of each of 4 trials. Residual feed intake (RFIp) was computed from linear regression of DMI on ADG and mid-test BW0.75 (MBW) with trial, trial by ADG and trial by MBW as random effects. Overall ADG, DMI and RFIp were 1.44 (SD = 0.29), 9.46 (SD = 1.31), and 0.00 (SD = 0.78) kg/d, respectively. Stepwise regression analysis revealed that inclusion of gain in BF and LMA in the base model increased R2 (0.76 vs. 0.78), and accounted for 9% of the variation in DMI not explained by MBW and ADG (RFIp). RFIp and carcass-adjusted RFI (RFIc) were moderately correlated with DMI (0.60 and 0.55) and FCR (0.49 and 0.45), and strongly correlated with partial efficiency of growth (PEG; -0.84 and -0.78), but not with ADG or MBW. Gain in BF was weakly correlated with RFIp (0.30), FCR (-0.15), and PEG (-0.11), but not RFIc. The Spearman rank correlation between RFIp and RFIc was high (0.91). Meal duration (0.41), head-down duration (0.38), and meal frequency (0.26) were correlated with RFIp, and accounted for 35% of the variation in DMI not explained by carcass-adjusted RFIc. These results suggest that adjusting RFI for carcass composition will facilitate selection to reduce feed intake in cattle without affecting rate or composition of gain.<br /> <br /> In the third experiment (Lancaster et al., 2009b; accepted), 468 Brangus heifers were used in 4 postweaning trials to characterize RFI and to estimate phenotypic and genetic correlations with performance and ultrasound carcass traits. The pedigree file from Camp Cooley Ranch included 31,215 animals. Heifers were individually fed a roughage-based diet (ME = 1.98 Mcal/kg DM) using Calan gate feeders for 70 d. Heifer BW were recorded weekly and ultrasound measures of 12-13th rib fat thickness (BF) and longissimus muscle area (LMA) obtained at d 0 and 70. (Texas report truncated at 4411 characters, originally 7430 characters.)<br />

Publications

Ahola, J.K. and Hill, R.A. (2008). Selection for Feed Efficiency in Beef Cattle: Risks, Benefits, & Opportunities. Nancy M Cummings Research, Education and Extension Center, Salmon ID. <br /> <br /> Ahola, J.K. and Hill, R.A. (2008). Defining and Measuring Feed Efficiency. Proc., Pacific Northwest Animal Nutrition Conference, October 7-9, 2008, Tacoma, Washington. pp. 157-162.<br /> <br /> Ahola, J.K., Kane, S.L., Wulfhorst, J.D., Keenan, L.D. and Hill, R.A. (2009). A Nationwide Survey of Beef Producers about Feed Efficiency  Motivating Factors for the Implementation of Selection Practices. Beef Improvement Federation, National Meeting, April, Sacramento, CA.<br /> <br /> Allen, J.D., Ahola, J.K., Chahine, M., Szasz, J.I., Hunt, C.W., Schneider, C.S., Murdoch, G.K. and Hill, R.A. (2009). Effect of feeding period and ractopamine hydrochloride on feedlot performance, carcass characteristics, and end product quality in market dairy cows. Journal of Animal Science. (accepted).<br /> <br /> Arthington, J. D., T. D. Maddock, G. C. Lamb. 2009. Effects of Mannheima haemolytica vaccination (One Shot®) on feed intake, feed efficiency, and the acute-phase protein response of heifers. J. Anim. Sci. (E-Suppl. 1) (In press).<br /> <br /> Bailey, C.L., M.J. Prado-Cooper, E.C. Wright, R.P. Wettemann, G.W. Horn, L.J. Spicer, and K.R. Krehbiel. 2009. Maintenance energy requirements of gestating beef cows and rumen temperature, plasma concentrations of IGF-I, glucose, thyroxine, and calf performance. J. Anim. Sci. (E-Suppl. 3) 87: in press.<br /> <br /> Brew, M., B. Myer, J. Carter, M. Hersom, G. Hansen. 2008. Water intake and factors affecting wáter intake of growing beef cattle in North Florida. Fl. Beef Res. Rep. pp. 1-3.<br /> <br /> Burnett, D.D., Kriese-Anderson, L.A., Wolfe, D.F. and Bergen, W.G. Transcriptomic signature of performance efficiency in finishing beef cattle. 2009. Animal Sciences and Clinical Science, Auburn University, AL 36849.<br /> <br /> Crawford, G. I., S. A. Quinn, T. J. Klopfenstein, and G. E. Erickson. 2008. Relationship between metabolizable protein balance and feed efficiency of steers and heifers. Nebraska Beef Report. pp. 133-134.<br /> <br /> DiCostanzo, A. 2009. Nutritional effects on cow size. Proceedings of 2009 Minnesota Beef Cow/Calf Days. pp. 10-17. <br /> <br /> Elzo, M. A., D. D. Johnson, D. G. Riley, G. R. Hansen, R. O. Myer, D. O. Rae, J. G. Wasdin, and J. D. Driver. 2008. Relationship between carcass traits and phenotypic residual feed intake, breed composition, temperament, and ELISA scores for paratuberculosis in an Angus-Brahman multibreed herd. J. Anim. Sci. (E-Suppl. 2):86:205.<br /> <br /> Elzo, M. A., D. G. Riley, G. R. Hansen, D. D. Johnson, R. O. Myer, D. O. Rae, J. G. Wasdin, and J. D. Driver. 2008. Association between breed composition, phenotypic residual feed intake, temperament, ELISA scores for paratuberculosis, and ultrasound carcass traits in an Angus-Brahman multibreed herd. J. Anim. Sci. (E-Suppl. 2):86:204-205. <br /> <br /> Elzo, M. A., D. G. Riley, G. R. Hansen, D. D. Johnson, R. O. Myer, D. O. Rae, J. G. Wasdin, and J. D. Driver. 2008. Effect of breed composition, temperament, and ELISA scores for paratuberculosis on phenotypic residual feed intake and growth in an Angus-Brahman multibreed herd. J. Anim. Sci. (E-Suppl. 2):86:204. <br /> <br /> Elzo. M. A., D. D. Johnson, D. G. Riley, G. R. Hansen, G. C. Lamb, R. O. Myer, J. G. Wasdin, and J. D. Driver. 2009. Association between carcass and meat quality traits, and phenotypic residual feed intake, breed composition, and temperament in Angus-Brahman multibreed cattle. J. Anim. Sci. (E-Suppl. 2) (In press).<br /> <br /> Hill, M., Chapalamadugu, K., Schneider, C., Hill, R.A., Gaylord, G., Ahola, J.K., Hunt, C.W., Szasz, J. and Murdoch, G.K. (2009). Effect of time of ractopamine feeding on growth, carcass characteristics, and muscle biology of steers. Journal of Animal Science (supplement 1) accepted.<br /> <br /> Hill, R.A. and Ahola, J.K. (2008). Residual Feed Intake: Benefits, Risks and Opportunities for Red Angus. Annual Convention of the Red Angus Association of America. September, Cheyenne, WY.<br /> <br /> Hill, R.A. and Aizen, M. (2009), Symposium chairs introduction to The molecular basis for feed efficiency. Journal of Animal Science (87(E. Suppl.):E39E40).<br /> <br /> Hill, R.A., Flint, D. J. and Pell, J.M. (2008). Antibodies as molecular mimics of biomolecules: roles in understanding physiological functions and mechanisms. Advances in Physiology Education. 32: 261-273.<br /> <br /> Hill, R.A., Kane, S.L., Ahola, J.K., Wulfhorst, J.D., Hough, R.L., Bolze Jr., R.P. and Keenan, L. (2008). Feed Efficiency Research and Outreach for the Beef Industry. National Research Initiative (USDA) Project Directors Meeting, July 6-7, Indianapolis, IN.<br /> <br /> Hill, R.A., Welch, C.M., Szasz, J.I., Hall, J.B., Keenan, L.D. and Ahola, J.K. (2009). Evaluating the feed efficiency and end-product quality relationship in the progeny of Red Angus sires divergent for Maintenance Energy EPD: A project overview. Beef Improvement Federation, National Meeting, April, Sacramento, CA.<br /> <br /> Krueger, W.K., G.E. Carstens, R.R. Gomez, B.M. Bourg, P.A. Lancaster, L.J. Slay, J.C. Miller, R.C. Anderson, S.M. Horrocks, N.A. Krueger, T.D.A. Forbes. 2009. Relationships between residual feed intake and apparent nutrient digestibility, in vitro methane producing activity and VFA concentrations in growing Brangus heifers. J. Anim. Sci. 87 (Suppl 1; Abstract In Press).<br /> <br /> Lancaster, P.A., G.E. Carstens, D.H. Crews, Jr., T.H. Welsh, Jr., T.D.A. Forbes, D.W. Forrest, R.D. Randel and F.M. Rouquette. 2009b. Phenotype and genetic relationships of residual feed intake with performance and ultrasound carcass traits in Brangus heifers. J. Anim. Sci. (Accepted; E-2009-2041.R).<br /> <br /> Lancaster, P.A., G.E. Carstens, F.R. Ribeiro, M.E. Davis, J.G. Lyons and T.H. Welsh, Jr. 2008. Effects of divergent selection for serum IGF-I concentration on performance, feed efficiency and ultrasound measures of carcass composition traits in Angus bulls and heifers. J. Anim. Sci. 86:2862-2871.<br /> <br /> Lancaster, P.A., G.E. Carstens, F.R.B. Ribeiro, L.O. Tedeschi and D.H. Crews, Jr. 2009a. Characterization of feed efficiency traits and relationships with feeding behavior and ultrasound carcass traits in growing bulls. J. Anim. Sci. 87: 1528-1539.<br /> <br /> Maddock, T. D., J. L. Foster, M. A. Elzo, and G. C. Lamb. 2009. Changes in temperament scores of cattle handled frequently failed to enhance feed intake. J. Anim. Sci. (E-Suppl. 2) (In press).<br /> <br /> McMurry, B. 2009. Functionality of cow size. Proceedings of 2009 Minnesota Beef Cow/Calf Days. pp. 1-9. <br /> <br /> Oltjen, J.W., A. Ahmadi, A.J. Romera, D.J. Drake and S.J.R.Woodward. 2008. PRANCH: Cow-calf herd simulation system. In: Agricultural Information and Information Technology Proceedings of IAALD AFITA WCCA (T. Nagatsuka and S. Ninomiya, Eds.) pp. 123-126. <br /> <br /> Oltjen, J.W., D.J. Drake, A.B. Ahmadi, A.J. Romera, S.J.R. Woodward, L.N. Bennett, F. Haque and L.J. Butler. 2008. Management simulation tool for estimating value of individual identification of beef cattle. J. Anim. Sci. 86(E-Suppl. 3):139.<br /> <br /> Prado-Cooper, M.J., R. D. Madden, J. W. Dillwith, C. L. Bailey, E. C. Wright, C. R. Krehbiel, D.L. Step, and R. P. Wettemann. 2009. Proteomic analyses in beef cows with low and high maintenance energy requirements. J. Anim Sci. (E-Suppl 2)87: in press.<br /> <br /> Rauw, W.M. (Ed.) 2008, Resource Allocation Theory Applied to Farm Animal Production, CABI Publishing, Wallingford, UK, 336 pp.<br /> <br /> Rauw, W.M. 2008, Introduction, In: Resource Allocation Theory Applied to Farm Animal Production (W.M. Rauw ed.), pp. 1-21.<br /> <br /> Rauw, W.M., T. Wuliji, D. Thain, M. Teglas, T. Filbin, D. Joos, L. Gomez-Raya, 2008. Body Weight Loss and Estimated Grazing Intake in Free Range Sheep and Cattle. Nevada Cattlemans Update, p. 33-35.<br /> <br /> Smith, S. N. 2008. Residual Feed Intake of Angus Cattle Divergently Selected for Feed Conversion Ratio. M.S. Thesis. The Ohio State University, Columbus.<br /> Welch, C.M., Ahola, J.K., Hall, J.B., Szasz, J.I., Keenan, L. and Hill, R.A. (2009). Physiological drivers of variation in feed efficiency in red angus-sired calves. Journal of Animal Science (supplement 1) accepted.<br /> <br />

Impact Statements

1. Committee members hosted and participated in a Symposium conducted at the national American Society of Animal Science meeting (Indianapolis, 2008) on Molecular Mechanisms underlying RFI. This symposium provided a mechanism to convey new research information and increased the visibility of the project.
2. Studies have increased understanding of the role of growth factors and cell signaling pathways in regulating metabolic processes that may lead to molecular- and cellular biology-based strategies to aid in selection of more feed-efficient beef cattle which will benefit both producers and consumers.
3. Gene expression studies have resulted in integration of knowledge from the whole animal level to the level of the gene and/or cell in the elucidation of mechanisms that contribute to whole animal variation in feed efficiency

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Report Information

Participants

Carstens, Gordon (g-carstens@tamu.edu) - Texas A&M University;
Crews, Denny (Denny.Crews@colostate.edu) - Colorado State University;
Davis, Michael (davis.28@osu.edu) - The Ohio State University;
Hansen, Gary (Gary_Hansen@ncsu.edu) - North Carolina State University;
Hess, Bret (Administrative Advisor)(brethess@uwyo.edu) - University of Wyoming;
Hill, Rod (rodhill@uidaho) - University of Idaho;
Kriese-Anderson, Lisa Ann (kriesla@auburn.edu) - Auburn University;
Oltjen, James (jwoltjen@ucdavis.edu) - University of California, Davis;

Brief Summary of Minutes

Members Not Attending: Jason Ahola and Cassie Welch, Idaho; Larry Berger, Illinois; Grant Crawford, Minnesota; Gustavo Cruz, California; Robert Dailey and Eugene Felton, West Virginia; Robert Herd, Australia; Travis Maddock, Florida; Robert Myer, Florida; Roberto Sainz, California; Thomas Welsh, Texas; Robert Wettemann, Oklahoma; Scott Whisnant, North Carolina.

The annual meeting of the W1010 technical committee was held in Columbia, Missouri on July 1 and 2, 2010. The meeting was called to order by esteemed chair, Professor Gordon Carstens.
The group was welcomed to the University of Missouri by Dr Rod Geisert, Director of the Division of Animal Sciences. Each of the stations attending prepared a brief written report and presented this information to the group in attendance. In the business meeting, Dr Bret Hess provided programmatic updates relevant to the technical committee and also provided insight into NIFA funding opportunities. It was decided that the next year meeting would be held immediately after BIF meetings in Montana. Dr Kerley will serve as Chair in 2010-11. Dr Kriese-Anderson was elected to serve as Secretary. Following experiment station presentations, the committee explored avenues, mechanisms and future plans for collaborative research and joint grant submissions. A great time was had by all, the weather was typical for Missouri in July, and all noted the children were above average in Columbia.

Accomplishments

Results of research conducted by members of the committee indicate that:<br /> <br /> - high efficiency heifers tend to carry less body fat and appear to reach puberty approximately seven days later for each one kg improvement of residual feed intake (FRI);<br /> - within animal repeatability of feed behavior traits are high and that they may be useful indicator traits for RFI in beef cattle;<br /> - RFI was not phenotypically associated with scrotal circumference or semen quality traits in growing bulls;<br /> - RFI in bulls and steers is not the same trait, which is probably not unexpected given the physiological differences between steers and bulls. Genetic correlations between bull and steer RFI may need to be taken into consideration when making genetic selection decisions;<br /> - thyroid hormone may be involved in the regulation of maintenance energy requirement (MR) of beef cows during late gestation. Identification of cows with lower MR and greater efficiency could improve the profitability of beef production;<br /> - selection for serum IGF concentration may affect mature weights in cattle and that heifers selected for high IGF-I concentration may have lighter mature weights and lower maintenance requirements as cows than those selected for low IFG-I concentration;<br /> - mitochondrial function explains, at least in part, RFI differences among cattle.

Publications

Davis, M.E., and R.C.M. Simmen. 2010. Estimates of inbreeding depression for serum insulin-like growth factor I concentrations, body weights, and body weight gains in Angus beef cattle divergently selected for serum insulin-like growth factor I concentration. J. Anim. Sci. 88:552-561.<br /> <br /> Smith, S.N., M.E. Davis, and S.C. Loerch. 2010. Residual feed intake of Angus beef cattle divergently selected for feed conversion ratio. Livest. Sci. doi:10.1016/j.livsci.2010.04.019.<br /> <br /> Qing, Q. 2010. Effect of Divergent Selection for Insulin-Like Growth Factor I (IGF-I) on Mature Weight and Growth Curves in Angus Cattle. M.S. Thesis. The Ohio State University, Columbus.<br /> <br /> Barioni, L.G., V.A.T. de León, J.W. Oltjen, and R.D. Sainz. 2009. A Hybrid Algorithm to Optimize Beef Feedlot Operations. 7th International Workship Modelling Nutrient Digestion and Utilization in Farm Animals, Paris, September 10-12. p.61<br /> <br /> de León, V.A., L.G. Barioni, J.W. Oltjen, and R.D. Sainz. 2009. Development of a heat balance model for cattle. 7th International Workship Modelling Nutrient Digestion and Utilization in Farm Animals, Paris, September 10-12. p.43.<br /> <br /> McPhee, M., J. Oltjen, J. Fadel, D. Mayer and R. Sainz. 2009. Parameter estimation and sensitivity analysis of fat deposition models in beef steers using acslXtreme. Mathematics and Computers in Simulation 79 :27012712.<br /> <br /> Oltjen, J.W., A. Ahmadi, A.J. Romera, D.J. Drake, P. Gaspar and S.J.R. Woodward. 2009. PCRANCH: Cow-Calf Herd Simulation System. 7th International Workship Modelling Nutrient Digestion and Utilization in Farm Animals, Paris, September 10-12. p. 64.<br /> <br /> Prado-Cooper, M., 2009. Maintenance energy requirements, postpartum reproduction, and ruminal temperature at parturition and estrus of beef cows. PhD Dissertation. Oklahoma State University<br /> <br /> Bailey, C.L., 2009. Identification of maintenance energy requirements and estrus in beef cows. MS Thesis. Oklahoma State University<br /> <br /> Prado-Cooper, M.J., R.D. Madden, J.W. Dillwith, C.L. Bailey, E.C. Wright, K.R. HR.Krehbiel, D.L. Step, and R.P. Wettemann. 2009. Proteomic analyses in beef cows with low and high maintenance energy requirements. J. Anim. Sci. (E-Suppl. 2)87:296.<br /> <br /> Pye, T.A., B.H. Boehmer, and R.P. Wettemann. 2010. Maintenance energy requirements of gestating beef cows, rumen temperature, and plasma concentrations of thyroxine and triiodothyronine. J. Anim. Sci. (E-Suppl. 2)88:403.<br /> <br /> Rutherford, William Cobie Jr. 2010. Thesis: Evaluation of residual feed intake in centrally-tested bulls and related steers. Accessed 8/16/2010. (http://etd.auburn.edu/etd/handle/10415/2038).<br /> <br /> Rutherford, W.C., L.A. Kriese-Anderson and G.S. Hecht. 2010. Heritability and genetic correlations of residual feed intake between Angus and Simmental bulls and resulting steer relatives. Abstract 69 presented at the American Society of Animal Science Annual Meeting. July 11-15, 2010. Denver, CO. Accessed 8/16/2010 (http://adsa.psa.ampa.csas.asas.org/meetings/2010/abstracts/0184.pdf). 88 (e-supplement 2):184-185.<br /> <br /> Hafla, A.N., P.A. Lancaster, G.E. Carstens, D.W. Forrest, J.T. Fox, M.E. Davis, R.D. Randel and J.W. Holloway. 2010. Relationships between feed efficiency traits, and scrotal circumference and semen-quality traits in yearling bulls. J. Anim. Sci. (E-Suppl. 3) 88:13.<br /> <br /> Mendes, E.D.M., G.E. Carstens and L.O. Tedeschi. 2010. Characterization of feeding behavior traits and associations with feed efficiency in beef heifers fed a high-grain diet. J. Anim. Sci. (E-Suppl. 2) 88:791.

Impact Statements

1. Most of the impact of RFI selection on beef production can be traced to activities between committee members and sire test facilities. Likewise, a preponderance of research information that has been generated regarding RFI in the US has come for researchers and discussions originating from the W1010 committee.

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Report Information

Participants

Carstens, Gordon (g-carstens@tamu.edu) - Texas A&M University;
Faulkner, Dan (danb@uiuc.edu)- University of Illinois;
Hill, Rod (rodhill@uidaho.edu)- University of Idaho;
Kerley, Monty (kerleym@missouri.edu)- University of Missouri;
Kriese-Anderson, Lisa (kriesla@auburn.edu)- Auburn University;
Oltjen, James (jwoltjen@ucdavis.edu)- University of California, Davis;
Hess, Bret (brethess@uwyo.edu)- Administrative Advisor, University of Wyoming;

Brief Summary of Minutes

Members Not Attending: Grant Crawford, Minnesota; Denny Crews, Colorado; Robert Dailey and Eugene Felton, West Virginia; Michael Davis and Thomas Turner, Ohio; Robert Herd, Australia; Gary Hansen, North Carolina; Robert Myer, Florida; Jane Parish, Mississippi; Roberto Sainz, California; Thomas Welsh, Texas; Robert Wettemann, Oklahoma; Scott Whisnant, North Carolina.

Members of W-2177 present: Jan Busboom and Mark Nelson, Washington State University; Chris Calkins, University of Nebraska; Scott Fausti, South Dakota State University; Rodney Kott and John Paterson, Montana State University; Joe Parcell, University of Missouri, Dustin Pendell, Colorado State University and Glynn Tonser, Kansas State University.

Guests: Dr. David Johnston, University of New England/AGBU in Armidale, Australia and Dr. Kent Anderson, Pfizer Beef Genomics.

The annual meeting of the W1010 research project was held May 31 and June 1, 2011 at Montana State University. This was a joint meeting with the W2177 research project. The meeting was held immediately prior to the 2011 Beef Improvement Federation Annual Meeting and Research Symposium also on the campus of Montana State University.

The meeting was opened by Dr. Monty Kerley of Missouri, W1010 chair, and Dr. Glynn Tonser of Kansas, W2177 chair. Dr. John Paterson welcomed both groups to Montana State and Bozeman. The meetings were held in the new Animal and Range Science Building for which sheep and cattle ranchers of Montana raised $10 million of the $16 million needed to build the new facilities. Each of the stations attending prepared a brief written report and presented this information to the group in attendance. It was beneficial for both W1010 and W2177 participants to share their research findings and recognize how their research work was interwoven. Additionally, two invited talks were presented by Dr. David Johnston (Australia) and Dr. Kent Anderson. Each was asked to speak on how genomics were playing a part in beef efficiency traits in Australia and America, respectively.

Dr. Bret Hess, Administrative Advisor to W1010, spoke on the proposed USDA budget and AFRI grant status for FY12. He noted in both the President and House budgets that earmarks are being eliminated. The money generally spent on the earmarks is being moved to basically hold budgets of AFRI and Hatch level to a slight reduction. Extension funding will be reduced. Bottom line is there will probably be fewer grants and most will be multi-disciplinary. The take home message on grants is to not give up and for those that continue to plan, they will be rewarded.

In the business meeting of W1010, it was discussed how we did not have the proposed producer symposium at BIF this year. This was the year for a reproductive seminar on the opening night of BIF and therefore, we could not have the time slot. So, Dan Faulkner will discuss with Dr. Jeremy Taylor the concept of a joint producer seminar on beef cattle efficiency for a future NCBA meeting. In 2012, according to our Plan of Work, we are to have a research symposium on RFI. Dr. Rod Hill will broach the subject of having an ASAS Board sponsored symposium at next years annual meeting. A committee of Rod Hill, Lisa Kriese-Anderson, and James Oltjen was named by Monty Kerley to steer this research symposium. It was decided to focus on beef cattle and look how RFI affects growing/finishing cattle, cow/calf sector, cattle behavior, and how RFI is being adapted by the industry. The next meeting of W1010 will be held in conjunction with ASAS in Phoenix, AZ July 15-19, 2012. Allison Meyer of Wyoming was elected secretary, but she will not move to the chair position in 2012.

Accomplishments

There appears to be a positive phenotypic association for residual feed intake (RFI) in calves fed forage diets and then fed grain diets. In two separate studies, the reported phenotypic correlations between forage-fed RFI and grain-fed RFI were 0.35 in Angus-Simmental heifers and 0.56 in Angus bulls. In both studies, age of calf is confounded with diet.<br /> <br /> Steers were classified for RFI (L, M, H) and studied for eating behavior. Steers with low (desirable) RFI values ate 15% less and were more efficient (F:G ratio) than high RFI values. Low RFI steers also had less carcass backfat and percentage intrasmuscular fat as compared to high RFI value steers. <br /> <br /> Steers with divergent RFI had distinctive feeding behavior patterns, and results suggest that feeding behavior traits may be an effective indicator trait for RFI in growing beef cattle. Steers with low RFI values had fewer bunk visits and spent less total time at the bunk eating than high RFI valued steers. However, low RFI steers took over 4 minutes longer to eat a meal that high RFI steers, and ate a similar number of meals as high RFI steers.<br /> <br /> Heifers were fed MGA and ractopamine HCL and also classified for RFI (L, M, H). The low RFI heifers did eat less and were 15% more efficient than high RFI heifers. However, there were no carcass differences or phenotypic correlations with Insulin, IGF-1, Glucose or NEFA concentrations.<br /> <br /> The relationship between maintenance energy (ME) EPD and RFI EPD remains unclear. Further interpretation of this relationship is greatly in need of further data and analysis. As the project progress and more progeny are generated, this relationship will become clearer.<br /> Calves produced from high-high and low-low RFI parents resulted in similar weaning weights. However, calves from the low-low matings ate 9% less feed with 13% higher feed to gain ratios in the feedlot saving approximately $100 in feed costs over the high-high progeny.<br /> <br /> The phenotypic correlation between RFI measured in heifer calves and dry matter intake (DMI) of those same heifers as cows changes depending on production cycle (rp = 0.20 in lactating cows and rp = 0.29 in dry cows).<br /> <br /> The phenotypic correlation between heifer RFI and heifer residual gain (RADG) is -0.18.<br /> <br /> Heifer RFI is not phenotypically related to cow body weight or hip height suggesting selection on RFI will not phenotypically alter cow size.<br /> <br /> The phenotypic correlation between heifer RADG and cow body weight is 0.21. This suggests selection using RADG phenotypically will increase cow size.<br /> <br /> There is no phenotypic correlation between NRC DMI to individual cow DMI. This suggests NRC is useful for pen feeding, but presents challenges when balancing on an individual basis.<br /> <br /> Bonsmara females with low RFI as heifers consumed 23% less forage during mid-gestation than high-RFI females, demonstrating that RFI of growing heifers was favorably associated with subsequent cow efficiency. Results suggest that between-animal variation in RFI was related to differences in heart rate and feeding behavior patterns.<br /> <br /> Angus cows were classified as having low, average or high maintenance energy requirements. During early lactation with ad libitum roughage, high maintenance energy cows had higher IGF-1 concentrations than low energy maintenance cows.<br /> <br /> Thyroxine and triiodothyronine plasma concentrations were influenced by maintenance energy classification of cows. This suggests IGF-1 and thyroxine could be biomarkers for maintenance energy in cows.<br /> <br /> Ruminal temperature was not affected by maintenance energy classification of cows pre-calving (fed to maintain body weight) or during early lactation (fed ad libitum roughage).<br /> <br /> IGF-1 levels for calves produced from low maintenance energy EPD Red Angus Bulls and low IGF-1 selected cows were higher (341 ± 20 ng/mL) than for calves produced from high maintenance energy EPD Red Angus Bulls and high IGF-1 selected cows (270 ± 17 ng.mL). Birth and weaning weights were also higher in the progeny of high maintenance energy EPD Red Angus Bulls and high IGF-1 selected cows. More progeny will need to be produced to determine if this trend holds true.<br /> <br /> The meeting minutes attachment file is a compilation of station reports.

Publications

Ahola, J.K., Skow, T.A., Hunt, C.W. and Hill, R.A. 2011. Relationship Between Residual Feed Intake and End Product Palatability in Longissimus Steaks from Steers Sired by Angus Bulls Divergent for Intramuscular Fat Expected Progeny Difference. Professional Animal Scientist.27:109-115.<br /> <br /> Bilgin, O.C., N. Esenbuga, and M.E. Davis. 2010. Comparison of models for describing the lactation curve of Awassi, Morkaraman, and Tushin Sheep. Archiv Tierzucht 53:447-456.<br /> <br /> Davis, M.E., and R. C.M. Simmen. 2010. Estimates of inbreeding depression for serum insulin-like growth factor I concentrations, body weights, and body weight gains in Angus beef cattle divergently selected for serum insulin-like growth factor I concentration. J. Anim. Sci. 88:552-561.<br /> <br /> Smith, S.N., M.E. Davis, and S.C. Loerch. 2010. Residual feed intake of Angus beef cattle divergently selected for feed conversion ratio. Livest. Sci. 132:41-47.<br /> <br /> Hafla, A.N., P.A. Lancaster, G.E. Carstens, D.W. Forrest, J.T. Fox, T.D. A. Forbes, M.E. Davis, R.D. Randel, and J.W. Holloway. 2011. Relationships between feed efficiency traits, and scrotal circumference and semen-quality traits in yearling bulls. J. Anim. Sci. (Accepted)<br /> <br /> Huang, H., H.C. Hines, K.M. Irvin, K. Lee, and M.E. Davis. 2011. Response to divergent selection for insulin-like growth factor-I concentration and correlated responses in growth traits in Angus cattle. J. Anim. Sci. (in review)<br /> <br /> Mendes, E.D.M, G.E. Carstens, L.O. Tedeschi, Pinchak, W.E. and T.H. Friend. 2011. Technical note: Validation of a system for monitoring feeding behavior in beef cattle. J. Anim. Sci. doi:10.2527/jas.2010-3489.<br /> <br /> Qin, Q., M.E. Davis, S.J. Moeller, and T.B. Turner. 2011. Comparison of four growth curve models for estimating mature weight and correlations between mature weight and postweaning serum IGF-I concentration in Angus cattle. Animal (in review)<br /> <br /> Non-Refereed Articles:<br /> <br /> Johnson, K.A., H. Neibergs, J.J. Michal, G.E. Carstens, M. Settles, A. Hafla, T.D.A. Forbes, J.W. Holloway and A. Brosh. 2010. Differential expression of mitochondrial genes in liver from beef calves with divergent phenotypes for feed efficiency. In: G. Matteo Crovetto (Ed.), Energy and Protein Metabolism and Nutrition. EAAP Pub. 127:7576.<br /> <br /> Crews, D.H., Jr., C.T. Pendley, G.E. Carstens, and E.D.M. Mendes. 2010. Genetic evaluation of feed intake and utilization traits in beef bulls. Proc. 9th World Congress on Genetics Applied to Livestock Production, Leipzig, Germany. CD-ROM #0667.<br /> <br /> Hill, R.A., Kane, S.L., Ahola, J.K., Wulfhorst, J.D., Hough, R.L., Bolze Jr., R.P. and Keenan, L. (2010). Feed Efficiency Research and Outreach for the Beef Industry. National Research Initiative (USDA) Project Directors Meeting, July 15-16, Denver, CO.<br /> <br /> Hill, R.A., Kane, S.L., Ahola, J.K., Wulfhorst, J.D., Hough, R.L., Bolze Jr., R.P. and Keenan, L. (2011). Feed Efficiency Research and Outreach for the Beef Industry. National Research Initiative (USDA) Project Directors Meeting, April 18-19, Washington, D.C.<br /> <br /> Tedeschi, L.O., D.G. Fox, G.E. Carstens and C.L. Ferrell. 2010. The partial efficiency of use of metabolisable energy for growth in ruminants. Energy and Protein Metabolism and Nutrition. EAAP Pub. 127:519-529.<br /> <br /> Thornton, K.J., Davis, L., Welch, C., Doumit, M., Hill, R.A. and Murdoch, G.K. (2010). Muscle Fiber Type is Altered by Selection of Sire for Maintenance Energy Proc., Pacific Northwest Animal Nutrition Conference, October 7-9, 2010, Vancouver, British Colombia<br /> <br /> Wulfhorst, J.D., Ahola, J.K., Kane, S.L., Keenan, L.D. and Hill, R.A. (2010). Factors affecting beef cattle producer perspectives on feed efficiency. Journal of Animal Science. 88: 3749-3758.<br /> <br /> Research Abstracts:<br /> <br /> Adcock, J. W., D. W. Shike, D. B. Faulkner, and K. M. Retallick. 2011. Utilizing heifer RFI to predict cow intake and efficiency. Midwestern section of American Society of Animal Science Abstract 81. (accessed: http://adsa.asas.org/midwest/2011/Midwest_Abstracts_2011-revised.pdf on 7/28/11).<br /> <br /> Bailey, J.C., G.E. Carstens, J.T. Walter, A.N. Hafla, E.D. Mendes, L.O. Tedeschi and R.K. Miller. 2011. Effects of residual feed intake classification and breed type on feed efficiency and feeding behavior traits in heifers fed a high-grain diet. J. Anim. Sci. 89(E-Suppl. 1):366.<br /> <br /> Bailey, J.C., G.E. Carstens, J.W. Behrens, R.K. Miller, J.T. Walter, A.N. Hafla, L.O. Tedeschi and D.S. Hale. 2011. Temperament classification affects feed efficiency, feeding behavior and carcass value traits in heifers fed a high-grain diet. Proc. Plains Nutrition Council (Abstr.).<br /> <br /> Bailey, J.C., L.O. Tedeschi, E.D. Mendes and G.E. Carstens. 2011. Evaluation of bimodal distributions to determine meal criterion in heifers fed a high-grain diet. J. Anim. Sci. 89(E-Suppl. 1):761.<br /> <br /> Hafla, A.N., G.E. Carstens, T.D.A. Forbes, J.C. Bailey and E.A. Dany. 2011. Heart rate and physical activity in growing Bonsmara heifers with divergent residual feed intake fed in confinement or on pasture. J. Anim. Sci. (In press).<br /> <br /> Hafla, A.N., G.E. Carstens, T.D.A. Forbes, J., C. Bailey, J.T. Walter, J.W. Holloway and J.G. Moreno. 2011. Relationship between postweaning RFI in heifers and intake and productivity of mid-gestation beef females. J. Anim. Sci. 89(E-Suppl. 1):416.<br /> <br /> McGee, M., Welch, C.M., Hall, J.B., Small, W. and Hill, R.A. (2011). Interactions of Residual Feed Intake and other Performance Parameters of Japanese Black (Wagyu) Bulls. Journal of Animal Science 89 (E Suppl. 2).<br /> <br /> Pye, T.A., B.H. Boehmer, and R.P. Wettemamnn. 2011. Maintenance energy requirements of gestating beef cows and plasma concentrations of thyroxine and triiodothyronine. J. Anim. Sci. (E-Suppl. 1)89:253-254 (accessed http://www.jtmtg.org/2011/abstracts/0251.PDF on 8/1/11).<br /> <br /> Soderquist, G.C., Welch, C.M., Murdoch, G.K., Ahola, J.K., Hall, J.B., Schneider, C. and Hill, R.A. (2011). Overview of IL-15/IL-15± Receptor and Their Role in Muscle Growth Related to Residual Feed Intake. Innovation Showcase. University of Idaho, April, 2011. (prize awarded).<br /> <br /> Walter, J.T., J.C. Bailey, G.E. Carstens, A.N. Hafla, E.D. Mendes and L.O. Tedeschi. 2011. Residual feed intake classification affects on feed efficiency and feeding behavior traits and net revenue in Angus-based composite steers. Proc. Plains Nutrition Council (Abstr.).<br /> <br /> Welch, C.M., Murdoch, G.K., Chapalamadugu, K., Thornton, K.J., Ahola, J.K., Hall, J.B. and Hill, R.A. (2011). Gene expression of Red Angus sired steers and heifers evaluated for residual feed intake Journal of Animal Science 89 (E- Suppl. 2).<br /> <br /> Thesis<br /> <br /> Qing, Q. 2010. Effect of Divergent Selection for Insulin-Like Growth Factor I (IGF-I) on Mature Weight and Growth Curves in Angus Cattle. M.S. Thesis. The Ohio State University, Columbus.<br /> <br /> Popular Press<br /> <br /> Published two articles for the Wyoming Roundup.<br /> Published on article for the University of Wyoming's Reflections publication.<br /> Published two articles for Hereford America.

Impact Statements

1. The major impact of these works continues to suggest RFI is phenotypically independent of growth traits. Feeding behavior may also serve an an indicator trait for RFI. Work is beginning to emerge that suggests low RFI parents are producing low RFI progeny that eat less and are more efficient than progeny from high RFI parents. IGF-1 and thyroxine may play a role in indentifying low maintenance requirement individuals. A significantly large, predigree connected database is needed to determine genetic relationships between RFI and other economically relevant traits. This W1010 group continues to be where the majority of RFI data is being generated.

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Report Information

Participants

Kriese-Anderson, Lisa (kriesla@auburn.edu) - Auburn University;
Bourg, Brandi (bbourg@ads.msstate.edu) - Mississippi State University;
Hill, Rod (rodhill@uidaho.edu) - University of Idaho;
Oltjen, James (jwoltjen@ucdavis.edu) - University of California, Davis;
Matthews, James (jmatthew@uky.edu) - University of Kentucky;
Sainz, Roberto (rdsainz@ucdavis.edu) - University of California, Davis;
Meyer, Allison (ameyer6@uwyo.edu) - University of Wyoming;
Hess, Bret (BretHess@uwyo.edu) - Administrative Advisor

Brief Summary of Minutes

The meeting called to order at 1 pm on Thursday, July 19, 2012.

Members Present: Lisa Kriese-Anderson (Auburn), Rod Hill (Idaho), Roberto Sainz (UC-Davis), Jamie Matthews (Kentucky), Brandi Bourg-Karisch (Mississippi State), Allison Meyer (Wyoming), Jim Oltjen (UC-Davis),

Non-members Present: Bret Hess (Administrative Advisor), Andrew Hess (Iowa State)

We started out with introductions and research interests of the group.

Bret Hess gave the administrative advisor report and NIFA update (for Steve Smith). He reminded us that Sept 30, 2013 is our 5-year termination date and briefly discussed the annual report, impact statements, new hires of NIFA, AFRI Foundational program new RFA and 2011 funding rates, and current Farm Bill and future funding discussions/updates.


The milestones of W1010 were reviewed. The 2008 Mechanisms of Feed Efficiency symposium at ASAS Joint Annual Meeting was held, but a 2012 symposium was not held (a similar symposium was held as the Cell Biology Symposium). The 2011 BIF symposium was also not held either, although plans were discussed for 2013 later in the meeting.

Attendance of W1010 annual meetings were discussed, including whether it is good to hold our meeting at the end of the ASAS Joint Annual Meeting, BIF, or on its own. A brief history of participation was discussed, as well as new members expectations of the committee.

Participation in the International Symposium on Energy and Protein Meeting at Davis, CA in September 2013 was discussed. It was decided to encourage the W1010 group to submit abstracts labeled with W1010 to create a virtual symposium. This will be used to advertise our group, help to satisfy our objectives, and share some research from the group

Plans for producer-level education (as outlined in our objectives) was discussed, using maybe the BIF or NCBA Cattlemens College as a location. It was brought up that regional meetings may also be an option with a 'traveling roadshow' sort of model. It was also mentioned that if we start meeting at universities for this committee, we could also do an extension component in conjunction with local extension and industry groups (e.g. state cattlemens groups). In general, it was determined that BIF would be the most appropriate for our goals, with NCBA being the 2nd option. Kentucky (with an extension component) is an option for 2014. Lisa Kriese-Anderson will begin making contacts for the 2013 BIF Convention in Oklahoma City for a producer-targeted symposium and our W1010 annual meeting. NCBA is the second option.

The new chair election was discussed (because Allison Meyer is not moving up after being secretary), and it was determined that an established member of the committee should be the chair. Rod Hill made a motion that Jim Oltjen serve as chair and Mike Davis serve as secretary. Lisa Kriese-Anderson seconded the motion. Motion passed (7-1).

Roberto Sainz moved to create another committee to write the renewal after an email polling with Rod Hill leading the effort. Jim Oltjen seconded the motion. Motion passed.

Research reports were given from Auburn, UC-Davis, Idaho, Kentucky, Wyoming, and Mississippi. Research was discussed at length, then the meeting was adjourned until the following day.

We rejoined at 7:30 am the next day. The rewrite and future of the committee was discussed, including a possible new framework or change from the broad umbrella of efficiency to a more specific aspect or maybe even to include other species. It was suggested that we focus of the mechanisms of system efficiency. A possible title of Physiological mechanisms that account for variation in efficiency of nutrient utilization of beef cattle at the animal, tissue, cellular, and molecular levels was agreed upon. A timeline for the rewrite was proposed: Aug 1, initial ½ pg out to committee to solicit interest; Sept 1, input of committee, determine who else will add in; Nov 15, initial draft of proposal out to the committee; Dec 15, input back, have a final draft; Dec 25, to Bret Hess; Jan 15- due. We were also reminded that this goes out for external review and to think of possibilities. We should plan to hear by March or April whether our proposal has been accepted as is or has minor/major revisions.

Rod Hill gave an overview of the Feed Efficiency in the Beef Industry book, which should be out in September.

We officially adjourned at 10:09 am.

Accomplishments

Short-term Outcomes: <br /> The main short-term outcome is increased scientific knowledge of beef cattle feed efficiency in the scientific and industry communities. This includes presenting at scientific meetings, training graduate students, working with bull test stations to determine RFI, working with feed companies to design diets that enhance efficiency of cattle fed forage and grain-based diets, working with breed associations to create efficiency-related EPDs, organizing and presenting at producer-targeted extension meetings, and producing producer-targeted publications to increase knowledge of feed efficiency.<br /> <br /> Outputs: <br /> Data outputs are described below. Collaborative grant proposals have been submitted by committee members, including some large AFRI Integrated proposals. Other outputs of the W1010 effort include the recently published book Feed Efficiency in the Beef Industry, which was led by Rod Hill. All chapters but 1 were authored or co-authored by members of this committee. Additionally, 13 peer-reviewed articles, 6 non peer-reviewed articles, 24 scientific abstracts, and 5 experiment station/extension reports have been published by this group on related topics (listed in Publications).<br /> <br /> Activities: <br /> Auburn University: Two studies were conducted and analyzed in 2011. One study was conducted under thermalneutrality from November 2010 to February 2011 in Auburn, AL. The other study was conducted under heat stress conditions from June to October 2011 in Auburn, AL. Both studies utilized Angusbased genetics, but should not be directly compared because the cattle are not of the same genetic makeup. Mechanisms underlying RFI are poorly understood while the relationship between RFI and meat quality is unknown. To address this issue, 48 steers were trained to the Calan Gate (Northwood, NH) system. Daily feed intake and RFI were assessed during a 70 d feeding trial. The test diet was 50% sorghumsudan silage, 50% grain (2.9 Mcal ME/kg DM). Feed intake was recorded daily while body weights and hip heights were recorded at 14 d intervals. Ultrasound measurements of rib eye area (REA) and backfat (BF) were recorded initially and prior to slaughter. RFI was calculated for each animal as the difference between actual DMI and the expected intake to create 2 divergent cohorts consisting of High (H) and Low (L) RFI individuals. Steers were humanely harvested and subcutaneous adipose tissue (SC), trigeminal ganglion (TG) and hypothalamic tissue (HT) samples were collected and stored at 80 °C. After chilling for 24 h post harvest, carcass characteristics were measured. In the thermoneutral study, the lsmeans for RFI were 1.3 and 1.5 respectively for the L and H cohorts (P < .001) and were greater than 2 standard deviations apart. As expected dry matter intake was higher for the H individuals versus the L steers (P < .001) while on test gain was not different between the 2 groups. There were no differences in marbling score, objective color measures L*, a*, and b*, adjusted BF, REA, or yield grade between L and H cohorts suggesting there is no relationship between RFI and meat quality. Initial targeted gene expression studies in the arcuate nucleus indicate that neuropeptide Y (NPY) mRNA is expressed 2.7fold lower and Proopiomelanocortin (POMC) mRNA is expressed 3.6fold higher in L than H animals. This suggests differences in neuropeptide expression in part underlie differences in feed efficiency observed in the L and H groups. POMC may also play a role by providing increased ±MSH, but its affect appears to be muted by the need to offset the decreased MC$R expression presumable helping to maintain the inhibitory tone of the melanocortin system. In the heat stress study, the lsmeans for RFI were -1.2 and .99 respectively for the L and H cohorts (P < .0001) and were greater than 2 standard deviations apart. As expected dry matter intake was higher for the H individuals versus the L steers (P < .0001) while on-test gain was not different between groups. Marbling score was greater in L than H steers (P<.05). However there were no differences in objective color measures L*, a*, and b*, adjusted back fat, ribeye area or yield grade between L and H cohorts. Real-Time PCR studies in the arcuate nucleus indicate that neuropeptide Y (NPY) and agouti related protein (AgRP) mRNA were expressed 2.8-fold and 1.85-fold greater while Pro-opiomelanocortin (POMC) mRNA was expressed 1.6-old lesser in L than H animals. These data suggest there is no relationship between RFI and meat quality while surprisingly the mRNA expression of neuropeptides that stimulate feed intake were increased in efficient animals during heat-stressed conditions. These data suggest that changes in the neuropeptide expression are associated with heat tolerance and indicate complicated relationships between heat tolerance and feed efficiency.<br /> <br /> Mississippi State University: The Applied Cattle Nutrition Workshop was conducted by the Mississippi State University Extension Service as a statewide beef and dairy cattle producer educational program on March 15, 2011 on the Mississippi State University main campus. Fifty participants completed the workshop. Seven hours of instruction via lectures and interactive exercises was performed including information on feed efficiency spread throughout the course. Participants completed a course evaluation rating the educational information on a scale from 1 = poor to 5 = excellent. The overall rating for the workshop was 4.4. Numerous county-level educational programs in which feed efficiency in beef cattle production was discussed were conducted throughout Mississippi during the year. Additionally, the 2 state beef cattle specialists responded to numerous individual producer requests for information regarding this topic throughout the year. The Mississippi State University Extension Service beef cattle website http://msucares.com/livestock/beef contains educational information to support Objective 6. An example of this is an article at http://msucares.com/livestock/beef/mca_sep2005.pdf.<br /> <br /> North Carolina State University: Project 1: Ten yearling Angus bulls were identified from a 84 d trial as the 5 most efficient and 5 least efficient bulls as determined by RFI. Bulls were fitted with indwelling jugular catheters and on the next day injected with 0.25 ug/kg BW of lipopolysaccharide (LPS). Blood samples were collected at 30 min intervals from -1 to 6 h after LPS injection. Plasma samples were analyzed for concentrations of cortisol, haptoglobin, tumor necrosis factor alpha (TNF) and testosterone. Concentrations of testosterone decreased after LPS while concentrations of the other parameters increased. There were no differences in TNF or testosterone concentrations between groups but haptoglobin and cortisol concentrations were higher (P < .01) in the more efficient (low RFI) bulls.<br /> Project 2: Cows which had been tested for RFI as heifers are being evaluated as part of an ongoing study relating heifer RFI to lactating cow RFI. Cows (n = 100) were placed in a Calan gate facility for 42 d and DMI was determined. Weigh suckle weigh was used to estimate cow milk production. Cows and calves were separated overnight. After returning calves to cows and allowing them to nurse for 15 min, they were again separated for 6 h and then calves were weighed, allowed to nurse for 15 min and re-weighed. Cows and calves were separated again for 6 h and the weigh suckle weigh process was repeated. Milk samples were collected from each cow at the beginning of the first weigh suckle period and are being analyzed for milk composition. Data are still being collected. Ultrasound measurements have been obtained on cows and calves for REA, backfat and IMF at 2 and 4 mo of age and at weaning. Calves will be analyzed this fall for postweaning RFI as part of our regular protocol. This years data will be combined with data from 2011 and the results will be submitted for publication. Project 3: In response to a discussion at BIF, testosterone concentrations were measured in samples collected from over 500 bulls sampled for RFI during the postweaning stage of growth and analyzed for correlation with RFI and other measures. No relationship was found between serum testosterone concentrations and RFI indicating that selection for RFI should not affect traits related to testosterone secretion.<br /> <br /> The Ohio State University: A divergent selection experiment was initiated in 1989 to investigate the influence of changes in serum IGF-I concentration on economically important traits in Angus cattle. The selection experiment included 100 spring-calving (50 high line and 50 low line) cows located at the Eastern Agricultural Research Station, Belle Valley, OH. Beginning with the 2009 breeding season, the selection criterion in the IGF-I selection lines was changed from serum IGF-I concentration to ME EPD as provided by the Red Angus Association. Females in the high line are mated to 1 of 3 high (undesirable) ME EPD bulls and cows and heifers in the low line are mated to 1 of 3 low (desirable) ME EPD bulls. The first calves produced in this project at the Ohio station were born in the spring 2010 calving season. Numbers of high and low line calves born in the spring 2010, 2011, and 2012 calving seasons were 26 and 19, 25 and 21, and 10 and 13, respectively. Number of calves born in 2012 was low due to a delayed shipment of semen. Birth weight, weaning weight, preweaning relative growth rate, and serum IGF-I concentration at weaning were analyzed using PROC GLM in SAS. The statistical model included the fixed effects of year-selection line, sex of calf, and age of dam, as well as the random effect of sire nested within year-line, and a covariate for age of calf at weaning for all dependent variables other than birth weight. Sire nested within line was used as the error term in analysis of variance F tests for selection line. Subclass numbers, significance levels, and least squares means and standard errors are shown in Table 1. High line calves tended to have heavier birth weights than low line calves in 2010, 2011, and 2012, although the differences were not statistically significant. Weaning weights were 9 and 15 kg heavier for high line than for low line calves in 2010 and 2011, respectively (P = 0.07). The effect of year-line on relative growth rate from birth to weaning was significant (P = 0.02), with most of the differences being between years rather than between selection lines. Low line calves (i.e., those sired by low or desirable ME EPD Red Angus bulls) born in 2010 averaged 341 + 20 ng/mL of serum IGF-I at weaning, whereas high line calves (i.e., those sired by high or undesirable ME EPD Red Angus bulls) born in the same year averaged 270 + 17 ng/mL (P = 0.09). This result was somewhat unexpected as most (but not all) previous studies have shown lower serum IGF-I concentration to be associated with more desirable feed efficiency. Serum IGF-I concentrations for calves born in 2011 and 2012 were not available at the time this report was written. Means for age of dam and for sire nested within year-line did not differ significantly for any of the dependent variables (P > 0.20). Although sire did not have a significant effect on IGF-I concentration at weaning (P = 0.25), it is interesting to note that all 3 bulls with low (desirable) ME EPDs sired progeny with greater IGF-I concentrations than the 3 bulls with high (undesirable) ME EPDs. Results from the first 3 yr of the study suggest that use of low (desirable) ME EPD sires tends to result in progeny with lighter birth weights and weaning weights, but greater serum IGF-I concentrations at weaning. All 3 bulls with low ME EPDs sired calves with greater IGF-I concentrations than the 3 bulls with high ME EPDs. Additional calf crops will be evaluated to determine if these trends hold true in the future. <br /> <br /> Oklahoma State University: Three experiments were conducted to identify potential biomarkers for energy efficiency in gestating beef cows. The net energy required for maintenance, based on metabolic body weight, differed by 33% between the most and least efficient cows. The amount of energy required by cows for maintenance did not influence growth of calves from birth to weaning at 7 mo of age. Energy required for maintenance was not related to rumen temperature or physical activity of cows as measure by walking activity. Ambient temperature influenced the effect of maintenance requirement on plasma concentrations of thyroxine and triiodothyronine. <br /> <br /> Texas A&M University: Project 1: Objectives of this study were to evaluate the effects of residual feed intake (RFI) classification on performance, feed efficiency and carcass traits, and to determine the relative contributions of between-animal variation in these traits on net revenue (NR) of feedlot steers. Individual DMI and performance were measured in Angus-based composite steers (N = 508; initial BW = 310 ± 56 kg) fed a high-grain diet (3.08 Mcal ME/kg DM) for 70 d for 3 consecutive yr. RFI was computed as actual DMI minus expected DMI from linear regression of DMI on ADG and mid-test BW0.75. Thereafter, steers were fed the same diet in group pens, harvested at 1.14 cm backfat depth, and carcass traits recorded to determine quality and yield grades. Feed costs were based on actual feed consumed during feed-intake measurement periods, and model-predicted intake adjusted for RFI during group-feeding periods. NR was calculated as grid-formula carcass value minus feeder calf, yardage and feed costs, using 3-yr average fixed prices from 2008-2010. Steers with low RFI (< 0.50 SD) had $48/hd lower (P < 0.0001) feed costs, $16/hd numerically (P = 0.29) higher carcass values and $62/hd more favorable (P < 0.0001) NR compared to steers with high RFI (> 0.50 SD). NR was positively correlated with ADG, HCW and marbling score (0.38, 0.49 and 0.24, respectively), and negatively correlated with DMI, F:G, RFI and YG (-0.14, -0.50, -0.48 and -0.20, respectively). Stepwise regression was used to determine factors contributing to between-animal variation in NR, with year, DMI, ADG, RFI, F:G, HCW, marbling score, and YG included as independent variables. The R2 of the full model was 0.775 with performance (HCW, ADG), carcass-quality (marbling score, YG), feed efficiency (DMI, F:G) and year accounting for 18.2, 12.4, 46.3 and 0.6% of the variation in NR. Results demonstrate that substantial variation in NR can be attributed to individual-animal variances in performance and feed efficiency of feedlot steers. Project 2: The objective of this study was to examine phenotypic relationships between heifer postweaning RFI, and efficiency, digestibility and productivity of mid-gestation cows. RFIh was measured in growing Bonsmara heifers (n = 115) during 2 yr. DMD was measured in 38 heifers with divergent RFI. Heifers classified as having low RFI consumed 20% less feed (P < 0.05) compared to those with high RFI but had similar BW, ADG and backfat depth. DMD was not affected by RFI group. Heifers with the lowest (n = 12/yr) and highest (n = 12/yr) RFIh were retained for breeding. During mid-gestation, females (19 second-parity cows, 23 primiparous heifers) were fed chopped (ME = 2.11 Mcal/kg DM) in pens equipped with GrowSafe bunks to measure individual intake. BW were measured at 7-d intervals and BCS and ultrasound measurements of rump fat thickness obtained. Females classified as low RFIh had lower (P < 0.01) DMI (9.00 vs 11.6 ± 0.54 kg/d) compared to females with high RFIh, but initial BW, ADG, BCS and rump fat thickness were similar. Age at calving was not affected by RFI classification. RFI for pregnant cows was calculated as the residual from the linear regression of DMI on conceptus-adjusted ADG and mid-test BW0.75. RFI was highly correlated with DMI (0.79), but not BW, ADG, backfat depth or BCS. Heifers classified as having low RFI continued to consume 22% less feed during mid-gestation with similar BW and BCS compared to heifers classified as having high RFI. While some re-ranking of animals occurred between RFI in heifers and mid-gestation females, differences in intake were still evident. Between-animal variation in digestibility and body composition did not contribute to significant sources of variance in RFI in this study.<br /> <br /> University of California-Davis: After collaboration with the original New Zealand researchers who developed the plant and animal submodels, we have tested our model of the cow-calf production system with producers. The resulting model can be used to improve genetics or to determine the appropriate management system for different genotypes, or animals with varying energetic efficiencies. Also useful for this ongoing effort are our previously published analytical results of production and economic relationships between genetics, management, and beef quality. We have identified appropriate links to quantify greenhouse gas emissions as well by linking digestion, metabolism, and composition models of ruminant growth. Initial results of our work to model the cow-calf production system shows some management strategy by animal efficiency interactions. For example, selecting replacements on phenotypic weaning weight improves subsequent system efficiency over selection on genetic breeding value for weaning weight alone. Based on publications and extension work using the outputs above, beef producers should improve their understanding of how to manage animals with inherently different genotypes and phenotypes. Also, producers will gain greater control over beef management and improve profitability.<br /> <br /> University of Idaho: Project 1: Ninety-two yearling Wagyu bulls were evaluated for residual feed intake (RFI) and other performance variables during a 70-d testing period. Bulls were fed a diet in which ingredients were formulated to match the nutritional equivalent of the diet fed to finishing Wagyu cattle. Post RFI testing, bulls were classified into the following groups: efficient (RFI <0.5 SD below the mean; n = 32), marginal (RFI ±0.5 SD mean; n = 34), and inefficient (RFI >0.5 SD above the mean; n = 26). Residual feed intake was positively correlated with DMI (r = 0.56; P <0.0001) but was not correlated (r < 0.10) with ADG. Metabolic BW was not correlated with RFI. Intramuscular fat % (IMF) tended to be negatively correlated with RFI (r = - 0.17, P = 0.11). Efficient, marginal and inefficient groups showed differences in G:F (P < 0.001), and DMI (P < 0.001), but no differences were observed for metabolic BW or ADG (P = 0.71 and P = 0.96 respectively). Inefficient bulls had greater DMI (P <0.001) than efficient bulls. Marginal bulls also had greater DMI (P <0.001) than efficient bulls. All groups showed similar (P > 0.05) ultrasound measures for rib fat, rib eye area (REA) and IMF. No differences were observed between groups for the other performance variables tested. Observations from the current study suggest that Wagyu sires that are superior for both feed efficiency and marbling can be identified. Project 2: The maintenance energy (MEM) EPD was developed by the Red Angus Association of America and is used as an indicator of energy expenditure, which may be closely associated with residual feed intake (RFI). The objectives of this study were to evaluate and quantify the following relationships using progeny of Red Angus (RA) sires divergent for MEM EPD: 1) post-weaning RFI and finishing phase feed efficiency (FE), 2) post-weaning RFI and carcass attributes, and 3) post-weaning RFI and sire MEM EPD. Studies were conducted over 3 y (cohorts). Post-weaning RFI and finishing phase FE of steer progeny tended to be positively correlated (r = 0.38; P = 0.06) in cohort 1 and were positively correlated (r = 0.50; P = 0.001) in cohort 3. In addition, post-weaning RFI was not phenotypically correlated (P > 0.05) with any carcass traits or end-product quality measurements. Sire MEM EPD was phenotypically correlated (P < 0.05) with carcass traits in cohort 1 (HCW, LM area, KPH, fat thickness, and yield grade) and cohort 2 (KPH and fat thickness). However, variation in measured LM area was not explained by the genetic potential of ribeye area EPD, and therefore, the observed correlation between sire MEM EPD and measured LM area may suggest an association between MEM EPD and LM area. In addition, no phenotypic relationship was observed (P > 0.05) between progeny post-weaning RFI and sire MEM EPD. Therefore, results suggest the following: 1) RFI measured during the post-weaning growth phase is indicative of FE status in the finishing phase, 2) neither RFI nor sire MEM EPD negatively affected carcass quality, and 3) RFI and sire MEM EPD are not phenotypically associated.<br /> <br /> University of Illinois: Project 1: This experiment consists of 2 phases; where the same individual females will be observed across 2 stages of production. The heifer phase of the experiment began on July 14, 2008 and lasted for 85 days. Approximately 75 Angus/Angus x Simmental heifers were allotted at random in pens with adequate GrowSafe bunk space to monitor individual intake. These cattle were fed a common diet consisting of: 40% WDG, 35% cracked corn, 15% oatlage, and 10% supplement. These heifers were weighed on 2 consecutive d to determine initial and final BW, then weighed and measured for hip height again every 14 d. Metabolic weight (MW), BF (via ultrasonic imaging) and ADG were utilized in SAS to generate a regression equation for predicted DMI. These predicted values were subtracted from their actual DMI to assign an RFI value to each individual heifer. Metabolic weight, BF, and DMI were utilized in SAS to generate a regression equation for predicted ADG. Individual RADG values were determined by subtracting each heifers predicted ADG from their actual ADG. At the conclusion of the intake evaluation period the heifers were taken to pasture. The second phase of the trial involved these females at 5 yr of age. Therefore, their heifer RFI and RADG values have been predetermined. These cows were observed at 240d postpartum (dry phase) when cows were brought into observation and allotted at random to 1 of 2 ad libitum diets (high vs. poor quality forage) in a switch-back design. The high quality diet was comprised of haylage. The poor quality diet consisted of: 80% switchgrass with 20% solubles on a DMB. Intake was monitored daily by GrowSafe during two 21-d periods (14-d adaptation between). At the end of each 21d observation period, data was collected for BW, hip height, body condition score (BCS), and BF via ultrasound. Project 2: This experiment consists of 3 phases; where the same individual female will be observed across 3 stages of production. This project is an ongoing study. The heifer phase begins on November 1 annually and last for 84 d. Approximately 60-70 Angus/Angus x Simmental heifers are allotted at random in 4 pens with adequate GrowSafe bunk space. These cattle are fed a common forage-based diet consisting of (75% conventional corn silage and 25% DDGS) and weighed as described in Project 1. RFI and RADG are determined as described above. These heifers will then be taken off observation and sent back to pasture. The second phase of the trial involves observing the same set of females as 2-yr-old cows. Therefore, their heifer RFI and RADG values have been predetermined. These cows are observed at 60d postpartum (lactating phase) and 240d postpartum (dry phase). During the lactating phase, cows and calves are brought into observation (21 d duration). At the beginning of the data collection period, a weigh-suckle-weigh procedure is conducted to quantify milk production. Cattle are fed haylage ad-libitum, and cows and calves are monitored daily by GrowSafe. At the end of the 21d observation period, cows are processed and data is collected for BW, hip height, body condition score (BCS), BF via ultrasound, and feed/fecal samples are taken to test for DM digestibility. Cows are returned to pasture and brought back into observation on d 240 postpartum for 14 d. Once cows are bred and returned to pasture, we collect reproductive data such as pregnancy rate, first-AI conception rate, etc. The third phase of the trial will involve the same set of females as 5-yr old cows with a similar protocol to yr 2.<br /> <br /> University of Missouri: A. We have continued our evaluation of progeny from cows divergently mated for RFI. Steers have been fed corn-based diets and heifers forage-based diets with performance measured. Our goal continues to be to identify high growth and reproduction females that are RFI negative and positive to place back into the herd as replacements. Steers are evaluated for parent RFI phenotype effect on their performance phenotype (growth, intake, RFI). At present we plan to continue this research, but this plan is contingent upon future funding. Our results have not deviated from preceding years, more efficient parents tend to produce more efficient progeny. In addition to measuring forage intake differences between RFI phenotypes in grazing cows, we also measured lactation differences this season. We will be compiling that data at grazing season end. B. This past year we also added measurement of RFI in developing dairy heifers. These heifers calve this spring and we are measuring intake of these animals (grazing dairy model) at 3 time points during the season. C. This past year we studied the effect of increasing post ruminal amino acid flow on feed efficiency across RFI phenotypes. We formulated diets that provided 80, 100 or 120 % of the predicted requirement for absorbable arginine (most limiting amino acid). RFI phenotype responded differently to amino acid supply. Most notably were that supplying RFI average calves with an increased supply of absorbable amino acids improved feed efficiency equal to RFI negative calves, and RFI positive calves to RFI average calves. We concluded that RFI phenotype affected absorbable amino acid to energy requirement. D. We found a significant correlation (r2 = 0.66) between complex I subunit protein concentrations and RFI in calves. These data were evaluated over a range of RFI phenotypes, not only clustered among negative and positive phenotypes. More importantly the mitochondrial analysis was reasonable accurate in categorically predicting RFI phenotype as negative, average and positive. We are presently conducting this analysis again in a second set of cattle to determine repeatability. E. As part of a NIFA grant on feed efficiency in cattle, we phenotyped 2 groups of calves annually for intake and RFI that will be used to identify gene markers for RFI.<br /> <br /> University of Wyoming: Project 1: We hypothesized that gestational nutrition would affect calf feed efficiency and small intestinal growth, and that feed efficiency would be correlated with small intestinal growth. Multiparous beef cows (n = 36) were fed 1 of 3 diets from d 45 to 185 of gestation: a control (CON) diet of native grass hay and supplement to meet NRC recommendations, a nutrient restricted (NR) diet providing 70% of CON NEm, or an NR diet with a ruminally undegradable protein supplement to provide similar essential AA as CON. Individual feed intake of calves was measured with the GrowSafe System during finishing. At slaughter (552.4 ± 10.2 kg BW), the small intestine was dissected and sampled for determination of DNA, RNA, and protein; crypt cell proliferation (histology and immunohistochemistry); and real time RT-PCR analysis of angiogenic factors (vascular endothelial growth factor [VEGF], VEGF receptor-1 [FLT1], VEGF receptor-2 [KDR], endothelial nitric oxide synthase 3 [NOS3] and soluble guanylate cyclase [GUCY1B3; nitric oxide receptor]). Data were analyzed with calf sex as a block in a mixed model. There was no effect (P e 0.52) of maternal nutrition on residual feed intake (RFI), G:F, or intake. Maternal nutrition affected calf small intestinal length, but not intestinal mass, cellularity, or proliferation. Despite this, RFI was positively correlated (P d 0.08) with jejunal mass (r = 0.35), small intestinal mass (r = 0.33), and total jejunal DNA content (r = 0.33), and was negatively correlated (P d 0.09) with jejunal mucosal density (r = -0.33) and DNA concentration (r = -0.34). Gain:feed was positively correlated (P d 0.09) with jejunal mucosal density (r = 0.42), jejunal DNA (r = 0.32) and protein (r = 0.40) concentrations, and total jejunal DNA (r = 0.34), protein (r = 0.39), and cells (r = 0.34). Jejunal RNA concentration (r = -0.44), RNA:DNA (r = -0.52), and total RNA (r = -0.37) were each negatively correlated (P d 0.05) with G:F. Intake was positively correlated (P d 0.09) with jejunal (r = 0.75), ileal (r = 0.34), and total small intestinal (r = 0.74) mass; small intestinal length (r = 0.32); and total jejunal DNA (r = 0.52), protein (r = 0.55), and cells (r = 0.52). Jejunal GUCY1B3 mRNA expression was affected by maternal nutrition (P = 0.03), where calves born to NRP dams had greater (P < 0.03) GUCY1B3 than CON and NR. There was no effect (P e 0.34) of maternal nutrition on VEGF, FLT1, KDR, or NOS3 expression. Feed intake was positively correlated with jejunal mRNA expression of KDR (r = 0.37; P = 0.05) and NOS3 (r = 0.35; P = 0.06) and tended to be negatively correlated with VEGF (r = -0.30; P = 0.11). Residual feed intake and G:F were not correlated (P e 0.20) with angiogenic factor mRNA expression. Small intestinal size and growth explains some variation in efficiency of nutrient utilization in feedlot cattle, where more efficient animals appear to have less small intestinal mass, but more dense small intestinal mucosa. Additionally, changes in intestinal expression of VEGF and NOS3 systems are associated with feed intake and may alter intestinal vasculature. The small intestine appears to be a potential target for development of strategies to improve feed efficiency. <br /> <br /> Milestones: <br /> (2008): and 2012: Sponsor a symposium on Mechanisms underlying variation in RFI at ASAS/ADSA National Meeting. This will allow us to convey research findings to interested individuals in these organizations.<br /> <br /> Update: A W1010-sponsored symposium was held in 2008, but W1010 did not sponsor a symposium at the 2012 meetings because a similar symposium titled Molecular Basis for Feed Efficiency was organized by the meeting programming committee.<br /> <br /> (2011): Sponsor a symposium at the annual meeting of the Beef Improvement Federation to (1) Overview the implementation of RFI and the continuing need for adherence to national standards for RFI testing. (2) To report on the development of indicator physiological traits and gene markers as potential indicators of RFI. This will provide an important interface for science and industry to review current issues in development of RFI and adoption by industry.<br /> <br /> Update: Despite active involvement of the W1010 group and its memebers with the Beef Improvement Federation Conference, this symposium has not been sponsored to date. Plans are underway to hold this symposium at the 2013 BIF Conference in Oklahoma City, OK.<br />

Publications

Book Chapters:<br /> 1. Hill, R.A. (editor). 2012. (delivered under contract 12/01/11  scheduled publication  summer 2012). Feed Efficiency in the Beef Industry. (322 pages, 60 line drawings, 60 B&W photographs, 50 Tables.) with 33 contributors. Wiley-Blackwell, Ames, Iowa.<br /> <br /> 2. Hill, R.A. 2012. Introduction. In : Hill, R.A. (editor). Feed Efficiency in the Beef Industry. pp 1-6 Wiley-Blackwell, Ames, Iowa.<br /> <br /> 3. Ahola, J.K. and Hill, R.A. 2012. Input Factors Affecting Profitability: A Changing Paradigm and a Challenging Time. (Chapter 1) In: Hill, R.A. (editor). Feed Efficiency in the Beef Industry. pp 7-20. Wiley-Blackwell, Ames, Iowa.<br /> <br /> 4. Crews, D.H., Jr. and G.E. Carstens. 2012. Measuring Individual Feed Intake and Utilization in Growing Cattle. (Chapter 2) In: Hill, R.A. (editor). Feed Efficiency in the Beef Industry. pp 7-20. Wiley-Blackwell, Ames, Iowa.<br /> <br /> 5. Wulfhorst, J.D., Kane, S., Ahola, J.K., Hall, J.B. and Hill, R.A. (2012) Producer Awareness and Perceptions of Feed Efficiency (Chapter 3) In: Hill, R.A. (editor). Feed Efficiency in the Beef Industry. pp 29-46. Wiley-Blackwell, Ames, Iowa.<br /> <br /> 6. Retallick, K.M. and D.B. Faulkner. 2012. Feed Efficiency in Different Management Systems: Cow-Calf and in the Feedyard (Chapter 4) In: Hill, R.A. (editor). Feed Efficiency in the Beef Industry. pp 29-46. Wiley-Blackwell, Ames, Iowa.<br /> <br /> 7. Herd, R.M. and P.F. Arthur. 2012. Lessons from the Austrailian Experience. (Chapter 5) In: Hill, R.A. (editor). Feed Efficiency in the Beef Industry. pp 29-46. Wiley-Blackwell, Ames, Iowa.<br /> <br /> 8. Kerley, M.S.. 2012. Nutrition and Feed Efficiency of Beef Cattle. (Chapter 6) In: Hill, R.A. (editor). Feed Efficiency in the Beef Industry. pp 29-46. Wiley-Blackwell, Ames, Iowa.<br /> <br /> 9. Arthur, P.F. and R.M. Herd. 2012. Genetic Improvement of Feed Efficiency. (Chapter 7) In: Hill, R.A. (editor). Feed Efficiency in the Beef Industry. pp 29-46. Wiley-Blackwell, Ames, Iowa.<br /> <br /> 10. Rauw, W.M. 2012. Feed Efficiency and Animal Robustness. (Chapter 8) In: Hill, R.A. (editor). Feed Efficiency in the Beef Industry. pp 29-46. Wiley-Blackwell, Ames, Iowa.<br /> <br /> 11. Basarab, J.A., C. Fitzsimmons, C.S. Whisnant, and R.P. Wettemann. 2012. Interactions with Other Traits: Reproduction and Fertility. (Chapter 9) In: Hill, R.A. (editor). Feed Efficiency in the Beef Industry. pp 29-46. Wiley-Blackwell, Ames, Iowa.<br /> <br /> 12. Hill, R.A. and Ahola, J.K. 2012. Interactions with other Traits: Growth and Product Quality. (Chapter 10). In: Hill, R.A. (editor). Feed Efficiency in the Beef Industry. pp 145-158. Wiley-Blackwell, Ames, Iowa.<br /> <br /> 13. Welch, C.M., McGee, M., Kokta, T.A. and Hill, R.A. 2012. Muscle and Adipose Tissue: Potential Roles in Driving Variation in Feed Efficiency. (Chapter 12). In: Hill, R.A. (editor). Feed Efficiency in the Beef Industry. pp 175-198. Wiley-Blackwell, Ames, Iowa.<br /> <br /> 14. Meyer, A.M., J.S. Caton, B.W. Hess, S.P. Ford, and L.P. Reynolds. 2012. Epigenetics and Effects on the Neonate That May Impact Feed Efficiency. (Chapter 13) In: Hill, R.A. (editor). Feed Efficiency in the Beef Industry. pp 29-46. Wiley-Blackwell, Ames, Iowa.<br /> <br /> 15. Davis, M.E., M.P. Wick, and M.G.Maquivar. 2012. Hormonal Regulation of Feed Efficiency. (Chapter 14) In: Hill, R.A. (editor). Feed Efficiency in the Beef Industry. pp 29-46. Wiley-Blackwell, Ames, Iowa.<br /> <br /> 16. Bottje, W.G. and G.E. Carstens. 2012. Variation in Metabolism: Biological Efficiency of Energy Production and Utilization That Affects Feed Efficiency. (Chapter 15) In: Hill, R.A. (editor). Feed Efficiency in the Beef Industry. pp 29-46. Wiley-Blackwell, Ames, Iowa.<br /> <br /> 17. Sainz, R. 2012. Modeling Feed Efficiency. (Chapter 16) In: Hill, R.A. (editor). Feed Efficiency in the Beef Industry. pp 29-46. Wiley-Blackwell, Ames, Iowa.<br /> <br /> Referred Journal Articles:<br /> 1. Mendes, E.D.M, G.E. Carstens, L.O. Tedeschi, Pinchak, W.E. and T.H. Friend. 2011. Validation of a system for monitoring feeding behavior in beef cattle. J. Anim. Sci. 89:2904-2910.<br /> <br /> 2. Hafla, A.N., P.A. Lancaster, G.E. Carstens, D.W. Forrest, J.T. Fox, T.D.A. Forbes, M.E. Davis, R.D. Randel and J.W. Holloway. 2012. Relationships between feed efficiency, scrotal circumference and semen-quality traits in yearling bulls. J. Anim. Sci. (Accepted).<br /> <br /> 3. Bailey, J.C., L.O. Tedeschi, E.D. Mendes, J.E. Sawyer and G.E. Carstens. 2012. Technical note: Evaluation of bimodal distribution models to determine meal criterion in heifers fed a high-grain diet. J. Anim. Sci. doi:10.2527/jas.2011-4634.<br /> <br /> 4. H. Huang, H. C. Hines, K. M. Irvin, K. Lee, and M. E. Davis. 2011. Response to divergent selection for insulin-like growth factor-I concentration and correlated responses in growth traits in Angus cattle. J. Anim. Sci. 89:3924-3934.<br /> <br /> 5. Chung, H. Y., and M. E. Davis. 2011. Effects of calpain genotypes on meat tenderness and carcass traits of Angus bulls. Mol. Biol. Rep. 38:4575-4581.<br /> <br /> 6. Chung, H., and M. Davis. 2012. Effects of genetic variants for the calpastatin gene on calpastatin activity and meat tenderness in Hanwoo (Korean cattle). Meat Science 90:711-714.<br /> <br /> 7. Chung, H., and M. Davis. 2012. PCR-RFLP of the ovine calpastatin gene and its association with growth. Asian Journal of Animal and Veterinary Advances 7:641-652.<br /> <br /> 8. Hafla, A. N., P. A. Lancaster, G. E. Carstens, D. W. Forrest, J. T. Fox, T. D. A. Forbes, M. E. Davis, R. D. Randel, and J. W. Holloway. 2012. Relationships between feed efficiency, scrotal circumference, and semen-quality traits in yearling bulls. J. Anim. Sci. doi:10.2527/jas.2011-4029.<br /> <br /> 9. Cruz, G.D., J. B. Trovo, J. W. Oltjen, and R. D. Sainz. 2011. Estimating Feed Efficiency: Evaluation of mathematical models to predict individual intakes of steers fed in group pens. J. Anim Sci. 89:1640-1649.<br /> <br /> 10. McGee, M., Welch, C.M., Hall, J.B., Small, W. and Hill, R.A. (2012). Optimizing Feed Efficiency, Growth and Marbling in Wagyu Cattle. Professional Animal Scientist. (in revision).<br /> <br /> 11. Welch, C.M., Ahola, J.K., Hall, J.B., Murdoch, G.K., Crews Jr., D.H., Szasz, J.I., Davis, L.C., Doumit, M.E., Price, W.J., Keenan, L.D. and Hill, R.A. (2012). Relationships among performance, residual feed intake, and product quality of progeny from Red Angus sires divergent for maintenance energy EPD. Journal of Animal Science. (in revision).<br /> <br /> 12. Ahola, J.K., Skow, T.A., Hunt, C.W. and Hill, R.A. (2011). Relationship Between Residual Feed Intake and End Product Palatability in Longissimus Steaks from Steers Sired by Angus Bulls Divergent for Intramuscular Fat Expected Progeny Difference. Professional Animal Scientist.27:109-115.<br /> <br /> 13. Huntington G, Cassady, J., PAS, Gray, K, Whisnant, S. and Hansen, G. Use of digital infrared thermal imaging to assess feed efficiency in Angus Bulls. Prof. Anim. Sci. 28:166-172, 2012.<br /> <br /> Non-Referred Articles:<br /> 1. Carstens, G.E. 2011. Associations between feed efficiency and other economically relevant traits in beef cattle. Proc. of XIV Symposium on Feedlot Cattle, Monterrey Mexico, pp. 113-117.<br /> <br /> 2. Hill, R.A., Wulfhorst, J.D., Kane, S, Welch, C.M. and Ahola, J.K. (2012). Controlling the cost of beef production through improving feed efficiency. National Institute for Animal Agriculture National Meeting. March 27, Denver CO.<br /> <br /> 3. Hill, R.A., Wulfhorst, J.D., Kane, S, Welch, C.M, Hall, J.B. and Ahola, J.K. (2012). Improving Cattle Feed Efficiency. Bonner-Boundary Cattle Assoc. Beef School, Feb 4, Ponderay, ID<br /> <br /> 4. Meyer, A. M., K. M. Cammack, K. J. Austin, J. M. Kern, M. Du, J. S. Caton, and B. W. Hess. 2012. Correlation of feed intake and efficiency with small intestinal angiogenic factor and receptor expression in finishing cattle born to dams fed varying levels of nutrients during early to mid-gestation. Proc. West. Sec. Amer. Soc. Anim. Sci. 63: In press.<br /> <br /> 5. Vraspir, R. A., M. J. Ellison, K. M. Cammack, and A. M. Meyer. 2012. The relationship of feed efficiency and visceral organ size in growing lambs fed a concentrate or forage-based diet. Proc. West. Sec. Amer. Soc. Anim. Sci. 63: In press.<br /> <br /> 6. Ellison, M. J., R. R. Cockrum, K. W. Christensen, R. A. Vraspir, L. Speiser, W. J. Means, A. M. Meyer, and K. M. Cammack. 2012. The effect of diet on feed intake traits and relationships with carcass traits in sheep. Proc. West. Sec. Amer. Soc. Anim. Sci. 63: In press.<br /> <br /> Research Abstracts:<br /> 1. Walter, J.T., A.N. Hafla, G.E. Carstens, J.C. Bailey, J.W. Behrens, J.G. Moreno, D.S. Hale, R.K. Miller, J.E. Sawyer, and D. Anderson. 2012. Effects of residual feed intake on feedlot performance, feed efficiency, and carcass traits and net revenue in Angus-based composite steers. J. Anim. Sci. 90(Suppl. 1):53.<br /> <br /> 2. Moreno, J.G. R. Kalina, G.E. Carstens, T. Wickersham, J.T. Walter and A.N. Hafla. 2012. Between-animal variation in intake and behavioral patterns associated with consumption of salt-limited dried distillers grain in forage-fed growing steers. J. Anim. Sci. 90(Suppl. 1):73.<br /> <br /> 3. Moreno, J.G., G.E. Carstens, D.H. Crews, Jr., L.O. Tedeschi, L.R. McDonald, and S. Williams. 2012. Evaluation of feed efficiency and feeding behavior traits in performance tested bulls. J. Anim. Sci. 90(Suppl. 2):345.<br /> <br /> 4. Pye, T.A., B.H. Boehmer, and R.P. Wettemann. 2011. Maintenance energy requirements of gestating beef cows and plasma concentrations of thyroxine and triiodothyronine. J. Anim. Sci. (E-Suppl. 2)89:142.<br /> <br /> 5. Oltjen, J.W., and J.C. Whittier. 2011. English and Spanish versions of the cattle producers library for disseminating beef cattle educational information. First Joint Meeting AAPA-ASAS., Mar del Plata, Argentina, October 4-7, Revista Argentina de Producción Animal 31(Suppl. 1):198.<br /> <br /> 6. Adcock, J. W., D.W. Shike, D.B. Faulkner, and K.M. Retallick. 2011. Utilizing Heifer RFI to Predict Cow Intake and Efficiency. J. Anim. Sci. 89(E-Suppl. 2): 81.<br /> <br /> 7. Hill, R.A., Kane, S.L., Ahola, J.K., Wulfhorst, J.D., Hough, R.L., Bolze Jr., R.P. and Keenan, L. (2011). Feed Efficiency Research and Outreach for the Beef Industry. National Research Initiative (USDA) Project Directors Meeting, April 18-19, Washington, D.C.<br /> <br /> 8. Welch, C.M., Ahola, J.K., Hall, J.B., Murdoch, G.K., Crews Jr., D.H., Szasz, J.I., Davis, L.C., Doumit, M.E., Price, W.J., Keenan, L.D. and Hill, R.A. (2012). Performance, residual feed intake, and carcass quality of progeny from Red Angus sires divergent for maintenance energy EPD. Journal of Animal Science 89 (E Suppl.).<br /> <br /> 9. Welch, C.M., Murdoch, G.K., Schneider, C.S., Chapalamadugu, K., Thornton, K.J., McGee, M., Ahola, J.K., Hall, J.B. and Hill, R.A. (2011). Muscle Gene Expression Suggests Pathways of Nutrient Partitioning in low and high Residual Feed Intake Red Angus-sired Steers and Heifers. Pacific Northwest Animal Nutrition Conference. Portland, Oregon.<br /> <br /> 10. McGee, M., Welch, C.M., Hall, J.B., Small, W. and Hill, R.A. (2011). Evaluation of Japanese Black (Wagyu) Bull Performance and Residual Feed Intake. Pacific Northwest Animal Nutrition Conference. Portland, Oregon.<br /> <br /> 11. Soderquist, G.C., Welch, C.M., Murdoch, G.K., Ahola, J.K., Hall, J.B., Schneider, C. and Hill, R.A. (2011). Overview of IL-15/IL-15± Receptor and Their Role in Muscle Growth Related to Residual Feed Intake. Innovation Showcase. University of Idaho, April, 2011. (prize awarded).<br /> <br /> 12. Welch, C.M., Murdoch, G.K., Chapalamadugu, K., Thornton, K.J., Ahola, J.K., Hall, J.B. and Hill, R.A. (2011). Gene expression of Red Angus sired steers and heifers evaluated for residual feed intake Journal of Animal Science 89 (E Suppl. 2).<br /> <br /> 13. McGee, M., Welch, C.M., Hall, J.B., Small, W. and Hill, R.A. (2011). Interactions of Residual Feed Intake and other Performance Parameters of Japanese Black (Wagyu) Bulls. Journal of Animal Science 89 (E Suppl. 2).<br /> <br /> 14. Meyer, A. M., K. M. Cammack, K. J. Austin, J. M. Kern, M. Du, J. S. Caton, and B. W. Hess. 2012. Correlation of feed intake and efficiency with small intestinal angiogenic factor and receptor expression in finishing cattle born to dams fed varying levels of nutrients during early to mid-gestation. J. Anim. Sci. In press.<br /> <br /> 15. Meyer, A. M., K. A. Vonnahme, D. A. Redmer, L. P. Reynolds, and J. S. Caton. 2012. Maternal feed efficiency during gestation is correlated to offspring birth weight and girth in nutrient restricted and control-fed ewes. J. Anim. Sci. In press.<br /> <br /> 16. Vraspir, R. A., M. J. Ellison, K. M. Cammack, and A. M. Meyer. 2012. The relationship of feed efficiency and visceral organ size in growing lambs fed a concentrate or forage-based diet. J. Anim. Sci. In press.<br /> <br /> 17. Doscher, F. E., A. M. Meyer, M. J. Ellison, K. M. Cammack, and K. C. Swanson. 2012. The relationship between feed efficiency and pancreatic ±-amylase and trypsin activity in growing lambs. J. Anim. Sci. In press.<br /> <br /> 18. Ellison, M. J., R. R. Cockrum, K. W. Christensen, R. A. Vraspir, L. Speiser, W. J. Means, A. M. Meyer, and K. M. Cammack. 2012. The effect of diet on feed intake traits and relationships with carcass traits in sheep. J. Anim. Sci. In press.<br /> <br /> 19. Meyer, A. M., K. M. Cammack, S. I. Paisley, P. Moriel, W. J. Means, M. Du, J. S. Caton, and B. W. Hess. 2012. Correlation of feed efficiency and small intestinal growth in finishing cattle born to dams fed varying levels of nutrients during early to mid-gestation. J. Anim. Sci. In press.<br /> <br /> 20. Minton, N.O., J.H. Porter, N.F. Johnson, J.G. Yoder, and M.S. Kerley. 2012. Comparison of fermentation end products within continuous culture among steers differing in residual feed intake (RFI) phenotypes. J. Anim. Sci. In press.<br /> <br /> 21. Ramos, M.H., D.H. Keisler, and M.S. Kerley. 2012. Glucose and epinephrine tolerance tests in steers categorized as residual feed intake efficient versus inefficient. J. Anim. Sci. In press.<br /> <br /> 22. C.N. Key, S. D. Perkins, C. F. Garrett, C. D. Foradori, C. L. Bratcher, L. A. Kriese-Anderson, and T. D. Brandebourg. 2012. Effect of residual feed intake on hypothalamic gene expression and meat quality in heat-stressed Angus-sired cattle. J. Anim. Sci. 90:296 (Suppl. 3).<br /> <br /> 23. Perkins, S.D., C. N. Key, C. F. Garrett, C. D. Foradori, C. L. Bratcher, L. A. Kriese-Anderson, and T. D.<br /> Brandebourg. 2012. Residual feed intake and meat quality in Angus-sired cattle. Presented at southern section of American Society of Animal Science. Accessed http://www.asas.org/southern/2012/2012ASAS_Southern_Abstracts.pdf. Page 1.<br /> <br /> 24. S. D. Perkins, C.N. Key, C. F. Garrett, C. D. Foradori, C. L. Bratcher, L. A. Kriese-Anderson, and T. D. Brandebourg. 2012. Effect of residual feed intake on meat quality and hypothalamic gene expression in Angus-sired cattle. J. Anim. Sci. 90:296 (Suppl. 3).<br /> <br /> Experiment Station/Extension Publications: <br /> 1. Walter, J.T., G.E. Carstens, J.C. Bailey, J.W. Behrens, A.N. Hafla, J.G. Moreno, D.S. Hale, R.K. Miller, J.E. Sawyer, and D. Anderson. 2011. Effects of residual feed intake classification on feedlot performance carcass traits and net revenue in Angus-based composite steers. Beef Cattle Research in Texas.<br /> <br /> 2. Hafla, A.N., G.E. Carstens, T.D.A. Forbes, J.C. Bailey, J.T. Walter, L.O. Tedeschi, J.W. Holloway and J.G. Moreno. 2011. Relationship between postweaning residual feed intake in heifers and forage intake of mature mid-gestation beef females. Beef Cattle Research in Texas.<br /> <br /> 3. Meyer, A. M., K. M. Cammack, S. I. Paisley, P. Moriel, W. J. Means, M. Du, J. S. Caton, and B. W. Hess. 2012. Correlation of feed efficiency and small intestinal growth in finishing cattle. University of Wyoming Agricultural Experiment Station Field Day Report. In press.<br /> <br /> 4. Ellison, M. J., R. R. Cockrum, K. W. Christensen, R. A. Vraspir, L. Speiser, W. J. Means, A. M. Meyer, and K. M. Cammack. 2012. The effect of diet on feed intake traits and relationships with carcass traits in sheep. University of Wyoming Agricultural Experiment Station Field Day Report. In press.<br /> <br /> 5. Meyer, A. M., K. M. Cammack, S. I. Paisley, P. Moriel, W. J. Means, M. Du, J. S. Caton, and B. W. Hess. 2011. Correlation of feed efficiency and small intestinal growth in finishing cattle born to dams fed varying levels of nutrients during early to mid-gestation. University of Wyoming Department of Animal Science Annual Report. 58-59.

Impact Statements

1. Feed constitutes a major input to beef production, and is, in fact, the largest single expense in most commercial beef production enterprises. Efficiency of feed utilization is, therefore, an obvious candidate for improvement in order to reduce cost of beef production. Studies conducted under the umbrella of W1010 will aid in the development of national and international genetic evaluation programs for improved feed efficiency. This, in turn, will allow beef cattle breeders to use high efficiency cattle in their herds to reduce the feed cost of production and improve profitability.
2. Maintenance energy requirement of beef cows accounts for about 50% of the energy required for beef production from birth to slaughter. Improvements in energy efficiency could increase profit because feed costs are the greatest cost of beef production. Use of biomarkers to identify cows that are more energy efficient will increase progress in the improvement of feed efficiency.
3. The educational programs provided by the Mississippi State University Extension Service to enhance technology adoption have created increased awareness of the importance of enhancing efficiency of feed utilization in beef production systems in Mississippi. In addition, web-based materials reach beyond state and national borders to help achieve this impact on an ongoing basis.
4. Feeding behavior traits may be useful as indicator traits for selection of beef cattle for improved residual feed intake. Ultimately development of these technologies will result in reduced production costs, mitigation of environmental effects of beef production systems and improve the competitive position of beef producers.
5. Determining correlations between residual feed intake (RFI) and other traits is important to scientists, breed societies and producers. This information is vital so that it can be determined whether there may be either antagonisms, no effects or synergies between RFI and other traits. In Red Angus-Sired Cattle: We have made an initial discovery that there appears to be a negative correlation between RFI EPD and Maintenance Energy EPD in Red Angus sired cattle. The impact is that we need to get a greater understanding between these two traits. A possible implication is that Red Angus breeders who are selecting for low Maintenance Energy EPD may be co-selecting for animals that are inefficient in terms of RFI.
6. Determining correlations between residual feed intake (RFI) and other traits is important to scientists, breed societies and producers. This information is vital so that it can be determined whether there may be either antagonisms, no effects or synergies between RFI and other traits.In Wagyu Cattle: This initial study of 92 Wagyu bulls suggests that intramuscular fat % (IMF) tends to be negatively correlated with RFI (r = - 0.17, P = 0.11). This is a favorable relationship in that more efficient Wagyu bulls may tend towards greater IMF and thus marbling, a highly prized aspect of Wagyu cattle. This requires further study to determine whether this relationship holds more broadly across a larger population sample.

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