Brief Summary of Minutes of Annual Meeting

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.

Short-term Outcomes: 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. Outputs: 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). Activities: 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. 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. 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. 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. 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. 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. 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. 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. 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. 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. 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. 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. Milestones: (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. 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. (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. 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.

Book Chapters: 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. 2. Hill, R.A. 2012. Introduction. In : Hill, R.A. (editor). Feed Efficiency in the Beef Industry. pp 1-6 Wiley-Blackwell, Ames, Iowa. 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. 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. 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. 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. 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. 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. 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. 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. 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. 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. 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. 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. 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. 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. 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. Referred Journal Articles: 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. 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). 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. 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. 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. 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. 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. 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. 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. 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). 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). 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. 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. Non-Referred Articles: 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. 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. 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 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. 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. 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. Research Abstracts: 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. 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. 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. 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. 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. 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. 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. 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.). 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. 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. 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). 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). 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). 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. 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. 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. 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. 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. 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. 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. 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. 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). 23. Perkins, S.D., C. N. Key, C. F. Garrett, C. D. Foradori, C. L. Bratcher, L. A. Kriese-Anderson, and T. D. 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. 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). Experiment Station/Extension Publications: 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. 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. 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. 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. 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.