Annual/Termination Reports:

[03/28/2006] [04/09/2007] [10/01/2007] [10/21/2008]

Report Information

Participants

West J. (joewest@uga.edu); Bernard, J. (jbernard@uga.edu); Williard, S. (SWillard@ads.msstate.edu); Smith, T. (trsmith@ads.msstate.edu); Edwards, L. (jedwards@utk.edu); Pantoja, J. (jpantoja@uprm.edu); Godfrey, R. (rgodfre@uvi.edu); Morrison, D. (dmorrison@agcenter.lsu.edu); Misztal, I. (ignacy@uga.edu)

Brief Summary of Minutes

The S-1023 Regional Meeting was called to order by the Chair, Scott Willard (MS), at 8:15 a.m. on February 4th. Self-introductions of all participants ensued followed by station reports (in the order they were presented) from R. Godfrey (USVI), S. Willard (MS), J. West (GA), J. Bernard (GA), and I. Misztal (GA). After a break for lunch station reports resumed as follows (in the order they were presented) from T. Smith / X. Wang (MS), J. Pantoja (PR) and L. Edwards (TN). At 3:20 p.m. Dr. D. Morrison (Administrative Advisor) made comments regarding the renewal of the project and thanked T. Smith (MS) and S. Willard (MS) for their contributions in writing/editing the document and all S-1023 participants that submitted information for the renewal document for their efforts. Dr. Morrison then referred the group to the e-mail and information provided by D. Hamernik (USDA-CSREES) prior to the meeting on federal USDA-NRI budgets and granting opportunities. The Business Meeting was then initiated and resulted in the following: (1) Election of Officers  After nominations it was decided that R. Godfrey (USVI) would serve as Chair-Elect and J. Bernard (GA) as incoming Secretary. L. Edwards (TN) will serve as Chair of the next meeting. (2) Meeting Location for 2007  It was decided that Mobile, AL would serve as the tentative next meeting site along with the SAAS meeting. (3) Protocols  R. Godfrey (USVI) indicated that if members have common use or sampling protocols that need to be posted on the S-1023 website that they should e-mail these materials to him. (4) Station Reports  S. Willard (Chair; MS) requested that station reports by submitted to him via e-mail by March 1st so that the annual report and minutes could be compiled and sent to D. Morrison by April 1st in accordance with SAAESD guidelines. (5) Collaborations - Discussion centered on collaborative granting efforts including an interest by the group in an integrated research/extension grant on prepartum cooling and prepartum indicators of postpartum reproductive/production performance. Discussions of a group paper or technical report on comparative methods for monitoring body temperature by the techniques used by the participants ensued, with interest by the group to work on the development of such a project.

Accomplishments

Note that the principal reporting station is indicated in relation to the stated accomplishment and subsequent impact, but may involve more than one investigator from that station. Multi-state collaborative projects are indicated within the Accomplishments under each sub-objective and are further reflected in the List of Publications and Plans for the Coming Year sections that follow the Accomplishments and Impacts.<br /> <br /> Objective 1. Defining the physiological characteristics of heat-stressed dairy cattle <br /> <br /> 1A. Quantifying heat stress in dairy cattle.<br /> <br /> Accomplishment: Current research is defining the physiological characteristics of heat stress in dairy cattle, with specific emphasis on the relationships between secondary cow characteristics (coat color and density; see also sub-objective 1E below) in relation to their ability to tolerate heat stress (PR). Preliminary study designs consist of rectal temperatures taken daily at various intervals along with vaginal temperatures taken with HOBOs mounted on intravaginal CIDR devices for seven consecutive days for comparisons of dairy cows (n = 17) that differ in hair coat density. The partial correlation between rectal and vaginal was 0.66 (P < 0.01). It was noted that there was more variation in rectal than in vaginal temperatures taken with the HOBO data loggers. Partial correlation coefficients between rectal temperatures and respiration rates were 0.50 (P < 0.01). These data will be compared in the future with rectal temperature:vaginal HOBO data acquired at other collaborating stations (GA, MS and USVI). <br /> <br /> Accomplishment: Digital infrared thermography (DITI) is being examined as a tool for evaluating the effects of climatic influences (i.e., heat stress) on cows in relation to black vs. white hair coat in a typical freestall environment and in relation to cooling strategies. Genetic effects are being further evaluated using DITI among Holstein, Jersey and Gir x Holstein cows. Results suggest that cow body surface temperatures are highly influenced by environmental conditions, which DITI can detect, including differences in responsiveness among breeds. These data establish relationships between cow body surface thermal signatures within production environments from which further studies can assess the use of DITI for the environmental monitoring of dairy cattle. DITI is also being used to evaluate environmental effects (cooling and ambient conditions) on the use of this tool for the detection of reproductive status. The current data suggest a tendency for right-side DITI as a better predictor of pregnancy than left-side DITI in Holstein heifers. However, the ability to truly discriminate pregnant from non-pregnant heifers remains questionable (as affected by: ambient temperature, hair coat condition or patterns, etc.). At the ambient temperatures when measures were acquired, thermography revealed no temperature difference between estrus and early diestrus in cycling cows, and the ability to discriminate between estrus and diestrus was greatly influenced by ambient temperature. <br /> <br /> Accomplishment: Studies are addressing the effects of heat stress on the bovine oocyte (TN). Current results provide strong supportive evidence that physiologically relevant elevated temperatures induce premature aging of the bovine oocyte, thereby reducing fertile lifespan. Specifically, we observed that direct exposure of bovine oocytes to an elevated temperature commonly seen in heat-stressed dairy cows hastened in vitro maturation (i.e., heat-stressed oocytes mature faster than controls). Moreover, earlier insemination in vitro prevented heat-induced reductions in oocyte development compared to controls<br /> <br /> 1B. The effect of various summer cooling strategies on symptoms of heat stress, endocrine status and lactation performance.<br /> <br /> Accomplishment: Data were collected from a trial designed to compare the effectiveness of high-speed fans (HS, 36 inch, 0.5 hp) with low-speed fans (LS, 20 ft., 1.0 hp; GA). Both fan systems are installed in a four-row free stall barn (100 ft wide x 440 ft long) with a drive through feed alley. Four rows of HS are installed ever 20 ft over the feed alley and free stalls. Four high pressure mister nozzles (~250 psi) are mounted to the face of each fan. The system is designed to operate automatically when the temperature exceeds 75 F. The high pressure misters automatically cut off when the relative humidity (RH) exceeds 85%. The LS are mounted in the center of the barn 60 ft centers. Individual core body temperatures (CBT) were recorded intravaginally using the HOBO Water Temp Pro. Treatments were switched each day at 0900 h in the randomized design trial and replicated across two years. Air flow measured at various locations in the free stall barn ranged from 2.5 to 5.0 mph for LS compared with 5.0 to 8.0 for HS. Air flow for areas not directly in line with HS dropped to 0 to 2 mph. Although the LS provided a more even airflow throughout the barn, the flow rates produced by this model of fan in this barn were considered lower than desired in the most critical areas. The 1030 CBT was used as a covariate in the statistical analysis. In both 2004 and 2005, CBT was higher for cows cooled with LS compared with HS. Mean CBT for HS and LS were 102.88 and 103.22 F in 2004 (SE = 0.08, P = 0.05) and 102.58 and 102.95 F in 2005 (SE = 0.09, P = 0.009). No interaction of treatment and time was observed in 2004, but an interaction was observed during 2005 (P < 0.0001) because differences in CBT between systems were greater from 1430 through 1800 compared with all other times except from 0600 through 0800 when CBT was lower with LS compared with HS. The LS fans were not turned off each 24 h period which may account for the lower CBT observed during the morning compared with HS which automatically turned off when the ambient temperature was less than 75 F. These results indicate that LS do not provide adequate airflow to cool lactating dairy cows as effectively as HS. <br /> <br /> 1C. Characterize the impact of prepartum cooling and identifying prepartum metabolic and endocrine markers as indicators of postpartum performance.<br /> <br /> Accomplishment: While work has not begun on this sub-objective, planning for a proposed collaborative project among several of the participating stations (GA, MS and NC) is underway. The goal is to identify prepartum cooling practices that will result in improved cow health and performance and possibly benefit the calf as well. Fans, sprinklers and other technologies will be used with dry cows and body temperatures, metabolic and endocrine parameters such as non-esterified fatty acids, plasma urea nitrogen, beta-hydroxybutyrate, insulin and thyroid hormones will be measured (linked to sub-objective 2B below). Production data, days to first ovulation and days to pregnancy will be recorded for cows and birth weight and growth measurements will be recorded for calves. An additional sub-objective may be formulated to address specifically calf performance and physiology in relation to dam treatments during the prepartum period.<br /> <br /> 1D. Characterize the effect of genetic selection in heat tolerance.<br /> <br /> Accomplishment: Heat stress was evaluated as a factor in the genotype x environment interaction in the United States for milk (GA). The national data set (NA) consisted of 56 million first-parity test day milk yields on 6 million Holsteins. The Northeastern subset (NE) included 12.5 million records on 1.3 million cows from eight states, and the Southeastern subset (SE) included 3.5 million records on 0.4 million cows from eleven states. Climatic data was available from 202 public weather stations. Correlations involved breeding values from SE and NE for sires > 300 daughters in each region. When heat stress was ignored (first model) the correlations of mild-climate PTA of sires were 0.86. When heat stress was considered in the model, the correlation increased by 0.01. The correlations of heat stress PTA between NE and SE daughters was 0.71. They increased to 0.81 for sires with > 700 daughters. Evaluations for heat tolerance are similar in cooler and hotter regions for high reliability sires. <br /> <br /> Accomplishment: A long-term goal is to identify genes controlling cellular thermotolerance and transfer these genes into Holstein cattle to reduce the magnitude of deleterious effects of elevated temperature on embryonic survival, immune function, and other aspects of physiological function in cattle. In cooperation with this aim, the production performance and genotypic differences in Gir (Bos indicus) x Holstein and Holstein cattle are being evaluated (MS). A comparison of reproductive parameters in Holstein vs. Gir X Holstein dairy cattle. Study results suggest that Gir X Holstein (G x H) heifers exhibited greater days to first estrus and days to conception, and were heavier at conception than Holstein heifers. Holstein heifers displayed greater mount frequency than G X H heifers, while no differences were observed in duration of estrus and mount duration. No difference in scrotal circumference or testosterone concentrations at 12 months between G X H and H ´ H bulls. G X H bulls also had greater scrotal circumference and testosterone than Holstein bulls at 18 months, yet ejaculate characteristics did not differ between G X H and Holstein bulls at 12 or 18 months, and G X H and Holstein bulls exhibited similar patterns of peripubertal growth (i.e., through 18 months of age). <br /> <br /> 1E. Determining the relationships between coat color and cow body size on production performance in heat stressed dairy cattle.<br /> <br /> Accomplishment: Studies conducted previously addressed the interaction between coat color (black versus white percentage) and heat stress on thermal heat load in dairy cattle (USVI). Pictures of cows on heat stress trials from 2004-2005 have been acquired (MS; PR), and will be analyzed in cooperation with USVI and included as a parameter in study analysis and future experimental designs. Standard measures of cow body size are also being developed (MS) for inclusion in study designs by other participating stations as an additional factor for post-study analysis. <br /> <br /> Objective 2. Improving fertility of heat-stressed dairy cows without decreasing milk production<br /> <br /> 2A. Use of supplemental hormone administration pre and post breeding to improve fertility of heat stressed dairy cattle.<br /> <br /> Accomplishment: The goal is to determine if CIDR can be used to enhance pregnancy rates in cows during heat stress periods. In one study conducted at NC, cows bred at a synchronized estrus were assigned to either Control (no CIDR) or Treatment (CIDR) beginning at day 5 after AI. Pregnancy rates to the synchronized breeding and to the subsequent breeding in those cows that showed estrus were recorded. There was no difference in pregnancy rate at the synchronized breeding but CIDR treated cows tended to have a higher pregnancy rate to the breeding at the subsequent estrus. In a companion study conducted at MS, the effects of supplemental progesterone administration on pregnancy rate and resynchronization in lactating dairy cattle during mild heat stress and nonheat stress conditions. Studies were conducted to assess the use of the CIDR as a supplemental P4 source during conditions of mild heat stress and nonheat stress in lactating dairy cows. Cows were synchronized for 7 d using CIDR with administration of PGF on d 6. Following CIDR withdrawal cows detected in estrus were bred by AI, with a timed insemination 54 h after PGF2± for all cows not detected in estrus. Cows were balanced for production variables and assigned as Control (CON; no supplemental CIDR) or CIDR+, which received a second CIDR 11 d after the timedAI. Summer study: Cows were managed under mild heat stress conditions. Ultrasonography at d 42 following the first AI postCIDR revealed a pregnancy rate (PR) of 27% for CIDR+, and 5% for CON. Ultrasonography at d 65, combining first AI and resynchronized AI, revealed an overall PR of 45% for CIDR+, and 18% for CON. Fall study: Cows were managed under cool season conditions. Ultrasonography at d 42 following the first AI postCIDR revealed a PR of 31% for CIDR+, 31% for CON. Ultrasonography at d 65, combining first AI and resynchronized AI, revealed an overall PR of 44% for CIDR+ and 41% for CON. In summary, the use of the CIDR as a supplemental source of P4 postbreeding increased pregnancy rate and accelerated rebreeding under mild heat stress conditions but not during the cool season in lactating dairy cows. <br /> Accomplishment: One strategy for improving fertility in cattle is mid-cycle administration of GnRH to increase progesterone secretion and delay luteolysis. This strategy might be especially useful during hot weather because heat stress increases uterine prostaglandin release and reduces development of the elongating embryo. A series of experiments were conducted at FL to test the efficacy of GnRH for increasing fertility. There was no effect of administration of 100 ¼g GnRH at Day 11 after anticipated ovulation on pregnancy rates in virgin heifers subjected to timed artificial insemination (TAI) during the summer. Similarly, there was no beneficial effect of administration of GnRH at Day 11 after anticipated ovulation on pregnancy rates of lactating cows subjected to TAI in summer and winter. Three experiments tested effects of injection of GnRH at Day 14 or 15 after anticipated ovulation on pregnancy rates of lactating cows. The first experiment used 477 lactating cows subjected to TAI. Cows receiving GnRH at Day 14 had higher pregnancy rates in both summer and winter than cows receiving vehicle (20.3% vs 12.7%; P<0.02). When this experiment was repeated during summer with 137 cows, there was a negative effect of GnRH treatment at Day 14 on pregnancy rate. In the third experiment, lactating cows during summer were inseminated at detected estrus and cows were assigned to treatment with either GnRH or vehicle at Day 14 or 15 after insemination. Pregnancy rates were 25.6% (32/125) for cows receiving vehicle, 20.7% (19/92) for cows receiving GnRH at Day 14, and 20.3% (16/79) for cows receiving GnRH at Day 15. In conclusion, GnRH administration at Day 11 to 15 after anticipated ovulation or estrus did not consistently increase pregnancy rates in either cool or warm seasons<br /> <br /> 2B. Establishing hormone markers pre breeding as predictors of reproductive success in heat stressed and non heat stressed dairy cows.<br /> <br /> Accomplishment: While administration of bovine somatotropin (bST) to lactating dairy cows increases milk production, it can also increase body temperature during heat stress and may therefore compromise fertility. However, bST increases secretion of insulin-like growth factor-I (IGF-I) and culture of bovine embryos with IGF-I blocks the reduction in blastocyst development and induction of apoptosis caused by heat shock. A study was performed at FL was to determine effects of bST on reproductive function in lactating dairy cows during heat stress. The experiment was conducted in South Georgia from July to November 2005 using 271 lactating Holstein cows. For first service timed artificial insemination (TAI), cows were presynchronized with two injections of PGF2a given 14 d apart followed by a modified Ovsynch protocol (GnRH given 72 h following PGF2a). Pregnancy was diagnosed using ultrasonography on d 29 and reconfirmed by palpation between d 45-80 post-TAI. Non-pregnant cows were resynchronized with the modified Ovsynch protocol and received TAI. Treatment with bST (500 mg; Posilac, Monsanto) started 1 wk prior to the start of Ovsynch and continued at 2-wk intervals. A subset of cows (n=38) were bled for IGF-I profiles immediately prior to the first bST injection, 1 wk later, and at d 35 of bST treatment. Rectal temperatures were taken on d 29 of bST treatment. Pregnancy rates (d 45-80 post-TAI) did not differ between control (n=129) and bST-treated cows (n=142) for first- (15.5% vs 16.9%) or second-service TAI (17.2% vs 15.0%). Milk yield and plasma concentrations of IGF-I were higher for bST-treated cows following the initiation of bST treatment (bST x time interaction, P<0.01) and bST increased rectal temperature (P<0.05; 39.17°C vs 39.31°C for control vs IGF-I cows, SEM=0.05°C). <br /> <br /> 2C. Use of interval cooling (i.e., immediately before and after breeding) to improve fertility of problem breeders and heat stressed dairy cows.<br /> <br /> This sub-objective is not being investigated currently, but may be addressed in future years of this project by collaborating stations or as coupled with other sub-objectives.<br /> <br /> 2D. Use of targeted vitamin and mineral supplementation in conjunction with estrous synchronization and timed AI to improve fertility in heat stressed dairy cows<br /> <br /> Accomplishment: The goal is to determine if supplementation with vitamin A and E before breeding at a synchronized estrus will improve pregnancy rates in heat stressed dairy cows (NC) and is being planned currently for implementation of this study. Cows will be treated with an injectable vitamin A and E preparation or carrier two weeks prior to the planed breeding date. Pregnancy rates will be monitored to the synchronized breeding<br /> Objective 3. Improving milk production of heat-stressed dairy cows without decreasing fertility<br /> <br /> 3A. The effect of heat stress on nutritional requirements of high-producing dairy cows.<br /> <br /> Accomplishment: Heat increment is the rise in digestive and metabolic heat production following a meal, and greater heat production is a liability during hot weather. Dietary ingredients have varying effects on heat production; low digestibility ingredients produce more heat proportional to NEL when compared with higher digestibility ingredients. Fats are used with a relatively high efficiency and have a lower heat increment. The high heat increment diet was formulated using cottonseed hulls, cottonseed meal, and higher forage content; low heat increment was formulated by using less total forage, more whole cottonseed, no cottonseed meal or hulls, and a rumen inert fat (GA). Three treatments were imposed: high heat increment fed ad libitum (HI), low heat increment fed ad libitum (LO), and LO fed restricted (LO-Res) to the same caloric intake as the HI diet. There was no difference between DMI per 100 kg BW for the HI and LO diets, while DMI/BW was lower for the LO-Res diet, as expected. Milk yield per DMI (kg/kg), a measure of efficiency, was greater for both the LO and LO-Res treatments when compared with HI, suggesting a slight improvement in efficiency for low heat increment diets. There were no significant differences in NE milk per NE intake (Mcal/Mcal). Respiratory rate was lowest for the LO-Res diet, probably because of the lower total DMI, because of restricted intake. <br /> <br /> 3B. The effects of high protein diets on production performance and summer breeding in dairy cows.<br /> <br /> This sub-objective is not being investigated currently, but may be addressed in future years of this project by collaborating stations or as coupled with other sub-objectives.<br /> <br /> 3C. The effect of dietary supplements (antioxidants, minerals and probiotics) to enhance nutrient intake and digestibility.<br /> <br /> This sub-objective is not being investigated currently, but may be addressed in future years of this project by collaborating stations or as coupled with other sub-objectives (See Plans for the Coming Year below).<br /> <br /> Plans for the Coming Year  Established Collaborations and On-going Projects:<br /> <br /> " Coat color studies and determination of percentages of black vs. white hair coat.<br /> (OBJ 1E; PR, MS, TN with VI-STX Lead)<br /> " Enzyme enhancements in diets while grazing southern forages.<br /> (OBJ 3C; PR, GA - Lead) <br /> " Body temperature and estrous cycle - data mining and/or implementation of a summer study<br /> (OBJ 1A - MS, and TN - Lead)<br /> " Retrospective data mining for seasonal effects on oocyte.<br /> (OBJ 2C; FL, TN - Lead)<br /> " Body temperature correlates among different measurement techniques, and the proposed coordination of a regional project review paper on the subject.<br /> (OBJ 1A - All stations - prelim e-mail to group: MS - Lead; meet in ASAS-MN)<br /> (Suggestion: Southern Cooperative series bulletin)<br /> " Prepartum Cooling - metabolic/postpartum/cooling methods will be investigated along with nutrition x reproduction interactions related to prepartum cooling. New sub-objective to be considered: calf physiology/responses to dam prepartum cooling<br /> (OBJ 1C - GA, TN, NC, MS - Lead)<br /> " Heat tolerant sires (OBJ 1D; GA lead on proposal)  will develop a plan for evaluating this among station and seek collaborators in the future to address the selection of heat tolerant sires.<br /> <br />

Publications

Bohmanova, J., I. Misztal, and J. K. Bertrand. 2005. Studies on multiple trait and random regression models for genetic evaluation of beef cattle for growth. J. Anim. Sci. 83:62-67.<br /> <br /> Edwards J.L., J.L. Lawrence, R.R. Payton, J.R. Dunlap, and A.M. Saxton. 2005. Exposure to a physiologically-relevant elevated temperature hastens maturation in bovine oocytes. J. Dairy Sci. 88:4326-4333. <br /> <br /> Finocchiaro, R., J. B. C. H. M. van Kaam, B. Portolano, and I. Misztal. 2005. Effect of Heat Stress on Production of Mediterranean Dairy Sheep. J. Dairy Sci. 88: 1855-1864<br /> <br /> Franco, M., Block, J., Jousan, F.D., de Castro e Paula, L.A., Brad, A., Franco, J.M., Grisel, F., Monson, R.L., Rutledge, J.J., and Hansen, P.J. (2005) Effect of transfer of one or two embryos and administration of gonadotropin releasing hormone on pregnancy rates of heat-stressed dairy cattle . Theriogenology, in press.<br /> <br /> Franco, M., and Hansen, P.J. (2006) Effects of hyaluronic acid in culture and cytochalasin B treatment before freezing on survival of cryopreserved bovine embryos produced in vitro. In Vitro Cell Dev. Biol. Anim., in press.<br /> <br /> Garcia-Peniche, T. B., B. G. Cassell, R. E. Pearson and I. Misztal. 2005. Comparisons of Holsteins with Brown Swiss and Jersey Cows on the Same Farm for Age at First Calving and First Calving Interval. J. Dairy Sci. 88:790-796.<br /> <br /> Iwaisaki, H., S. Tsuruta , I. Misztal , and J. K. Bertrand. 2005. Estimation of Correlation Between Maternal Permanent Environmental Effects of Related Dams in Beef Cattle. J. Anim. Sci. 83:537-542.<br /> <br /> Iwaisaki, H., S. Tsuruta , I. Misztal , and J. K. Bertrand. 2005. Genetic parameters estimated with multi-trait and linear spline-random regression models using Gelbvieh early growth data. J. Anim. Sci. 83:499-506.<br /> <br /> Jousan, F.D., Drost, M., and Hansen, P.J. (2005) Factors associated with early and mid-to-late fetal loss in lactating and non-lactating Holstein cattle in a hot climate. J. Anim. Sci., 83, 1017-1022.<br /> <br /> Robbins, K. R., I. Misztal, and J. K. Bertrand. 2005. A practical longitudinal model for evaluating growth in Gelbvieh cattle. J. Anim. Sci. 83:29-33.<br /> <br /> Robbins, K. R., I. Misztal and J. K. Bertrand. 2005. Joint longitudinal modeling of age of dam and age of animal for growth traits in beef cattle. J. Anim Sci. 2005 83:2736-2742.<br /> <br /> Roth, Z., and Hansen, P.J. (2005) Disruption of nuclear maturation and rearrangement of cytoskeletal elements in bovine oocytes exposed to heat shock during maturation. Reproduction, 129, 235-244.<br /> <br /> Tsuruta, S., I. Misztal, and T. J. Lawlor. 2005. Current Day's Prediction of a Changing Trait. Productive Life of US Holsteins. J. Dairy Sci. 88:1156-1165.<br /> <br /> Meeting Abstracts and Experiment Station Reports:<br /> <br /> Carothers, RE, CS Whisnant. 2005. Effects of post-insemination CIDR on embryonic loss associated with heat stress in dairy cattle. J Anim Sci 83: Suppl. 1, p. 169.<br /> <br /> Cuadra, E.J., R.C. Vann, W.A. Bennett, R. Johnson, S.T. Willard and T. Kiser. 2005. Effects of intra-vaginal progesterone releasing devices on the survival of embryos transferred to recipient suckling multiparous beef cows. Southern Section American Society of Animal Science, Little Rock, AR, p. 12 (abstract # 43).<br /> <br /> Denson, A., M. Jones, S. Bowers, A. Dos Santos, K. Graves, K. Moulton and S. Willard. 2005. Effects of supplemental progesterone administration on pregnancy rate and resynchronization in lactating dairy cattle during mild heat stress and non-heat stress conditions. ASAS Annual Meeting, Cincinnati, OH; July, 2005.<br /> <br /> Denson, A., S. Schmidt, S. Bowers, T. Dickerson, K. Graves, R. Vann and S. Willard. 2005. Growth traits and reproductive parameters of Holstein and Gir (Bos indicus) x Holstein bulls and heifers. Southern Section American Society of Animal Science, Little Rock, AR, p. 12 (abstract # 46).<br /> <br /> Frietas, M., I. Mistral, J. Bohmanova, and J. West. 2005. Quantifying the level of heat stress in a southeastern dairy using weather recording on- and off-farm. J. Dairy Sci. 88(Suppl. 1):353.<br /> <br /> Jones, M., A. Denson, E. Williams, A. Dos Santos, K. Graves, A. Kouba and S. Willard. 2005. Assessing pregnancy status using digital infrared thermal imaging in Holstein heifers. ASAS Annual Meeting, Cincinnati, OH; July, 2005.<br /> <br /> Jones, M., A. Denson, S. Bowers, K. Moulton, E. Williams, K. Graves, A. Dos Santos, A. Kouba and S. Willard. 2005. Thermography of the vulva in Holstein dairy cows: A comparison of estrus vs. diestrus. ASAS Annual Meeting, Cincinnati, OH; July, 2005.<br /> <br /> West, J. W. 2005. Feeding and nutrition management for hot weather. Pages 97-106 in Proc. 7th Western Dairy Mgt. Conf.,Reno, NV.<br /> <br /> Whisnant, C.S. 2006. Summary of Heat Stress Related Research at Annual Meeting of North Carolina Dairy Producers, February 23, 2006, Salisbury, NC<br /> <br /> Wildman, C., J. West, and J. Bernard. 2005. A comparison of methods for determining body temperature of Holstein cows during hot weather. J. Dairy Sci. 88(Suppl. 1):43.<br /> <br /> Wildman, C. D., J. W. West, and J. K. Bernard. 2005. Relationship between dietary cation-anion difference and protein metabolism in lactating dairy cows. Univ. of GA, College of Agric. and Environ. Sci., Dept. of Anim. & Dairy Sci. 2004 Annual Report, pp. 200-208.<br /> <br /> Worley, J. W. and J. K. Bernard. 2005. Use of high volume low speed (HVLS) fans for cooling dairy cows in a free stall barn in a hot humid climate. ASAE Paper No. 054112. ASAE, St. Joseph, MI.<br /> <br /> <br />

Impact Statements

1. Standardization of measures of cow responses to heat stress and how to measure core body temperature assessments are critical to study designs and comparisons among locations and regions. By gaining a more resolved quantification of heat stress we may better understand how cow physiological responses effect production performance and how to mitigate such effects.
2. The use of new technologies (e.g., DITI) may provide non-invasive assessments of heat stress within the production environment to assess the efficiency of cooling or the impact of extraneous factors on heat load and/or abatement, however significant influences of the ambient environment on DITI measures may preclude its use under certain conditions.
3. Information gained from these studies will help prevent negative effects of environmental heat stress that can reduce reproduction in agriculturally-important animals as well as human beings. This research will thus result in more efficient livestock production, thereby ensuring an ample and economical food supply, and will additionally provide technologies that can combat fertility problems in humans.
4. Results of these data suggest that low speed fans may not provide adequate air flow to cool cows as effectively as high speed fans. There was a slight increase in CBT observed after the high-pressure mister system cut off when RH exceeded 85% indicating that other management strategies should be considered.
5. Results from this project will enable us to identify cooling practices that improve cow and calf performance and quantify the benefits of these practices.
6. The identification of the specific genes involved in thermotolerance among breeds could lead to novel ways to increase resistance of cattle to heat stress. Moreover, a greater understanding of the production performance characteristics of cross-bred (Bos indicus influenced) dairy cattle is needed under current southern U.S. production-management environments.
7. Understanding factors which may influence the quantification of heat stress (e.g., coat color, breed, cow body size etc.) are critical to data interpretation and establishing not only selection criteria but also animal-specific appropriate counter-measures to mitigate the effects of heat stress in the production environment.
8. Understanding the efficacy of hormonal therapies in dairy cattle is critical to establishing new methods for manipulating reproductive processes to improve fertility in heat stressed dairy cattle.
9. Treatment with bST during heat stress increased IGF-I concentrations and milk production over time and rectal temperature without compromising first- or second-service pregnancy rates.
10. By allowing dairy producers to achieve acceptable pregnancy rates during times of heat stress this treatment has the potential to decrease days open (when cows are not pregnant) by as much as three months. Each day open costs producers $1-2 per cow. Improved pregnancy rates would pay for vitamin and mineral supplementation.
11. There were some indicators that improved efficiency resulted from the use of low heat increment diets. Lower metabolic heat production will improve efficiency with which energy is used by the dairy cow, a particular benefit during hot weather.

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Report Information

Participants

Bernard, John - University of Georgia;
Edwards, Lannett - University of Tennessee;
Godfrey, Robert - University of the Virgin Islands;
Morrison, David - LSU Agricultural Center (Administrative Advisor);
Willard, Scott - Mississippi State University;
Hockett, Mitch - North Carolina State University;
Schrock, G. - University of Tennessee (Ph.D. Student);

Brief Summary of Minutes

The meeting was called to order by the Chair, L. Edwards (TN) at 8:30 am in the Blakely Room of the Riverview Plaza Hotel in Mobile, AL. The agenda was reviewed with participants before presentation of station reports. Thereafter, participants engaged in a general discussion relaying concerns about lack of participation from majority of members to attend annual meetings/submit station reports. Participants from GA, MS, TN, and USVI have served as the core of this group with some participation by individuals from NC and PR to attend annual meeting/submit station reports. While travel conflicts prevented members from PR and KS from attending this year, participation by others has been limited. Dr. Morrison (administrative advisor) informed the S-1023 that Department Heads review multi-state projects and inquire about faculty participation. It was agreed that additional effort was needed to determine non-participating members interest in being members of the S-1023. In addition, J. Bernard (GA) agreed to update listserve to reflect current membership. Ideas regarding how to increase collaborative efforts, increase member participation and overall membership were also discussed. As a continuum of this effort, the possibility of holding next years annual meeting with the W173 (August 2007 in St. Croix) was discussed at length. This option was initially posed by Dr. Hamernik (CSREES representative) via email as the W173 has a dairy heat stress sub-focus group and this group had previously extended an invitation for the S-1023 to meet jointly with them. As only a few members were present at annual meeting, it was decided that Edwards (TN) would query entire S-1023 membership via list serve after conclusion of annual meeting. Assuming that majority of members favored a joint meeting, it was agreed that an informal meeting of the S-1023 should still be scheduled for 2008 (Dallas, TX in association with SAAS meetings). Collaborative efforts of the past year were then highlighted and each project objective was reviewed for determining what has been done versus what was to be planned for the 2007 reporting period. Discussion also focused on collaborative efforts for development of an integrated research/extension grant on prepartum cooling and prepartum indicators of postpartum reproductive/production performance. In addition, development of a group paper or technical report highlighting comparative methods for monitoring body temperature by the techniques used by the participants was also discussed. Thereafter, the business portion of the meeting was initiated and entailed the following: (1) Election of Officers  S. Willard (MS) agreed to serve as incoming Secretary in case S. Whisnant (NC) was not able to accept appointment. Bob Godfrey (UVI) agreed to serve as Chair for the next annual meeting and reporting period. J. Bernard (GA) agreed to serve as Chair-Elect. (2) R. Godfrey (UVI) called for project members to submit shared protocols for posting on website. Protocols for data collection of coat color and measuring cow size have been developed and will be posted on the project web page soon. However, a protocol for reproductive and metabolic hormones still needs to be developed. (3) NRI-funding information previously distributed to S-1023 by Dr. Deb Hamernik via list serve was reviewed in her absence (4) L. Edwards (Chair; TN) requested that annual station reports be submitted to her via e-mail by March 1st so that the annual report and minutes can be compiled and sent to D. Morrison by April 1st in accordance with stated guidelines. No additional business was brought before the group so the meeting was adjourned at approximately 6:00 pm.

Accomplishments

Note that the principal reporting station is indicated in relation to the stated accomplishment and subsequent impact, but may involve more than one investigator from that station. Multi-state collaborative projects are indicated within the Accomplishments under each sub-objective and are further reflected in the List of Publications and Plans for the Coming Year follow the Accomplishments.<br /> <br /> OBJECTIVE 1: DEFINING THE PHYSIOLOGICAL CHARACTERISTICS OF HEAT-STRESSED DAIRY CATTLE<br /> <br /> 1A: Quantifying heat stress in dairy cattle.<br /> <br /> " Accomplishments: Mississippi is coordinating an effort to include S-1023 participants (TN, GA, NC, USVI and others interested) to develop a review paper or compendium on the effectiveness and comparative aspects of body temperature measures as applied to dairy cattle. It is hoped that this work will not only serve as a resource to investigators across the country, but also aid the group in standardizing body temperature measures across experiments to permit greater comparisons of body temperature measures and treatment effects across studies. Correlations of temperature readings among measurement methods (rectal thermometers, tympanic probes, rumen, implanted or intravaginal temperature recording devices and others) with ambient temperature and THI have been conducted among participating stations and are in the process of be consolidated into an outline for preparation of a body temperature measurement manuscript. Impact: Comparing the different body temperature assessments that have been conducted among participants will facilitate a standardized temperature measurement procedure with the greatest resolution for broader comparisons among studies. This will enhance collaborative research through uniform measurements and provide a resource for other investigators regarding body temperature correlates in dairy cattle.<br /> <br /> " Accomplishments: A study was conducted in Mississippi to compare body temperature measures between Holstein and Gir x Holstein cows in relation to environment and stage of the estrous cycle. It has been previously shown that Gir x Holstein (GxH) cows have higher body surface and lower rectal temperatures (RT) than Holstein (HOL) cows under heat-stressed conditions. However the influence of coat color and stage of the estrous cycle on body temperatures (BT) have not been evaluated, therefore our objective was to compare BT responses of HOL vs. GxH cows in relation to these parameters (coat color and estrous cycle) during summer heat stress. Cows were fitted with the HeatWatch estrus detection system, an intravaginal temperature probe inserted, and cows received two injections of PGF2-alpha 11 d apart to synchronize estrus (d -10 and 0). From d -10 to d 46 (56 d), measurement periods were conducted weekly (three times AM and five times PM weekly) and included: ambient temperature, temperature-humidity index, rectal temperature, respiration rate, digital infrared thermography of the eye (maximum eye temperature), and a blood sample (serum) for progesterone (P4) by RIA. Cow body temperature measures were analyzed in relation to environmental measures and stage of the estrous cycle [luteal (LUT) vs. follicular (FOL) phases]. To summarize findings, HOL and GxH cows were similar in body temperature measures during the estrous cycle (LUT and FOL). For environmental measures, HOL cows exhibited higher body temperatures and respiration rates than GxH cows. These data demonstrate breed and time of day, but not stage of the estrous cycle differences, on body temperature measures that are important in assessing the relative impact of ambient environment and heat stress on cow responsiveness. Mississippi is collaborating with Tennessee to assess changes in body temperature in relation to stage of the estrous cycle and post-breeding in dairy cattle. Impact: Through an enhanced understanding of the interactions between physiological changes (e.g., the estrous cycle) and body temperature responses to environmental temperature we can more accurately interpret collected data in relation to economic end-points (e.g., fertility) and management criteria (e.g., use of cooling systems, synchronization protocols, etc.).<br /> <br /> 1B: The effect of various summer cooling strategies on symptoms of heat stress, endocrine status and lactation performance. No accomplishments to report for this Objective within this reporting year.<br /> <br /> 1C: Characterize the impact of prepartum cooling and identifying prepartum metabolic and endocrine markers as indicators of postpartum performance.<br /> <br /> " Accomplishments: A preliminary study was conducted in Mississippi to determine the endocrine parameters related to the prepartum period in Holstein dairy cattle in relation to cooling strategy (Fans vs. Fans and Sprinklers). Samples were collected starting 21 days prior to anticipated calving date through day 60 postpartum. In addition to environmental measures (ambient temperature and relative humidity), body temperature measures (rectal temperatures and coat surface thermal measurements) and postpartum production data (milk production, calf weights, postpartum reproduction etc.) were acquired. Data is being analyzed currently, and will be used as preliminary data for a multi-state effort with Georgia, North Carolina and Tennessee to address prepartum cooling effectiveness on postpartum production performance and rebreeding. Impact: Investigations of prepartum cooling may lead to changes in dry cow management strategies for improved postpartum milk production performance, enhanced reproductive function and general improvements in cow comfort/welfare. Costs of prepartum cooling may be off-set by improved postpartum performance, illustrating the economic benefits of this management change in relation to production end-points. <br /> <br /> 1D: Characterize the effect of genetic selection in heat tolerance.<br /> <br /> " Accomplishment/Impact: Virginia is in the process of collecting data to examine potential benefits of crossbreeding to improve milk yield and reproductive performance of heat-stressed dairy cows. <br /> <br /> 1E: Determining the relationships between coat color and cow body size on production performance in heat-stressed dairy cattle<br /> <br /> " Accomplishments: Mississippi, compared physiological responses between Holstein and Gir x Holstein cows of different coat color characteristics and assessed in relation to environmental parameters. Non-lactating Holstein [n=5 white (WH) and n=6 black (BH)] and GxH [n = 7 dark (DK) and n = 4 light (LT)] were fitted with intravaginal temperature probes to acquire vaginal temperatures at 5 min intervals from July to Sept 2006. During the 56 d measurement period, data was collected weekly (three times AM and five times PM weekly) and included: ambient temperature, temperature-humidity index, rectal temperature, respiration rate and digital infrared thermography of the eye. Cow body temperature was analyzed in relation to environmental measures. Ambient temperature differed AM vs. PM, with THI ranging from 69.8 to 90.6. DK and LT GxH cows did not differ in BT AM or PM. While BH was similar to WH in the AM, they differed from one another in the PM. Body temperature of Holstein cows increased from AM to PM, while GxH cows decreased or increased only slightly depending on the body temperature measure. Holstein cows had a greater increase in respiration rate from AM to PM than GxH cows. In summary, non-lactating HOL and GxH cows were similar in body temperature measures in the AM environment. However for PM measures, Holstein cows exhibited higher body temperatures and respiration rates which were further influenced by coat color. Mississippi has continued their collaboration with Virgin Islands to examine the extent to which coat color in dairy cattle correlates with body temperature and physiological responses. Also during this reporting period, Virgin Islands received images from Puerto Rico; analysis will be performed after technician is hired. Impact: Understanding the influence of secondary characteristics such as coat color and cow body size on production performance under heat stressed conditions assists in establishing selection criteria for dairy cows for specific environments to maximize the balance between production and economic efficiency.<br /> <br /> OBJECTIVE 2: IMPROVING FERTILITY OF HEAT-STRESSED DAIRY COWS WITHOUT DECREASING MILK PRODUCTION<br /> <br /> 2A: Use of supplemental hormone administration pre- and post-breeding to improve fertility of heat-stressed dairy cattle<br /> <br /> " Accomplishments: Previous efforts have shown that the size of the ovulatory follicle may be reduced in heat-stressed cows and that the oocyte contained within that follicle may mature faster than in cows not experiencing heat-stressed. A research project at Tennessee was initiated in October 2006 to test the efficacy of various strategies to enhance size of ovulatory follicle and to alter timing of ovulation. Impact: Information gained from these studies is an important first step towards the development of management strategies for minimizing the negative effects of environmental heat stress to reduce reproduction in dairy cows and in other agriculturally-important animals. Doing so would allow for more efficient livestock production, thereby ensuring an ample and economical food supply.<br /> <br /> 2B: Establishing hormone markers pre-breeding as predictors of reproductive success in heat-stressed and non-heat-stressed dairy cows<br /> <br /> " Accomplishment: North Carolina, using low doses of follicle stimulating hormone (FSH), attempted to improve follicle development and oocyte competence in heat stressed cows. In the experiment lactating dairy cows were synchronized using the Ovsynch protocol and then assigned to either FSH (N=23) or control (N=22) groups. The Ovsynch protocol consists of an injection of gonadotropin releasing hormone (GnRH) followed seven days later by an injection of prostaglandin F2 alpha (PGF) and then 48 hours after PGF another injection of GnRH. This protocol has been shown to reliably induce a synchronized ovulation in lactating dairy cows. FSH-treated cows received injections of 30 mg FSH twice daily on days 3-6 after ovulation in response to the Ovsynch protocol and in the AM of day 7 after Ovsynch induced ovulation for a total of 210 mg FSH. Luteolysis was induced with 25 mg of PGF at 40 hours after the final FSH injection. Cows were inseminated 12 hours after estrus detection or if not detected in estrus at 72 hours after PGF and simultaneously treated with 100 ug GnRH. Ultrasonography was used at day eight after insemination to determine the number of corpora lutea (CL) and again 30 days after insemination to determine if cows were pregnant and if so the number of embryos in each. Multiple ovulations were more common in FSH treated cows. The average number of CL were greater in FSH treated cows (2.21 ± 0.3 FSH vs. 1.09 ± 0.1 controls). One FSH treated cow had five CL. No control cows had more than two CL. However the number of embryos was not affected by FSH treatment. Average number of embryos per cow for those that became pregnant was 1.0 ± 0.1 for controls vs. 1.3 ± 0.2 for FSH treated. No cows had more than two embryos. Pregnancy rates were not different between groups (26.1% FSH vs. 18.2% controls) due to low numbers per treatment. It was encouraging that the FSH treatment did not induce more multiple births or any greater than twins. FSH treatment had no effect on milk production. Repetition of the experiment this year will enable us to determine if pregnancy rates will be different for the treatment groups. Israeli researchers had reported that FSH could improve follicular quality and oocyte competence in heat stressed dairy cows (Roth et al., 2002) but further research is needed. Impact: Making summer breeding possible and reducing days open through hormonal manipulation would improve dairy producer profitability.<br /> <br /> 2C: Use of interval cooling (i.e., immediately before and after breeding) to improve fertility of problem breeders and heat-stressed dairy cows No accomplishment to report for this Objective within this reporting year. <br /> <br /> 2D. Use of targeted vitamin and mineral supplementation in conjunction with estrous synchronization and timed-AI to improve fertility in heat-stressed dairy cows No accomplishment to report for this Objective within this reporting year.<br /> <br /> OBJECTIVE 3. IMPROVING MILK PRODUCTION OF HEAT-STRESSED DAIRY COWS WITHOUT DECREASING FERTILITY<br /> <br /> 3A: The effect of heat stress on nutritional requirements of high-producing dairy cows<br /> <br /> " Accomplishment: Heat increment (HI) is the rise in digestive and metabolic heat production following a meal, and greater heat production is a liability during hot weather. More digestible feeds generally have a higher TDN and NEL and lower HI. This inverse relationship is generally applicable to all feeds. A more digestible feed or ration will require less energy to metabolize thereby reducing the HI value The high heat increment diet was formulated using cottonseed hulls, cottonseed meal, and higher forage content; low heat increment was formulated by using less total forage, more whole cottonseed, no cottonseed meal or hulls, and a rumen inert fat (Georgia). Thirty-two lactating Holstein cows averaging 169 ±35 days-in-milk were used to determine changes in energy use due to ration heat increment (HI) and resulting changes in production. Mean maximum and minimum temperature, relative humidity, and temperature-humidity index (THI) during the treatment period were 31.2 and 22.7oC; 99 and 61%; and 82.2 and 72.8, respectively. Dietary treatments were high HI offered ad libitum (HA), low HI offered ad libitum (LA), and low HI offered at restricted caloric intake (LR). The LR cows were paired individually with HA cows to achieve similar NEL intake (Mcal/100 kg BW). The HA diet was formulated with a greater proportion of forage and fibrous byproducts whereas the low HI diets were formulated using less forage, no fibrous byproducts, and increased proportions of grain and fat. For DMI, HA (24.6 kg) was greater than both LA (22.8 kg) and LR (20.5 kg). Milk yield/100 kg body weight (1.4, 1.5, 1.6 kg/kg) and energy-corrected milk yield/100 kg body weight (1.3, 1.4, 1.5 kg/kg) for HA, LA, and LR, respectively, were different for HA versus LR. Contrasts were not different for body weight or tissue change. Milk yield and concentration of fat, protein, and total solids were similar across dietary treatments. Treatment group LR demonstrated greater net energy efficiency, measured as intake energy/ milk yield (Mcal/kg). Net energy balance was not different for treatments. The data suggest that treatment group LR converted feed energy into milk energy more efficiently than treatments HA and LA, suggesting that heat stress was reduced and feed efficiency improved with the low HI, restricted diet. Impact: Feed efficiency for the dairy industry is often measured as the increase in milk yield observed because of an increase in feed consumed, but this ratio does not consider the percentage of the feed energy that is converted to milk energy. Feeds with lower HI that are more digestible have the potential for more efficient conversion to milk energy and could reduce metabolic heat production. Even though high HI treatment cows consumed more feed than their low heat increment counterparts, both groups consumed a similar amount of energy and produced similar quantities of milk (average of 34.5 kg/day). There was a minor trend for improved efficiency of energy use for cows fed the low heat increment diet. In addition, the low heat increment cattle had an improved energy balance over the high heat increment fed cattle. Additional research is needed to determine if feeding lower heat increment, or cooler diets will lead to improved production due to lower heat stress, and greater efficiency of production. However, results suggest that there is potential to feed diets formulated for reduced metabolic heat production in dairy cattle during hot weather, which may help to alleviate heat stress and contribute to improved efficiency of production and greater economic returns. The data suggest that cows offered the LR treatment converted feed energy into milk energy more efficiently than cows receiving the HA or LA treatments, suggesting that heat stress was reduced and feed efficiency improved with the low HI, restricted diet.<br /> <br /> 3B: The effects of high protein diets on production performance and summer breeding in dairy cows. This sub-objective is not being investigated currently, but may be addressed in future years of this project by collaborating stations or as coupled with other sub-objectives.<br /> <br /> 3C. The effect of dietary supplements (antioxidants, minerals and probiotics) to enhance nutrient intake and digestibility<br /> <br /> " Accomplishment: A trial was performed in Puerto Rico where eight lactating Holstein cows in early lactation were assigned to one of four dietary treatments in a 4x4 latin square design. Experiment was replicated twice. Diets were be based on corn silage and perennial peanut hay with or without the application of exogenous enzymes Promote (Cellulase and Xylanase, Biovance Technology Inc, Omaha NE) Biocellulase A (Cellulase; Loders Croklaan, Channahon IL) or Combo (Lipase, amylase and cellulose; American Biosystems, Roanoke VA) and applied at the manufacturers recommended rate. Cows were be housed in an open-sided barn fitted with free stalls and feed gates (Calan Gates) to determine individual feed consumption. Each treatment period consisted of 10 days of adjustment to the treatments and 4 days for data collection. Experimental cows were be assigned to treatments according to date of calving and were be trained to open their feed gates two weeks before parturition. Prior to calving, animals received a standard diet. Diets were formulated to contain at least 18% crude protein and followed NRC (2001) recommendations. Chromic oxide was used as an internal marker to determine digestibility. Feed was offered after the morning and afternoon milking; the amount fed was adjusted daily based on 10% orts. Feed was weighed individually for each cow prior to feeding, and orts removed and weighed prior to the morning feeding. Milk production was recorded individually at each milking by the use of DHI approved methods. Milk samples were collected during four consecutive milkings during the data collection period. Milk samples were analyzed for fat and protein content, and somatic cell count by the PR DHIA milk laboratory. Cows were weighed three times per week. Feed samples were collected twice weekly to monitor DM and diet composition. A sample of grass and concentrate was be collected daily during the data collection period and composite for each period to determine CP, ADF, NDF, NEL and mineral content. During the last week of each experimental period an intra-vaginal device fitted with a HOBO thermometer was inserted in each cow to determine vaginal temperature every five minutes. Relative humidity and air temperature were determined also every five minutes. The trial was completed at the end of august 2006. Preliminary data show relatively low dry matter intakes with no differences among treatments (14.69, 15.18, 15.28 and 14.84 kg/day for the control, Biocellulase A, Promote and Combo respectively). Milk production (14.94, 15.76, 15.04, 15.84 kg/day for the control, Biocellulase A, Promote and Combo, respectively) was not affected by treatments. The information on milk composition, diet digestibility and relationships between ambient temperature and animal temperature are still under analysis.<br /> <br /> " Accomplishment: Tifton 85 bermudagrass is the latest cultivar released by Dr. Glen Burton. It is more digestible and produces greater yields than other bermudagrass cultivars. Previous research has shown a decline in intake and milk yield as the proportion of Tifton 85 in the diet increased compared with comparable diets containing alfalfa hay; however, milk fat percentage, dairy efficiency, and income over feed cost improved. Tifton 85 is more economical to produce locally compared with purchasing alfalfa hay, so its use in dairy rations could potentially reduce production costs. Tifton 85 also reduces soil erosion compared to planting annuals and can effectively use nutrients from dairy waste in support of growth. Commercial enzyme products currently available could potentially improve fiber digestibility supporting improved DMI and nutrient supply in support of improved milk yield and reduce the amount of waste. Limited data are available on the use of Tifton 85 bermudagrass in diets for lactating dairy cows or the potential return for use of enzymes. To determine if a cellulase enzyme applied to the TMR would improve milk production of lactating cows fed diets containing different forages, forty-four Holstein cows were used in an 8 wk randomized block design trial with 2 x 2 factorial arrangement of treatments in Georgia. Cows were trained to eat behind Calan doors before beginning the trial. Experimental treatments included diets formulated to provide equal concentrations of NDF, CP, and energy using either Tifton 85 bermudagrass haylage or alfalfa hay at 12% of the ration DM with 0 or 4 g/d of a commercial cellulase enzyme. Total intake and milk yield were measured daily and composition of milk was determined weekly. Impact: Cows fed the indicate that Tifton 85 can be effectively used in rations for high producing dairy cows. Since Tifton 85 is more economical to produce, this could reduce feed cost compared to purchasing alfalfa hay. No gains in intake or producer were observed with using the cellulase enzyme. The trial did not examine the ration of application or other factors that could influence enzyme activity.<br /> <br /> PLANS FOR THE COMING YEAR  ESTABLISHED COLLABORATIONS AND ON-GOING PROJECTS<br /> <br /> " Coat color studies and determination of percentages of black vs. white hair coat. (OBJ 1E; PR, MS, TN and others?; USVI Lead)<br /> " Enzyme enhancements in diets while grazing southern forages.<br /> (OBJ 3C; PR, GA, Others?, GA - Lead) <br /> " Body temperature and estrous cycle - data mining and/or implementation of a summer study (OBJ 1A - MS, TN; TN- Lead)<br /> " Body temperature correlates among different measurement techniques, and the proposed coordination of S-1023 to compose a review article (i.e., for Southern Cooperative Series Bulletin; OBJ 1A - All stations - MS  Lead)<br /> " Prepartum Cooling - metabolic/postpartum/cooling methods will be investigated along with nutrition x reproduction interactions related to prepartum cooling (OBJ 1C - GA, TN, NC, MS - Lead). Mitch Hockett from NC attended meeting and will join as a member to collaborate on this objective. Mississippi agreed to take lead effort to organize/develop a research proposal to be submitted as an integrated research and extension project to NRI-CGP. <br />

Publications

Refereed Journals and Peer-Reviewed Proceedings:<br /> <br /> Bowers, S., S. Gandy, K. Graves, A. Moore and S. Willard. 2006. Relationships between measurements of vaginal electrical impedance, uterine involution and hormonal profiles in postpartum dairy cows. J. Anim. Vet. Advances 5(7): 552-558.<br /> <br /> Deng, X., B. J. Barnett, D. V. Vedenov, and J. W. West. 2007. Hedging dairy production losses using weather-based index insurance. Ag. Econ. 36:271-280. <br /> <br /> Chandler, J.E., T.M. Taylor, A.L. Canal, R.K. Cooper, E.B. Moser, M. E. McCormick, S.T. Willard, H.E. Rycroft and G.R. Gilbert. 2006. Calving sex ratio as related to the predicted Y-chromosome-bearing spermatozoa ratio in bull ejaculates. Theriogenology, doi:10.1016/j.theriogenology. 2006.09.006 (on-line).<br /> <br /> Smith, T.R., A. Chapa, S. Willard, C. Herndon, R. J. Williams, J. Crouch, T. Riley and D. Pogue. 2006. Evaporative tunnel cooling for dairy cows in the Southeastern United States. I: Cooling characteristics and their effect on body temperature and respiration rate. J. Dairy Sci. 89: 3915  3923.<br /> <br /> Smith, T.R., A. Chapa, S. Willard, C. Herndon, R. J. Williams, J. Crouch, T. Riley and D. Pogue. 2006. Evaporative tunnel cooling for dairy cows in the Southeastern United States. II: Impact on lactation performance. J. Dairy Sci. 89: 3904-3914.<br /> <br /> Schmidt, S.J., S.D. Bowers, T. Dickerson, B.S. Gandy, F. Holholm, K.B. Graves, J. White, R.C. Vann and S.T. Willard. 2006. Gestational, periparturient and preweaning growth traits of Holstein versus Gir x Holstein F1 crossbred dairy calves born to Holstein dams. Tropical Animal Health and Production 38: 249-260.<br /> <br /> Wildman, C. D., J. W. West, and J. K. Bernard. 2007. Effects of dietary cation-anion difference and potassium to sodium ratio on lactating dairy cows in hot weather. J. Dairy Sci. 90:970-977.<br /> <br /> <br /> Popular Press Articles/Meeting Abstracts/Experiment Station Reports/Others:<br /> <br /> Freitas, M. S., I. Misztal, J. Bohmanova, and J. West. 2006. Utility of on- and off-farm weather records for studies in genetics of heat tolerance. Livestock Sci. 105:223-228.<br /> <br /> Pacetti, L. M., J. W. West, and J. K. Bernard. 2006. Using dietary heat increment to alter energy use in dairy cows during hot weather. J. Dairy Sci. 89(Suppl. 1):129. (Abstr.)<br /> <br /> Payton, R.R., L.A. West-Rispoli, and J.L. Edwards. 2006. Analysis of RNA profiles in bovine oocytes versus cumulus and granulosa cells. Biol. Reprod. Special Issue p 152. <br /> <br /> Schrock G.E., J.L. Lawrence, R.R. Payton, F.N. Schrick, and J.L. Edwards. 2006. Development of heat-stressed bovine oocytes after chemical activation versus fertilization. Biol. Reprod. Special Issue p 134.<br /> <br /> West, J. W., 2006. Relationship of heat stress and acidosis in dairy cattle. In Proc. 1st Seminario Actualizacion en Ganado Lechero. Phibro Animal Health. May 17-18, Torreon, Mexico. <br /> <br /> West, J. W. 2006. Important considerations when preparing for heat stress. Dairyfax. April/May.<br /> <br /> West, J. W. 2006. Battle the summer acidosis syndrome. Hoards Dairyman. June, p. 409.<br /> <br /> West-Rispoli, L.A., C.R. Rozanas, T.A. Stoming, J.L. Edwards. 2006. Proteomic analysis of bovine oocytes during maturation using 2-D fluorescence difference gel electrophoresis (DIGE). Biol. Reprod. Special Issue p 152.<br /> <br /> White, M.B., M. Jones, S. Schmidt, A. Chromiak and S. T. Willard. 2006. The use of digital infrared thermography for monitoring environmental physiology in dairy cattle. J. Anim. Sci. 84 (Suppl. 1): 212 (Abstr. # T164)  ASAS Nationals, Minneapolis, MN.<br /> <br /> Willard, S. 2006. Invited Talk: Indicators of heat stress and environmental monitoring of animal responses. American Society of Animal Science  Southern Section Meeting, February, 2006.<br /> <br /> Worley, J. W., and J. K. Bernard. 2006. Comparison of high volume low speed (HVLS) vs. conventional fans in a free stall dairy barn in a hot humid climate. ASABE Paper No. 064033. ASABE, St. Joseph, MI..<br /> <br /> Worley, J. W. and J. K. Bernard. 2006. Are HVLS fans right for your farm? Hoards Dairyman Vol. 151, No. 10, pg 370.<br />

Impact Statements

1. Comparing the different body temperature assessments that have been conducted among participants will facilitate a standardized temperature measurement procedure with the greatest resolution for broader comparisons among studies. This will enhance collaborative research through uniform measurements and provide a resource for other investigators regarding body temperature correlates in dairy cattle.
2. Through an enhanced understanding of the interactions between physiological changes (e.g., the estrous cycle) and body temperature responses to environmental temperature we can more accurately interpret collected data in relation to economic end-points (e.g., fertility) and management criteria (e.g., use of cooling systems, synchronization protocols, etc.).
3. Investigations of prepartum cooling may lead to changes in dry cow management strategies for improved postpartum milk production performance, enhanced reproductive function and general improvements in cow comfort/welfare. Costs of prepartum cooling may be off-set by improved postpartum performance, illustrating the economic benefits of this management change in relation to production end-points.
4. Understanding the influence of secondary characteristics such as coat color and cow body size on production performance under heat stressed conditions assists in establishing selection criteria for dairy cows for specific environments to maximize the balance between production and economic efficiency.
5. Information gained from these studies is an important first step towards the development of management strategies for minimizing the negative effects of environmental heat stress to reduce reproduction in dairy cows and in other agriculturally-important animals. Doing so would allow for more efficient livestock production, thereby ensuring an ample and economical food supply.
6. Making summer breeding possible and reducing days open through hormonal manipulation would improve dairy producer profitability.
7. Results suggest that there is potential to feed diets formulated for reduced metabolic heat production in dairy cattle during hot weather, which may help to alleviate heat stress and contribute to improved efficiency of production and greater economic returns.

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Report Information

Participants

2007 Officers:
D. Morrison LA S-1023 Administrative Advisor
D. Hamernik USDA-CSREES USDA-CSREES Representative
R. Godfrey VI Chair
J. Bernard GA Chair-Elect
S. Whisnant NC Secretary

Participating Members:
W. Kellogg AK D. Morrison LA
L. Edwards UT S. Willard MS
R. Godfrey VI J. Smith KS
J. Pantoja PR

Non-Member Participants:
C. Ketring VI I. Misztal GA
J. Arthington FL S. Coleman, ARS-STARS
D. Spiers MO C.N. Lee HI
H. Xin, IA P. Hillman NY
A. Parkhurst NE R. Collier AZ
T. Friend TX T. Mader NE
K. Gebremedhin NY D. Lay ARS-IN
C. Kaltenbach AZ H. Kattesh TN
C. Chase ARS-STARS J. Carroll ARS-LIRU
T. Engle CO

Brief Summary of Minutes

Bob Godfrey (Chair and host of the meeting) called the joint meeting of the W-1173 and S-1023 projects to order at 8:30 a.m. Attendance was taken and self introductions were made. Both groups met together to share information. Don Lay - Chair of the W-1173 group, made some general introductory comments about the format of the meeting. There were two presentations discussing an overview of each group followed by poster presentations. Bob Godfrey, in place of Scott Willard, presented a summary/overview of the S-1023 project describing what activities were taking place and which participants were working in each area. Don Lay gave an overview of Stress physiology past and present. After both presentations there was a general discussion that generated extensive discussion among the group regarding difference in terminology and general measurements of stress. What is/are the best measurements of stress? This was followed by general group discussion regarding-best/appropriate measurements of animal stress. The group discussed the possibility of conducting a review of all food animal stress (heat stress primarily) experiments and evaluate the data to see what is missing in the literature. Further discussion included developing a publication through the Journal of Animal Science regarding the minimum measurements that should be taken when trying to study and publish stress in animals based on the outcome of the above mentioned review paper. Several researchers were interested in potentially leading this effort. Further discussion followed indicating that this seems like a good idea but caution needs to be used when trying to dictate what measurements are best to measure stress because of the array of different types of stress and the difficulty in defining stress. Concern was also expressed regarding the potential impact on producers having to implement the recommendations from the standardized research guidelines and outputs to production operations.

General comments that resulted: 1) Needs to be biologically significant, 2) Measure production output, 3) Genetic/environment interaction, 4) Types of stress, 5) Develop a stress index (overall change rather than absolute values), 6) Combination of physiology and behavior, 7) Standard methods. There were also suggested guidelines to standardize stress research in production animals: 1) Minimal measures/standards of stress in animals in order to publish data related to stress, 2) Combination between physiological and behavioral measurements, 3) Sample size. A discussion followed regarding the Journal of Animal Science and different types of communications that the Journal was considering.

Two 1-hour poster sessions were held in the afternoon. The first hour session, ½ of the attendees stood by their poster and answered questions, and then the second group stood by their posters and answered questions during the second hour. The poster session was well received.
Afterwards, collaborations among participants were discussed.

Business Meeting:

1) The station reports were discussed and it was decided that they should be sent to Bob Godfrey by September 15 to be summarized for the annual report.
2) The issue of the joint meeting was discussed and it was decided that it was a good idea to meet together, but the entire S-1023 group would be polled to see if there is a consensus.
3) It was also discussed as to whether S-1023 should merge into W-1173 in the future instead of trying to stand alone with a specific dairy heat stress focus. The dwindling number of active participants in S-1023 is an indicator that this may be a worthwhile move.
4) The poster session met with good reviews. All members present liked the extra time for discussion and the ability to focus on specific studies of interest to them.
5) The topic of research protocols and their placement on the web page was brought up. Bob Godfrey has been keeping the web page and will make an effort to get it up to date (new project number, protocols, members list, etc.).
6) John Smith (KS) was nominated and accepted as secretary.
7) Because of the short time between meetings it was decided that we would not meet as we usually do in conjunction with the Southern Section Animal Science Meetings, but instead will meet jointly with W-1173 again, pending a poll of all S-1023 members. That meeting will be in Colorado in August 2008.
8) After the business meeting the group met jointly with the W-1173 group to have a final discussion followed by adjournment.

Accomplishments

Accomplishments and Impacts:<br /> <br /> Note that the principal reporting station is indicated in relation to the stated accomplishment and subsequent impact, but may involve more than one investigator from that station. Multi-state collaborative projects are indicated within the Accomplishments under each sub-objective and are further reflected in the List of Publications and Plans for the Coming Year follow the Accomplishments and Impacts.<br /> <br /> OBJECTIVE 1: DEFINING THE PHYSIOLOGICAL CHARACTERISTICS OF HEAT-STRESSED DAIRY CATTLE<br /> <br /> 1A: Quantifying heat stress in dairy cattle.<br /> " Accomplishments: Mississippi is coordinating an effort by S-1023 participants to develop a review paper or compendium on the effectiveness and comparative aspects of body temperature measures as applied to dairy cattle. It is hoped that this work will not only serve as a resource to investigators across the country, but also aid the group in standardizing body temperature measures across experiments to permit greater comparisons of body temperature measures and treatment effects across studies. Correlations of temperature readings among measurement methods (rectal thermometers, tympanic probes, rumen, implanted or intravaginal temperature recording devices and others) with ambient temperature and THI have been conducted among participating stations and are in the process of be consolidated into an outline for preparation of a body temperature measurement manuscript.<br /> <br /> In Mississippi a study was conducted to compare body temperature measures between Holstein and Gir x Holstein cows in relation to environment and stage of the estrous cycle. We have previously shown that Gir x Holstein (GxH) cows have higher body surface and lower rectal temperatures (RT) than Holstein (HOL) cows under heat-stressed conditions. However the influence of coat color and stage of the estrous cycle on body temperatures (BT) have not been evaluated, therefore our objective was to compare BT responses of HOL vs. GxH cows in relation to these parameters (coat color and estrous cycle) during summer heat stress. Cows were fitted with the HeatWatch estrus detection system, an intravaginal temperature probe inserted, and cows received two injections of PGF2-a 11 d apart to synchronize estrus (d -10 and 0). From d -10 to d 46 (56 d), measurement periods were conducted weekly (three times AM and five times PM weekly) and included: ambient temperature, temperature-humidity index, rectal temperature, respiration rate, digital infrared thermography of the eye (maximum eye temperature), and a blood sample (serum) for progesterone (P4) by RIA. Cow body temperature measures were analyzed in relation to environmental measures and stage of the estrous cycle [luteal (LUT) vs. follicular (FOL) phases]. To summarize our findings, HOL and GxH cows were similar in body temperature measures during the estrous cycle (LUT and FOL). For environmental measures, HOL cows exhibited higher body temperatures and respiration rates than GxH cows. These data demonstrate breed and time of day, but not stage of the estrous cycle differences, on body temperature measures that are important in assessing the relative impact of ambient environment and heat stress on cow responsiveness. <br /> <br /> 1B: The effect of various summer cooling strategies on symptoms of heat stress, endocrine status and lactation performance. <br /> " No accomplishments to report for this Objective within this reporting period.<br /> <br /> 1C: Characterize the impact of prepartum cooling and identifying prepartum metabolic and endocrine markers as indicators of postpartum performance.<br /> " Accomplishments: In Mississippi a preliminary study was conducted to determine the endocrine parameters related to the prepartum period in Holstein dairy cattle in relation to cooling strategy (Fans vs. Fans and Sprinklers). Samples were collected starting 21 days prior to anticipated calving date through day 60 postpartum. In addition to environmental measures (ambient temperature and relative humidity), body temperature measures (rectal temperatures and coat surface thermal measurements) and postpartum production data (milk production, calf weights, postpartum reproduction etc.) were acquired. Data is being analyzed currently, and will be used as preliminary data for a multi-state effort addressing prepartum cooling effectiveness on postpartum production performance and rebreeding.<br /> <br /> 1D: Characterize the effect of genetic selection in heat tolerance.<br /> <br /> " Accomplishment/Impact: Virginia is in the process of collecting data to examine potential benefits of crossbreeding to improve milk yield and reproductive performance of heat-stressed dairy cows. <br /> <br /> 1E: Determining the relationships between coat color and cow body size on production performance in heat-stressed dairy cattle<br /> " Accomplishments: In Mississippi a comparison of physiological responses between Holstein and Gir x Holstein cows of different coat color characteristics were assessed in relation to environmental parameters. Non-lactating Holstein [n=5 white (WH) and n=6 black (BH)] and GxH [n = 7 dark (DK) and n = 4 light (LT)] were fitted with intravaginal temperature probes to acquire vaginal temperatures at 5 min intervals from July to Sept 2006. During the 56 d measurement period, data was collected weekly (three times AM and five times PM weekly) and included: ambient temperature, temperature-humidity index, rectal temperature, respiration rate and digital infrared thermography of the eye. Cow body temperature was analyzed in relation to environmental measures. Ambient temperature differed AM vs. PM, with THI ranging from 69.8 to 90.6. DK and LT GxH cows did not differ in BT AM or PM. While BH was similar to WH in the AM, they differed from one another in the PM. Body temperature of Holstein cows increased from AM to PM, while GxH cows decreased or increased only slightly depending on the body temperature measure. Holstein cows had a greater increase in respiration rate from AM to PM than GxH cows. In summary, non-lactating HOL and GxH cows were similar in body temperature measures in the AM environment. However for PM measures, Holstein cows exhibited higher body temperatures and respiration rates which were further influenced by coat color.<br /> <br /> OBJECTIVE 2: IMPROVING FERTILITY OF HEAT-STRESSED DAIRY COWS WITHOUT DECREASING MILK PRODUCTION<br /> <br /> 2A: Use of supplemental hormone administration pre- and post-breeding to improve fertility of heat-stressed dairy cattle<br /> " Accomplishments: Previous efforts have shown that the size of the ovulatory follicle may be reduced in heat-stressed cows and that the oocyte contained within that follicle may mature faster than in cows not experiencing heat-stressed. With this in mind, efficacy of various strategies to increase ovulatory follicle size and reduce time to ovulation has become a focus in our laboratory. In Tennessee lactating Holsteins (65-115 DIM) received an EAZI-BREED CIDR and administered 100 ¼g of GnRH. Seven days later, CIDRs were removed, 500 ¼g of cloprostenol was administered. Cows were then randomly allocated to receive either 80 mg FSH (Folltropin-V) or sterile saline (SAL). Forty-eight hours later, cows within the FSH and SAL groups were then subdivided to receive 100 ¼g Cysterolin or 3000 IU Chorulon. Growth of the ovulatory follicle and ovulation was assessed using ultrasound. Although data analysis is ongoing, initial assessments have shown that the size of the ovulatory follicle at GnRH or hCG administration did not differ for FSH or SAL cows (16.7 ± 0.7 v. 17.5 ± 0.6 mm); nor did the total growth of the ovulatory follicle from CIDR removal to ovulation differ. As calculated from time of CIDR removal, ovulation occurred earlier in FSH (63.6 ± 4.5 h) versus SAL-treated cows (77.2 ± 4.4 h; P < 0.05). Combination of FSH\GnRH produced the earliest ovulation. Regardless of FSH or SAL treatment, cows treated with GnRH ovulated earlier than hCG (75.5 ± 0.7 v. 78.3 ± 0.6 h; respectively, P < 0.05).<br /> <br /> " Accomplishments: In North Carolina low doses of follicle stimulating hormone (FSH) were used to try and improve follicle development and oocyte competence in heat stressed cows. Lactating dairy cows were synchronized using the Ovsynch protocol and then assigned to either FSH (N=40) or control (N=38) groups. The Ovsynch protocol consists of an injection of gonadotropin releasing hormone (GnRH) followed seven days later by an injection of prostaglandin F2 alpha (PGF) and then 48 hours after PGF another injection of GnRH. FSH-treated cows received injections of 30 mg FSH twice daily on days 3-6 after ovulation in response to the Ovsynch protocol and in the AM of day 7 after Ovsynch induced ovulation for a total of 210 mg FSH. Luteolysis was induced with 25 mg of PGF at 40 hours after the final FSH injection. Cows were inseminated 12 hours after estrus detection or if not detected in estrus at 72 hours after PGF and simultaneously treated with 100 ug GnRH. Ultrasonography was used at day eight after insemination to determine the number of corpora lutea (CL) and again 30 days after insemination to determine if cows were pregnant and if so the number of embryos in each. The average number of CL were greater in FSH treated cows (2.31 ± 0.3 FSH vs. 1.09 ± 0.1 controls). One FSH treated cow had five CL. No control cows had more than two CL. The number of embryos was not affected by FSH treatment. Average number of embryos per cow for those that became pregnant was 1.0 ± 0.1 for controls vs. 1.3 ± 0.2 for FSH treated. No cows had more than two embryos. Pregnancy rates were not different between groups (26.1% FSH vs. 18.2% controls) due to low numbers per treatment. It was encouraging that the FSH treatment did not induce more multiple births or any greater than twins. FSH treatment had no effect on milk production. Repetition of the experiment this year will enable us to determine if pregnancy rates will be different for the treatment groups. <br /> <br /> 2B: Establishing hormone markers pre-breeding as predictors of reproductive success in heat-stressed and non-heat-stressed dairy cows<br /> " No accomplishments to report for this Objective within this reporting period.<br /> <br /> 2C: Use of interval cooling (i.e., immediately before and after breeding) to improve fertility of problem breeders and heat-stressed dairy cows <br /> " No accomplishment to report for this Objective within this reporting year. <br /> <br /> 2D. Use of targeted vitamin and mineral supplementation in conjunction with estrous synchronization and timed-AI to improve fertility in heat-stressed dairy cows <br /> " Accomplishment: A field trial was initiated at Rose Ark Dairy Farm [elevation 802 ft (244 m), location N 35o 21.6 and W 92o 07.7] near Rosebud, Arkansas on July 1, 2005 to evaluate the effects of feeding Tasco Ascophyllum nodosum to high producing dairy cows under heat stress. Cow fed Tasco had improved respirations per minute on August 3rd (77.3 compared to 88.5 for control cows; P < 0.05), on August 10th (80.0 compared to 91.4 for control cows; P < 0.01), on August 31st (66.6 compared to 71.5 for control cows; P < 0.05), and on September 7th (60.6 compared to 68.1 for control cows; P < 0.01). These cows were bred, but the number of pregnancies from the larger breeds was very low (3 of 50) for control cows. That is probably typical of Holstein cows in the region, and many herd managers in the region do not even try to breed cows during hot weather because of low breeding efficiency. With Tasco in the diet, the pregnancy rate was enhanced (P < 0.01) dramatically (20 of 55). While that is not an exceptionally high percentage, it is quite high for summer months in central Arkansas. The number of inseminations per conception and the days open before first service did not vary (P > 0.05) among treatment groups.<br /> <br /> OBJECTIVE 3. IMPROVING MILK PRODUCTION OF HEAT-STRESSED DAIRY COWS WITHOUT DECREASING FERTILITY<br /> <br /> 3A: The effect of heat stress on nutritional requirements of high-producing dairy cows<br /> " No accomplishments to report for this Objective within this reporting period.<br /> <br /> 3B: The effects of high protein diets on production performance and summer breeding in dairy cows. <br /> " This sub-objective is not being investigated currently, but may be addressed in future years of this project by collaborating stations or as coupled with other sub-objectives.<br /> <br /> 3C. The effect of dietary supplements (antioxidants, minerals and probiotics) to enhance nutrient intake and digestibility<br /> " Accomplishment: Cows fed Tasco produced more (P < 0.01) milk during July, August, and September (Table 2). However, there was a significant interaction with size of cows during August (P < 0.01) and September (P < 0.05) caused by approximately a 2.3 kg difference for the larger cow groups compared to similar yield for smaller cows, and that should be considered in making recommendations. In other words, Tasco prevented the steep decline in milk yield of the larger cows. The results in central Arkansas indicate that Tasco is beneficial to milking cows during heat stress.<br /> <br /> PLANS FOR THE COMING YEAR  ESTABLISHED COLLABORATIONS AND ON-GOING PROJECTS<br /> <br /> " Coat color studies and determination of percentages of black vs. white hair coat.<br /> (OBJ 1E; PR, MS, TN and others?; VI-STX Lead)<br /> " Enzyme enhancements in diets while grazing southern forages.<br /> (OBJ 3C; PR, GA, Others?, GA - Lead) <br /> " Body temperature and estrous cycle - data mining and/or implementation of a summer study<br /> (OBJ 1A - MS, TN; TN- Lead)<br /> " Body temperature correlates among different measurement techniques, and the proposed coordination of S-1023 to compose a review article (i.e., for Southern Cooperative Series Bulletin; OBJ 1A - All stations - MS  Lead)<br /> " Prepartum Cooling - metabolic/postpartum/cooling methods will be investigated along with nutrition x reproduction interactions related to prepartum cooling (OBJ 1C - GA, TN, NC, MS - Lead). <br /> " Mississippi agreed to take lead effort to organize/develop a research proposal to be submitted as an integrated research and extension project to NRI-CGP. <br /> <br />

Publications

Refereed Journals and Peer-Reviewed Proceedings:<br /> 1) Schrock G.E., A.M. Saxton, F.N. Schrick, and J.L. Edwards. 2007. Early in vitro fertilization improves development of bovine ova heat stressed during in vitro maturation. Journal of Dairy Science 90:4297-4303.<br /> <br /> 2) Giordano J.O., J. L. Edwards, G. M. Schuenemann, N. Rohrbach, and F. N. Schrick. Strategies to increase ovulatory follicle size and reduce ovulation time in lactating dairy cows. (Abstract submitted for consideration by International Embryo Transfer Society Meetings).<br /> <br /> 3) Kellogg, D.W., Pennington, J.A., Johnson, Z.B., Anschutz, K.S., Colling, D.P., and Johnson, A.B. 2006. Effects of feeding Tasco Ascophyllum nodosum to large and small dairy cows during summer months in central Arkansas. J. Dairy Sci. 89:65 (Abstr.). <br /> <br /> 4) Harrington, T.W., Pennington, J.A., Johnson, Z.B., Brown, A.H., Jr., Kellogg, D.W., Rosenkrans, C.F., Andrews, M.C., and Hawkins, J.A. 2006. Factors affecting udder singeing in dairy cattle. J. Dairy Sci. 89:112 (Abstr.).<br /> <br /> 5) Eicher, S.D., M.M. Shutz, S.T. Willard, S. Bowers, S. Gandy and K. Graves. 2007. Pre-partum milking and parlor habituation in primiparous Holstein heifers. Journal of Dairy Research 74 (4): 413-417.<br /> <br /> 6) Tyra, J.D., M. McGee, S. Bowers, A. Harris, A. Musselwhite and S.T. Willard. 2007. Development of a model for temperament modification in cattle: Investigation of fluphenazines effect on animal activity and physiological response. CVM Summer Research Fellowship Program, Mississippi State University, July, 2007.<br /> <br /> 7) Dray, S., A. Harris, R. Farrar, G. Grissett, S. Laird and S. Willard. 2007. A comparison of body temperature measures between Holstein and Gir x Holstein cows in relation to environment and stage of the estrous cycle. ASAS National Meeting  San Antonio, TX.<br /> <br /> 8) Willard, S.T., S. Dray, R. Farrar, M. McGee, S. Bowers, A. Chromiak and M. Jones. 2007. Use of infrared thermal imaging to quantify dynamic changes in body temperature following LPS administration in dairy cattle. American Society of Animal Science - Southern Section; Mobile, AL; Feb. 2007.<br /> <br /> Popular Press Articles/Meeting Abstracts/Experiment Station Reports/Others:<br /> 1) Kellogg, D.W., Anschutz, K.S., and Pennington, J.A. 2006 Report of research trial with Tasco at Rose Ark Dairy in Arkansas during summer 2005. Z.B. Johnson and D.W. Kellogg (ed). Arkansas Agric. Exp. Stat. Res. Series. 2006 Arkansas Anim. Sci. Rep. 100-104.<br />

Impact Statements

1. Comparing the different body temperature assessments that have been conducted among participants will facilitate a standardized temperature measurement procedure with the greatest resolution for broader comparisons among studies. This will enhance collaborative research through uniform measurements and provide a resource for other investigators regarding body temperature correlates in dairy cattle.
2. Through an enhanced understanding of the interactions between physiological changes (e.g., the estrous cycle) and body temperature responses to environmental temperature we can more accurately interpret collected data in relation to economic end-points (e.g., fertility) and management criteria (e.g., use of cooling systems, synchronization protocols, etc.).
3. Investigations of prepartum cooling may lead to changes in dry cow management strategies for improved postpartum milk production performance, enhanced reproductive function and general improvements in cow comfort/welfare. Costs of prepartum cooling may be off-set by improved postpartum performance, illustrating the economic benefits of this management change in relation to production end-points.
4. Understanding the influence of secondary characteristics such as coat color and cow body size on production performance under heat stressed conditions assists in establishing selection criteria for dairy cows for specific environments to maximize the balance between production and economic efficiency.
5. Information gained from these studies is an important first step towards the development of management strategies for minimizing the negative effects of environmental heat stress to reduce reproduction in dairy cows and in other agriculturally-important animals. Doing so would allow for more efficient livestock production, thereby ensuring an ample and economical food supply.

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Report Information

Participants

Participants from S-1023; Ignacy Mistal, University of Georgia; Robert Godfrey, University of Virgin Islands; Wayne Kellogg, University of Arkansas; David Morrison, Louisiana State University Agricultural Center; Deb Hammernik, USDA-CREES; Participants from W-1173; Susan Eicher, USDA-ARS; Anne Parkhurst, University of Nebraska; Terry Mader, University of Nebraska; Jeremiah Davis, Mississippi State University; Bob Collier, University of Arizona; Colin Kaltenbach, University of Arizona; Don Spires, University of Missouri; Hank Kattesh, University of Tennessee; Ernie Minton, Kansas State University; K. G. Gebremedhin, Cornell University

Brief Summary of Minutes

Dr. Terry Engle, Colorado State University (Host of the meeting) called the joint meeting of S-1023 and W-1173 to order at 8:30 a.m. on August 12, 2008. The attendees introduced themselves and attendance was recorded. Dr Engle outlined the format of the meeting and Colin Kaltenbach made a few house keeping announcements. Dr. Hammernik provided an update on CREES programs to the group. Participants presented progress reports for each of the objectives to the group by either oral or poster presentation. During the brief business meeting, S-1023 participants agreed to poll the members regarding termination of the project. Several of the group members have changed positions and are not able to continue their involvement. Those remaining members that are interested in continuing collaborative work in the area of heat stress were encouraged to join W-1173. The meeting concluded on August 13, 2008 after all reports and plans for future collaborations were completed.

Accomplishments

1a. Quantifying heat stress in dairy cattle:<br /> <br /> Thermal images and body temperatures from Senepol cattle (n = 43 cows) were recorded while the cow was restrained in a squeeze chute (USVI, MS) to evaluate the potential of using thermal images to accurately measure body temperature. Data collection was carried out in the shade, during the morning hours before the suns rays could interfere with the thermal imaging. The ambient temperature and relative humidity were recorded every five minutes throughout the duration of data collection, from 9:50 AM to 12:05 PM, using a HOBO data logger. A digital infrared thermal camera was used to record the thermal images of both the left and right eyes as well as the muzzle of each cow were recorded using a digital infrared thermal camera (FLIR ThermaCAM EX320) at a distance of approximately 1 m from the head. Muzzle color was noted. Vaginal and rectal temperature of each cow was recorded using a digital veterinary thermometer (GLA Agricultural Electronics, M700 series). To be sure that the sterile environment of the vagina was not compromised, vaginal temperature was first recorded, then rectal temperature, followed by the sterilization of the thermometer before being inserted into the vagina of the next cow. Thermographs were analyzed using ThermaCAM Researcher Pro 2.7 FLIR Systems software. Thermographs of eyes were analyzed by taking the maximum temperature of the area of the whole eye, based on previous studies in our lab (Willard et al., 2006; Godfrey et al., 2007). Thermographs of muzzles were analyzed by recording the maximum temperature of the area between the nostrils. The average of the left and right eyes for each cow was calculated, and this variable, called the mean eye temperature, was then used in the statistical analysis. Both vaginal temperature and rectal temperature were correlated with mean eye temperature. Muzzle temperature was moderately correlated only with the mean eye temperature. Muzzle color had no impact on the results. Thermal imaging is an effective way to assess body temperature in cattle, thus reducing the need to handle animals. With further study, this could have implications as a non-invasive means of measuring the body temperature in both domestic and non-domestic animals.<br /> <br /> <br /> 1b. The effect of various summer cooling strategies on symptoms of heat stress, endocrine status and lactation performance.<br /> <br /> The impact of using feedline soakers in combination with Korral Kools® to cool early lactation cows housed in desert style barns was determined in a trial in Saudi Arabia (KS). The feedline soakers were set to come on at a barn temperature of 21°C with a soaking frequency of 5 min (36 s on and 264 s off). Korral Kools® were spaced every 6 m over the resting area and were operated, with the fans coming on at a barn temperature of 27°C and the water at 30°C. Feedline soakers were alternately turned on and off for 24 h periods over 4 d. Vaginal temperatures of 7 primiparous (53 d in milk, 41.2 kg/d milk production) and 6 multiparous cows (28 d in milk, 48.1 kg/d milk production, 2.8 lactations), located in separate groups, were collected every 5 min using data loggers (HOBO U12) attached to a blank CIDR. Ambient temperature during the trial was 29.7°C (range: 21.7 to 38.5°C), relative humidity was 44.4% (16 to 85%) and THI was 75.6 (68 to 82). Feedline soakers significantly decreased mean 24-h vaginal temperatures from 38.98 to 38.80°C (P < 0.001). Treatment by time interaction was also significant (P < 0.001), with greatest treatment effects during peak heat stress; feedline soakers reduced vaginal temperatures from 39.72 to 39.42°C at 2400 h and from 39.32 to 38.98°C at 500 h. Additional research is needed to determine how to operate the Korral Kool® system with feedline soakers. <br /> <br /> In a second trial, the impact of using evaporative pads and fans in combination with feedline soakers to reduce heat stress of prepartum cows was conducted at the KSU dairy in August 2007 (KS). To complete this trial, an addition was constructed to the maternity barn to incorporate the use of evaporative pads and fans to cool the bedded pack area.<br /> Evaporative pads were alternately turned on and off for 24 h periods over 4 days. When the pads were on, water was circulated through the evaporative pads from 830 h to 230 h. The fans pulling air through the evaporative pads were operated anytime the barn temperature was above 21°C. The feedline soakers were set to come on at a barn temperature of 21°C with a soaking frequency of 15 min (5 min on and 10 min off).<br /> Logging devices collected ambient temperature and relative humidity data at 15-min intervals. Vaginal temperatures of 8 cows located in the same group were collected every 5 min using data loggers (HOBO U12) attached to a blank CIDR. Evaporative cooling significantly decreased mean 24-h barn temperature by 3.8°C and temperature-humidity index (THI) by 2.3 units. The greatest differences in barn temperature and THI occurred at 1700 h, when temperature was reduced by 6.8°C and THI by 3.1 units. Evaporative cooling significantly decreased mean 24-h vaginal temperatures from 38.95 to 38.79°C (P < 0.001). The treatment by time interaction was also significant (P < 0.001), with the greatest treatment effects during peak heat stress times (39.2 vs. 38.9°C at 1500 h, 39.3 vs. 39.1°C at 2300 h for pads off and on, respectively). Evaporative cooling in combination with feedline soakers can be used to reduce body temperatures of prepartum cows experiencing heat stress.<br /> <br /> 1c. Characterize the impact of prepartum cooling and identifying perpartum metabolic and endocrine markers as indicators of postpartum performance.<br /> No effort in this area reported.<br /> <br /> <br /> 1d. Characterize the effect of genetic selection in heat tolerance. <br /> <br /> Past studies in genetics of heat tolerance assumed a fixed threshold in sensitivity to heat stress. The objective of this study (GA) was to assess the genetic component on individual variation for that threshold. Data included 379,833 first-parity test day records on 40,986 Holsteins. Inferences were obtained by a Bayesian non-linear hierarchical animal model. Effects in the model included DIM x milking frequency, HYS of the milking day, and two animal effects: the intercept (Ii) and the regression (Si) on the temperature-humidity index (THI) above an animal specific threshold (Ti). In the second hierarchical stage the means and the genetic and environmental (co)variances of were estimated using a linear mixed model. The estimated heritabilities (posterior standard deviations) of IS, SS and TS were 0.22(0.02), 0.26(0.05), 0.24(0.05), respectively; the genetic correlations were rg,I-S=-0.53(0.05), rg,I-T=-0.42(0.1) and rg,S-T=0.97(0.08). The estimated average of the threshold across all animals was 22.7(0.16) THI Cº. The threshold to response to heat stress is variable per cow. Cows with higher threshold also have lower sensitivity to heat past the threshold.<br /> <br /> Data included 585,119 test-days (TD) in first to third parity for milk (M), fat (F) and protein (P) from 38,608 Holsteins in Georgia (GA). Daily temperature humidity indices (THI) were available from public weather stations. Models included a repeatability test-day model (MREP) with a random regression on heat stress index (HSI), and a test-day random regression model (MRRM) using linear splines with 4 knots and HSI, which was defined as THI over 22C from the 3rd day before the TD. Knots were placed at 5, 50, 200, and 305 days-in-milk (DIM). For both models the regular genetic variance increased by 30-40% from 1st to 2nd parity but slightly declined in 3rd parity for M and P. The heat stress variance doubled from 1st to 2nd parity and additionally increased by 20-100% in 3rd parity. The genetic correlations between heat-stress effects in different parities were e0.56-0.79 while the genetic correlations between regular and heat stress effects across parities and traits were between -0.30 and -0.47. With MRRM, the variance of the heat stress effect was about half of that with MREP. Genetic variance of heat stress strongly increases with parity. <br /> <br /> Records of approximately 5 million Holsteins with about 80 million test days were used to estimate trends for milk under temperate climate and for reduction of milk under high THI (GA). For all parities, the trend for milk was positive and close to a straight line. The trend for decline under high THI was almost nil for the first parity but strong (i.e., lower milk yield under high THI) for 2nd and third parties. For first parity, the negative selection for heat stress is compensated by correlated selection for longevity, fertility and dairy form. For later parities, the compensation is incomplete due to much higher sensitivity in heat stress in later parities.<br /> <br /> 1e. Determining the relationships between coat color and cow body size on production performance in heat-stressed dairy cattle.<br /> Data has been collected and submitted to R. Godfrey for analysis. Additional data will be collected and submitted (USVI, PR, MS, and NCSU).<br /> <br /> 2a. Use of supplemental hormone administration pre- and post-breeding to improve fertility of heat-stressed dairy cows.<br /> <br /> Because multiple ovulation embryo transfer procedures are occasionally performed in cows experiencing heat stress, a major goal of this study was to assess the developmental competence of otherwise morphologically-normal embryos from heat-stressed ova (TN). To this end, ability of compact morulae from heat-stressed and nonheat-stressed ova to undergo blastocyst development after culture at 38.5 or 41.0°C was examined. Preference for use of compact morulae was based on previous findings demonstrating this embryonic stage to be thermotolerant. Because the maturing ovum contributes half of its genetic material and > 99% of its cytoplasm to the embryo, it was hypothesized that heat-induced perturbations in the ooplasm carry over to increase the susceptibility of the preattachment embryo to heat stress. Initially, ova were matured at 38.5 or 41.0°C. Consequences of heat stress did not include altered cleavage, but reduced proportion of 8- to 16-cell stage embryos. Although proportionately fewer, compact morulae from heat-stressed ova were equivalent in quality to those from nonheat-stressed ova. Culture of compact morulae from nonheat-stressed ova at 41.0°C did not affect blastocyst development. Furthermore, development of compact morulae from heat-stressed ova was similar to those from nonheat-stressed ova after culture at 38.5°C. However, blastocyst development was reduced when compact morulae from heat-stressed ova were cultured at 41.0°C. In summary, reduced compaction rates of heat-stressed ova explains in part why fewer develop to the blastocyst stage after fertilization. Thermolability of the few embryos that do develop from otherwise developmentally-challenged ova emphasizes importance of minimizing exposure to stressor(s) during maturation. <br /> <br /> 2b. Establishing hormone markers pre-breeding as predictors of reproductive success in heat-stressed and non-heat-stressed dairy cows.<br /> No effort in this area reported.<br /> <br /> 2c. Use of interval cooling to improve fertility of problem breeders and heat-stressed cows.<br /> No effort in this area reported.<br /> <br /> 2d. Use of targeted vitamin and mineral supplementation in conjunction with estrous synchronization and timed AI to improve fertility in heat-stressed dairy cows.<br /> No effort in this area reported.<br /> <br /> 3a. The effect of heat stress on nutritional requirements on high-producing dairy cows.<br /> <br /> The impact of feeding crude glycerin, a by-product of the bio-diesel industry, on in vitro true digestibility and digestion kinetics of various forages (AK). Four levels of crude glycerin (0, 5, 10, and 20%) included with wheat, crabgrass, or bermudagrass forages. In vitro digestibility of the forage and crude glycerin mixtures increased linearly for each forage. However, when digestibility of the crude glycerin was accounted for, crude glycerin had limited impact on digestion of crabgrass and wheat forage. Likewise overall digestion kinetic measurements varied among forages but were not impacted by crude glycerin level. Therefore, it appears that crude glycerin may be included at levels up to 20% of the total diet without having negative impacts on digestibility. Nutritionists and managers should be cautioned that crude glycerin from the manufacture of biodiesel may contain methanol that is harmful to animals.<br /> <br /> 3b. The effects of high protein diets on production performance and summer breeding in dairy cows. <br /> No effort in this area reported.<br /> <br /> 3c. The effect of dietary supplements to enhance nutrient intake and digestibility.<br /> <br /> A trial was conducted in central Arkansas from July 1 to September 30 (2005) to evaluate the effects of feeding Tasco Ascophyllum nodosum to high-producing dairy cows during hot weather (AR). The 525 cows were divided in 4 free-stall barns to achieve 2 similar groups of large cows and small cows. Milk yield of cows averaged 28.8 kg/d for control and treatment groups during June, the preliminary period. All cows received a total mixed ration containing either 0 or 0.25% Tasco. Respirations were counted on 60 cows weekly. Cow fed Tasco had fewer respirations per minute on August 3 (77.3 compared to 88.5 for control cows; P < 0.05), on August 10 (80.0 compared to 91.4 for control cows; P < 0.01), on August 31 (66.6 compared to 71.5 for control cows; P < 0.05), and on September 7 (60.6 compared to 68.1 for control cows; P < 0.01). Cows fed Tasco produced more (P < 0.01) milk during July, August, and September; however, there was a significant interaction with size of cows during August (P < 0.01) and September (P < 0.05) caused by 2.3-kg/d more milk for the larger cows fed Tasco compared to similar yield for smaller cows. Cows were bred, but the number of pregnancies from the larger breeds was very low (3 of 50) for control cows. With Tasco in the diet, the pregnancy rate was enhanced (P < 0.01) dramatically (20 of 55). The number of inseminations per conception and the days open before first service did not vary (P > 0.05) among treatment groups. With Tasco in the diet, respiration rates were reduced for both large and small cows, although the effect appeared dependent upon time. Tasco reduced the steep decline in milk yield of the larger cows and dramatically enhanced the pregnancy rate of the larger cows, but smaller cows were not affected.<br /> <br />

Publications

Refereed Journal and Peer-Reviewed Proceedings:<br /> <br /> 1. Aguilar, I., and I. Misztal. 2008. Recursive algorithm for inbreeding coefficients assuming non-zero inbreeding of unknown parents. J. Dairy Sci. 91:1669-1672.<br /> <br /> 2. Bohmanova, J., I. Misztal, S. Tsuruta, H.D. Norman, and T.J. Lawlor. 2008. Heat Stress as a Factor in Genotype x Environment Interaction in U.S. Holsteins. J. Dairy Science. 91:840-846.<br /> <br /> 3. Dhuyvetter, K.C., J.P. Harner, J.F. Smith, and B.J. Bradford. 2008. Economic considerations of low profile cross ventilated barns. Pg. 89-100. Proc. Dairy Housing of the Future. Kansas State Univ. Ext. Res.<br /> <br /> 4. Edwards J.L. 2008. Challenges of improving dairy cow fertility during summer heat stress: An ovums perspective. J. Dairy Sci. 90:E-Supplement 1.<br /> <br /> 5. Edwards J.L., A. Bogart, L. Rispoli, F. Scenna, G. Schrock, T. Wilson, F. Schrick. 2008. Application of heat stress during oocyte maturation increases susceptibility of preattachment bovine embryos to heat stress. Biol. Reprod. Special Issue p. 176.<br /> <br /> 6. Giordano J.O., J.L. Edwards, G.M. Schuenemann, N. Rohrbach, and F.N. Schrick. 2008. Strategies to increase ovulatory follicle size and reduce ovulation time in lactating dairy cows. Reprod. Fertil. Dev. 20(1):87<br /> <br /> 7. Harner, J.P. and J.F. Smith. 2008. Design considerations for low profile cross ventilated freestall facilities. Pg. 21-34. Proc. Dairy Housing of the Future. Kansas State Univ. Ext. Res. <br /> <br /> 8. Harner, J.P., J. Zulovich, J.F. Smith, and S. Pohl. 2008. Let it flow, Let it flow; Moving air into the freestall Space. Pg. 39-44. Proc. Dairy Housing of the Future. Kansas State Univ. Ext. Res. <br /> <br /> 9. Harner, J.P., J.F. Smith, J. Zulovich, and S. Pohl. 2008. Cooling inlet air in low profile cross ventilated freestall facilities. Pg. 45-56. Proc. Dairy Housing of the Future. Kansas State Univ. Ext. Res. <br /> <br /> 10. Harner, J.P., J.F. Smith, and K. Janni. 2008. To see, or not to see, that is the question; lighting low profile cross ventilated dairy houses. Pg. 65-76. Proc. Dairy Housing of the Future. Kansas State Univ. Ext. Res. <br /> <br /> 11. Harner, J.P., J.F. Smith, S. Pohl, and J. Zulovich. 2008. Insulation in low profile cross ventilated freestall facilities. Pg. 77-82. Proc. Dairy Housing of the Future. Kansas State Univ. Ext. Res. <br /> <br /> 12. Harner, J.P., and J. F. Smith. 2008. Assessment of traffic patterns in LPCV facilities-a collection of organized things. Pg. 83-88. Proc. Dairy Housing of the Future. Kansas State Univ. Ext. Res. <br /> <br /> 13. Harner, J.P. and J.F. Smith. 2008. Special design considerations. Pg. 101. Proc. Dairy Housing of the Future. Kansas State Univ. Ext. Res. <br /> <br /> 14. Huang, C., S. Tsuruta, J. K. Bertrand, I. Misztal, T. J. Lawlor, and J. S. Clay. 2008. Environmental Effects on Conception Rate of Holsteins in New York and Georgia. J. Dairy Sci. 92:818-825.<br /> <br /> 15. Legarra, A., and I. Misztal. 2008. Computing strategies in genome-wide selection. J. Dairy Sci. 91:360-366. <br /> <br /> 16. Panivivat, R., Kegley, E.B., Pennington, J.A., Kellogg, D.W., and Krumpelman, S.L. 2004. Growth performance and health of dairy calves bedded with different types of materials. J. Dairy Sci. 87:3736-3745.<br /> <br /> 17. Panivivat, R., Kegley, E.B., Kellogg, D.W., Pennington, J.A. VanDeveder, K., Hellwig, D.H., Wistuba, T.J., and Krumpleman S.L. 2005. Preference for free-stalls bedded with sand or granite fines and changes in bacterial counts in those materials. Professional Anim. Scientist 21:248-253.<br /> <br /> 18. Payton R.R., L.A. Rispoli, and J.L. Edwards. 2008. Total RNA and transcript abundance in heat-stressed bovine oocytes and surrounding cumulus. Reprod. Fertil. Dev. 20(1):172. <br /> <br /> 19. Rose, C., W.B. Tucker, S.T. Willard, A. Williams, J. Fuquay, P.L. Ryan and C.S. Whisnant. 2008. Evaluation of hormone treatments in a modified ovulation synchronization protocol in dairy heifers. J. Anim. Vet. Advances 7 (2): 154-159.<br /> <br /> 20. Sheffield, R.E., M. de Haro Marti, S. Pohl, R.S. Pohl, D. Nicoli, J.F. Smith, and J.P. Harner. 2008. Air quality in a low profile cross ventilated dairy barn. Pg. 57-64. Proc. Dairy Housing of the Future. Kansas State Univ. Ext. Res. <br /> <br /> 21. Smith, J. F., B.J. Bradford, A. Oddy, J.P. Harner, and M.J. Brouk. 2008. Impact of using feedline soakers in combination with Korral Kools to cool early lactation cows housed in desert style barns. J. Dairy Sci. 81:131 (Abstr).<br /> <br /> 22. Smith, J.F., B.J. Bradford, J.P. Harner, and M.J. Brouk. 2008. Impact of using evaporative pads and fans in combination with feedline soakers to reduce heat stress in prepartum cows. J. Dairy Sci. 81:131 (Abstr.).<br /> <br /> 23. Smith, J.F., J.P. Harner, B.J. Bradford, and M. Overton. 2008. Opportunities with low profile cross ventilated freestall facilities. Pg. 1-20. Proc. Dairy Housing of the Future. Kansas State Univ. Ext. Res <br /> <br /> 24. Smith, J.F., J.P. Harner. 2008. Low-profile cross-ventilated freestall facilities, another option for cow housing. Proc. 2008 Tri-State NW Dairy Shortcourse. January 30-31, 2008. Boise, ID.<br /> <br /> 25. Zulovich, J., J.P. Harner, J.F. Smith, and S. Pohl. 2008. Fans: airflow versus static pressure. Pg. 35-38. Proc. Dairy Housing of the Future. Kansas State Univ. Ext. Res. <br /> <br /> <br /> Popular Press Articles/Meeting Abstracts/Experiment Station Reports/Other:<br /> <br /> 1. Harner, J.P., J.F. Smith, and M.J. Brouk. 2008. Potential impact of facilities on cow behavior. MN Milk Producer Assoc. Dairy Management Workshops. March 4, 2008. Sleepy Eye, MN.<br /> <br /> 2. Panivivat, R., Kegley, E.B., Kellogg, D.W., Pennington, J.A. VanDeveder, K., Hellwig, D.H., Wistuba, T.J., and Krumpleman S.L. 2002. Preference for and bacterial counts in sand and granite fines as bedding for lactating cows. Univ. Arkansas Agric. Exp. Sta. Res. Series 499. Pg. 143-146.<br /> <br /> 3. Panivivat, R., Pennington, J.A., Kegley, E.B., Kellogg, D.W., and Krumpelman, S.L. 2003. Growth performance and health of dairy calves bedded with different types of materials. Univ. Arkansas Agric. Exp. Sta. Res. Series 509. Pg. 83-87.<br />

Impact Statements

1. Thermal imaging is an effective tool for assessing body temperature in cattle which reducing the need to handle animals. This technology has potential implications as a non-invasive means of measuring the body temperature in both domestic and non-domestic animals.
2. Feedline soakers in combination with evaporative cooling effectively reduces the body temperature of prepartum cows experiencing heat stress.
3. The genetic threshold to response to heat stress is variable per cow. Cows with higher threshold also have lower sensitivity to heat past the threshold. The genetic variance of heat stress strongly increases with parity. For first parity, the negative selection for heat stress is compensated by correlated selection for longevity, fertility and dairy form. For later parities, the compensation is incomplete due to much higher sensitivity in heat stress.
4. A reduced compaction rate of heat-stressed ova partially explains why fewer ova develop to the blastocyst stage after fertilization. Thermalability of the few embryos that do develop from otherwise developmentally-challenged ova emphasizes the importance of minimizing exposure to stressor(s) during maturation.
5. Feeding crude glycerin at levels up to 20% of the total diet did not impact digestion kinetics or total fiber digestibility of forages. Inclusion of Tasco Ascophyllum nodosum reduced respiration rate, maintained milk yield, and improved pregnancy rate of dairy cows.

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