Brief Summary of Minutes of Annual Meeting

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.

1a. Quantifying heat stress in dairy cattle: 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. 1b. The effect of various summer cooling strategies on symptoms of heat stress, endocrine status and lactation performance. 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. 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. 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). 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. 1c. Characterize the impact of prepartum cooling and identifying perpartum metabolic and endocrine markers as indicators of postpartum performance. No effort in this area reported. 1d. Characterize the effect of genetic selection in heat tolerance. 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. 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. 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. 1e. Determining the relationships between coat color and cow body size on production performance in heat-stressed dairy cattle. Data has been collected and submitted to R. Godfrey for analysis. Additional data will be collected and submitted (USVI, PR, MS, and NCSU). 2a. Use of supplemental hormone administration pre- and post-breeding to improve fertility of heat-stressed dairy cows. 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. 2b. Establishing hormone markers pre-breeding as predictors of reproductive success in heat-stressed and non-heat-stressed dairy cows. No effort in this area reported. 2c. Use of interval cooling to improve fertility of problem breeders and heat-stressed cows. No effort in this area reported. 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 effort in this area reported. 3a. The effect of heat stress on nutritional requirements on high-producing dairy cows. 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. 3b. The effects of high protein diets on production performance and summer breeding in dairy cows. No effort in this area reported. 3c. The effect of dietary supplements to enhance nutrient intake and digestibility. 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.

Refereed Journal and Peer-Reviewed Proceedings: 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. 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. 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. 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. 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. 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 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. 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. 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. 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. 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. 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. 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. 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. 15. Legarra, A., and I. Misztal. 2008. Computing strategies in genome-wide selection. J. Dairy Sci. 91:360-366. 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. 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. 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. 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. 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. 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). 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.). 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 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. 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. Popular Press Articles/Meeting Abstracts/Experiment Station Reports/Other: 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. 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. 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.