The impact of hair coat color on body temperature in beef cattle

Authors: HOLLIDAY, CARRIELEE - Missouri State University; Carroll, Jeffery - Jeff Carroll; Sanchez, Nicole; GOERNDT, MICHAEL - Missouri State University; WALKER, ELIZABETH - Missouri State University; MCGEE, ADAM - Missouri State University

Submitted to: Journal of Animal Science Supplement
Publication Type: Abstract Only
Publication Acceptance Date: 12/5/2022
Publication Date: N/A
Citation: N/A

Interpretive Summary:

Technical Abstract: Ambient temperature plays a fundamental role in animal health and performance. Selecting for coat color may improve animal productivity and welfare through management and breeding decisions. The thermoneutral zone of cattle, 0°C - 25°C, is characterized as the range in ambient temperature that does not require cattle to expend energy to maintain core body temperature. When the ambient temperature is above or below these values, cattle must expend energy to keep their body temperature in homeostasis resulting in a reduction in efficiency. A proper herd management plan to mitigate heat stress can increase efficiency and decrease mortality in serious cases. Thirty-nine registered Hereford and commercial black cows (average 4 yrs of age) were placed in a 23-ha pasture, to determine if coat color affects internal body temperature. Cattle were on a typical fescue dominated pasture located in Mountain Grove, Missouri, with areas of shade and one pond centralized in the pasture. Cattle were divided into treatments based on hair coat color: black (n=13) or red (n=26). Using temperature data loggers, vaginal temperatures were recorded in 5-min intervals during a 14-d period in Mid-July, 2022 and combined into 6 hour timing intervals, A=0400-1000, B=1001-1600, C=1601-2200, and D= 2201-0359. Environmental temperature data loggers were suspended in two locations of partial sun to record ambient temperature. In addition, the Mountain Grove weather station operated by the University of Missouri Extension provided a daily data archive that recorded wind speed, total precipitation, maximum and minimum air temperature. Throughout the study, the mean environmental temperature was 34.4°C and ranged from 19.5°C to 40.2°C. Temperature data was evaluated using the Glimmix procedure of SAS and pairwise comparisons between timepoints were determined utilizing the GLM procedure of SAS. Differences were considered significant at P = 0.05. Black-haired cattle were warmer at all intervals (P = 0.04) with temperature differences between the treatments of 0.07, 0.10, 0.03, and 0.09 °C for timepoints A, B, C, and D respectively. Based on our results black hided cattle get warmer earlier in the day and take longer to dissipate heat than those with red hair coats.