Modeling heat loss from the udder of a dairy cow.
A mechanistic model that predicts sensible and latent heat fluxes from the udder of a dairy cow was developed. The prediction of the model was spot validated against measured data from the literature, and the result agreed within 7% of the measured value for the same ambient temperature. A dairy cow can lose a significant amount of heat (388W/m(2)) from the udder. This suggests that the udder could be considered as a heat sink. The temperature profile through the udder tissue (core to skin) approached the core temperature for an air temperature ≥37°C whereas the profile decreased linearly from the core to skin surface for an air temperature less than 37°C. Sensible heat loss was dominant when ambient air temperature was less than 37.5°C but latent heat loss was greater than sensible heat loss when air temperature was ≥37.5°C. The udder could lose a total (sensible + latent) heat flux of 338W/m(2) at an ambient temperature of 35°C and blood-flow rate of 3.2×10(-3)m(3)/(sm(3) tissue). The results of this study suggests that, in time of heat stress, a dairy cow could be cooled by cooling the udder only (e.g., using an evaporative cooling jacket).
Department of Biological and Environmental Engineering, Cornell University, Ithaca, NY 14853, United States.
Kifle G
KG
Gebremedhin
Department of Biological and Environmental Engineering, Cornell University, Ithaca, NY 14853, United States.
Binxin
B
Wu
D000818:Animals; D001831:Body Temperature; D001833:Body Temperature Regulation; D002417:Cattle / Q000502:physiology*; D003198:Computer Simulation; D005260:Female; D018882:Heat Stress Disorders / Q000662:veterinary; D008321:Mammary Glands, Animal / Q000098:blood supply / Q000502:physiology*; D008954:Models, Biological; D013696:Temperature
Dairy cow; Heat flux; Heat stress; Model; Udder