Modeling heat loss from the udder of a dairy cow. (July 2016)

• Record Type: Journal Article
• Authors: Gebremedhin, Kifle G.; Wu, Binxin
• Is Part Of: Journal of thermal biology. Volume 59(2016)
• Page Start: 34
• Page End: 38
• Publication Date: 2016-07
• Subjects: Udder -- Dairy cow -- Model -- Heat flux -- Heat stress; Thermobiology -- Periodicals; Temperature -- Periodicals; Biology -- Periodicals; Thermobiologie -- Périodiques; Thermobiology; Periodicals; 571.46
• DOI: 10.1016/j.jtherbio.2016.04.011
• Languages: English
• ISSNs: 0306-4565

Abstract

Abstract: 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 (388 W/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 338 W/m 2 at an ambient temperature of 35 °C and blood-flow rate of 3.2×10 −3 m 3 /(s m 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). Highlights: Mechanistic model that predicts heat loss from the udder of a cow was developed. Udder tissue temperature approached core temperature for an air temperature 37°C. The udder can be considered as a heat sink. Cow cooling could be done by cooling the udder only.