Albedo and Thermal Ecology of White, Red, and Black Cows (Bos taurus) in a Cold Rangeland Environment

Cattle in high-elevation rangelands experience cold and hot extremes. Given the increase in black hided cattle globally, thermoregulation options on rangelands, and hide color function affecting mammal thermal ecology, this study quantified winter albedo, external cattle temperatures (Temp_cow), and differences (ΔT) between Temp_cow and ambient air temperature (Temp_amb), for different color cattle along a thermal gradient (≈-33 °C to +33 °C). From 2016 to 2018, I measured 638 individual Temp_cow × Temp_amb combinations for white (n = 183), red (n = 158), and black (n = 297) Bos taurus female cattle free roaming extensive Wyoming, USA rangelands. Pixel brightness of cow images relative to snow indicated mean (±standard error) albedo for white, red, and black cows (n = 3 of each) was 0.69 (±0.15), 0.16 (±0.04), and 0.04 (±0.01), respectively (p = 0.0027). Temp_cow was explained by Temp_amb (+), clear sky insolation index (+), and cow albedo (-). However, ΔT was explained by Temp_amb (-), long-wave radiation (infrared; Rad_LW (-)), Temp_cow (+), and cow albedo (+). Temp_amb relative to ΔT was correlated for all hide colors (all p-values < 0.0001; all r² values > 0.7)), yet slopes (m) were ~2× greater for red and black cows than white cows.