Effect of Melatonin Supplementation from Mid to Late Gestation on Hair Growth and Skin Temperature of Beef Cattle

In a study conducted on commercial beef heifers (n = 32) and cows (n = 25), researchers investigated the effects of melatonin supplementation on core body temperature, skin temperature, and hair growth during mid to late gestation. The animals were divided into two groups, with the melatonin group (n = 29) receiving two 24-mg melatonin ear implants on days 180, 210, and 240 of gestation. Various measurements were taken on days 180 and 240, including body weight, rectal temperature, ambient temperature, humidity, and hair weight, along with thermal imaging of shaved and unshaved skin areas. The study found that melatonin supplementation did not significantly affect body weight, rectal temperature, or the temperature of the shaved skin areas. However, on day 240, the temperature of the unshaved skin area was significantly lower in the melatonin group (32.7 ± 0.4°C) compared to the control group (33.5 ± 0.3°C), suggesting that melatonin may decrease skin temperature in unshaved areas of beef cattle during gestation. Hair weight was not affected by the treatment.