Effect of Shearing for Improving the Thermoregulatory Responses of Crossbred Sheep During Heat Stress

Abstract

Shearing is a common practice to improve heat losses in wool sheep. However, little is known about this practice in hair x wool crosses. This study tested how sheep change thermoregulation and could improve heat loss after shearing. At fourteen days after shearing, thermal regulation did not improve in sheep exposed to consecutive heat stress episodes from 10 to 13 h, reaching 37 ± 1.0 °C of air temperature. The ocular surface temperature and skin temperatures were higher after shearing, indicating that wool could be a barrier to heat acquisition, which could explain the higher sweating rate in unshorn animals caused by the difficulty of convection. The glandular area was similar between treatments, and the sweat glands had a tendency to be located more superficially. This research contributes to the management of sheep production systems, as crossbreed unshorn sheep presented similar thermoregulatory responses as sheared ones.