Hair Coat and Steroidal Implant Effects on Steers Grazing Endophyte-Infected Tall Fescue During the Summer

The study involved 60 steers grazing on toxic tall fescue for 104 days to assess the effects of hair coats and steroidal ear implants on physiological responses. Steers were divided by body weight and hair coat color into six pastures, with treatments of clipped or unclipped hair and two types of steroidal implants (Synovex-S and Compudose). The hair growth rate was 0.29 mm/day, and the sweating rate decreased over time, being higher with the estradiol implant. Clipped cattle had lower rectal temperatures during high ambient temperatures. The study concluded that winter hair coat retention, continuous hair growth, and reduced sweating impaired thermoregulation, leading to decreased grazing frequency and poor animal performance.