Effects of Altrenogest on Behavior and Reproductive Function of Stallions

Administering altrenogesta to mature stallions at the labeled dosage (0.044 mg/kg) for 30 days had no effect on spermatozoal quantity or quality, with only minimal effects on stallion behavior at 30 days following treatment. However, this regimen of altrenogest significantly suppressed blood plasma concentrations of luteinizing hormone, testosterone, estrogen conjugates, and inhibin at the end of the treatment period. Authors’ addresses: Depts. of Anatomy and Public Health (Johnson) and Large Animal Medicine and Surgery (all other authors), The Texas Veterinary Medical Center, Texas A&M University, College Station, TX 77843. r 1997 AAEP.