Ujvari S, Gerber V, Sieme H, Fouché N, Burger D
Effect of Pergolide Therapy on Semen Parameters in a Stallion With Pituitary Pars Intermedia Dysfunction
JEVS November 2017 Volume 58, Pages 64–67
This paper, looking at 1 stallion with PPID only, looked at semen collected before (July) and 90 days after (~October) treatment with pergolide (at 0.002 mg/kg bw, so 1 mg for a 500 kg horse). After 90 days semen volume was lowered, but semen density increased, resulting in an equal total sperm count. Possible reasons for this might be altered prolactin levels, season (and effect of season on PPID as the sperm examinations took place around the start and end of the seasonal rise), and pergolide. The study concluded that pergolide may alter semen parameters but this was unlikely to affect fertility, and further research in larger numbers of stallions is needed.