GONADOTROPIN-RELEASING-HORMONE TREATMENT OF HOLSTEIN COWS WITH FOLLICULAR CYST MONITORED BY SKIM MILK PROGESTERONE DETERMINATION

Progesterone was assayed in skim milk fraction of 38 cystic cows, 26 ( 68.4%) of which had basal ( 0.5 ng/ml) progesterone concentrations and were diagnosed as having follicular cysts. These cows were allotted a t random to one of 3 treatments: (1) a sham injection of sterile water in 7 cows as controls; (2) a single injection (1 mg) of a GRH analog in 8 cows; (3) double injections (1 mg) of the GRH analog al 7-day int erval in 11 cows. According to rectal palpation confirmed by skim milk progesterone determination, the double injection group responded well (p < 0.05) compared with the single injection and control groups (81. 8% vs 62.5% vs 42.9%). The interval from calving to 1(st) insemination , the interval from treatment to conception and the interval from calv ing to conception were significantly (p < 0.01) shorter in the double injection group than in the other 2 groups. Also, the conception rate to first insemination was significantly (p < 0.05) higher (63.6% vs 37 .5% vs 42.9%). The data provide evidence for reduction in infertility and reproductive disorders in cystic cows given double injections of G RH.