Effects of human menopausal gonadotrophin (hMG) for superovulation in Japanese Black cattle

Sixty-four Japanese Black parous cows were divided into 5 dosage groups (I, II, III, IV, V) and administered either human menopausal gonadotrophin (hMG) or FSH by intramuscular injection. No significant differences were observed between the hMG-treated groups. The average number of recovered ova/embryos in cows treated with 900 IU was significantly greater (P < 0.05) than in cows treated with FSH. The percentage of high-quality transferable embryos was highest in the 600 IU hMG-treated group. Also, FSH-treated cows produced a significantly larger number of unfertilized ova compared to hMG-treated cows. The results suggest that hMG treatment is sufficient for Japanese Black Cattle at a dose of 600 IU for 3 days, and that a 2-day treatment regime is also possible.