Abstract
The objective of this investigation was to determine the appropriate dose of refined follicle stimulating hormone (FSH-R) dissolved in polyvinylpyrrolidone (PVP) and administered as a single intramuscular (i.m.) injection for superovulation in cows. Seventy Holstein parous cows were alotted to 4 treatment groups and were given 20 mg (A), 30 mg (B), 40 mg (C) or 50 mg (D) FSH-R in 10 ml of 30% PVP. Standing estrus was observed in groups A (1/1), B (9/20), C (6/8) and D (4/5) at 40-60 h after the first PGF2α treatment. However, 2/8 in group C and 1/5 in group D showed standing estrus before 40 h, and 11/20 in group B showed estrus at 60-72 h after PGF2α treatment. There were no significant differences in the mean number of recovered ova/embryos among groups B, C and D. However, the mean number of transferable embryos in groups B (6.2 ± 3.8) and C (7.1 ± 5.9) was significantly higher (P<0.05) than in group D (1.0 ± 0). The rate of unfertilized eggs was significantly higher (P<0.01) in group D (82.6%) than in groups B (18.7%) and C (38.5%). A single injection of 40 mg FSH-R in PVP was effective for superovulation in Holstein cows.
