Effects of Exogenous Supplementation of Progesterone on Conception Rates in Lactating Murrah Buffaloes

The objective of this study was to deduce the effect of exogenous supplementation of progesterone as an intramuscular injection at the time of artificial insemination (AI) on time of ovulation and conception rate in lactating Murrah buffaloes. A total of 30 buffaloes were included in the experiment and randomly divided into two groups (Treatment, <i>n</i> = 13 and Control, <i>n</i> = 17). Only those buffaloes which were in heat according to visual observation and had clear vaginal discharge, good uterine tone and a large follicle (>12 mm on ultrasound scanning) were reported. Ultrasound scanning was carried out at 6 h intervals after insemination until ovulation. The results revealed that significantly higher numbers of buffaloes ovulated within 24 h post AI in the control group (82.4%) as compared to only 15.4% in the treatment group. In the treatment group, 53.8% of ovulations occurred after 24 h post AI, whereas in the control group only 11.8% of ovulations occurred after 24 h post AI. Up to 96 h post AI, 30.8% of buffaloes in the treatment group and only 5.9% of buffaloes in the control group remained anovulatory. No significant difference was found in CL size between the treatment (226.5 ± 17.4 mm²) and control (238.9 ± 7.9 mm²) groups. Following insemination, 52.9% of buffaloes in the control group conceived, whereas in the treatment group, only 38.5% of buffaloes conceived.