Synchronization of Estrus and Ovulation Using CIDR and Prostaglandin for Improving Pregnancy Rate of Repeat Breeder Egyptian Buffaloes

To synchronize estrus and ovulation for improving pregnancy rate (PR) of repeat-breeder buffaloes, Controlled Internal Drug Release (CIDR) + prostaglandin (PGF2α) was used before service of repeat breeder buffaloes. Total of 20 cyclic lactating buffalo-cows (4-7 years, 400-500 kg, non-pregnant up to 90-postpartum day) and 10 cyclic buffalo-heifers (2.5-4 years, 350-400 kg, not conceived after 3 services) were used in this study. In the 1st group, a CIDR was inserted for 9 days, regardless reproductive status, and then animals were intramuscularly injected with PGF2α 24 h prior to CIDR removal. In the 2nd group, control animals were used at the same interval. Animals in heat were naturally served and blood samples were collected on different days post-service for serum P4 determination. Pregnancy was diagnosed on day 25 post-service. Results showed that overall mean of PR was higher (P<0.01), while serum P4 at estrus was lower (P<0.001) in CIDR than in control, but both parameters were not affected significantly by animal type or CIDR x animal type interaction. Serum P4 at estrus was lower (P<0.05) in pregnant than in non-pregnant, regardless treatment or animal type. At the following post-service days, serum P4 showed the same trend of change, being higher (P<0.001) in CIDR than in control animals and in pregnant than in non-pregnant animals, regardless animal type. It could be concluded that the random usage of CIDR device for 9 days and prostaglandin F2α injection 24 h pre-CIDR withdrawal can be applied to improve pregnancy rate of repeat breeder Egyptian buffaloes.