Ovarian activity and sexual behavior in the postpartum Swamp Buffalo (Bubalus bubalis)

Early postpartum follicular activity and sexual behavior was evaluated in the swamp buffalo (Bubalus bubalis) in a tropical climate. Sixteen multiparous postpartum swamp buffaloes, 4-12 years of age, (432 - 676 kg) were studied starting between 5-29 days after parturition. Ovarian follicular activity was examined daily in the morning with a real-time B-mode linear array ultrasound scanner (Aloka SSD-500, Tokyo, Japan) equipped with a 7.5 MHz transrectal transducer. Estrous detection was performed daily using a mature bull, via personal observation as well as via video registration. In addition, vaginal discharge around estrus was evaluated. Uterine involution took 28.74+1.21 days (mean +SEM, range 22-41 d, n=16). Follicular activity prior to the first ovulation was characterized by a wave like pattern. Follicular growth rates and maximum diameter of the follicle in the second, third and fourth cycle post partum did not differ while that of the first ovulation follicle was significantly lower (p<0.05). Short ovarian cycles were observed in 93.3% of the buffaloes in the first to second ovulation interval (10.14+40 d), and in 50.0% of the buffaloes in the second to third ovulation interval (12.00+1.53 d), while one buffalo cow then had a long estrus cycle (27 d). The behavioral characteristics of estrus around the first postpartum ovulation were not as obvious as around the second, third and fourth postpartum ovulation. It can be concluded that for optimal reproductive efficiency the swamp buffalo should be mated between 1- 2 months postpartum at the second ovulation.