Effect of progesterone administration during growing phase of first dominant follicle on follicular wave pattern in buffalo heifers

In this study, we examined the preponderance of 2- versus 3-wave patterns in 46 interovulatory intervals (IOIs) from 36 buffalo heifers, in which a subset of 10 heifers was scanned for 2 consecutive IOIs to record the repeatability of follicular wave pattern. Two-wave pattern was detected in 63.0% and 3-wave follicular pattern in 27.0% IOIs. The dominant follicles (DF) of both wave 1 as well as the ovulatory wave attained a smaller (P< 0.05) maximum diameter in 3-wave cycle as compared to 2-wave cycle. The mean duration of IOI was significantly shorter in 2-wave compared to three-wave cycles (20.5 ± 0.3 vs. 22.3 ± 0.2 days;P< 0.05). Out of 10 buffalo heifers, 7 displayed non-alternating patterns and 3 had alternating follicular wave patterns. We also tested the hypothesis that progesterone administration during early IOI results in increased preponderance of 3-wave pattern and heifers inseminated after ovulation of the third wave DF will have greater fertility. Sixteen heifers subjected to progesterone treatment from D0 (day of ovulation) in a decreasing dose until D5 were compared with control heifers (n = 10). Progesterone treatment significantly reduced the maximum diameter of DF of wave 1 (P< 0.001), whereas the mean duration of IOI remained unchanged (P> 0.05) between the two groups. Progesterone administration during early IOI significantly increased the proportion of 3-wave cycles as compared to control (P< 0.05). The hypothesis that progesterone admin...
Source: Tropical Animal Health and Production - Category: Veterinary Research Source Type: research