Follicular dynamic in buffaloes undergone to two superovulation protocols

The trial was performed on 18 multiparous Mediterranean buffaloes, pre-synchronized by a double injection of 0.524 mg of PGF2α. Animals were divided into two groups (A and B), that underwent two superovulation (SO) treatments, starting 8 days after estrus (day 0): Group A (n=9) received a 4-days double daily decreasing dosage of 400 mg NIH-FSH-P1 (Folltropin®, Bio98, Italy). Group B (n=9) received the same treatment as Group A for the first 2 days, and a single injection of 1000 IU of eCG (Ciclogonina®, Fortdodge, Italy). On day 10 all buffaloes received a double injection of 0.524 mg of PGF2α to induce luteolysis. Ultrasound follicular development was assessed daily on each buffalo from the start of the SO treatments until 48 hours after estrus detection to record the total number of the follicles, grouped into 3 categories according to their diameter: small (between 0.20 and 0.50 cm), medium (between 0.51 and 1.00 cm) and large (more than 1.01 cm). The statistical analysis was carried out by using the chi-square test and the analysis of variance. Buffaloes in Group B showed a higher (P<0.05) number of large follicles (3.7±0.5 vs. 7.1±1.2 in Group A and B, respectively) with larger diameter (1.27±0.0 vs. 1.45±0.0 in Group A and B, respectively) compared to those in Group A at the end of the SO treatments. Although a similar total number of ovulations (4.22±0.8 vs. 6.22±1.3 in Group A and B, respectively), the ovulations recorded within 28 hours after estrus was significantly (P<0.01) higher in Group B compared to group A (0.89±0.3 vs. 4.44±1.0 in Group A and B, respectively). In conclusion, the replacement of the last four injections of FSH with a single administration of eCG results in a good superovulatory response, in terms of both number and size of the follicles and ovulations.