Intravenous PGF2α administration at the time of artificial insemination in buffalo species: preliminary results.

The efficiency of artificial insemination (AI) in buffalo species is low, above all if the animals are inseminated when day length is increasing. It was recently demonstrated in cattle that the administration of a PGF2α analogous at the time of AI increased plasma progesterone concentration on day 6 post-insemination and pregnancy rate (PR) in repeat breeder bovines. The aim of this study was to evaluate the effect of a single intravenous administration of PGF2α on the day of AI in synchronized buffaloes. The trial was carried out on 116 multiparous Italian Mediterranean Buffaloes at 160±128 days in milk and 57 heifers 767±139 days old. The animals were synchronized by using the Ovsynch-TAI Program, which consists of 12 mcg buserelin acetate on Day 0, 0.524 mg PGF2α on Day 7 and 12 mcg buserelin acetate on Day 9. Each buffalo was inseminated twice, 16 and 40 h after the second injection of GnRH. On day of the first AI buffaloes were divided in two groups: animals in Group A received an intravenous administration of cloprostenol, a PGF2α analogue, while buffaloes in Group B did not receive any injection. On day 26 post-insemination buffaloes underwent trans-rectal ultrasonography examination, in order to assess pregnancies, that were confirmed on Day 45 by rectal palpation. Statistical analysis was performed by chi-square test. A higher, although not statistically significant, PR was recorded in Group A vs. Group B, both in pluriparous buffaloes and in heifers, on day 26 and 40 (Table 1). Further studies are needed in order to increase the number of animals and verify if the administration of cloprostenol will be able to significantly increase PR in buffalo species and reduce the phenomenon of early embryo mortality.