Superovulatory response to FSH+LH treatment with or without progesterone supplementation in buffalo.

The multiple ovulation and embryo transfer (MOET) technique represents an attempt to further contribute to genetic improvement. Several authors reported a scanty recovery rate in terms of embryos in buffalo species after superovulatory treatment, with an average of 1.43, 2.38 and 1.4-3.1 embryos/flushing/donor. The aim of this study was to verify if the presence of progesterone during the first two days of a FSH-LH superovulatory treatment may improve embryo recovery. The trial was carried out on 14 multiparous Italian Mediterranean Buffaloes at 113±98 days in milk from December to May. The animals were synchronized by a double injection of 0.524 mg of PGF2α 12 days apart. After 60 hours from the last injection of PGF2α buffaloes undergone clinical examination of the genital tract in order to evaluate estrus status: animals with tonic uterus and a follicle higher than 1.2 mm, with or without mucus vaginal discharge, were considered in estrus and a progesterone releasing intravaginal device was inserted (Day 0). Buffaloes were, hence, divided in two groups, according to parity and days in milk. In Group A (n=7) PRID was removed on Day 8, whereas in Group B (n=7) it was left till day 10. Both groups received a 4-day decreasing dosage of an equal mixture of 500 I.U. of FSH and LH since day 8. On day 10 all treated buffaloes were injected twice 12 hours apart with 0.524 mg PGF2α. Two artificial inseminations were performed 60 and 84 h after the second injection of PGF2α. Six days after the first insemination buffaloes undergone a uterine flushing with phosphate buffered saline supplemented with 1% fetal calf serum: each uterine horn was washed with at least 500 ml of solution. Embryos were immediately searched by filtration and vitrified, according to Neglia et al. (2001). Statistical analyses was carried out by t Student test. Two animals (one for each treatment) did not result responsive to the superovulation treatment. A higher, although not statistically significant, number of embryos was recorded in Group B vs. Group A if all animals are considered. However, if the analysis is carried out only on responsive buffaloes, a higher (P<0.05) recovery rate was recorded in Group B vs. Group A. These results are in accordance with previous reports in buffalo species. Progesterone supplementation during the first two days of the superovulation treatment seems to enhance the number of recovered embryos, although further studied are needed in order to apply the MOET in buffalo.