SUPEROVULATION AND EMBRYO PRODUCTION IN EWES USING A COMMERCIAL p-FSH

The effectiveness of a commercial porcine pituitary extract (p-FSH) with a 1:1 FSH/LH ratio was assessed on ovarian response and embryo yield in ewes. During the breeding season, 60 Altamurana ewes were synchronized with FGA-impregnated intravaginal sponges and subdivided into four treatment groups (n=15). Beginning 24 h before sponge removal, ewes were treated with 250 (Group 1), 500 (Group 2), 750 (Group 3) or 1000 IU p-FSH (Group 3) administered in a series of four decreasing doses over a period of 36 h. The ewes were monitored for estrus every 4 h, with ovarian response and embryos evaluated on the seventh day following sponge removal. No differences were found among the treatments in incidence of estrus and ovulation. Although treatment with 250 IU p-FSH produced the fewest ovulations, animals in this group yielded a higher (P<0.01) number of viable embryos, a lower (P<0.01) number of unfertilized ova, and a lower (P<0.05) incidence of unovulated follicles and abnormal corpora lutea when compared with animals treated with 750 or 1000 IU p-FSH, while treatment with 500 IU p-FSH yielded intermediate results. It is concluded that the commercial porcine pituitary extract (Pluset) at moderate doses (250 IU) is suitable for superovulation in ewes as it induces a high ovulatory response and transferable embryo yield.