SUPEROVULATORY RESPONSE OF MURCIANA GOATS TO TREATMENTS BASED ON PMSGANTI-PMSG OR COMBINED FSH/MSG ADMINISTRATION/

Superovulation in goats is frequently restricted by the cost of gonado tropin or the handling requirements. In this situation PMSG has the ad vantage of a lower cost and single dose protocol, but the variability of response obtained restricts its use. Thus, 2 alternative treatments with the advantages of PMSG were tested. In Experiment I, we compared the ovulatory response of does treated with PMSG in combination or no t with anti-PMSG antibodies at the onset of estrus, during season and out of season. In Experiment 2, we explored the effect of a partial su bstitution of FSH by PMSG at the end of treatment, comparing this trea tment with a standard FSH protocol. Our results showed a significant ( P<0.01) seasonal effect on the incidence of corpora lutea (CL) regress ion in both experiments. The mean of viable embryos collected from doe s treated with anti-PMSG antibodies (mean = 5.75) was significantly hi gher than in the control PMSG-treated group (mean = 2.74) during sprin g (P<0.05). Response during the fall was significantly lower regardles s of treatment, and administration of antibody did not provide any sig nificant improvement in superovulatory response (2.14 vs 1.77). In Exp eriment 2, the partial substitution of 3 doses of FSH by a single admi nistration of PMSG did not reduce the number of CL or viable embryos, and no seasonal differences were observed, comfirming that FSH provide s a less variable response. From our results, it can be concluded that the use of PMSG antibodies for superovulating goats is an efficacious treatment which increases the number of viable embryos collected. How ever, partial replacement of FSH with PMSG at the end of treatment als o did not compromise the number of embryos collected. Both approaches can be considered a valid alternative to treatments based on FSH. (C) 1998 by Elsevier Science Inc.