COMPARISON OF 2 SOURCES OF GONADOTROPIN FOR ESTRUS SYNCHRONIZATION INDOES

Two sources of gonadotropin, combined with norgestomet implants and cl oprostenol, were compared to induce estrus in 137 lactating dairy goat s during the period of transition from anestrus to estrus. Does receiv ed either reagent-grade PMSG or commercially available hCG/PMSG produc t labeled for use in swine. Of the does treated with hCG/PMSG, 63 of 7 0 (90%) became pregnant compared with 50 of 66 (76%) does treated with reagent-grade PMSG. The pregnancy rates were significantly associated with the source of gonadotropin (P=0.047). No difference in estrus re sponse or litter size was detected; however, more does in the PMSG gro up appeared to have an extended interval from implant removal to breed ing than did the hCG/PMSG-treated does. The results of this study indi cate that the hCG/PMSG combination product is a satisfactory source of PMSG for extra-label use with norgestomet implants and cloprostenol t o synchronize estrus in transitional period does.