Use of PMSG antiserum in superovulated cattle?

Two Pregnant Mare Serum Gonadotrophin (PMSG) antisera were tested in 174 dairy cows that were superovulated with PMSG and were then given prostaglandin at 60 hours after PMSG. At 48 hours after injection of prostaglandin, the cows were given either PMSG antiserum (monoclonal (n=56) or polyclonal (n=57)), or saline as control (n=61). Ova (n=1,206) were recovered either nonsurgically or after slaughter. Of these, 757 were evaluated morphologically to be transferable embryos. A proportion of these embryos (n=295 from 52 flushed donors) were transferred to synchronized recipients and the pregnancy results were recorded. The reproductive function of 37 flushed donors was followed for 6 months after superovulation. No significant effect of the PMSG antisera could be demonstrated in any of the parameters studied (i.e., ovulation rate, number of follicles at collection, total yield of ova, fertilization rate, number of transferable embryos, pregnancy results after transfer of embryos, or period required by the donor cows for restitution of reproductive function after superovulation and recovery). It is concluded that use of PMSG antiserum did not improve the embryo yield in terms of the number and quality of transferable embryos or enhance normalization of reproductive function of the donor in the 6-month period after superovulation. Therefore, in an embryo transfer operation, the routine use of PMSG antiserum in a PMSG superovulation regimen in cattle is not recommended.