Superovulation and non-surgical embryo recovery in the lactating dairy cow

Abstract

A simple non-surgical technique was used to recover embryos from lactating dairy cattle, given 3000 IU PMSG to induce superovulation and the results obtained were compared with the ovulation rate and recovery of embryos from slaughtered cows.In the slaughtered cows, which were treated late in lactation, mean ovulation rate was only 8·3 ± 1·24 or 9·8 ± 1·26 excluding cows that failed to ovulate. A mean of 6·1 ± 0·63 eggs was recovered but only 4·2 ± 0·63 were normally developed embryos. In the cows treated in mid-lactation for non-surgical embryo recovery, 25/92 had fewer than three ovulations. A mean of 3·5 ± 0·45 eggs was obtained non-surgically from 58 cows that were flushed, and 3·1 ± 0·44 were normal embryos. The estimated recovery rate of normal embryos non-surgically was 38 % of those ovulated compared with 43 % from slaughtered animals.It appears that the lactating dairy cow has a rather low ovulatory response to PMSG but by the repeated use of the non-surgical embryo recovery method described, sufficient numbers of embryos may be obtained on a yearly basis to justify the use of the procedure for the improvement and dissemination of dairy breeds.