Calving performance after embryo transfer-induced twinning - a summary of 30 studies

摘要

Twin calving in beef cows has been proposed as a strategy to increase the biological as well as economic efficiency of beef production. The aim of this paper is to summarise the calving performance of cows induced to calve twins following embryo transfer using data from 30 published studies. The pooled data shows that 45, 28 and 27% of recipients give birth to either 0, 1 or 2 calves resulting in 82 calves born/100 recipients and 47% of calving cows producing twins. Overall mean embryo survival ratewas only 41 %. Compared with recipients which received in vitro-produced embryos, a higher proportion of recipients that received either a pair of in vivo-derived embryos or a single such embryo in conjunction with AI were pregnant (60 vs 43%) or produced twin calves (52 vs 39%). In addition, more calves were bom (90 vs 60%). Considerable variation exists in all parameters, particularly the proportion of number of calves bom.