The possible use of superovulation and embryo transfer in cattle to increase response to selection

Abstract

SUMMARY: The possible use of superovulation and embryo transfer in selection programmes in cattle is investigated theoretically, in terms of both rates of response and inbreeding.In a selection programme for growth rate, it should be possible to achieve about twice the response of a conventional performance testing programme, so that 400-day weight, for example, could be increased by 16 rather than 9 kg per year.The improvement of reproductive performance by the use of laparoscopy to measure the natural ovulation rate of animals over several oestrous cycles followed by superovulation of selected animals is investigated. The rate of progress is dependent upon the incidence of twin ovulations in the base population and is unlikely to exceed 0·6% per year unless the initial frequency is 8% or more.