Predisposition to repeat breeding in UK cattle and success of artificial insemination alone or in combination with embryo transfer

摘要: To investigate whether there was a subpopulation of repeat breeders (cows or heifers that returned to oestrus after three inseminations) were less fertile fourth artificial insemination (AI) with without additional embryo transfer, and estimate the efficacy AI plus transfer overcome breeding problems, two-part investigation carried out. Part 1 involved 85 controls subjected alone. In part 2, 128 received on day 0 an seven days later, while alone 7. breeders, interval between calving pregnancy 80 longer than in (P=0.01), irrespective previous fertility treatment which had mainly focused ovaries. The incidence dystocia similar controls, but higher moderate uterine infection compared (P=0.04). breeder cows, rates for 30 per cent (controls: 45 64 one 52.6 (controls alone: 49 cent). Successful pregnancies produced 6.25 twins.