O'Farrell K J, Langley O H, Hartigan P J, Sreenan J M
Vet Rec. 1983 Jan 29;112(5):95-7. doi: 10.1136/vr.112.5.95.
Seventy-three Friesian dairy cows culled as repeat breeders were slaughtered three to six, 16 to 19 or 40 to 49 days after insemination to establish fertilisation and embryo survival rates. Fertilisation rate following a single insemination was 72 per cent. The estimated embryo survival rates for days 16 to ¿19 and 40 to 49 were 67 per cent and 76 per cent, respectively. The previous breeding history of the cows showed that only eight (11 per cent) had consistently regular returns (18 to 24 days) to service. Fifty-three (75 per cent) had a combination of both long and short returns to service. Before service on experiment, 64 (89 per cent) cows had regular cycles and the six cows which repeated from the 40 to 49 days group, five (83 per cent) had regular return intervals. It is suggested that errors in oestrus detection contribute substantially to the problem of repeated returns to service of dairy cows in Ireland.
73头作为屡配不孕牛只被淘汰的弗里生奶牛在输精后3至6天、16至19天或40至49天被屠宰，以确定受精率和胚胎存活率。单次输精后的受精率为72%。16至19天和40至49天的估计胚胎存活率分别为67%和76%。这些奶牛以前的繁殖记录显示，只有8头（11%）的发情周期一直规律（18至24天）。53头（75%）的发情周期长短不一。在开始实验输精前，64头（89%）奶牛的发情周期规律，而在40至49天组中反复输精的6头奶牛，有5头（83%）的发情间隔规律。研究表明，发情检测失误在很大程度上导致了爱尔兰奶牛屡配不孕的问题。
