Ruiter T
Tijdschr Diergeneeskd. 1978 Dec 15;103(24):1334-8.
The annual number of weaner lambs per ewe is a factor of major importance in the profitability of sheep farming. In the Netherlands, approximately 80 per cent of the incomes are derived from the returns for lambs sold. Induction of oestrus makes it possible for the ewes to lamb three times in two years. To achieve a high conception rate, tupping should take place under supervision. In the Experimental Livestock-Farming Station, Lelystad, studies on the possibilities of inducing oestrus were done in ewes in which tupping occurred for the first time at an age of approximately seven months during natural oestrus in the months of October and November. The results obtained by inducing oestrus in July and August were similar to those obtained with natural oestrus in October and November. The results obtained in February and March were slightly inferior, which probably was also due to the fact that the condition of the ewes was not very good immediately after weaning of the lambs at six weeks. The number of lambs born showed an average increase of 0.5 lamb per ewe mating with the ram per year. A further increase of the annual number of lambs per ewe is likely to be achieved.
每只母羊每年所产断奶羔羊的数量是养羊业盈利能力的一个至关重要的因素。在荷兰，约80%的收入来自出售羔羊的收益。诱导发情能使母羊在两年内产羔三次。为达到高受孕率，配种应在监督下进行。在莱利斯塔德实验畜牧站，对首次在10月和11月自然发情期、约七个月龄时配种的母羊进行了诱导发情可能性的研究。7月和8月诱导发情所获结果与10月和11月自然发情所获结果相似。2月和3月所获结果略逊一筹，这可能也是由于羔羊在六周龄断奶后母羊的状况不太好所致。每年每只与公羊交配的母羊所产羔羊数量平均增加了0.5只。每只母羊每年产羔数量有望进一步增加。
