Minton J E, Coppinger T R, Spaeth C W, Martin L C
Dept. of Anim. Sci. and Ind Kansas State University, Manhattan 66506-0201.
J Anim Sci. 1991 Aug;69(8):3314-20. doi: 10.2527/1991.6983314x.
Twenty Polypay-sired ewes (Group P) and 14 Suffolk ewes (Group S) were bled at 48-h intervals for 10 d beginning on April 6, 1989, and the serum was assayed for progesterone to determine which ewes were anestrous; 9/20 Group P ewes were anestrous, compared with 14/14 Group S ewes (P less than .001). Catheters were placed into the jugular vein of anestrous ewes from both breed groups (eight of Group P, seven of Group S), and samples of serum were collected at 12-min intervals for 4 h. Then, the ewes were exposed to mature, intact rams, and additional samples were taken at 12-min intervals for 4 h after ram exposure. The serum was later analyzed to determine the secretion of LH in response to ram introduction. After the acute bleeding period, all Group P and Group S ewes were commingled and exposed to a ram continuously for 42 d. Samples of serum were collected thrice weekly and analyzed for progesterone to monitor ovulatory response to ram introduction through the 42-d period. In addition, breeding activity and lambing data were recorded. When all Group P ewes were compared to Group S ewes, a greater proportion (P less than .001) of Group P ewes were mated (20/20 vs 3/13; one Group S ewe died during the 42-d mating period) by the end of the 42-d period and more (P less than .001) ewes lambed in the fall (17/20 Group P vs 2/13 Group S).(ABSTRACT TRUNCATED AT 250 WORDS)
1989年4月6日起，20只波利帕伊（Polypay）品种的母羊（P组）和14只萨福克（Suffolk）品种的母羊（S组）每隔48小时采血一次，持续10天，检测血清中的孕酮，以确定哪些母羊处于发情间期；P组20只母羊中有9只处于发情间期，而S组14只母羊均处于发情间期（P<0.001）。从两个品种组处于发情间期的母羊的颈静脉插入导管（P组8只，S组7只），每隔12分钟采集一次血清样本，持续4小时。然后，让这些母羊与成熟、未阉割的公羊接触，并在公羊接触后每隔12分钟采集一次样本，持续4小时。之后分析血清，以确定引入公羊后促黄体生成素（LH）的分泌情况。急性采血期结束后，所有P组和S组母羊混合在一起，持续42天与一只公羊接触。每周采集三次血清样本，检测孕酮，以监测42天内引入公羊后的排卵反应。此外，记录配种活动和产羔数据。在42天结束时，将所有P组母羊与S组母羊进行比较，P组母羊中有更大比例（P<0.001）成功配种（20/20对3/13；一只S组母羊在42天配种期内死亡），秋季产羔的母羊也更多（P组17/20对S组2/13）。（摘要截选至250词）
