Pratt S L, Spitzer J C, Burns G L, Plyler B B
Anim. Dairy and Vet. Sci. Dept., Clemson University, SC 29634-0361.
J Anim Sci. 1991 Jul;69(7):2721-6. doi: 10.2527/1991.6972721x.
Two experiments were conducted to determine whether dosage of estradiol valerate (EV) or day of estrous cycle when treatment was administered affected response to Syncro-Mate-B (SMB). Suckled beef cows received a 6-mg Norgestomet (NOR) ear implant (in situ 9 d) and a 3-mg NOR i.m. injection. In Exp. 1, 74 cows received NOR treatments concurrently with either 5 or 6 mg of EV administered i.m. on either d 1, 3, or 5 of an estrous cycle (estrus = d 1). In Exp. 2, 169 cows received NOR treatments concurrently with either 5, 7, or 9 mg of EV administered i.m. on either d 3 or 9 of an estrous cycle. In Exp. 1, 67, 50 and 92%, respectively, of cows receiving 5 mg of EV on d 1, 3, or 5 had functional corpora lutea (CL) at implant removal, whereas 42, 75, and 77%, respectively, of cows receiving 6 mg of EV had functional CL at implant removal (dosage P greater than .10; day P less than .05). Synchronized estrous responses were 50, 33, and 23%, respectively, when cows received 5 mg of EV on d 1, 3, or 5, and 67, 33, and 38%, respectively, when cows received 6 mg of EV (dosage P greater than .10; day P less than .05). First-service pregnancy rate was decreased (P less than .05) in cows treated on d 5 (33%) compared with cows treated on d 1 (63%), but dosage of EV had no effect on pregnancy rate.(ABSTRACT TRUNCATED AT 250 WORDS)
进行了两项试验，以确定戊酸雌二醇（EV）的剂量或给药时的发情周期天数是否会影响对同步伴侣B（SMB）的反应。哺乳的肉牛接受了6毫克诺孕美特（NOR）耳部植入物（原位9天）和3毫克NOR肌肉注射。在试验1中，74头母牛在发情周期的第1、3或5天（发情期=第1天）接受NOR处理的同时，肌肉注射5或6毫克EV。在试验2中，169头母牛在发情周期的第3或9天接受NOR处理的同时，肌肉注射5、7或9毫克EV。在试验1中，在植入物取出时，分别在第1、3或5天接受5毫克EV的母牛中，有67%、50%和92%具有功能性黄体（CL），而接受6毫克EV的母牛中，分别有42%、75%和77%具有功能性CL（剂量P大于0.10；天数P小于0.05）。当母牛在第1、3或5天接受5毫克EV时，同步发情反应分别为50%、33%和23%，当母牛接受6毫克EV时，同步发情反应分别为67%、33%和38%（剂量P大于0.10；天数P小于0.05）。与在第1天（63%）接受处理的母牛相比，在第5天（33%）接受处理的母牛首次配种妊娠率降低（P小于0.05），但EV剂量对妊娠率没有影响。（摘要截断于250字）
