Stellflug J N, Rodriguez F, LaVoie V A, Glimp H A
U. S. Sheep Experiment Station, ARS, USDA, Dubois, ID 83423.
J Anim Sci. 1994 Jan;72(1):29-33. doi: 10.2527/1994.72129x.
The objective of this study was to test the hypothesis that a combination of induced estrus (IE) and melatonin (MEL) would increase reproductive performance in breeds characterized by late maturity more than either IE or MEL alone. Spring-born Columbia (C; n = 161; 188 to 222 d range of age at breeding; 49 to 80 kg range of BW at breeding) and Targhee (T; n = 166; 183 to 210 d range of age at breeding; 40 to 68 kg range of BW at breeding) ewe lambs were stratified randomly by breed to treatments: ambient controls (AC); IE; MEL; and MEL+IE. Melatonin (18 mg of Regulin) was implanted on September 7. Estrus induction included medroxyprogesterone acetate (MAP) pessaries inserted for 12 d and pregnant mare's serum gonadotropin (PMSG; 500 IU i.m.) at time of MAP removal. Ewe lambs were placed into two pens with five rams per pen by breed. Targhee ewes lambed at an increased rate with IE vs no IE (84.5 vs 67.9%; P < .01) and tended to lamb at an increased rate with MEL vs no MEL (82.5 vs 70.6%; P = .07). The 92.7% lambing rate observed in the Targhee ewe lambs for the combined treatment (MEL+IE) was slightly higher than an additive effect but the interaction between IE and MEL was not significant (P = .24). By contrast, none of the treatments altered (P = .5) lambing rate, number of lambs born, or number born alive for Columbia ewe lambs.(ABSTRACT TRUNCATED AT 250 WORDS)
诱导发情（IE）和褪黑素（MEL）联合使用，相比单独使用IE或MEL，能更有效地提高晚熟品种的繁殖性能。春季出生的哥伦比亚（C；n = 161；配种时年龄范围为188至222天；配种时体重范围为49至80千克）和塔吉（T；n = 166；配种时年龄范围为183至210天；配种时体重范围为40至68千克）母羊按品种随机分层接受以下处理：环境对照组（AC）；IE；MEL；以及MEL + IE。9月7日植入褪黑素（18毫克Regulin）。诱导发情包括插入醋酸甲羟孕酮（MAP）阴道栓12天，并在取出MAP时肌肉注射孕马血清促性腺激素（PMSG；500国际单位）。母羊按品种被放入两个围栏，每个围栏有五只公羊。与未进行IE处理相比，塔吉母羊经IE处理后产羔率提高（84.5%对67.9%；P < 0.01），与未使用MEL相比，使用MEL后产羔率有提高的趋势（82.5%对70.6%；P = 0.07）。在塔吉母羊中，联合处理（MEL + IE）的产羔率为92.7%，略高于相加效应，但IE和MEL之间的交互作用不显著（P = 0.24）。相比之下，所有处理均未改变（P = 0.5）哥伦比亚母羊的产羔率、产羔数或存活产羔数。（摘要截断于250字）
