Fitzgerald J A, Ruggles A J, Stellflug J N, Hansel W
J Anim Sci. 1985 Aug;61(2):466-9. doi: 10.2527/jas1985.612466x.
Estrous cycles of adult (n = 27), farm-flock, Suffolk ewes and Polypay range ewes (n = 224) were controlled with medroxyprogesterone acetate (MAP)-impregnated vaginal pessaries inserted (d 0) for 7 d in combination with prostaglandin F2 alpha (PGF2 alpha) injected on d 6. Descriptive criteria of the effects of this treatment regimen on endocrine characteristics of the estrous cycle were evaluated in the experiment with farm-flock ewes. The efficacy of this synchronization regimen on reproductive performance of range-bred ewes was tested in a second trial. Suffolk ewes bred at the second observed estrus after treatment to provide comparisons of cycle length between treated and control ewes. Polypay ewes were exposed to fertile rams at the controlled estrus. Eighty-nine percent of Suffolk ewes were in estrus within 3 d after pessary removal. All nonsynchronized Suffolk ewes (n = 24) were in estrus over a 21-d period. Estrous cycle lengths of treated ewes averaged 16.8 +/- .2 d. Plasma progesterone concentrations were similar for treated and control ewes during the luteal phase of the estrous cycle. Ninety-one percent of the range-bred, controlled ewes lambed. Sixty-two percent of these ewes lambed within 150 d after exposure to fertile rams compared with only 17% of nonsynchronized ewes (P less than .05). Lambing percentage was similar by 167 d for treated (87%) or control (88%) ewes. Lambs per ewe exposed averaged 1.68 and 1.80 for treated and nonsynchronized groups, respectively. These data indicate the effectiveness of this 7-d treatment method for control of the estrous cycle of ewes during the normal breeding season. Results further show that this treatment scheme has practical application for range breeding of ewes.
对成年（n = 27）农场饲养的萨福克母羊和波利佩伊母羊（n = 224）的发情周期进行控制，在第0天插入含醋酸甲羟孕酮（MAP）的阴道栓，持续7天，并在第6天注射前列腺素F2α（PGF2α）。在农场饲养母羊的实验中评估了该治疗方案对发情周期内分泌特征的影响的描述性标准。在第二项试验中测试了这种同步方案对放牧母羊繁殖性能的有效性。治疗后在第二次观察到的发情期配种萨福克母羊，以比较治疗母羊和对照母羊的周期长度。波利佩伊母羊在控制发情期与可育公羊接触。89%的萨福克母羊在取出阴道栓后3天内发情。所有未同步的萨福克母羊（n = 24）在21天内发情。治疗母羊的发情周期长度平均为16.8±0.2天。在发情周期的黄体期，治疗母羊和对照母羊的血浆孕酮浓度相似。91%的放牧、经控制的母羊产羔。这些母羊中有62%在与可育公羊接触后150天内产羔，相比之下未同步母羊只有17%（P<0.05）。到167天时，治疗母羊（87%）和对照母羊（88%）的产羔率相似。治疗组和未同步组每只接触母羊的平均产羔数分别为1.68和1.80。这些数据表明这种7天治疗方法在正常繁殖季节控制母羊发情周期方面是有效的。结果进一步表明，该治疗方案在母羊放牧繁殖中有实际应用价值。
