Follicular growth, estrus and pregnancy after fixed-time insemination in beef cows treated with intravaginal progesterone inserts and estradiol benzoate
Follicular growth, estrus and pregnancy after fixed-time insemination in beef cows treated with intravaginal progesterone inserts and estradiol benzoate
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DOI：
10.1016/s0093-691x(99)00153-3
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发表时间：
1999-09-01
期刊：
影响因子：
2.8
通讯作者：
Inskeep, EK
中科院分区：
文献类型：
--
作者：
Bridges, PJ;Lewis, PE;Inskeep, EK
本试验比较了3种短期黄体酮和苯甲酸雌二醇（EB）对产后哺乳期肉牛固定时间人工授精后卵泡生长、发情同步和受孕率的影响。在治疗1 （n = 46）中，每头奶牛在插入装置时注射EB (2 mg, im)，并连续7天注射含黄体酮的阴道内插入物。在治疗2 （n = 46）中，插入剂仅使用5天，插入时注射EB (2mg, im)；处理3 （n = 47）的奶牛连续5 d接受插入，插入时没有EB。3组奶牛在取出插入物时注射PGF(2) α (25 mg, im)， 30 h后注射EB （1 mg, im）。然后在EB处理后28 ~ 30 h（去除插入物后58 ~ 60 h）进行授精。在处理1和处理2中，2 mg EB分别终止了16/16和14/15头奶牛在插入装置时最大卵泡（直径0.5 mm）的生长。处理1、处理2和处理3中分别有93%、87%和81%的奶牛在8 h目标期内（去除插入物后48 ~ 56 h）可以发情（P < 0.05）。处理1、处理2和处理3的受精率分别为60%、50%和51% （P < 0.05）。无排卵奶牛和治疗前排卵奶牛的妊娠率（54%），以及产后28 ~ 40天、41 ~ 60天和60 ~ 60天奶牛的妊娠率（分别为43.59和54%）没有差异。孕酮植入剂治疗5或7天，取出植入剂时使用PGF2a， 30小时后使用1mg EB，可诱导固定时间人工授精所需的高程度的发情和排卵同步。(C) 1999年Elsevier Science Inc.
An experiment was performed to compare the effects of 3 short-term treatments with progesterone and estradiol benzoate (EB) on follicular growth, synchrony of estrus and pregnancy rate after fixed-time insemination in lactating postpartum beef cows. In Treatment 1 (n = 46), each cow received a progesterone-containing intravaginal insert for 7 d with injection of EB (2 mg, im) at the time of device insertion. In Treatment 2 (n = 46), the insert was used for only 5 d with injection of EB (2 mg, im) at the time of insertion; Cows in Treatment 3 (n = 47) received an insert for 5 d with no EB at the time of insertion. Each cow in the 3 groups received PGF(2)alpha (25 mg, im) at the time of insert removal, followed by EB (1 mg, im) 30 h later. The cows were then inseminated 28 to 30 h after treatment with EB (58 to 60 h after insert removal). Treatment with 2 mg EB terminated the growth of the largest ovarian follicle (>5 mm in diameter) at device insertion in 16/16 and 14/15 cows in Treatments 1 and 2, respectively. Estrus was detected within an 8-h target period (48 to 56 h after insert removal) in 93, 87 and 81% of cows in Treatments 1, 2 and 3, respectively (P>0.05). Pregnancy rates at 39 d post insemination were 60, 50 and 51% for Treatments 1, 2 and 3, respectively (P>0.05). The pregnancy rates did not differ between cows that were anovulatory or those that had ovulated before the initiation of treatments (54%), or among cows that were 28 to 40, 41 to 60 or >60 days post partum at insemination (43, 59 and 54%, respectively). Treatment with progesterone inserts for 5 or 7 d, PGF2a at the time of insert removal and 1 mg EB 30 h later induced the high degree of synchrony of estrus and ovulation necessary for fixed-time insemination. (C) 1999 by Elsevier Science Inc.