Carvalho N A T, Soares J G, Souza D C, Maio J R G, Sales J N S, Martins Júnior B, Macari R C, D'Occhio M J, Baruselli P S
Unidade de Pesquisa e Desenvolvimento de Registro-Polo Regional do D.S.A. do Vale do Ribeira/APTA, Registro, São Paulo, Brazil.
Departamento de Reprodução Animal, VRA-FMVZ-USP, São Paulo, São Paulo, Brazil.
Theriogenology. 2017 Jan 1;87:333-338. doi: 10.1016/j.theriogenology.2016.09.006. Epub 2016 Sep 13.
The aim of this study was to compare estradiol benzoate (EB) and GnRH for the induction of ovulation in a TAI protocol in buffalo during the nonbreeding season. In experiment 1, 141 buffaloes (56 cows and 85 heifers) received an intravaginal P4 device (1.0 g) plus EB (2.0-mg, intramuscular [im]) at random stage of the estrous cycle (Day 0). On Day 9, the P4 device was removed, and buffaloes were given PGF (0.53-mg im sodium cloprostenol) plus eCG (400-IU im). Buffaloes were then randomly allocated to one of three groups and treated as follows: EB24 (n = 47), EB (1.0 mg im) 24 hours after P4 device removal; EB36 (n = 50), EB 36 hours after P4 device removal; GnRH48 (n = 44), GnRH (10 μg im buserelin acetate) 48 hours after P4 device removal. Ultrasound examinations were performed on Day 0 to ascertain ovarian follicular status, Day 9 to measure follicular diameter, and from Day 11 to Day 14 (every 12 hours for 60 hours) to establish the time of ovulation. There were no significant differences between EB24, EB36, and GnRH48 for diameter of the ovulatory follicle (13.1 ± 0.3, 13.7 ± 0.3, and 13.7 ± 0.3 mm; P = 0.26) and ovulation rate (78.7%, 82.0%, and 84.1%; P = 0.93). When compared with heifers, cows had a greater diameter of the dominant follicle on Day 9 (10.3 ± 0.3 and 8.6 ± 0.2 mm; P = 0.0001), diameter of the ovulatory follicle (14.1 ± 0.3 and 13.1 ± 0.2 mm; P = 0.01), ovulation rate (91.1% and 75.3%; P = 0.02), and interval from P4 device removal to ovulation (76.3 ± 1.3 and 72.5 ± 1.4 hours; P = 0.05). In experiment 2, 511 buffaloes (354 cows and 157 heifers) were assigned to the same treatments described in experiment 1 (EB24, n = 168; EB36, n = 172; and GnRH48, n = 171), and all animals were submitted to timed artificial insemination (TAI) 64 hours after P4 device removal. Pregnancy diagnosis was undertaken 30 days after TAI. There were no significant differences between EB24, EB36, and GnRH48 for pregnancy rate (45.2%, 43.0%, and 49.7%; P = 0.46), and the pregnancy rate did not differ (P = 0.31) for cows (47.5%) and heifers (42.7%). The findings from the two experiments indicated that EB (24 or 36 hours) and GnRH (48 hours) induce comparable follicular responses, ovulation, and pregnancy rates in buffalo cows and heifers. Although there were some differences in the follicular responses between cows and heifers, the pregnancy rate to TAI was nonetheless similar.
本研究的目的是比较苯甲酸雌二醇（EB）和促性腺激素释放激素（GnRH）在非繁殖季节水牛定时人工授精（TAI）方案中诱导排卵的效果。在实验1中，141头水牛（56头母牛和85头小母牛）在发情周期的随机阶段（第0天）接受阴道内孕酮（P4）装置（1.0 g）加EB（2.0 mg，肌肉注射[im]）。在第9天，取出P4装置，给水牛注射前列腺素F2α（PGF，0.53 mg氯前列醇钠im）加促性腺激素（eCG，400 IU im）。然后将水牛随机分为三组并按以下方式处理：EB24（n = 47），在取出P4装置后24小时注射EB（1.0 mg im）；EB36（n = 50），在取出P4装置后36小时注射EB；GnRH48（n = 44），在取出P4装置后48小时注射GnRH（10 μg醋酸布舍瑞林im）。在第0天进行超声检查以确定卵巢卵泡状态，在第9天测量卵泡直径，并在第11天至第14天（每12小时一次，共60小时）确定排卵时间。EB24、EB36和GnRH48组在排卵卵泡直径（13.1±0.3、13.7±0.3和13.7±0.3 mm；P = 0.26）和排卵率（78.7%、82.0%和84.1%；P = 0.93）方面无显著差异。与小母牛相比，母牛在第9天的优势卵泡直径更大（10.3±0.3和8.6±0.2 mm；P = 0.0001），排卵卵泡直径更大（14.1±0.3和13.1±0.2 mm；P = 0.01），排卵率更高（91.1%和75.3%；P = 0.02），从取出P4装置到排卵的间隔时间更长（76.3±1.3和72.5±1.4小时；P = 0.05）。在实验2中，511头水牛（354头母牛和157头小母牛）被分配到与实验1相同的处理组（EB24，n = 168；EB36，n = 172；GnRH48，n = 171），所有动物在取出P4装置后64小时进行定时人工授精（TAI）。在TAI后30天进行妊娠诊断。EB24、EB36和GnRH48组在妊娠率方面无显著差异（45.2%、43.0%和49.7%；P = 0.46），母牛（47.5%）和小母牛（42.7%）的妊娠率也无差异（P = 0.31）。两个实验的结果表明，EB（24或36小时）和GnRH（48小时）在水牛母牛和小母牛中诱导出相似的卵泡反应、排卵和妊娠率。尽管母牛和小母牛在卵泡反应上存在一些差异，但TAI后的妊娠率相似。
