Tonizza de Carvalho Nelcio Antonio, Soares de Carvalho Júlia Gleyci, Sales José Nélio de Sousa, Guerreiro Bruna Martins, Freitas Bruno Gonzalez de, D'Occhio Michael J, Baruselli Pietro Sampaio
Research and Development Unit of Registro / Diversified Animal Science Research Center / Institute of Animal Science, Registro, São Paulo, Brazil.
Human Reproduction Section, Division of Urology, Department of Surgery, São Paulo Federal University, São Paulo, São Paulo, Brazil.
Theriogenology. 2020 Nov;157:498-502. doi: 10.1016/j.theriogenology.2020.08.024. Epub 2020 Aug 24.
The aim of this study was to determine if treatment with estradiol cypionate (EC) at the time of P4 withdrawal induced ovulation in a synchronization/timed-AI (TAI) protocol in buffalo. In Experiment 1, 56 buffaloes received an intravaginal P4 device (1.0 g) plus estradiol benzoate (EB, 2.0 mg im) on Day 0 (D0). 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 two groups: Group GEC (n = 29), treated with EC (1.0 mg im) at P4 device removal; Group GEB (n = 27), treated with EB (1.0 mg im) 24 h after P4 device removal. Ovarian ultrasound was undertaken on: D0, to ascertain general ovarian status; D9 to D11 (every 24 h), to measure diameter of the largest follicle (LF) and follicular growth rate; D11 to D13 (every 12 h for 72 h), to determine the time of ovulation and ovulation rate. Following P4 device removal, Groups GEC and GEB had a similar follicular growth rate (0.9 ± 0.1 and 1.1 ± 0.1 mm/day, respectively; P = 0.15) and similar LF diameter on D11 (11.4 ± 0.6 and 12.5 ± 0.5 mm; P = 0.12). Groups GEC and GEB also had a similar diameter of the ovulatory follicle (13.0 ± 0.5 and 13.4 ± 0.6 mm; P = 0.52), interval from P4 device removal to ovulation (68.2 ± 2.8 and 71.1 ± 1.4 h; P = 0.41) and ovulation rate (62.1% and 70.4%; P = 0.44). In Experiment 2, 199 buffaloes were assigned to the two treatments in Experiment 1 (GEC, n = 100; GEB, n = 99). All animals underwent TAI 56 h after P4 device removal and pregnancy diagnosis was preformed on D41. The pregnancy rate was similar for Groups GEC and GEB (50.0 and 45.5%, respectively; P = 0.45). The findings indicate that treatment with EC at the time of P4 withdrawal induces ovulation and achieves the same pregnancy rate to TAI as treatment with EB 24 h after P4 removal. The use of EC requires one less handling which is highly important in facilitating practical adoption of TAI in assisted breeding and genetic improvement in buffalo.
本研究的目的是确定在水牛同步/定时人工授精（TAI）方案中，在孕酮（P4）撤药时使用环丙孕酮（EC）治疗是否能诱导排卵。在实验1中，56头水牛在第0天（D0）接受阴道内P4装置（1.0 g）加苯甲酸雌二醇（EB，2.0 mg，肌肉注射）。在第9天，取出P4装置，给水牛注射前列腺素F（0.53 mg，肌肉注射氯前列醇钠）加促性腺激素（400 IU，肌肉注射）。然后将水牛随机分为两组：GEC组（n = 29），在取出P4装置时用EC（1.0 mg，肌肉注射）治疗；GEB组（n = 27），在取出P4装置24小时后用EB（1.0 mg，肌肉注射）治疗。在以下时间进行卵巢超声检查：D0，以确定一般卵巢状态；D9至D11（每24小时一次），测量最大卵泡（LF）直径和卵泡生长率；D11至D13（每12小时一次，共72小时），以确定排卵时间和排卵率。取出P4装置后，GEC组和GEB组的卵泡生长率相似（分别为0.9±0.1和1.1±0.1 mm/天；P = 0.15），D11时的LF直径相似（11.4±0.6和12.5±0.5 mm；P = 0.12）。GEC组和GEB组排卵卵泡的直径也相似（13.0±0.5和13.4±0.6 mm；P = 0.52），从取出P4装置到排卵的间隔时间相似（68.2±2.8和71.1±1.4小时；P = 0.41），排卵率也相似（62.1%和70.4%；P = 0.44）。在实验2中，199头水牛被分配到实验1中的两种治疗方法（GEC组，n = 100；GEB组，n = 99）。所有动物在取出P4装置56小时后进行TAI，并在D41进行妊娠诊断。GEC组和GEB组的妊娠率相似（分别为50.0%和45.5%；P = 0.45）。研究结果表明，在P4撤药时用EC治疗可诱导排卵，并与在取出P4后24小时用EB治疗达到相同的TAI妊娠率。使用EC减少了一次操作，这对于在水牛辅助育种和遗传改良中促进TAI的实际应用非常重要。
