Pessoa G A, Martini A P, Carloto G W, Rodrigues M C C, Claro Júnior I, Baruselli P S, Brauner C C, Rubin M I B, Corrêa M N, Leivas F G, Sá Filho M F
Embryolab - Laboratório de Embriologia Animal, Departamento de Clínica de Grandes Animais-DCGA, Centro de Ciências Rurais - CCR, Universidade Federal Santa Maria (UFSM), Santa Maria RS, Brazil.
Laboratório de Biotecnologia da Reprodução (Biotech), Universidade Federal do Pampa, Uruguaiana, Rio Grande do Sul, Brazil.
Theriogenology. 2016 Mar 15;85(5):792-799. doi: 10.1016/j.theriogenology.2015.09.057. Epub 2015 Oct 19.
This study evaluated the effect of different doses of eCG (control, 300 or 400 IU) administered at progesterone (P4) device removal in suckled Bos taurus beef cows undergoing a timed artificial insemination (TAI) protocol. A total of 966 cows received a P4 insert and 2.0 mg intramuscular estradiol benzoate at the onset of the synchronization. After 9 days, P4 insert was removed, and 12.5 mg of dinoprost tromethamine and 1 mg of estradiol cypionate were administered, followed by TAI 48 hours later. Then, the cows received one of three treatments as follows: control (n = 323), 300 (n = 326), or 400 IU of eCG (n = 317). A subset (n = 435) of cows in anestrus had their ovaries evaluated using ultrasound at the time of P4 removal and at TAI. Data were analyzed by orthogonal contrasts (C): C1 (eCG effect) and C2 (eCG dose effect). Estrous occurrence (control = 53.7%, 300 IU = 70.6%, and 400 IU = 77.0%) and pregnancy per artificial insemination (control = 29.7%, 300 IU = 44.8%, and 400 IU = 47.6%) were improved by eCG treatment (C1; P = 0.0004 and P < 0.0001, respectively). Furthermore, the cows receiving eCG presented larger follicles at TAI (control = 13.5 ± 0.3 mm, 300 IU = 14.0 ± 0.2 mm, and 400 IU = 15.1 ± 0.3 mm; P < 0.0001; C1). However, there was no effect of eCG dose on any response variables studied (C2; P > 0.15). In conclusion, the eCG treatment administered at the time of P4 removal increased the occurrence of estrus, the larger follicles at TAI, and pregnancy per artificial insemination of suckled B taurus beef cows. Despite the greater occurrence of estrus in noncyclic cows receiving 400 IU of eCG, both eCG doses (300 and 400 IU) were equally efficient to improve pregnancy to artificial insemination.
本研究评估了在接受定时人工授精（TAI）方案的哺乳型黄牛肉牛中，在取出孕酮（P4）装置时给予不同剂量的孕马血清促性腺激素（对照、300或400国际单位）的效果。总共966头母牛在同步化开始时接受了P4植入物和2.0毫克肌肉注射苯甲酸雌二醇。9天后，取出P4植入物，并给予12.5毫克氯前列醇钠和1毫克环丙孕酮，48小时后进行TAI。然后，母牛接受以下三种处理之一：对照（n = 323）、300（n = 326）或400国际单位的孕马血清促性腺激素（n = 317）。一部分处于乏情期的母牛（n = 435）在取出P4时和TAI时使用超声评估其卵巢。数据通过正交对比（C）进行分析：C1（孕马血清促性腺激素效应）和C2（孕马血清促性腺激素剂量效应）。孕马血清促性腺激素处理提高了发情发生率（对照 = 53.7%，300国际单位 = 70.6%，400国际单位 = 77.0%）和每次人工授精后的妊娠率（对照 = 29.7%，300国际单位 = 44.8%，400国际单位 = 47.6%）（C1；P = 0.0004和P < 0.0001，分别）。此外，接受孕马血清促性腺激素的母牛在TAI时卵泡更大（对照 = 13.5 ± 0.3毫米，300国际单位 = 14.0 ± 0.2毫米，400国际单位 = 15.1 ± 0.3毫米；P < 0.0001；C1）。然而，孕马血清促性腺激素剂量对所研究的任何反应变量均无影响（C2；P > 0.15）。总之，在取出P4时给予孕马血清促性腺激素处理增加了哺乳型黄牛肉牛的发情发生率、TAI时更大的卵泡以及每次人工授精后的妊娠率。尽管接受400国际单位孕马血清促性腺激素的非周期性母牛发情发生率更高，但两种孕马血清促性腺激素剂量（300和400国际单位）在提高人工授精妊娠率方面同样有效。
