Veterinary Medicine R&D, Pfizer Animal Health Parkville, Victoria, Australia.
J Anim Sci. 2012 Nov;90(11):3718-28. doi: 10.2527/jas.2011-4826. Epub 2012 Jun 4.
The objective of this study was to determine the effects of a GnRH vaccine on feedlot performance and meat quality in Bos indicus Zebu × Brown Swiss bulls. The study was a 2 × 2 factorial arrangement of treatments with 1,600 bulls allocated by BW into 4 groups of ≈ 400 animals. The GnRH vaccine (Bopriva) was injected on d 0 and 42, and anabolic implants given on d 0 (Component E-S) and d 84 (Synovex Choice). Group designations were: Con = placebo control; Imp = implants alone; Vac = GnRH vaccine alone; and Vac+Imp = GnRH vaccine together with implants. The second GnRH vaccination at d 42 resulted in elevated titers of IgG antibody and suppressed concentrations of testosterone in vaccinated groups (Vac and Vac+Imp) at d 56 (P < 0.001), with titers and suppressed testosterone persisting to d 147 (P < 0.001). Groups Vac and Vac+Imp had reduced testes weights at slaughter on d 147 (P < 0.001). Bulls in group Vac were not different in final BW, HCW, or ADG (d 42 to 147) relative to bulls in group Con. Bulls in group Vac+Imp had greater final BW than bulls in group Imp (P = 0.008) and greater BW than bulls in group Vac and group Con (P < 0.001). The HCW of Vac+Imp bulls was greater than the Vac or Con bulls (P < 0.001) but was not different to the Imp bulls (P = 0.294). Improved ADG was obtained by vaccination with the GnRH vaccine, in the presence of implants (group Vac+Imp compared with group Imp, P < 0.001) or absence of implants (group Vac compared with group Con, P = 0.028). Meat quality of bulls receiving the GnRH vaccine was improved irrespective of implant status, with a 1.6- to 2.6-fold increase in the proportion of bulls in groups Vac and Vac+Imp, respectively, grading as USDA Choice (P < 0.002) and with greater fat depth at the 12th rib (P < 0.001). Meat tenderness was improved in the vaccine groups (Vac and Vac+Imp) compared with groups Con and Imp (P < 0.004). Use of the GnRH vaccine Bopriva in Bos indicus × Brown Swiss bulls finishing in a feedlot under Mexican husbandry conditions can provide improved performance in combination with implants (increased BW and ADG) and improved meat quality, with or without implants, and in particular, better USDA carcass grading and loin fat cover.
本研究旨在确定 GnRH 疫苗对瘤牛杂交牛（Bos indicus Zebu×Brown Swiss）育肥性能和肉质的影响。该研究采用 2×2 因子设计，将 1600 头公牛按体重分为 4 组，每组约 400 头。GnRH 疫苗（Bopriva）于第 0 天和第 42 天注射，第 0 天（Component E-S）和第 84 天（Synovex Choice）给予合成代谢植入物。组的指定如下：Con = 安慰剂对照；Imp = 单独植入物；Vac = GnRH 疫苗单独；Vac+Imp = GnRH 疫苗与植入物联合使用。第 42 天的第二次 GnRH 疫苗接种导致接种组（Vac 和 Vac+Imp）的 IgG 抗体滴度升高和睾酮浓度降低（第 56 天，P<0.001），在第 147 天仍保持高滴度和低睾酮水平（P<0.001）。在第 147 天屠宰时，Vac 和 Vac+Imp 组的睾丸重量降低（P<0.001）。与 Con 组公牛相比，Vac 组公牛的最终体重、HCW 或 ADG（第 42 天至第 147 天）没有差异。与 Imp 组相比，Vac+Imp 组公牛的最终体重更大（P=0.008），与 Vac 组和 Con 组公牛相比，体重更大（P<0.001）。Vac+Imp 组公牛的 HCW 大于 Vac 组或 Con 组公牛（P<0.001），但与 Imp 组公牛没有差异（P=0.294）。GnRH 疫苗接种可提高 ADG，无论是否存在植入物（与 Imp 组相比，Vac+Imp 组，P<0.001）。接种 GnRH 疫苗的公牛的肉质得到改善，无论植入物状态如何，与 Con 组相比，Vac 和 Vac+Imp 组的公牛中分别有 1.6 至 2.6 倍的比例被评为美国农业部选择（P<0.002），并且第 12 肋处的脂肪深度更大（P<0.001）。与 Con 组和 Imp 组相比，疫苗组（Vac 和 Vac+Imp）的肉质嫩度更高（P<0.004）。在墨西哥养殖条件下育肥的 Bos indicus×Brown Swiss 公牛使用 GnRH 疫苗 Bopriva 可以提高性能（增加体重和 ADG）和改善肉质，无论是否使用植入物，尤其是更好的美国农业部胴体分级和腰肉脂肪覆盖率。
