Department of Veterinary Physiology and Pharmacology, Texas A&M University College of Veterinary Medicine and Biomedical Sciences, College Station 77843-4466, USA.
J Anim Sci. 2011 Jun;89(6):1939-43. doi: 10.2527/jas.2010-2923. Epub 2011 Jan 28.
Intramuscular injections of drugs and vaccines cause tissue damage and subsequent effects on tenderness and consumer acceptability of beef. In the 2007 National Market Cow and Bull Beef Quality Audit, 100% of plants reported fabricating subprimal cuts such as rib eyes and tenderloins from cow and bull carcasses. Dairy beef quality should therefore be a consideration when injections are given to dairy animals. The discussion about injection site reactions and tenderness has focused on vaccines and antimicrobial drugs with little concern for the effects of reproductive hormones. The objective of this study was to quantify antemortem the effects of semimembranosis/semitendinosis muscle injection of dinoprost and GnRH in lactating dairy cows by estimating the weight of tissue damaged and comparing that with a drug known to cause extensive tissue damage, flunixin meglumine. Tissue damage was estimated from previously reported equations for grams of muscle tissue damage based on area under the curve of serum concentrations of the muscle enzyme creatine kinase over time. Dinoprost and flunixin injection both caused a significantly increased estimate of muscle tissue damaged compared with needle only (P = 0.0351 and 0.0355, respectively). Dinoprost and flunixin caused a marginally significant increased muscle tissue damage compared with GnRH (P = 0.1394 and 0.1475, respectively). No statistically significant difference was found between the estimated weight of muscle tissue damaged by flunixin compared with dinoprost (P = 1.0000), or by saline compared with GnRH (P = 0.7736) or needle only (P = 0.4902). The assumption that reproductive hormones are less damaging than vaccines and antimicrobial drugs should be examined more closely, including postmortem evaluation of injection site lesions and effects on tenderness.
肌肉内注射药物和疫苗会导致组织损伤，并随后对牛肉的嫩度和消费者接受度产生影响。在 2007 年全国市场奶牛和公牛牛肉质量审计中，100%的工厂报告说，从奶牛和公牛胴体中制造肋眼和里脊肉等次级切块。因此，在给奶牛注射时，应考虑到奶牛的奶牛肉质量。关于注射部位反应和嫩度的讨论主要集中在疫苗和抗菌药物上，而很少关注生殖激素的影响。本研究的目的是通过估计受损组织的重量，并与已知会引起广泛组织损伤的药物氟尼辛 meglumine 进行比较，来量化半膜肌/半腱肌注射前列腺素 F2α和 GnRH 对泌乳奶牛的生前影响。组织损伤是根据血清肌酸激酶浓度时间曲线下的面积，根据先前报道的基于肌肉损伤的肌肉组织损伤的克数方程来估计的。与仅使用针头（分别为 P = 0.0351 和 0.0355）相比，前列腺素 F2α和氟尼辛 meglumine 注射都会导致肌肉组织损伤的估计值显著增加（P = 0.0351 和 0.0355）。与 GnRH 相比，前列腺素 F2α和氟尼辛 meglumine 引起的肌肉组织损伤略有增加（分别为 P = 0.1394 和 0.1475）。与氟尼辛 meglumine 相比，没有发现与 dinoprost 相比（P = 1.0000）、与生理盐水相比（P = 0.7736）或与仅使用针头相比（P = 0.4902），flunixin meglumine 引起的肌肉组织损伤的估计重量存在统计学差异。应该更仔细地检查生殖激素是否比疫苗和抗菌药物的危害性更小，包括对注射部位病变和嫩度影响的死后评估。
