Gwartney B L, Calkins C R, Rasby R J, Stock R A, Vieselmeyer B A, Gosey J A
Department of Animal Science, University of Nebraska, Lincoln 68583-0908, USA.
J Anim Sci. 1996 May;74(5):1014-22. doi: 10.2527/1996.7451014x.
A 2-yr study was conducted to determine the effect of EPD for marbling on marbling score, palatability traits, and carcass fatness in beef. Steer (n = 122) and heifer (n = 123) carcasses were obtained by mating Angus bulls having a high ( > .4) or low ( < -.16) EPD for marbling to MARC II cows (1/4 Angus, 1/4 Hereford, 1/4 Simmental, and 1/4 Gelbvieh). Carcass traits, composition of primals, quarters, and sides, palatability, and shear force data were obtained and adjusted to the mean number of days on feed, equal marbling score (Small50), fat thickness (1.0 cm), and carcass weight (318 kg) end points. Steer carcasses from the high marbling EPD group, adjusted to the mean number of days on feed, had significantly more marbling (P < .01) and less subcutaneous fat in the side and the hindquarter (P < .10) than their low marbling EPD counterparts. Adjusting steers to Small50 marbling produced smaller longissimus muscle area (by 5 cm2), less fat thickness (1.15 vs 1.28 cm), and lighter side weights (306 vs 333 kg) for high marbling vs low marbling EPD groups, indicating a faster rate of marbling deposition. Similar relationships of a greater magnitude were found for heifers, perhaps because the heifers were older than the steers at slaughter. No differences in taste panel ratings or shear force values were noted among steer carcasses. Heifer carcasses from the high marbling EPD group had better (P < .05) ratings for juiciness, muscle fiber tenderness, and overall tenderness than the low marbling EPD group heifers. These results indicate that it is possible, using existing genetic resources, to maintain marbling score and decrease fat in other depots of the carcass without compromising palatability.
进行了一项为期两年的研究，以确定牛肉大理石花纹的预期 progeny 差异（EPD）对大理石花纹评分、适口性特征和胴体脂肪含量的影响。通过将具有高（>.4）或低（<-.16）大理石花纹 EPD 的安格斯公牛与 MARC II 母牛（1/4 安格斯、1/4 赫里福德、1/4 西门塔尔和 1/4 吉尔维耶）交配，获得了阉牛（n = 122）和小母牛（n = 123）的胴体。获取了胴体性状、主要切块、四分体和半边的组成、适口性和剪切力数据，并将其调整到平均饲养天数、相等的大理石花纹评分（Small50）、脂肪厚度（1.0 厘米）和胴体重量（318 千克）的终点。与低大理石花纹 EPD 的阉牛胴体相比，高大理石花纹 EPD 组的阉牛胴体在调整到平均饲养天数后，大理石花纹显著更多（P <.01），半边和后躯的皮下脂肪更少（P <.10）。将阉牛调整到 Small50 大理石花纹后，高大理石花纹 EPD 组与低大理石花纹 EPD 组相比，背最长肌面积更小（小 5 平方厘米）、脂肪厚度更薄（1.15 厘米对 1.28 厘米）、半边重量更轻（306 千克对 333 千克），这表明大理石花纹沉积速度更快。在小母牛中发现了更大程度的类似关系，可能是因为小母牛在屠宰时比阉牛年龄更大。阉牛胴体之间在味觉评分或剪切力值方面没有差异。高大理石花纹 EPD 组的小母牛胴体在多汁性、肌纤维嫩度和总体嫩度方面的评分优于低大理石花纹 EPD 组的小母牛（P <.05）。这些结果表明，利用现有的遗传资源，有可能在不影响适口性的情况下，保持大理石花纹评分并减少胴体其他部位的脂肪。
