Sherbeck J A, Tatum J D, Field T G, Morgan J B, Smith G C
Department of Animal Sciences, Colorado State University, Fort Collins 80523, USA.
J Anim Sci. 1995 Dec;73(12):3613-20. doi: 10.2527/1995.73123613x.
Short-yearling steer of known genotypes-straightbred Hereford (100H, n = 80) 75% Hereford x 25% Brahman (75H:25B, n = 80), and 50% Hereford x 50% Brahman (50H:50B, n = 80) were sampled serially at four time-on-feed endpoints (84, 98, 112, 126 d) to compare feedlot performance and carcass and palatability traits of Hereford and Hereford x Brahman steers. After slaughter, USDA yield grade and quality grade factors were recorded, and a portion of the longissimus muscle was removed from the left side of each carcass and fabricated into four 2.54-cm steaks for palatability analyses. Paired steaks from each carcass were aged (6 and 18 d after death), and sensory panel and shear force evaluations were performed. At a constant live weight, 100H steers had higher ADG and produced less mature carcasses with smaller longissimus muscle areas and higher marbling scores than did 75H:25B and 50H:50B steers. The 50H:50B steers had the highest (P < .05) values for dressing percentage. Loin steak tenderness and juiciness decreased (P < .05) and shear force values increased (P < .05) as the percentage of Brahman breeding increased. EXtending the postmortem aging period from 6 to 18 d improved shear force values by 20% and panel tenderness ratings by approximately 14%. Beef from steers of the three breeds responded similarly to aging. When Certified Hereford Beef (CHB) specifications were applied, steaks from 100H steers and 75H:25B steers had similar shear force values, suggesting that beef from quarter-blood Brahman crossbred steers could be included in the CHB Program without detrimental effects on product tenderness.
对已知基因型的短周岁阉牛——纯种海福特牛（100%海福特牛，n = 80）、75%海福特牛×25%婆罗门牛（75H:25B，n = 80）以及50%海福特牛×50%婆罗门牛（50H:50B，n = 80），在四个育肥期终点（84、98、112、126天）进行连续采样，以比较海福特牛以及海福特牛×婆罗门牛阉牛的育肥性能、胴体和适口性特征。屠宰后，记录美国农业部的产量等级和质量等级因素，并从每个胴体的左侧取出一部分背最长肌，加工成四块2.54厘米厚的牛排用于适口性分析。将每个胴体的配对牛排进行排酸处理（死后6天和18天），并进行感官评定小组和剪切力评估。在活重恒定的情况下，100%海福特牛阉牛的平均日增重更高，与75H:25B和50H:50B阉牛相比，其胴体成熟度更低，背最长肌面积更小，大理石花纹评分更高。50H:50B阉牛的屠宰率最高（P < 0.05）。随着婆罗门牛血统比例的增加，腰大肌牛排的嫩度和多汁性降低（P < 0.05），剪切力值增加（P < 0.05）。将宰后排酸时间从6天延长至18天，剪切力值提高了20%，感官评定小组的嫩度评分提高了约14%。三个品种阉牛的牛肉对排酸处理的反应相似。当应用认证海福特牛肉（CHB）标准时，100%海福特牛阉牛和75H:25B阉牛的牛排具有相似的剪切力值，这表明四分之一婆罗门牛杂交阉牛的牛肉可以纳入CHB计划，而不会对产品嫩度产生不利影响。
