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。