Department of Animal & Avian Sciences, University of Maryland, College Park, MD 20742, USA.
College of Life Sciences and Food Engineering, Hebei University of Engineering, Handan 056021, PR China.
Animal. 2021 Nov;15(11):100381. doi: 10.1016/j.animal.2021.100381. Epub 2021 Oct 29.
The increasing demand for natural products is currently transforming the meat industry, making grass-fed and finished beef a valuable option for improving profits. However, the transformation of conventional operations to grass-fed systems comprises many modifications, such as logistical, technological, and financial that could be very complex and expensive, involving economic risk. Therefore, in this study, we analyzed the growth curve, critical economic traits, and carcass quality and finished characteristics over several consecutive years in closely related grass-fed and finished Angus steers, to reduce the genetic effect on the results. We found that grass-fed steers require around 188 additional days to reach the market weight (approx. 470 kg) and had approximately 70% less average daily gain compared to the grain-fed and finished steers. Regression analysis demonstrated an interaction between feed and age (P < 0.01); thus, individual regressions were fitted for each regimen style, obtaining almost perfect linear curves for both treatments, which could be straightforwardly used in practical situations due to its simplicity. Six of eight carcass traits were different between grain-fed and grass-fed and finished steers. Hot-carcass weight, dressing, back fat, and quality grade were superior in grain-fed individuals, contrarily to yield grade and ribeye area/carcass ratio, which were better in grass-fed and finished steers (P < 0.05). Interestingly, the meat tenderness was certainly low and similar in both treatments (P = 0.25), indicating the feasibility of producing tender meat with animals under a grass-fed diet. Nevertheless, according to the quality grade analysis, grain-fed carcasses were greater ranked compared to grass-fed bodies (P < 0.01), regardless of their same tenderness. The results will provide valuable information for better understanding beef cattle in grass-feeding finishing systems, especially from weaning to harvest. Additionally, the study will expand the knowledge about the quality of meat obtained from animals that received grass exclusively, becoming relevant information for economic evaluation and management decisions for grass-based cattle operations.
对天然产品的需求不断增加，正在改变肉类行业的格局，使草饲牛肉成为提高利润的有价值选择。然而，将传统运营转变为草饲系统需要进行许多修改，例如物流、技术和财务方面的修改，这些修改可能非常复杂和昂贵，涉及经济风险。因此，在这项研究中，我们分析了连续几年中密切相关的草饲和育肥 Angus 阉牛的生长曲线、关键经济性状以及胴体质量和育肥特征，以减少遗传效应对结果的影响。我们发现，草饲牛需要大约 188 天才能达到市场体重（约 470 公斤），与谷物喂养和育肥的牛相比，平均日增重减少了约 70%。回归分析表明，饲料和年龄之间存在交互作用（P<0.01）；因此，为每个饲养方案拟合了个体回归，两种处理都获得了几乎完美的线性曲线，由于其简单性，可以直接用于实际情况。谷物喂养和草饲育肥牛之间有 8 个胴体性状的 6 个不同。热胴体重量、屠宰率、背膘和肉质等级在谷物喂养个体中较高，而产肉等级和肋眼面积/胴体比例则在草饲育肥牛中较好（P<0.05）。有趣的是，两种处理的肉嫩度都很低且相似（P=0.25），表明可以用草饲动物生产嫩肉。然而，根据质量等级分析，谷物喂养的胴体比草饲的胴体排名更高（P<0.01），而不管它们的嫩度相同。该研究结果将为更好地理解草饲育肥系统中的肉牛提供有价值的信息，特别是从断奶到收获。此外，该研究将扩展有关仅接受草饲的动物获得的肉质的知识，成为基于草的牛场经济评估和管理决策的相关信息。
