State Key Laboratory of Animal Nutrition, College of Animal Science and Technology, China Agricultural University, Beijing, China.
Institute of Animal and Dairy Sciences, University of Agriculture, Faisalabad, Pakistan.
J Anim Physiol Anim Nutr (Berl). 2020 Sep;104(5):1197-1208. doi: 10.1111/jpn.13340. Epub 2020 Mar 19.
The objective of this study was to evaluate the effect of different dietary densities on growth performance, carcass characteristics, meat quality, serum metabolism, ruminal papillae morphology and liver injuries of steers. For this purpose, a total of eighteen Holstein steers were randomly fed one of the three diets: high energy and protein diet (H), standard energy and protein diet (C), and low energy and protein diet (L) for 11 months fattening with three-step finishing strategy. Steers fed with H diet had higher (p < .05) average daily gain, feed efficiency, hot carcass weight, serum aspartate aminotransferase to alanine aminotransferase ratio, and monounsaturated fatty acids along with continuous low ruminal pH value, severer hepatic steatosis and ruminal papillae parakeratosis. Meanwhile, steers fed L diet increased the proportion of C20:0, C22:6n-3, saturated fatty acids and n-3 polyunsaturated fatty acids along with lower n-6 to n-3 ratio in longissimus dorsi muscle as compared to that of steers fed H diet. Dietary densities did not influence (p > .10) proximate nutrients and sensory characteristics of beef. The present study indicates that Holstein steers could achieve better growth and carcass performance under high-density diet, whereas they are under threat of visceral injuries and metabolic disorders. This study gives comprehensive relationship between productivity and animal health and suggests that a proper diet should be adopted for fattening Holstein steers in consideration of both beef quality and quantity and animal health.
本研究旨在评估不同饲粮密度对育肥牛生长性能、胴体特性、肉质、血清代谢、瘤胃乳头形态和肝脏损伤的影响。为此，将 18 头荷斯坦公牛随机分为 3 组，分别饲喂高能量高蛋白饲粮（H）、标准能量高蛋白饲粮（C）和低能量低蛋白饲粮（L），进行 11 个月的育肥，采用三阶段育肥策略。与 C 组相比，H 组育肥牛具有更高的平均日增重（ADG）、饲料效率、热胴体重、血清天冬氨酸转氨酶/丙氨酸转氨酶比值、单不饱和脂肪酸，同时瘤胃 pH 值持续较低，肝脏脂肪变性更严重，瘤胃乳头角化过度。同时，与 H 组相比，L 组育肥牛背最长肌中的 C20:0、C22:6n-3、饱和脂肪酸和 n-3 多不饱和脂肪酸比例增加，n-6/n-3 比值降低。饲粮密度对牛肉的常规养分和感官特性没有影响（p>.10）。本研究表明，荷斯坦育肥牛在高密度饲粮下可获得更好的生长和胴体性能，但存在内脏损伤和代谢紊乱的风险。本研究全面揭示了生产性能与动物健康之间的关系，建议在考虑牛肉产量和质量以及动物健康的前提下，为育肥荷斯坦公牛选择适宜的饲粮。
