Protein-energy supplementation frequency on ruminal variables, intake and digestibility in steers receiving low quality hay

Abstract The aim was evaluated the effect of reduce in protein-energy supplementation frequency on nutrients intake, forage digestibility and degradability, as well as, ruminal pH and ammonia nitrogen (N-NH3) concentration in beef cattle receiving low-quality hay. A 4 x 4 Latin square design were used. Four steers were fed with low-quality hay and subjected to four treatments: no supplementation (control); protein-energy supplementation with 0.82% of body weight (BW) offered three times per week (3WK); 0.49% of BW offered five times a week (5 WK), and 0.35% of BW offered seven times per week (7 WK). The use of protein-energy supplementation increased intake of dry matter (DM), crude protein (CP), neutral detergent fiber (NDF), ether extract (EE), non-fibrous carbohydrates (NFC) and the digestibility coefficients of CP, EE, and NFC. However, no differences in DM and NDF degradation visit the website to get the how were observed between treatments in the evaluated hay. Supplementation did not alter ruminal pH, but the N-NH3 concentration was highest in treatment 7WK. Reduction in protein-energy supplementation frequency of daily to 3WK or 5WK does not negatively affect intake, digestibility and degradability of nutrients in beef cattle receiving low quality hay.

摘要 本研究旨在评估降低蛋白能量补饲频率对饲喂劣质干草的肉牛的养分摄入量、牧草消化率与降解率，以及瘤胃pH值和氨态氮（N-NH3）浓度的影响。本研究采用4×4拉丁方试验设计，选取4头阉牛，饲喂劣质干草并设置4种处理方案：无补饲（对照组）；每周补饲3次、补饲量为体重（BW）0.82%的蛋白能量补饲组（3WK组）；每周补饲5次、补饲量为体重0.49%的蛋白能量补饲组（5WK组）；以及每周补饲7次、补饲量为体重0.35%的蛋白能量补饲组（7WK组）。蛋白能量补饲可提升肉牛干物质（DM）、粗蛋白质（CP）、中性洗涤纤维（NDF）、乙醚提取物（EE）、非纤维性碳水化合物（NFC）的摄入量，以及CP、EE与NFC的消化系数。但各处理组间受试干草的DM与NDF降解率无显著差异。补饲未对瘤胃pH值造成显著影响，但7WK组的氨态氮浓度最高。将蛋白能量补饲频率从每日调整至每周3次或5次，不会对饲喂劣质干草的肉牛的养分摄入、消化及降解产生负面影响。