Protein supplementation of dairy cows grazing Tifton 85 during the dry season

ABSTRACT Concentrates with high crude protein and minerals and lower energy concentration could be used in smaller quantities in balancing diets with tropical bulk. The objective of this study was to evaluate the dry matter intake, the productive and economical response of Girolando cows kept in Tifton 85 pasture during dry season receiving different concentrations of protein supplementation. Twelve lactating Girolando cows with initial mean milk yield of 18.00±1.615kg/day were used. The animals were distributed in three Latin squares (4x4), consisting of four treatments and four experimental periods, each lasting 15 days. The treatments were composed of control diet with only mineral salt, and three levels of protein supplementation with 40, 50, and 60% crude protein (CP) being supplied in the amounts of 2.5kg/animal/day. It was found that the protein supplement supplies provided a substitutive effect of forage relative to mineral supplementation. The use of concentrated supplementation with 40% crude protein content was more efficient in terms of production, production of crude protein in milk and economically.

摘要：粗蛋白质与矿物质含量较高、能量浓度较低的浓缩饲料，在搭配热带粗饲料开展日粮平衡时可采用较小添加量。本研究旨在评估旱季饲养于提夫顿85（Tifton 85）饲草牧场的吉罗兰特（Girolando）奶牛，在饲喂不同粗蛋白质水平的蛋白质补充剂时的干物质采食量、生产性能与经济效益响应。本试验选用12头泌乳期吉罗兰特奶牛，其初始平均产奶量为18.00±1.615千克/天。将试验动物划分为3个4×4拉丁方设计组，共设置4种处理方式与4个试验周期，每个周期时长为15天。试验处理包括仅饲喂矿物盐的对照组，以及3个粗蛋白质（CP）水平分别为40%、50%与60%的蛋白质补充剂组，补充剂饲喂量均为2.5千克/头/天。研究表明，相较于仅饲喂矿物盐的对照组，蛋白质补充剂的饲喂可发挥饲草替代效应。饲喂粗蛋白质含量为40%的浓缩补充剂，在生产性能、牛奶粗蛋白质产量以及经济效益方面均表现更优。