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：高粗蛋白、高矿物质且低能量浓度的浓缩饲料，在与热带粗饲料搭配进行日粮平衡时可减量使用。本研究旨在评估旱季饲养于提夫顿85（Tifton 85）牧草牧场的吉罗兰多奶牛，饲喂不同水平蛋白质补充料时的干物质采食量、生产性能与经济效益响应。试验选用12头泌乳期吉罗兰多奶牛，初始平均产奶量为18.00±1.615千克/天。试验动物采用3个4×4拉丁方试验设计进行分组，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质盐的对照组日粮，以及3种粗蛋白（crude protein, CP）含量分别为40%、50%、60%的蛋白质补充料，补充量均为2.5千克/头/天。研究发现，与仅补充矿物质盐的对照组相比，饲喂蛋白质补充料可产生饲草替代效应。饲喂粗蛋白含量为40%的浓缩补充料，在生产性能、乳中粗蛋白产量以及经济效益方面均表现更优。