摘要
Early weaning Holstein dairy calf programs used low milk-replacer feeding rates and fat levels to limit feed costs, foster calf-starter intake, and facilitate rumen development. Milk replacers in those programs contained about 22% CP on an as-fed basis, from 8 to 15% fat, and were fed to wean calves at about 1 mo of age. Later milk replacers migrated to contain about 20% CP and fat, the proverbial 20/20 “industry standard.” As milk-replacer fat and milk-replacer feeding levels increased, this inversely affected calf-starter intake. The 2001 Dairy NRC Young Calf Model emerged at about the same time as a series of research trials at Cornell University and the University of Illinois began an accelerated feeding of milk replacers. These studies illustrated that increasing amount fed of milk replacers with higher protein concentration increased body protein deposition and growth rate without excessive fattening until milk-replacer fat percentage increased to 20% or more. Increasing average daily feeding rates beyond about 0.6 to 0.7 kg/d of DMI before weaning of higher protein (> 25 to 26%) milk replacers with 15% or more fat led to reduction of calf-starter intake so that daily gain during and after full weaning decreased considerably. Male and female calves in these studies seemed unable to adjust their starter intake quickly enough on high milk-replacer feeding rates to avoid major performance decreases during and after weaning. Although potential benefits of accelerated milk-replacer feeding programs were originally postulated as reducing age at first calving, recent analyses of about 10 studies indicated primary benefits may be increased first, and possibly later, lactation milk yield.
摘要译文
早期断奶的荷斯坦奶牛小牛计划使用低代乳喂养率和脂肪水平来限制饲料成本，促进小牛起子摄入，并促进瘤胃发育。这些计划中的代乳品含有约22％的CP，以8％至15％的脂肪含量，并且在约1个月龄时喂给断奶的小牛。后来的牛奶替代品迁移到含有约20％的CP和脂肪，这是众所周知的20/20“行业标准”。随着牛奶替代品脂肪和代乳粉的饲喂水平增加，这反过来影响了小牛起动器的摄入量。2001年Dairy NRC Young Calf模型与康奈尔大学和伊利诺伊大学的一系列研究试验几乎同时出现，开始加速代替牛奶。饲喂具有较高蛋白质浓度的代乳品的量增加了体内蛋白质沉积和生长速率而没有过度增肥，直到代乳品脂肪百分比增加至20％或更多。平均每日喂养率增加超过约0.6至0。f断奶前较高蛋白质（ 25％至26％）的脂肪含量为15％或更多的牛奶替代品导致牛犊 - 开胃菜摄入减少，因此在完全断奶期间和之后的日增重明显减少。虽然加速代乳喂养计划的潜在好处最初被假定为首次产犊时减少年龄，最近对大约10项研究的分析表明，初期效益可能首先增加，甚至可能在之后增加泌乳量。
A.F.KertzPAS*;J.R.Loften†;. Review: A historical perspective of specific milk-replacer feeding programs in the United States and effects on eventual performance of Holstein dairy calves[J]. The Professional Animal Scientist, 2013,29(4): 321-332