Luchini N D, Lane S F, Combs D K
Department of Meat and Animal Science, University of Wisconsin, Madison 53706.
J Dairy Sci. 1991 Nov;74(11):3949-55. doi: 10.3168/jds.S0022-0302(91)78589-5.
The objectives of this study were to evaluate two levels of CP in starter diets offered to calves weaned on d 26 and to compare postweaning intake of starter diets and performance of calves weaned at 26 or 42 d. Forty Holstein calves were housed in individual outdoor hutches and assigned to one of four treatments. Treatments consisted of weaning on d 26 after offering a 20% CP starter diet from d 1, or d 21, or after offering a 25% CP starter diet from d 21, or weaning on d 42 after offering a 20% CP starter diet from d 1 (control). Between d 42 and 84, calves were commingled in outdoor group pens. On d 42, BW of control calves was heavier than that of early weaned calves. On d 84, BW did not differ among treatments. Consumption of starter diet was not affected by the age at which it was first offered. Weaned calves consumed more starter diet than controls from d 29 to 42. Postweaning performance was not affected by increasing CP in the starter diet. Weaning treatment did not affect the incidence of scours. Comparison of CP intakes with current NRC recommendations suggests that CP requirements for young milk-fed calves are adequate.
本研究的目的是评估在第26天断奶的犊牛开食料中两种粗蛋白（CP）水平，并比较在26日龄或42日龄断奶的犊牛开食料的断奶后采食量及生长性能。40头荷斯坦犊牛被安置在室外的单栏牛舍中，并被分配到四种处理之一。处理方式包括：从第1天开始提供20%CP的开食料，或从第21天开始提供20%CP的开食料，在第26天断奶；从第21天开始提供25%CP的开食料，在第26天断奶；从第1天开始提供20%CP的开食料，在第42天断奶（对照）。在第42天至84天期间，犊牛被混养在室外的群栏中。在第42天，对照犊牛的体重比早期断奶的犊牛重。在第84天，各处理组的体重没有差异。开食料的采食量不受首次提供开食料的年龄影响。从第29天至42天，断奶犊牛比对照犊牛消耗更多的开食料。断奶后生长性能不受开食料中CP增加的影响。断奶处理不影响腹泻的发生率。将CP摄入量与当前美国国家研究委员会（NRC）的建议进行比较表明，哺乳幼犊的CP需求量是足够的。
