Coleman D A, Moss B R, McCaskey T A
Department of Animal and Dairy Sciences, Aubum University 36849-5415.
J Dairy Sci. 1996 Nov;79(11):2038-43. doi: 10.3168/jds.S0022-0302(96)76577-3.
Two studies were conducted during consecutive years to determine the effects of providing supplemental shade to dairy calves reared in commercial hutches made of translucent plastic in a southern environment. Calves were assigned at birth to polyethylene calf hutches located in either an open control area or under supplemental shade (n = 9 to 12 per group per year). Shade reduced temperatures both inside the hutches and in the outer exercise areas during both years. However, shade increased humidity in the exercise area during yr 1. Shaded calves had lower rectal temperatures than control calves during yr 1, but differences were not significant during yr 2. Shade did not alter plasma cortisol concentrations. Shaded calves consumed less concentrate feed but had average daily gains that were similar to those of control calves, resulting in a tendency for greater feed efficiency for shaded calves. Counts for both total and fecal coliforms were greater in bedding collected from hutches under supplemental shade, but there was no difference in the incidence of health disorders. Providing supplemental shade to calves reared in plastic hutches in a warm southern environment altered the calf environment in a predictable manner but had little effect on overall growth and health.
连续两年开展了两项研究，以确定在南方环境中，为饲养在半透明塑料制成的商用犊牛栏中的奶牛犊提供补充遮荫的效果。犊牛出生时被分配到位于开放控制区或补充遮荫下的聚乙烯犊牛栏中（每年每组9至12头）。在这两年中，遮荫均降低了犊牛栏内和外部活动区域的温度。然而，在第1年，遮荫增加了活动区域的湿度。在第1年，遮荫犊牛的直肠温度低于对照犊牛，但在第2年差异不显著。遮荫并未改变血浆皮质醇浓度。遮荫犊牛消耗的精饲料较少，但平均日增重与对照犊牛相似，因此遮荫犊牛有饲料效率更高的趋势。从补充遮荫下的犊牛栏收集的垫料中，总大肠菌群和粪便大肠菌群的数量均更多，但健康问题的发生率没有差异。在温暖的南方环境中，为饲养在塑料犊牛栏中的犊牛提供补充遮荫以可预测的方式改变了犊牛的环境，但对总体生长和健康影响不大。
