娟姗牛和荷斯坦奶牛的粪便养分排泄量。

Department of Dairy Science, Virginia Polytechnic Institute and State University, Blacksburg 24061, USA.

J Dairy Sci. 2010 Jan;93(1):407-12. doi: 10.3168/jds.2009-2617.

The objective of this study was to evaluate feces, urine, and N excretion by Jersey and Holstein cows. Sixteen multiparous cows (n=8 per breed) were fed 2 experimental rations at calving in a switchback experimental design. Diets were 50% forage and based on corn meal (control) or whole cottonseed. Half the cows in each breed started on the control diet and half started on the whole cottonseed diet. Cows were switched to the other diet at 60 d in milk and switched back to their original diet at 165 d in milk. Pairs of cows were moved into open-circuit respiration chambers on d 49, 154, and 271 of lactation for 7-d measurement periods. While in the chambers, total collection of feed refusals, milk, recovered hair, feces, and urine was conducted. No effect of the interaction of diet and breed was observed for measures of nutrient digestibility and manure excretion. Total daily manure excretion was lower in Jersey cows than in Holstein cows, with reductions generally proportional to changes in feed intake. Jersey cows consumed 29% less feed and excreted 33% less wet feces and 28% less urine than Holstein cows. Intake, fecal, and urinary N were reduced by 29, 33, and 24%, respectively, in Jersey cows compared with Holstein cows. Equations from American Society of Agricultural and Biological Engineers underpredicted observed values for all manure measures evaluated (urine, manure solids, N, wet manure), and breed bias was observed in equations predicting excretion of urine, N, and wet manure. Although these equations include animal and dietary factors, intercepts of regression of observed values on predicted values differed between Holsteins and Jerseys for those 3 measures. No breed bias was observed in the prediction of manure solids excretion, however, making that equation equally appropriate for Jerseys and Holsteins. The effect of breed on manure and nutrient excretion has significant nutrient management implications.

本研究旨在评估泽西牛和荷斯坦奶牛的粪便、尿液和 N 排泄量。16 头经产奶牛（每品种 8 头）在交叉试验设计中于产后接受 2 种试验日粮。日粮以 50%粗饲料为基础，基于玉米粉（对照）或全棉籽。每个品种的一半奶牛开始饲喂对照日粮，另一半奶牛开始饲喂全棉籽日粮。奶牛在泌乳 60 天开始转换到另一日粮，泌乳 165 天再转回原来的日粮。在泌乳第 49、154 和 271 天，每对奶牛进入开路呼吸室进行为期 7 天的测量。在呼吸室内，对饲料残茬、牛奶、回收毛发、粪便和尿液进行了总收集。未观察到日粮和品种之间的互作效应对养分消化率和粪便排泄量的影响。泽西牛的总日粪便排泄量低于荷斯坦牛，减少幅度通常与采食量的变化成正比。与荷斯坦牛相比，泽西牛的饲料采食量减少了 29%，湿粪便排泄量减少了 33%，尿液排泄量减少了 28%。与荷斯坦牛相比，泽西牛的氮摄入量、粪便氮和尿氮分别减少了 29%、33%和 24%。美国农业与生物工程师学会的方程低估了所有评估的粪便指标（尿液、粪便固体、N、湿粪便）的实测值，并且在预测尿液、N 和湿粪便排泄量的方程中观察到品种偏差。尽管这些方程包含了动物和饮食因素，但实测值与预测值之间的回归截距在荷斯坦牛和泽西牛 3 个指标中存在差异。然而，在预测粪便固体排泄量方面没有观察到品种偏差，因此该方程对泽西牛和荷斯坦牛同样适用。品种对粪便和养分排泄的影响对养分管理具有重要意义。