DeVries T J, von Keyserlingk M A G
Department of Animal and Poultry Science, University of Guelph, Kemptville Campus, Kemptville, Ontario, K0G 1J0, Canada.
J Dairy Sci. 2009 Aug;92(8):3922-9. doi: 10.3168/jds.2008-1934.
The objective of this study was to determine how competition for feed influences the feeding behavior of young, growing dairy heifers. Thirty-six prepubertal Holstein heifers (231.5 +/- 12.1 d old, weighing 234.7 +/- 24.0 kg), consuming a total mixed ration ad libitum, were assigned to 1 of 2 treatments: noncompetitive (1 heifer/feed bin), or competitive (2 heifers/feed bin). After 7 d of treatment adaptation, dry matter intake and feeding behavior were monitored for 7 d for each animal. Fresh feed and orts were sampled on the last 3 d of the treatment period from each bin and were subjected to particle size analysis. The particle size separator consisted of 3 screens (18, 9, and 1.18 mm) and a bottom pan resulting in 4 fractions (long, medium, short, and fine). Sorting activity for each fraction was calculated as the actual intake expressed as a percentage of the predicted intake. There was no difference in sorting behavior or dry matter intake between the treatments. Overall, the heifers sorted against long particles (94%), and sorted for medium (102%) and short (103%) particles. The competitively fed heifers tended to have 10% shorter feeding times, particularly at peak feeding periods. The competitively fed heifers also consumed 9% fewer meals per day, although the duration of these meals were 10% longer, and tended to be 13% larger. Competition for feed also tended to increase the day-to-day variation in feeding time, meal duration, and meal size. It can be concluded that competition for feed for growing dairy heifers alters feeding patterns, reduces access to feed, particularly during periods of peak feeding activity, and tends to increase day-to-day variation in feeding behavior.
本研究的目的是确定饲料竞争如何影响幼年生长奶牛小母牛的采食行为。36头青春期前的荷斯坦小母牛（年龄231.5±12.1天，体重234.7±24.0千克），自由采食全混合日粮，被分配到2种处理方式中的1种：非竞争组（1头小母牛/饲料槽）或竞争组（2头小母牛/饲料槽）。经过7天的处理适应期后，对每头动物的干物质摄入量和采食行为进行7天的监测。在处理期的最后3天，从每个饲料槽中采集新鲜饲料和剩料，并进行粒度分析。粒度分离器由3个筛网（18毫米、9毫米和1.18毫米）和一个底盘组成，产生4个部分（长、中、短和细）。每个部分的分选活性计算为实际摄入量占预测摄入量的百分比。处理之间的分选行为或干物质摄入量没有差异。总体而言，小母牛倾向于不采食长颗粒（94%），而采食中颗粒（102%）和短颗粒（103%）。竞争采食的小母牛采食时间往往短10%，尤其是在采食高峰期。竞争采食的小母牛每天采食次数也少9%，尽管这些采食餐的持续时间长10%，且每餐量往往大13%。饲料竞争还倾向于增加采食时间、餐持续时间和餐量的每日变化。可以得出结论，生长奶牛小母牛的饲料竞争会改变采食模式，减少采食机会，尤其是在采食活动高峰期，并倾向于增加采食行为的每日变化。
