Miller-Cushon E K, Vogel J P, DeVries T J
Department of Animal Sciences, University of Florida, Gainesville 32611.
Department of Animal and Poultry Science, University of Guelph, Kemptville Campus, Kemptville, ON, K0G 1J0, Canada.
J Dairy Sci. 2015 Apr;98(4):2687-92. doi: 10.3168/jds.2014-8782. Epub 2015 Jan 23.
This study investigated the effect of exposing heifers to individual feed components on the extent and pattern of feed sorting upon transition to a novel ration. Holstein heifers (394 ± 62 d old, weighing 409.8 ± 37.3 kg; mean ± SD), consuming a familiar mixed silage-based ration [55% corn silage and 45% haylage, dry matter (DM) basis], were transitioned to a novel total mixed ration [TMR; 41.6% haylage, 36.5% corn silage, 14.6% high-moisture corn, and 7.3% protein supplement, DM basis] by 1 of 2 treatments: direct transition to novel TMR (DIR; n = 5) or exposure to novel TMR components individually before receiving novel TMR (COM; n = 6). During the baseline period (d 1 to 4), all heifers were offered the familiar silage-based ration. During transition (d 5 to 12), DIR heifers received the novel TMR, whereas COM heifers received the novel TMR components offered separately, in amounts according to TMR composition (target 15% orts). After transition (d 13 to 20), all heifers received the novel TMR. Feed intake and feeding time were determined daily and fresh feed and individual orts were sampled every 2d for particle size analysis and neutral detergent fiber content. 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 actual intake expressed as a percentage of predicted intake. We detected no effect of treatment on dry matter intake or feeding time. After transition to the novel TMR, COM heifers sorted to a greater extent than did DIR heifers, sorting against long particles (95.4 vs. 98.9%) and for short particles (101.7 vs. 100.6%). Differences in sorting patterns resulted in COM heifers tending to have lower neutral detergent fiber intake as a percentage of predicted intake (98.9 vs. 100.5%). The results of this study suggest that the degree of feed sorting may be influenced by method of transition to a novel ration.
本研究调查了在向新日粮过渡时，让小母牛接触单一饲料成分对饲料分选程度和模式的影响。荷斯坦小母牛（394±62日龄，体重409.8±37.3千克；平均值±标准差），采食一种熟悉的以青贮饲料为主的日粮[55%玉米青贮和45%禾本科牧草青贮，以干物质（DM）计]，通过以下两种处理之一向新的全混合日粮[TMR；41.6%禾本科牧草青贮、36.5%玉米青贮、14.6%高水分玉米和7.3%蛋白质补充料，以DM计]过渡：直接过渡到新TMR（DIR；n = 5）或在接受新TMR之前分别接触新TMR成分（COM；n = 6）。在基线期（第1至4天），给所有小母牛提供熟悉的青贮饲料日粮。在过渡期间（第5至12天），DIR组小母牛接受新TMR，而COM组小母牛分别接受按TMR组成提供的新TMR成分（目标剩料15%）。过渡后（第13至20天），所有小母牛接受新TMR。每天测定采食量和采食时间，每2天采集新鲜饲料和个体剩料用于粒度分析和中性洗涤纤维含量测定。粒度分离器由3个筛网（18、9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以实际采食量占预测采食量的百分比表示。我们未检测到处理对干物质采食量或采食时间有影响。过渡到新TMR后，COM组小母牛的分选程度高于DIR组小母牛，排斥长颗粒（95.4%对98.9%）并偏好短颗粒（101.7%对100.6%）。分选模式的差异导致COM组小母牛中性洗涤纤维采食量占预测采食量的百分比往往较低（98.9%对
