Department of Ruminant Production, Institut de Recerca i Tecnologia Agroalimentàries (IRTA), 08140 Caldes de Montbui, Spain.
J Dairy Sci. 2012 Jan;95(1):286-93. doi: 10.3168/jds.2011-4405.
One hundred seventy-nine Holstein male calves [44.7 kg of body weight (BW) and 8.3 d of age] participated in a series of 3 experiments to evaluate the effect of different forage sources on performance, apparent digestibility, and feeding behavior. Animals in each study were randomly assigned to 1 of 3 different dietary treatments: control (CON) calves were fed starter feed without any forage provision (this treatment was repeated in each of the 3 experiments), and the 2 other treatments consisted of the same starter feed plus a forage source: chopped alfalfa (AH) or rye-grass hay (RH) in the first study; chopped oat hay (OH) or chopped barley straw (BS) in the second study; corn silage (CS) or triticale silage (TS) in the third study. All calves were offered 2L of milk replacer (MR) at 12.5% dry matter (DM) twice daily via a bottle until 50 d of age, and 2L of MR at 12.5% DM during the week before weaning (57 d of age). The study finished when calves were 71 d old. Starter feed, MR, and forage intakes were recorded daily and BW weekly. Calves were individually housed and bedded with wood shavings. Compared with CON, animals receiving OH, TS, and BS consumed more starter feed (0.88 vs. 1.14, 1.17, 1.06 kg/d, respectively) and had greater average daily gain (0.72 vs. 0.93, 0.88, 0.88 kg/d, respectively). Animals in treatments RH, BS, CS, and TS consumed less forage (51 g/d) than AH (120 g/d) and OH (101 g/d) calves. Apparent organic matter, DM, and neutral detergent fiber digestibilities did not differ among treatments (81.5, 81.1, and 54.4%, respectively). Apparent crude protein digestibility was greater in RH, CS, and AH treatments than in CON (80.5 vs. 76.4%, respectively). Compared with CON calves, animals in the AH treatment spent less time eating starter feed and lying, animals in AH and RH treatments spent more time ruminating, with odds ratios (OR) of 5.24 and 5.40, respectively. The AH and RH calves devoted less time to performing nonnutritive oral behaviors (OR: 0.38 and 0.34, respectively), and TS calves tended to devote less time to perform nonnutritive oral behaviors (OR: 0.21) 1h after being offered MR and solid feed. In conclusion, free-choice provision of a forage source to young calves improves feed intake and performance without impairing digestibilities of DM, organic matter, crude protein, and neutral detergent fiber, and, depending on forage source, reduces nonnutritive oral behaviors and stimulates rumination.
179 头荷斯坦公犊（体重 44.7 千克，8.3 日龄）参与了一系列 3 项实验，以评估不同饲草来源对性能、表观消化率和采食行为的影响。每个研究中的动物随机分配到 3 种不同的饮食处理之一：对照（CON）犊牛不提供任何饲草的开食料（这一处理在 3 项实验中重复），其余 2 种处理是相同的开食料加饲草来源：在第一项研究中是切碎的紫花苜蓿（AH）或黑麦干草（RH）；在第二项研究中是切碎的燕麦干草（OH）或切碎的大麦秸秆（BS）；在第三项研究中是玉米青贮（CS）或小黑麦青贮（TS）。所有犊牛在 50 日龄前每天通过奶瓶提供 2L 12.5%干物质（DM）的代乳料，在断奶前一周（57 日龄）每天提供 2L 12.5% DM 的代乳料。研究在犊牛 71 日龄时结束。开食料、代乳料和饲草的摄入量每天记录，体重每周记录。犊牛单独饲养，铺有木屑。与 CON 相比，采食 OH、TS 和 BS 的动物摄入更多的开食料（0.88 比 1.14、1.17、1.06kg/d），日增重更大（0.72 比 0.93、0.88、0.88kg/d）。RH、BS、CS 和 TS 处理的动物消耗的饲草（51g/d）少于 AH（120g/d）和 OH（101g/d）犊牛。各处理间的有机物、DM 和中性洗涤纤维表观消化率无差异（分别为 81.5%、81.1%和 54.4%）。RH、CS 和 AH 处理的粗蛋白表观消化率大于 CON（分别为 80.5%比 76.4%）。与 CON 犊牛相比，采食 AH 处理的动物采食开食料和躺着的时间减少，采食 AH 和 RH 处理的动物反刍时间增加，比值比（OR）分别为 5.24 和 5.40。采食 AH 和 RH 处理的动物进行非营养性口腔行为的时间减少（OR：0.38 和 0.34），TS 处理的动物在给予代乳料和固体饲料后 1h 进行非营养性口腔行为的时间减少（OR：0.21）。总之，自由选择提供饲草源可提高幼犊的采食量和性能，而不会降低 DM、有机物、粗蛋白和中性洗涤纤维的消化率，并且根据饲草来源的不同，减少非营养性口腔行为并刺激反刍。
