Hosseini S M, Ghorbani G R, Rezamand P, Khorvash M
1Department of Animal Sciences,Isfahan University of Technology,Isfahan 84156,Iran.
2Department of Animal and Veterinary Science,University of Idaho,Moscow,ID 83844,USA.
Animal. 2016 Apr;10(4):607-15. doi: 10.1017/S1751731115002499. Epub 2015 Nov 16.
The present study was conducted to determine the optimum age of Holstein dairy calves for an effective inclusion of alfalfa hay (AH) in starter feed on performance, apparent digestibility and feeding behavior. A total of 40 Holstein dairy calves (20 female and 20 male) were used in a completely randomized design in which calves were randomly assigned to one of four different dietary treatments including control (CON) calves fed starter feed without any forage and three treatments consisting of the same starter feed plus 15% chopped AH fed when calves were at the 2nd (AH2), 4th (AH4) or 6th (AH6) week of age. Calves were individually housed and bedded with sand that was replaced every other day. Feed and water were available ad libitum throughout the experiment. Calves were fed milk at 10% of birth BW twice daily until d 57. The study concluded when calves were 73 days old. Starter intake was recorded daily and BW was measured weekly. Data were analyzed as a complete randomized design by MIXED procedures of SAS. Results demonstrate that calves receiving AH treatments numerically consumed more starter feed (0.62 v. 0.78, 0.71 and 0.65 kg/day for CON, AH2, AH4 and AH6, respectively) and had greater average daily gain (ADG) compared with CON (0.48 v. 0.57, 0.49 and 0.49 kg/day for CON, AH2, AH4 and AH6), although the significant difference was observed only between AH2 and CON. Among AH treatments, calves in AH2 had better performance than AH6 in several cases including starter intake, ADG. No detectable differences were observed, however, in apparent dry matter, organic matter or CP digestibility among treatments. Ruminal pH and NH3 concentrations, measured on weeks 4, 6, 8 and 10, were lower for calves fed CON compared with other treatments, with ammonia concentrations decreasing over time. Calves in the AH treatments spent more time eating and ruminating compared with CON. Calves fed CON, however, spent more time on laying down compared with other treatments. Overall, results from the present study illustrated that inclusion of alfalfa in starter feed for calves at 2 weeks of age may improve feed intake, ADG and stimulate rumination in young Holstein dairy calves. Results, however, should be viewed with caution as the number of calves per treatment was small and large calf-to-calf variation may have affected the results reported.
本研究旨在确定荷斯坦奶牛犊牛的最佳年龄，以便在开食料中有效添加苜蓿干草（AH），从而研究其对犊牛生长性能、表观消化率和采食行为的影响。总共40头荷斯坦奶牛犊牛（20头雌性和20头雄性）被用于完全随机设计试验，犊牛被随机分配到四种不同的日粮处理组之一，包括对照组（CON）犊牛，饲喂不添加任何粗饲料的开食料；以及三个处理组，即犊牛在2周龄（AH2）、4周龄（AH4）或6周龄（AH6）时，在相同的开食料基础上添加15%的切碎AH。犊牛单独饲养，铺垫料为沙子，每隔一天更换一次。在整个试验期间，自由提供饲料和饮水。犊牛在出生体重的10%时每天分两次饲喂牛奶，直至第57天。研究在犊牛73日龄时结束。每天记录开食料摄入量，每周测量体重。数据采用SAS的MIXED程序按完全随机设计进行分析。结果表明，与对照组相比，接受AH处理的犊牛在数值上消耗了更多的开食料（CON、AH2、AH4和AH6组分别为0.62、0.78、0.71和0.65千克/天），且平均日增重（ADG）更高（CON、AH2、AH4和AH6组分别为0.48、0.57、0.49和0.49千克/天），不过仅在AH2组和CON组之间观察到显著差异。在AH处理组中，AH2组犊牛在包括开食料摄入量、ADG等几个方面的表现优于AH6组。然而，各处理组在表观干物质、有机物或粗蛋白消化率方面未观察到可检测到的差异。在第4、6、8和10周测量的瘤胃pH值和氨浓度，与其他处理组相比，饲喂CON组的犊牛较低，且氨浓度随时间降低。与CON组相比，AH处理组的犊牛花费更多时间采食和反刍。然而，与其他处理组相比，饲喂CON组的犊牛花费更多时间躺卧。总体而言，本研究结果表明，在犊牛2周龄时在开食料中添加苜蓿可能会提高采食量、ADG，并刺激年轻荷斯坦奶牛犊牛的反刍。然而，由于每个处理组的犊牛数量较少，且犊牛个体间差异较大可能影响了所报告的结果，因此对这些结果应谨慎看待。
