Johnsen J F, Beaver A, Mejdell C M, Rushen J, de Passillé A M, Weary D M
Norwegian Veterinary Institute, Department of Health Surveillance, PO Box 750, 0106 Oslo, Norway.
University of British Columbia, Faculty of Land and Food Systems, 2357 Main Mall, Vancouver, BC V6T 1Z4, Canada.
J Dairy Sci. 2015 Jul;98(7):4800-10. doi: 10.3168/jds.2014-9128. Epub 2015 Apr 23.
Dam rearing can provide health and welfare benefits, but separation and weaning are major welfare challenges. We investigated whether access to an additional source of milk from an automatic milk feeder (AMF) would improve weight gains after separation and weaning. During the first 6wk of life (dam phase), calves were assigned to 1 of 3 treatments using a parallel group design with repeated measures: nursing (n=10) and combined (n=10) calves could suckle from their dams at night (between 2000 and 0800h), and combined calves also had access to 12 L of milk/d accessible 24h/d from an AMF. Milk feeder calves (n=10) also had access to an AMF 24h/d and were housed with the dam at night but were prevented from suckling by an udder net. Separation from the dam occurred after 6wk in 2 phases with decreasing contact between cow and calf: partial separation (duration 4d) and total separation (duration 3d). At separation, all calves were granted access to 12 L of milk 24h/d from the AMF until weaning began at 7wk of age. We hypothesized that access to an AMF during the dam phase would result in less weight loss at separation and weaning compared with calves that had been nutritionally dependent upon the cow (i.e., nursing calves). Calf weight gain during the dam phase averaged (±SD) 1.1±0.26kg/d and did not vary with treatment. Combined calves drank less milk from the AMF compared with milk feeder calves during the dam phase (mean ± SEM daily milk intake: 1.1±0.38 vs. 8.2±0.34 L/d) and tended to drink less during partial separation (6.7±1.28 vs. 9.8±1.02 L/d), but milk intake from the AMF did not differ between these treatments in the later phases. During the same phases, nursing calves consumed less milk from the AMF than the other treatments; of the 10 calves, 6 did not use the AMF (consuming <1.5 L/d) after the dam phase. After separation, nursing calves gained less weight than calves in both the milk feeder and combined treatments (0.8±0.16 vs. 1.2±0.08kg/d). Calves using the AMF after separation (n=23; 4 nursing calves, 9 combined calves, and 10 milk feeder calves) had a higher average daily gain compared with calves that did not (n=7; 6 nursing calves and 1 combined calf; 1.2±0.07 vs. 0.6±0.21kg, respectively). In conclusion, use of the AMF after separation varied, but providing an additional milk source reduced nutritional dependency on the dam, improving calf performance at weaning and separation.
饲养犊牛可以带来健康和福利方面的益处，但母子分离和断奶是主要的福利挑战。我们研究了通过自动喂奶器（AMF）提供额外的奶源是否会改善犊牛在分离和断奶后的体重增加情况。在犊牛出生后的前6周（哺乳阶段），采用平行组设计并重复测量，将犊牛分为3种处理方式之一：哺乳组（n = 10）和混合组（n = 10）的犊牛可以在夜间（20:00至08:00）从母牛处 suckle，混合组的犊牛还可以每天24小时从AMF获取12升牛奶。喂奶器组犊牛（n = 10）同样每天24小时可以使用AMF，夜间与母牛关在一起，但通过乳房网阻止其 suckle。在6周龄时，分两个阶段与母牛分离，母牛与犊牛之间的接触逐渐减少：部分分离（持续4天）和完全分离（持续3天）。分离时，所有犊牛都可以每天24小时从AMF获取12升牛奶，直到7周龄开始断奶。我们假设，与营养上依赖母牛的犊牛（即哺乳组犊牛）相比，在哺乳阶段使用AMF将导致犊牛在分离和断奶时体重损失更少。犊牛在哺乳阶段的体重增加平均（±标准差）为1.1±0.26千克/天，且不受处理方式的影响。在哺乳阶段，混合组犊牛从AMF摄入的牛奶比喂奶器组犊牛少（平均±标准误每日牛奶摄入量：1.1±0.38升/天对8.2±0.34升/天），并且在部分分离期间摄入的牛奶也往往较少（6.7±1.28升/天对9.8±1.02升/天），但在后期阶段，这些处理方式从AMF摄入的牛奶量没有差异。在同一阶段，哺乳组犊牛从AMF摄入的牛奶比其他处理方式少；10头犊牛中有6头在哺乳阶段后未使用AMF（摄入量<1.5升/天）。分离后，哺乳组犊牛的体重增加比喂奶器组和混合组犊牛少（0.8±0.16千克/天对1.2±0.08千克/天）。分离后使用AMF的犊牛（n = 23；4头哺乳组犊牛、9头混合组犊牛和10头喂奶器组犊牛）的平均日增重高于未使用的犊牛（n = 7；6头哺乳组犊牛和1头混合组犊牛；分别为1.2±0.07千克对0.6±0.21千克）。总之，分离后AMF的使用情况各不相同，但提供额外的奶源减少了对母牛的营养依赖，改善了犊牛在断奶和分离时的生长性能。
