Vickery Holly M, Neal Rachael A, Stergiadis Sokratis, Meagher Rebecca K
Department of Animal Sciences, University of Reading, Reading, United Kingdom.
Department of Animal Science and Aquaculture, Dalhousie University, Truro, NS, Canada.
Front Vet Sci. 2023 Jun 1;10:1200849. doi: 10.3389/fvets.2023.1200849. eCollection 2023.
Most dairy goat farms rear kids on milk replacer; calf research suggests this improves growth and welfare, but solid feed intakes are problematic. Weaning can be gradual (incremental milk reduction) or abrupt (sudden, complete milk removal, which evidence suggests reduces welfare). Three treatments were created: abrupt weaning (AW: milk until weaning) and gradual weaning [milk until day 35, then milk unavailable 3.5 h/day until day 45 when milk removal was a 7 h/day block (gradual weaning 1: GW1) or two 3.5 h/day blocks (gradual weaning 2; GW2)]; complete milk removal occurred at day 56 for all. Experiment 1 investigated on-farm feasibility, behavior, and average daily gain (ADG). Experiment 2 investigated feed intakes, behavior, and ADG for AW and GW2. Experiment 1 had 261 kids (nine pens of 25-32), CCTV recorded 6 h/day, and group-level scan sampling recorded target behaviors. Kruskal-Wallis tests showed GW2 kids spent more time feeding on solids during weaning ( = 0.001) and displayed lower levels of 'frustrated suckling motivation' PostWean ( = 0.008). However, feeding competition differed PreWeaning ( = 0.007). ADG data from 159 female kids analyzed by a general linear model (fixed factor: treatment; covariate: day 34 weight) found GW2 had the highest ADG from day 35-45 ( ≤ 0.001) and no differences from day 45 to 56, and AW had the highest ADG PostWean (day 56-60). Experiment 2 had two AW pens (9 kids/pen) and two GW2 pens (8 and 9 kids/pen). A computerized feeder recorded milk intakes from day 22 to 56. Pen-level solid feed/water intakes were recorded from day 14-70. General linear models (fixed factor: treatment; covariate: PreWean value) found GW2 kids had higher ADG ( = 0.046) and lower milk intake ( = 0.032) from day 45-55, and PostWean (day 56-70) trended toward GW2 higher ADG ( = 0.074). Mann-Whitney tests showed pen-level feed intake differences: AW had higher creep and straw throughout, GW2 showed higher creep during weaning (day 35-55), and higher water PostWean (>56 d). Behavioral observations suggest that gradually weaned kids may have enhanced welfare. Pen-level gradual weaning is feasible and, while weight gain results were mixed, it reduced milk intake, increased creep intake, and therefore combined with behavioral evidence can be recommended.
大多数奶山羊养殖场使用代乳品饲养羔羊；犊牛研究表明，这有助于提高生长速度和福利，但固体饲料的摄入量存在问题。断奶可以是渐进式的（逐步减少牛奶量），也可以是突然式的（突然完全停止喂奶，有证据表明这会降低福利）。设置了三种处理方式：突然断奶（AW：断奶前一直喂奶）和渐进式断奶[第35天前喂奶，然后从第35天开始每天有3.5小时不提供牛奶，直到第45天，此时每天有7小时不提供牛奶（渐进式断奶1：GW1）或分两个3.5小时的时段（渐进式断奶2；GW2）]；所有羔羊在第56天完全停止喂奶。实验1研究了农场可行性、行为和平均日增重（ADG）。实验2研究了AW和GW2的饲料摄入量、行为和ADG。实验1有261只羔羊（9个栏，每栏25 - 32只），闭路电视每天记录6小时，采用组水平扫描抽样记录目标行为。Kruskal - Wallis检验表明，GW2组的羔羊在断奶期间吃固体饲料的时间更多（P = 0.001），断奶后“受挫的吮乳动机”水平更低（P = 0.008）。然而，断奶前的采食竞争存在差异（P = 0.007）。对159只雌性羔羊的ADG数据进行一般线性模型分析（固定因子：处理方式；协变量：第34天体重）发现，GW2组在第35 - 45天的ADG最高（P≤0.001），第45 - 56天无差异，AW组断奶后（第56 - 60天）的ADG最高。实验2有两个AW栏（每栏9只羔羊）和两个GW2栏（一栏8只，一栏9只）。电脑控制的喂食器记录了第22天到56天的牛奶摄入量。记录了第14 - 70天栏水平的固体饲料/水摄入量。一般线性模型（固定因子：处理方式；协变量：断奶前的值）发现，GW2组的羔羊在第45 - 55天的ADG更高（P = 0.046），牛奶摄入量更低（P = 0.032），断奶后（第56 - 70天）GW2组的ADG有更高的趋势（P = 0.074）。Mann - Whitney检验显示栏水平的饲料摄入量存在差异：AW组整个期间的开食料和稻草摄入量更高，GW2组在断奶期间（第35 - 55天）的开食料摄入量更高，断奶后（>56天）的水摄入量更高。行为观察表明，渐进式断奶的羔羊福利可能更好。栏水平的渐进式断奶是可行的，虽然体重增加的结果不一，但它减少了牛奶摄入量，增加了开食料摄入量，因此结合行为证据可以推荐采用。
