VetSouth Ltd, Winton, New Zealand.
Northern Australia Quarantine Strategy, Australian Government Department of Agriculture, Water and the Environment, Cairns, Australia.
N Z Vet J. 2022 Sep;70(5):248-255. doi: 10.1080/00480169.2022.2069174. Epub 2022 May 18.
To explore factors associated with the frequency of tail damage in dairy cows on 29 New Zealand farms participating in an animal welfare monitoring programme.
Herd-level tail score data were collected at the cow level and then summarised at the herd level as counts for each lactation over the period 1 June 2014 to 31 May 2018. A cow's tail was considered damaged if there was evidence of any injury that deformed the anatomical structure involving either bone or soft tissue and could include loss of use. There were four categories for tail scoring. Fracture or dislocation of tail bones was considered as a deviation (score 1). When the tail had been docked above the top of the cow's udder, this was considered as docked short tail (score 2). When there was evidence of soft tissue trauma (score 3) or bone damage but no fracture (score 4), this was recorded as damaged (other). Tails were scored for each whole dairy herd. Tail scoring was performed by trained veterinarians or veterinary technicians. The primary outcome variable was counts of deviated tails (DT). Other outcome variables were docked short, damaged (other), and total tail injuries (TTI) which was a summation of all tail injuries. The potential predictor variables were area, season, farm, region, replacement rate, and herd size. A mixed-effects negative binomial or Poisson regression was fitted to the count data.
A total of 29 farms contributed data for tail scoring, with 54,831 cows individually scored. The unadjusted regional prevalence of TTI ranged from 3.5% (64/1,835) in Taranaki in 2014-2015 to 28.7% (1,434/4,988) in Southland/Otago in 2017-2018. The unadjusted regional herd prevalence of DT ranged from 2.1% (280/6,862) in Taranaki (2014-2015) to 13.2% (4,627/30,165) in Southland/South Otago (2017-2018). The incident rate ratio (IRR) of DT in 2015-2016 was 1.74 (95% CI = 1.20-2.53; p = 0.003) times the incident rate for the reference group (2014-2015). The IRR for TTI in 2015-2016 was 1.70 (95% CI = 1.60-1.81; p = 0.001) times the incident rate for the reference group (2014-2015).
This is the first quantitative study of the frequency of tail damage within New Zealand dairy farms and whilst variable between regions, it indicates that the frequency is increasing. Opportunities exist to better understand the causes of tail injuries and to improve animal welfare.
探讨新西兰 29 个参与动物福利监测计划的奶牛场中与奶牛尾部损伤频率相关的因素。
在 2014 年 6 月 1 日至 2018 年 5 月 31 日期间，以奶牛个体水平收集牛群水平的尾部评分数据，并在牛群水平上对每头奶牛的每次泌乳进行汇总。如果牛的尾部有任何导致解剖结构变形的损伤，包括骨骼或软组织损伤，且可能影响使用，就认为该牛的尾部受损。尾部评分有四个等级。尾部骨骼骨折或脱位被认为是畸形（评分 1）。如果尾部被截短至牛的乳房顶部以上，则认为是截短短尾（评分 2）。如果有软组织创伤（评分 3）或骨骼损伤但无骨折（评分 4），则记录为受损（其他）。对整个奶牛群进行尾部评分。尾部评分由经过培训的兽医或兽医技术员进行。主要结局变量是畸形尾部（DT）的计数。其他结局变量是截短短尾、受损（其他）和总尾部损伤（TTI），即所有尾部损伤的总和。潜在的预测变量包括面积、季节、农场、地区、替代率和牛群规模。使用混合效应负二项式或泊松回归对计数数据进行拟合。
共有 29 个农场提供了尾部评分数据，共有 54831 头奶牛接受了个体评分。未经调整的 TTI 在地区间的患病率从 2014-2015 年塔朗加的 3.5%（64/1835）到 2017-2018 年南地/奥塔哥的 28.7%（1434/4988）。未经调整的 DT 在地区间的牛群患病率从 2014-2015 年塔拉纳基的 2.1%（280/6862）到 2017-2018 年南地/南奥塔哥的 13.2%（4627/30165）。2015-2016 年 DT 的发病率比（IRR）是参考组（2014-2015 年）的 1.74 倍（95%置信区间 [CI] 1.20-2.53；p=0.003）。2015-2016 年 TTI 的 IRR 是参考组（2014-2015 年）的 1.70 倍（95%CI 1.60-1.81；p=0.001）。
这是新西兰奶牛场尾部损伤频率的首次定量研究，尽管在不同地区之间存在差异，但表明其频率正在增加。有机会更好地了解尾部损伤的原因，并改善动物福利。
