Institute of Veterinary Medicine and Animal Sciences, Estonian University of Life Science, 51014, Tartu, Estonia.
Department of Clinical Sciences, Swedish University of Agricultural Sciences, 750 07, Uppsala, Sweden.
Acta Vet Scand. 2020 Mar 12;62(1):15. doi: 10.1186/s13028-020-0513-x.
On-farm mortality (unassisted death and euthanasia) is the unwanted loss of animals, and it comes with negative economic consequences. On-farm mortality rates reflect a herd's animal welfare status. The objective of this historical longitudinal single cohort study was to identify the associations between herd characteristics, animal housing conditions and management routines and within-herd calf and cow mortality rates in participating Estonian dairy herds. All farmers enrolled in the voluntary production recording system with a herd size of 20 or greater cow-years in 2015-2017 were contacted by mail or telephone between October 2017 and March 2018. The survey included questions about management routines and housing conditions of calves up to 3 months of age and of cows. In total, 214 completed questionnaires were returned, corresponding to a 63.3% response rate. The within-herd mortality rate of calves (aged 21-90 days) and cows (cattle over 24 months of age) in years 2017-2018 were calculated and used as outcome variables. Negative binomial and linear regression models were applied for risk factor analysis in calf and cow datasets, respectively.
The median within-herd mortality rate for calves aged 21 to 90 days was 0.15 per 100 calf-months (quartiles 0.00; 0.36). The median within-herd mortality rate for cattle over 24 months of age was 4.57 per 100 cow-years (quartiles 2.44; 6.86). Factors significantly associated with increased mortality of calves were larger herd size, higher proportion of stillbirths and abortions in a herd, prophylactic administration of vitamins to all calves and housing pre-weaned calves in single pens only compared with housing in both single and group pens. Also, farmers who attended more frequent trainings had higher calf mortality rates. Calving in a group pen or in a tie-stall compared with calving in multiple systems was associated with higher calf mortality rates. Higher cow mortality rates were present in herds that had a higher proportion of stillbirths and on farms where employees handled cows. Housing cows in free-stall barns, grazing cows and more frequent hoof trimming were protective for cow on-farm mortality.
This study identified the importance of housing conditions for on-farm cow and calf mortality rates. Our study results suggest that providing good care might ensure better health and welfare of dairy cows and calves.
农场死亡率（非协助死亡和安乐死）是动物的非预期损失，会带来负面的经济后果。农场死亡率反映了畜群的动物福利状况。本历史纵向单队列研究的目的是确定畜群特征、动物饲养条件和管理常规与参与爱沙尼亚奶牛场的畜群内犊牛和母牛死亡率之间的关联。2015-2017 年，所有参加了具有 20 头或更多奶牛年规模的自愿生产记录系统的农民都通过邮件或电话在 2017 年 10 月至 2018 年 3 月期间联系。调查包括关于 21-90 日龄犊牛和 24 个月以上奶牛的管理常规和住房条件的问题。共有 214 份完整的问卷被退回，对应 63.3%的回复率。2017-2018 年，计算了犊牛（21-90 日龄）和奶牛（24 个月以上牛）的畜群内死亡率，并将其用作结局变量。在犊牛数据集和奶牛数据集中分别应用负二项和线性回归模型进行风险因素分析。
21-90 日龄犊牛的畜群内死亡率中位数为每 100 头犊牛-月 0.15（四分位数 0.00；0.36）。24 个月以上牛的畜群内死亡率中位数为每 100 头奶牛-年 4.57（四分位数 2.44；6.86）。与犊牛死亡率增加显著相关的因素包括更大的畜群规模、畜群中更高的死产和流产比例、对所有犊牛预防性给予维生素以及与同时在单栏和群栏中饲养相比，仅将未断奶犊牛饲养在单栏中。此外，参加更频繁培训的农民犊牛死亡率更高。与在多系统中分娩相比，在群栏或系留栏中分娩与犊牛死亡率较高有关。在死产比例较高的畜群和员工处理奶牛的农场中，母牛死亡率较高。在自由畜栏中饲养奶牛、放牧奶牛和更频繁的蹄修剪对农场母牛死亡率具有保护作用。
本研究确定了饲养条件对农场母牛和犊牛死亡率的重要性。我们的研究结果表明，提供良好的护理可能确保奶牛和犊牛的健康和福利更好。
