Valio Ltd., Box 10, 00039 Valio, Finland; Department of Production Animal Medicine, Faculty of Veterinary Medicine, University of Helsinki, Paroninkuja 20, 04920 Saarentaus, Finland.
Department of Production Animal Medicine, Faculty of Veterinary Medicine, University of Helsinki, Paroninkuja 20, 04920 Saarentaus, Finland.
J Dairy Sci. 2018 Jul;101(7):6253-6261. doi: 10.3168/jds.2017-13420. Epub 2018 Apr 5.
On-farm death (OFD) of a dairy cow is always a financial loss for a farmer, and potentially a welfare issue that has to be addressed within the dairy industry. The aim of this study was to explore the associations between OFD of dairy cows, housing, and herd management in freestall barns. To achieve the goal, we followed 10,837 cows calving in 2011 in 82 herds. Data were gathered with observations and a structured interview during farm visits and from a national dairy herd improvement database. The hazard of OFD was modeled with a shared frailty survival model, with SAS 9.3 PHREG procedure (SAS Institute Inc., Cary, NC). The study population was 58% Ayrshire and 42% Holstein cows. The median herd size and mean milk yield in the study herds were 116 cows and 9,151 kg of milk per cow per year. The overall probability of OFD was 6.0%; 1.8% of the cows died unassisted and 4.2% were euthanized. Variation in OFD percentage between individual herds was large, from 0 to 16%, accounting for 0 to 58% of all removals in the herds. Keeping close-up dry cows in their own group was associated with higher hazard of OFD [hazard ratio (HR) = 1.37] compared with keeping them in the same pen with far-off dry cows. Higher hazard on OFD was observed when barns had only one kind of calving pen; single (HR = 2.09) or group pens (HR = 1.72), compared with having both of those types. The hazard of OFD was lower if the whole herd was housed in barns or pens that had only 1 type of feed barrier at the feed bunk, namely post-and-rail (HR = 0.51) or a type with barriers between the cow's heads (HR = 0.49), compared with having 2 types. Lower OFD hazard was observed with wider than 340 cm of walking alley next to the feeding table (HR = 0.75), and with housing a whole herd in pens with only 1 type of walking alley surface, specifically slatted (HR = 0.53) or solid (HR = 0.48), compared with having both types. The hazard of OFD was higher with stalls wider than 120 cm (HR = 1.38) compared with narrower stalls. The hazard of OFD was also associated with breed, parity, and calving season. This study identified many factors that contribute to the incidence of OFD of dairy cows. The solutions for reducing on-farm mortality include housing, management, and breeding choices that are most probably herd specific.
奶牛在农场死亡（OFD）对农民来说总是一笔经济损失，也可能是奶牛养殖业需要解决的福利问题。本研究旨在探讨奶牛在厩舍中的 OFD、饲养和畜群管理之间的关联。为了实现这一目标，我们对 2011 年在 82 个畜群中分娩的 10837 头奶牛进行了跟踪调查。数据是通过在农场访问期间的观察和结构化访谈以及从国家奶牛群改良数据库中收集的。使用 SAS 9.3 PHREG 程序（SAS Institute Inc.，Cary，NC）对 OFD 风险进行了共享脆弱性生存模型建模。研究人群中 58%是 Ayrshire 牛，42%是荷斯坦牛。研究畜群的中位畜群规模和平均产奶量分别为 116 头和每头奶牛每年 9151 公斤牛奶。总的 OFD 概率为 6.0%；1.8%的奶牛未得到协助而死亡，4.2%的奶牛被实施了安乐死。个体畜群之间的 OFD 百分比差异很大，从 0 到 16%不等，占畜群中所有淘汰牛的 0 到 58%。将待挤奶牛单独饲养在自己的畜栏中比将它们与远处的干奶牛一起饲养在同一畜栏中，OFD 的风险更高[风险比（HR）=1.37]。畜舍中只有一种分娩畜栏时，OFD 的风险更高；单栏（HR=2.09）或群栏（HR=1.72），而同时具有这两种类型的畜栏则风险较低。如果整个畜群都被安置在畜栏或畜栏中，只有 1 种类型的饲料障碍物，即柱栏（HR=0.51）或牛头部之间的障碍物（HR=0.49），则 OFD 的风险较低，与具有 2 种类型的畜栏相比。如果饲喂台旁边的走道宽度超过 340 厘米（HR=0.75），并且畜群全部安置在只有 1 种类型的走道表面的畜栏中，具体来说是条板（HR=0.53）或实心（HR=0.48），则 OFD 的风险较低，与同时具有两种类型的畜栏相比。畜栏的牛栏宽度大于 120 厘米（HR=1.38）时，OFD 的风险高于较窄的牛栏。OFD 的风险还与品种、胎次和产犊季节有关。本研究确定了许多导致奶牛 OFD 发生率的因素。降低农场死亡率的解决方案包括住房、管理和繁殖选择，这些选择很可能是畜群特有的。
