Adams A E, Lombard J E, Fossler C P, Román-Muñiz I N, Kopral C A
Department of Animal Sciences, Colorado State University, Fort Collins 80523; USDA-APHIS-VS Center for Epidemiology and Animal Health, National Animal Health Monitoring System, Fort Collins, CO 80526.
USDA-APHIS-VS Center for Epidemiology and Animal Health, National Animal Health Monitoring System, Fort Collins, CO 80526.
J Dairy Sci. 2017 Mar;100(3):2119-2136. doi: 10.3168/jds.2016-11517. Epub 2016 Dec 29.
The objective of this study was to determine the association among different housing and management practices on the prevalence of lameness, hock lesions, and thin cows on US dairy operations. This study was conducted as part of the National Animal Health Monitoring System's Dairy 2014 study, which included dairy operations in 17 states. Size categories were assigned as follows: small (30-99 cows), medium (100-499 cows), and large (≥500 cows). Trained assessors visited 191 dairy operations from March through July 2014 and recorded locomotion and hock scores (on a 3-point scale), and the number of thin cows (body condition score ≤2.25) from a total of 22,622 cows (average 118 cows per farm). The majority of cows (90.4%) were considered to be sound (locomotion score = 1), 6.9% were mild/moderately lame (locomotion score = 2), and 2.7% were severely lame (locomotion score = 3). Similarly, most cows (87.3%) had no hock lesions (hock score = 1), 10.1% had mild lesions (hock score = 2), and 2.6% had severe hock lesions (hock score = 3). A low percentage of cows (4.2%) were thin. Univariate comparisons were performed using PROC LOGLINK, which accounts for study design and weighting. Variables meeting the univariate screening criterion of P < 0.20 were eligible for entry into multivariable models. Statistical significance in the multivariable models was declared at P < 0.05. Large operations had a lower within-herd prevalence of cows with locomotion score ≥2 and locomotion score = 3 compared with small or medium-sized operations. Operations on which cows were kept primarily on pasture had a lower percentage of locomotion score = 3 than those housed in freestall or open/dry lot operations. The use of sand bedding was associated with a lower within-herd prevalence of locomotion score ≥2 than straw/hay or dry/composted manure as the primary bedding material. Sand bedding was also associated with a lower within-herd prevalence of locomotion score = 3 than other bedding types except for rubber mats or mattresses. Operations that housed cows in an open/dry lot had a lower percentage of hock score ≥2 and hock score = 3 than other housing types. Providing sprinklers for heat abatement and having a nutritionist balance rations for cows was associated with a lower percentage of thin cows. Results from this study highlight management practices that may reduce the prevalence of lameness, hock lesions, and thin cows on dairy operations in the United States.
本研究的目的是确定美国奶牛场中不同的饲养和管理方式与跛足、跗关节损伤及消瘦母牛患病率之间的关联。本研究是作为国家动物健康监测系统2014年奶牛研究的一部分开展的，该研究涵盖了17个州的奶牛场。规模类别划分如下：小型（30 - 99头奶牛）、中型（100 - 499头奶牛）和大型（≥500头奶牛）。2014年3月至7月，经过培训的评估人员走访了191个奶牛场，记录了22622头奶牛（平均每个农场118头）的运动能力和跗关节评分（采用3分制）以及消瘦母牛（体况评分≤2.25）的数量。大多数奶牛（90.4%）被认为健康（运动能力评分 = 1），6.9%为轻度/中度跛足（运动能力评分 = 2），2.7%为重度跛足（运动能力评分 = 3）。同样，大多数奶牛（87.3%）没有跗关节损伤（跗关节评分 = 1），10.1%有轻度损伤（跗关节评分 = 2），2.6%有重度跗关节损伤（跗关节评分 = 3）。消瘦母牛的比例较低（4.2%）。使用PROC LOGLINK进行单变量比较，该方法考虑了研究设计和加权因素。满足单变量筛选标准（P < 0.20）的变量有资格纳入多变量模型。多变量模型中的统计学显著性设定为P < 0.05。与小型或中型养殖场相比，大型养殖场中运动能力评分≥2和运动能力评分 = 3的奶牛群体患病率较低。主要将奶牛饲养在牧场的养殖场中，运动能力评分 = 3的奶牛比例低于那些采用散栏或开放式/干燥栏饲养方式的养殖场。与以秸秆/干草或干/堆肥粪便作为主要垫料相比，使用沙子作为垫料与养殖场内运动能力评分≥2的奶牛群体患病率较低相关。与其他垫料类型相比，除了橡胶垫或床垫外，使用沙子作为垫料也与养殖场内运动能力评分 = 3的奶牛群体患病率较低相关。采用开放式/干燥栏饲养奶牛的养殖场中，跗关节评分≥2和跗关节评分 = 3的奶牛比例低于其他饲养类型。为奶牛提供降温喷头以及配备营养师平衡日粮与消瘦母牛比例较低相关。本研究结果突出了一些管理措施，这些措施可能会降低美国奶牛场中跛足、跗关节损伤及消瘦母牛的患病率。
