Ito K, Chapinal N, Weary D M, von Keyserlingk M A G
Animal Welfare Program, University of British Columbia, Vancouver, BC V6T 1Z4, Canada; Novus International Inc., St. Charles, MO 63304.
Animal Welfare Program, University of British Columbia, Vancouver, BC V6T 1Z4, Canada.
J Dairy Sci. 2014;97(4):2081-9. doi: 10.3168/jds.2013-6861. Epub 2014 Jan 31.
Our objective was to investigate the associations between herd-level factors and lying behavior of high-producing dairy cows housed in freestall barns. Lying behavior of approximately 40 focal cows in one high-producing pen was monitored on each of 40 farms in the northeastern United States (NE) and 39 farms in California (CA). All cows within the pen were gait scored using a 1-to-5 scale to calculate the prevalence of clinical lameness (score ≥3) and severe lameness (score ≥4). Facility and management measures, including stall design, bedding, and flooring type within the pen, were collected. Herd-level factors associated with daily lying time, standard deviation (SD) of daily lying time, frequency of lying bouts, and lying bout duration at the univariate level were submitted to multivariable general linear models. In the NE, daily lying time increased with the use of deep bedding (estimate = 0.80±0.31h/d) and as average days in milk (DIM) of the focal cows increased (estimate = 0.08±0.04h/d for a 10-d increase in DIM). The SD of daily lying time decreased as stall stocking density increased (estimate = -0.08±0.03h/d for a 10% increase), and increased with the presence of rubber flooring in the pen (estimate = 0.16±0.08h/d) and percentage of stalls with fecal contamination (estimate = 0.04±0.01h/d for a 10% increase). Frequency of lying bouts decreased (estimate = -1.90±0.63 bouts/d) and average bout duration increased (estimate = 15.44±3.02 min) with the use of deep bedding. In CA, where all farms used deep bedding, daily lying time increased as average DIM of the focal cows increased (estimate = 0.08±0.03h/d for a 10-d increase). The SD of daily lying time decreased when feed was delivered more than once per day (estimate = -0.24±0.08h/d). The percentage of lame cows was correlated with the percentage of stalls with fecal contamination (r=0.45), which in turn was associated with fewer (estimate = -0.25±0.06 bouts/d) and longer lying bouts (estimate = 1.85±0.39 min/d). These findings suggest that lying time be interpreted in conjunction with variability in lying time and bout structure and in context with lameness prevalence, production parameters, and facility characteristics.
我们的目标是研究群体水平因素与饲养在散栏式牛舍中的高产奶牛躺卧行为之间的关联。在美国东北部（NE）的40个农场和加利福尼亚州（CA）的39个农场中，对一个高产牛栏内约40头重点奶牛的躺卧行为进行了监测。对牛栏内所有奶牛的步态进行1至5分评分，以计算临床跛足（评分≥3）和严重跛足（评分≥4）的患病率。收集了设施和管理措施，包括牛栏内的畜栏设计、垫料和地面类型。将在单变量水平上与每日躺卧时间、每日躺卧时间的标准差（SD）、躺卧次数频率和躺卧时长相关的群体水平因素纳入多变量一般线性模型。在NE地区，随着使用厚垫料（估计值 = 0.80±0.31小时/天）以及重点奶牛的平均泌乳天数（DIM）增加（DIM每增加10天，估计值 = 0.08±0.04小时/天），每日躺卧时间增加。随着畜栏饲养密度增加，每日躺卧时间的SD降低（饲养密度每增加10%，估计值 = -0.08±0.03小时/天），并且随着牛栏内有橡胶地面（估计值 = 0.16±0.08小时/天）以及粪便污染畜栏的百分比增加（百分比每增加10%，估计值 = 0.04±0.01小时/天）而增加。使用厚垫料时，躺卧次数频率降低（估计值 = -1.90±0.63次/天），平均躺卧时长增加（估计值 = 15.44±3.02分钟）。在CA地区，所有农场都使用厚垫料，随着重点奶牛的平均DIM增加，每日躺卧时间增加（DIM每增加10天，估计值 = 0.08±0.03小时/天）。当每天投喂饲料超过一次时，每日躺卧时间的SD降低（估计值 = -0.24±0.08小时/天）。跛足奶牛的百分比与粪便污染畜栏的百分比相关（r = 0.45），而这又与躺卧次数减少（估计值 = -0.25±0.06次/天）和躺卧时长增加（估计值 = 1.85±0.39分钟/天）有关。这些发现表明，躺卧时间应结合躺卧时间的变异性、躺卧结构以及跛足患病率、生产参数和设施特征来进行解读。
