Lukas J M, Reneau J K, Linn J G
Department of Animal Science, University of Minnesota, St. Paul 55108, USA.
J Dairy Sci. 2008 Sep;91(9):3385-94. doi: 10.3168/jds.2007-0926.
This study investigates whether dry matter (DM) or water intake is affected by the presence of disease or estrus in dairy cows and whether water intake can serve as an accurate substitute for monitoring changes in DM intake (DMI). A combined cumulative sum (CUSUM) and Shewhart monitoring scheme is proposed to detect DMI changes and emerging disease or estrus. Daily readings from 35 inline water meters for 35 water cups in a tie-stall barn at the University of Minnesota were collected from September 2005 until June 2006. Two cows were assigned to each water cup. Individual DMI were recorded for each of the 70 cows on the study. All drug or hoof treatments administered to the cows along with breeding and calving events were also recorded and classified as 1 of the following 6 event categories: estrus, calving, mastitis, fever, hoof treatment, and other. Analysis of covariance was used to identify factors significantly changing intake. Only the first 150 d in milk (DIM) were considered in the analysis. Six event categories plus DIM, ambient temperature, relative humidity, and parity were entered as independents into the model. Calving, primiparity, and health events categorized as "other" were associated with decreased DM and water intake. Mastitis decreased DMI and fever negatively affected water intake. Both intakes increased with DIM, and water intake decreased with increase in humidity. Covariance analysis was used to investigate the relationship between DMI and water intake. In model 1, analysis was done for a pair of cows, whereas model 2 modeled DMI of the whole group of 70 cows. Water intake, ambient temperature, humidity, and DIM were entered as independents in both models and parity was entered in model 1. Polynomial models and 2-way interactions were also considered. Water intake, ambient temperature, DIM, and DIM(2) were kept in final models 1 and 2, and parity was kept in model 1. Final models for cow pairs and a group of 70 cows resulted in R(2) of 0.50 and 0.82, respectively. The proposed CUSUM-Shewhart DMI monitoring scheme successfully detected emerging disease even in the first week of lactation. Monitoring water intake can serve as an alternative to measurements of DMI for groups of cows and has the potential of predicting change in individual cow health and estrus status.
本研究调查了干物质（DM）摄入量或饮水量是否受奶牛疾病或发情的影响，以及饮水量是否可作为监测干物质摄入量（DMI）变化的准确替代指标。提出了一种累积和（CUSUM）与休哈特监测方案相结合的方法来检测DMI变化以及新出现的疾病或发情情况。2005年9月至2006年6月期间，收集了明尼苏达大学一个拴系牛舍中35个水杯对应的35个在线水表的每日读数。每个水杯分配两头奶牛。记录了研究中70头奶牛每头的个体DMI。还记录了所有给奶牛进行的药物或蹄部治疗以及配种和产犊事件，并将其归类为以下6种事件类别中的一种：发情、产犊、乳腺炎、发热、蹄部治疗和其他。采用协方差分析来确定显著改变摄入量的因素。分析中仅考虑产奶的前150天（DIM）。将6种事件类别加上DIM、环境温度、相对湿度和胎次作为自变量纳入模型。产犊、初产以及归类为“其他”的健康事件与DM和饮水量减少有关。乳腺炎会降低DMI，发热对饮水量有负面影响。两种摄入量均随DIM增加，饮水量随湿度增加而减少。采用协方差分析来研究DMI与饮水量之间的关系。在模型1中，对一对奶牛进行分析，而模型2对70头奶牛的整个群体的DMI进行建模。在两个模型中均将饮水量、环境温度、湿度和DIM作为自变量纳入，在模型1中纳入胎次。还考虑了多项式模型和双向交互作用。饮水量、环境温度、DIM和DIM(2)保留在最终模型1和2中，胎次保留在模型1中。奶牛对和70头奶牛群体的最终模型的R(2)分别为0.50和0.82。所提出的CUSUM - 休哈特DMI监测方案即使在泌乳的第一周也成功检测到了新出现的疾病。监测饮水量可作为奶牛群体DMI测量的替代方法，并且有预测个体奶牛健康和发情状态变化的潜力。
