Hady P J, Domecq J J, Kaneene J B
Population Medicine Center, Michigan State University East Lansing 48825.
J Dairy Sci. 1994 Jun;77(6):1543-7. doi: 10.3168/jds.S0022-0302(94)77095-8.
The objectives of this project were 1) to determine whether mean body condition scores for 30-d lactation and dry period intervals can be utilized to appraise body condition changes in a herd and 2) to determine the precision of the mean body condition score for 30-d lactation and dry period intervals. Cows in a commercial dairy herd were visually scored for body condition on a five-point scale in increments of .25. Dry period intervals were based on expected calving date; lactation intervals were calculated from the calving date for each cow. The first objective was accomplished by comparison of mean body condition scores for the 30-d lactation and dry period intervals. A Student's t test was used to test for differences between adjacent means for body condition score. Mean body condition scores for each 30-d lactation and dry period interval can be used to detect changes in body condition across stages of lactation and the dry period. The precision of the mean body condition score for each 30-d lactation and dry period interval was determined. Precision (or significance) was 95, 90, and 80%. Significance was 95% for all but one of the lactation and dry period intervals, indicating that mean body condition scores for a given interval are significant and precise. Body condition scoring may provide useful management information with the procedures developed in this study.
1)确定30天泌乳期和干奶期的平均体况评分是否可用于评估牛群的体况变化;2)确定30天泌乳期和干奶期平均体况评分的精确性。对一个商业奶牛场的奶牛进行体况视觉评分,采用五分制,以0.25分为增量。干奶期根据预期产犊日期确定;泌乳期从每头奶牛的产犊日期开始计算。第一个目标是通过比较30天泌乳期和干奶期的平均体况评分来实现的。使用学生t检验来检验体况评分相邻均值之间的差异。每个30天泌乳期和干奶期的平均体况评分可用于检测泌乳期各阶段和干奶期的体况变化。确定了每个30天泌乳期和干奶期平均体况评分的精确性。精确性(或显著性)为95%、90%和80%。除一个泌乳期和干奶期间隔外,所有间隔的显著性均为95%,这表明给定间隔的平均体况评分具有显著性和精确性。通过本研究制定的程序,体况评分可为管理提供有用信息。