Frequency and precision of body condition scoring in dairy cattle.

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.