Body condition score and its relationship to ultrasound backfat measurements in beef cows

Abstract

Spring calving beef cows from two genotypes were used in two different trials to examine the effectiveness of visual scoring systems to predict body condition. In trial 1, data on body condition score and ultrasound backfat measurements were collected at three different stages of the production cycle: dry, nursing and weaning. Scoring was by three different assessors and ultrasonic measurements by one experienced technician. Visual scores were positively but inconsistently related to ultrasound measurements (R2 = 0.14, 0.27 and 0.41 for dry, nursing and weaning times, respectively). In the second trial, two different subjective scoring methods were studied, general condition score based on an overall visual assessment of condition with scores ranging from 1 to 5, increasing in half units, and a specific site score based on visual assessment of condition identified at six specific sites on the animal’s body, with scores ranging from 6 to 30. Differences in scores between levels of experience which were observed with the general method were removed with the specific site method. Precision of estimating ultrasound measurements (R2) was improved from 54% for the general to 64% for the specific site assessment when scoring was by experienced assessors. Visual assessment could be improved by more specific scoring, although for research purposes visual assessment would still be inadequate in measuring condition relative to ultrasonic measurements. Key words: Beef cows, ultrasound measurements, condition scoring