Repeatability of weight-corrected ultrasonic fat-depth measurements made on ewes at intervals of one year

摘要

The repeatability of ultrasonically measured fat depths in Southdown and Romney ewes was investigated by making these measurements shortly before mating in each of four successive years.Animals were allocated to fat or meaty groups within each breed based on the first weight-corrected measurement,and group differences were effectively maintained over the duration of the experiment.The fat groups of both breeds had shorter average body lengths at a set weight than the corresponding meaty groups, but the groups did not differ significantly in withers height.Intra-class correlations indicated that weight-corrected assessments of fat depth,body length, and withers height were only moderately repeatable over the four years, with the values for fat depth of Southdowns (n = 68) and Romneys(n = 71) being 0.36 and 0.54 respectively.