Repeatability of litter characteristics from birth to weaning in the Large White breed

Abstract

Data from 801 births of 255 Large White sows, mated to 25 boars under subtropical conditions were analised to estimate repeatability. Estimated values were 0.143±0.038 for number of stillborn, 0.241+0.039 for litter size at birth, 0.278±0.039 for Utter weight at birth, 0.239±0.039 for litter size at 21 days of age, 0.268±0.039 for litter weight at 21 days, 0.241 ±0.039 for litter size at weaning and 0.163±0.038 for litter weight at weaning. The effects of these values on the accuracy of the breeding value predictor and on the relative efficiency of selection based on "n" numbers of litters per sow compared to that of the first litter are studied. The mainly conclusion is that the first litter is not a good prediction of the following litters and the choice of mothers of future sows must be made only after the third litter, in order to improve the efficiency and accuracy of selection.