CAUSES OF MORTALITY IN YORKSHIRE PIGS FROM BIRTH TO 20 WEEKS OF AGE

Abstract

The mortality rate in 6890 Yorkshire piglets from birth to 20 weeks was 25.6%, of which 7.2% occurred at farrowing, and 16.4% from birth to weaning. The average number of mummified or decomposed pigs was 0.13 per litter. Of the total mortality, 15.3% occurred on the first day and 43.7% occurred during the first week. Major causes of death were: general congenital weakness and inanition, 26.9%; overlain or bitten by dam, 19.2%; scours, 14.2%; and paralysis, 10.2%. When inbreeding increased from less than 5% to 25% and over, mortality before birth went from 5.9% to 14.1%, and before weaning from 15.1% to 20.9%. No significant effect of farrowing quarters on mortality was detected, but there were significant effects of fines and years. Curvilinear relationships between average pig weight, litter size and mortality were fitted, and maximum rates were calculated. A linear relationship was observed between the survival at weaning and the within-litters coefficient of variation of pig weights at birth.