DESCRIPTION OF COW CALF PRODUCTIVITY IN NORTHWESTERN QUEBEC AND PATH MODELS FOR CALF MORTALITY AND GROWTH

A random sample of 651 assumed-pregnant cows was drawn from 26 randomly selected beef herds in Northwestern Quebec, Canada. The cows were followed with their calves (n=568) for one production period. Data were collected on calving conditions, calf mortalities, and the presence of diarrhea and pneumonia in calves during the first 2 weeks of life, The calves were weighed and measured for withers height, at 3-4 weeks of age and at the weaning (median of 203 days of age). Cow-calf productivity was described and two path models were built, one for calf mortalities and the other for calf growth. The percentage of weaned calves was 78.8%, the risk of perinatal mortality, within 24 h of birth, 4.4%, and the risk of neonatal mortality, from 24 h to 30 days of age, 7.7%, were estimated. The mean 200 day weight (adjusted for sire breed) was 217 kg for female calves and 232 kg for male calves. Birth with assistance and birth between December and March (versus in April or May) were associated with an increased risk of dying during the perinatal period; birth in a maternity pen was associated with a decreased risk of perinatal mortality. The presence of diarrhea or pneumonia during the first 2 weeks of life was associated with an increased risk of dying between 24 h and 30 days of age and with a decreased achieved growth at 30 days without a subsequent full compensatory gain at the weaning.