Management variables associated with high mortality rates attributable to respiratory tract problems in female calves prior to weaning.

OBJECTIVE

To identify risk factors associated with high mortality rates attributable to respiratory tract problems in female calves prior to weaning.

DESIGN

Cross-sectional national survey.

SAMPLE POPULATION

1,685 dairies.

PROCEDURE

Dairies that had > or = 3 female calves that were born by a herd member or purchased during a 3-month period were classified into operations with high or low mortality rates attributable to respiratory tract problems in female calves prior to weaning. Step-wise logistic regression was used to identify management practices associated with high mortality rates caused by respiratory tract problems.

RESULTS

1,363 of 47,057 (2.9%) calves died of respiratory tract problems during a 3-month period. Management variables associated with high mortality rates caused by respiratory tract problems were housing of > or = 7 calves in a group and rolling herd average for milk production of < or = 9,072 kg. Also, dairies located in the West or Southeast had higher mortality rates.

CLINICAL IMPLICATIONS

Dairy operators that house calves in large groups prior to weaning may need to pay close attention to respiratory tract illness in their calves. Herds with high milk production have lower mortality from respiratory tract illness than herds with low milk production. Dairies in the West and Southeast have higher mortality attributable to respiratory tract problems than dairies in other regions of the country.