Risk factors associated with Cryptosporidium parvum infection in dairy cattle in southeastern New York State

An observational analytical epidemiologic study was carried out to identify factors associated with the risk of infection with Cryptosporidium parvum in dairy herds in southeastern New York state. A random sample of 2943 catt le on 109 farms was selected from the target population. Fecal samples were collected from animals in three different age groups and examined for the presence of C. parvum using a quantitative centrifugation concentration flo tation method. Data on intrinsic, preweaning, postweaning, maternity, and g eneral management factors were collected and evaluated for their associatio n with the risk of infection with C. parvum. Indices for each of these cate gories of management were developed from factors significantly associated w ith the risk of infection with C. parvum. Significant factors were identifi ed using the logistic regression statistical technique. A final analysis, i ncluding the indices, age, and season, was performed to identify factors si gnificantly associated with the risk of infection with C. parvum while simu ltaneously controlling for the effect of other factors. The farm effect was evaluated using a mixed effect model. Preweaning factors found to be significantly associated with a decreased ri sk of infection were: use of ventilation in calf rearing areas, daily addit ion of bedding, feeding of milk replacer, daily disposal and cleaning of be dding, and use of antibiotics. Postweaning factors such as moving of the an imals after weaning, cleaning of soiled bedding, and use of antibiotics and ionophores as preventive measures were significantly associated with the d ecreased risk of an infection with C. parvum. Consideration of maternity ma nagement factors showed that winter housing of cows individually within 2 m onths of calving, use of fresh colostrum to feed calves, and having a concr ete floor in the calving area were significantly associated with decreased risk of C. parvum infection. The total number of dairy cattle, total number of other species of agricultural animals on the farm, and the distance of the barn water source from the septic system were found to be significantly associated with increased risk of C. parvum infection. In the final analysis, the risk of infection with C. parvum was significant ly decreased with an increased value of the maternity management index scor e. The general management significantly affected the risk of infection with C. parvum where the risk increased with the increase of the value of the i ndex. The risk of infection significantly decreased with increase in the ag e of the animal. (C) 1999 Elsevier Science B.V. All rights reserved.