Survey of Selected Risk Factors and Therapeutic Strategies for Parasitism on Milk Production Response of Lactating Dairy Cattle

  A recent review of studies on the effect of parasite control programs on productivity of lactating dairy cattle has reported positive, but variable, results. A conjoint analysis survey was conducted, using dairy industry professionals and practicing veterinarians, to estimate the impact of various management strategies on the control of parasites on milk production in dairy herds. The results of the survey suggested positive associations of confinement housing systems, replacement heifer treatment programs and cow treatment programs with milk production. Spreading manure on pastures and not using a treatment program in heifers were determined to have the most important negative association with milk production. The survey responses also suggested that topical treatment for external parasites, and strategic use of endectocide products in the prepartum period, would have a positive effect on production. Areas of high priority for research on the association between parasites and productivity in dairy cattle would include the relative impact of whole herd versus strategic lactation cycle treatment programs.