An economic analysis of hyperketonemia testing and propylene glycol treatment strategies in early lactation dairy cattle

Abstract

The purpose was to develop stochastic economic models which address variation in disease risks and costs in order to evaluate different simulated on-farm testing and propylene glycol (PG) treatment strategies based on herd hyperketonemia (HYK) incidence during the first 30 DIM. Data used in model development concerning the difference in health and production consequences between HYK and non-ketotic cows were based on results from 10 studies representing over 13,000 cows from 833 dairy farms in North America, Canada, and Europe. Inputs for PG associated variables were based on a large field trial using cows from 4 free-stall dairy herds (2 in New York and 2 in Wisconsin). Four simulated on-farm testing and treatment strategies were analyzed at herd HYK incidences ranging from 5% to 80% and included: 1) treating all cows with 5d of PG starting at 5 DIM, 2) testing all cows for HYK 1 day per week (e.g. Mondays) from 3 to 16 DIM and treating all positive cows with 5d of oral PG, 3) testing all cows for HYK 2 days per week (e.g. Mondays and Thursdays) from 3 to 9 DIM and treating all positive cows with 5d of oral PG, and 4) testing all cows for HYK 3 days per week (e.g. Mondays, Wednesdays, and Fridays) from 3 to 16 DIM and treating all positive cows with 5d of oral PG. Cost-benefit analysis included the costs associated with labor to test cows, β-hydroxybutyrate test strips, labor to treat cows, PG, and the associated gain in milk production, decrease in DA and early removal risks of PG treated HYK positive cows compared to non-treated HYK positive cows. Stochastic models were developed to account for variability in the distribution of input variables. Per 100 fresh cows in a herd with an HYK incidence of 40%, the mean economic benefits of the 4 different strategies were $1088, $744, $1166, and $760, respectively. Testing cows 2 days per week from 3 to 9 DIM was the most cost-effective strategy for herds with HYK incidences between 15% and 50%; above 50%, treating all fresh cows with 5d of PG was the most cost-effective strategy. These results show that for herds similar to those used in model, when herd HYK incidences rise above 25%, almost any HYK testing and treatment protocol will be economically beneficial for the farm.