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

Abstract

The negative associations of subclinical ketosis (SCK) with downstream health events and production have been well described in dairy cattle during early lactation. Cows with SCK have an increased risk of developing additional postpartum diseases such as displaced abomasum (DA), are at an increased risk of leaving the herd, and have decreased milk yield during early lactation. Thus, the cost per case of SCK depends on a variety of factors including increased occurrence of postpartum diseases, cost of herd replacements, and loss of milk production. The intensity and accuracy of diagnostic testing used to define a case of SCK then affects the reliability of the cost estimate. Additionally, overall herd costs of SCK vary based on herd SCK incidence, and a cost-to-treatment benefit ratio depends on the frequency and accuracy with which cows are tested. Although a higher testing frequency improves accuracy, it may not improve the cost-to-treatment benefit. Following accurate identification of SCK-positive cows, individual cow treatment with propylene glycol (PG) is an effective means ofreducing the risks associated with SCK. The purpose of this study was to develop stochastic economic models which address variation in disease risks and costs in order to evaluate different simulated on-farm testing and PG treatment strategies based on herd SCK incidence.