Controlling Strongyle Parasites of Horses: A Mandate for Change

1. Introduction
Historically, practical management of equine parasitism has been based on pervasive misconceptions about the basic objectives of parasite control: unrealistic assumptions that eradication was both desirable and feasible, inappropriate emphasis was placed on therapeutic rather than prophylactic approaches, and exclusive use of drugs for implementing programs. The ultimate abandonment of traditional control practices is inevitable,¹  but the prospect of prevalent and expanding resistance of target parasites to multiple classes of equine anthelmintics lends particular urgency. Future approaches to equine parasite control must seek greater sustainability by exploiting inherent host resistance and acquired immunity, implementing management procedures that reduce transmission, and by using chemical treatments much less frequently and only in selected members of a herd.

2. Objectives of Strongyle Control
The overall goal of effective parasite control is to optimize the health and performance of our equine patients. Health goals are relatively straightforward, but parameters of performance vary with the use or classification of the horse and can be very difficult to quantify. Examples of improved performance include more live foals for stallions, more weaned foals for broodmares, more blue ribbons for competitive horses, and faster times for racing athletes. For backyard horses, optimal health and performance might be achieved simply by fewer episodes of colic and easy maintenance of body condition. Qualitative outcomes are more common than quantitative measurements, because Western civilization has romanticized the horse to the point that it is rarely viewed as a production animal. [...]