Piecing Together the Equine Parasite Puzzle
Since there are only three major classes of deworming agents available, resistance to drug classes is increasing and cases of resistant parasites are now being reported worldwide. Deworming agents do not create resistance, but as more and more of the parasites with resistance genes survive, treatment of the horses with that deworming agent will fail. Horses move frequently from state to state and internationally as well and may move resistant parasites to new farms. Many horse owners, who have been faithfully deworming their horses every six weeks and rotating products, now realize that this is no longer the recommended procedure and need information to develop a better plan.
To respond to this need, the Penn State Equine Stewardship team offered a full day short course in Northampton and Lancaster Counties that was designed to help farm managers develop an integrated program to reduce parasite levels on farms and reduce the proliferation of resistant parasites. Over 146 farm owners attended the short courses. Some of the top specialists and researchers in the field discussed the life cycles of equine parasites and the importance of identifying horses with high parasite burdens. Speakers from Penn State and
Rutgers Universities presented current, research-based information about parasite resistance and the effects of temperature, rainfall, pasture rotation and manure composting on parasite development, survival and movement in pasture. Participants were invited to attend a special session designed to teach them how to monitor parasites in their horses and learned to perform parasite egg counts.
After completing the full day workshops, participants reported that they had a large to very large increase in knowledge about:
- How parasites develop resistance (78%
- Why conducting a fecal analysis is the first step in combating resistance (76%
- The importance of identifying those animals that shed eggs (81%
- How environmental conditions affect the presence of infectious stage larvae (90%)
Participants reported that they intended to take the following actions to help reduce parasite burdens on their farm:
- Over 78% intend to purchase microscopes and monitor parasite levels in their horses
- 94% plan to only deworm horse when fecal egg counts indicate that it is necessary
- 88% are going to work with their veterinarian to develop an effective program
- 95% plan to deworm new horse before putting them out on pasture.
- 97% plan to reduce the use of deworming products when environmental conditions are not conducive to larval development
- 97% plan to adopt pasture management practices to reduce the risk of exposure.