SURVEILL ANCE DEWORMING BASICS
• Use fecal egg counts to identify those horses in a herd who need deworming. By analyzing manure samples, a veterinarian can determine which horses are shedding problematic numbers of parasite eggs and require treatment with an appropriate dewormer. Some horses are naturally—probably g y others despite
looking extremely healthy. Others seem resistant to parasites, never carrying a significant load even after months of nontreatment. Once the horses that fall into each category have been identified, a deworming program can be adjusted accordingly, targeting the high shedders for more frequent testing and possible treatment.
• Confirm that treatments are working. A second fecal egg count is done 10 to 14 days after a horse has been treated with a deworming chemical to ensure the egg levels have dropped as expected. If they haven’t, it’s possible the parasites on the property have become resistant to that chemical. Once a drug is ineffective on a farm, it will always be ineffective there.
• The weather is a consideration. Deworming may be suspended on a property during periods of prolonged, subzero temperatures or lengthy hot, dry spells because parasite eggs will not develop into infective larvae under these extremes. However, treatments must resume when the moderate weather returns.
For more information, go to “The Deworming Revolution,” EQUUS 401, also available on EquusMagazine.com.