Modernize your deworming plan

This is a resolution that benefits not only your horse but, ultimately, all of horsekind. It’s a two-pronged approach, the first being to address your use of chemical dewormers and the second to improve your manure management practices to control parasites.

That internal parasites can develop resistance to chemical dewormers isn’t a distant possibility—it’s a scientifically proven reality. Resistance develops over several generations of parasites, when the ones that survive treatment are the only ones left to reproduce. Eventually, the parasites that remain on a farm are genetically selected to resist the chemicals (anthelmintics) used to control them. Experts warn that eventually we may have no effective anthelmintics for certain parasites, a devastating reality that sheep breeders are already facing.

Anthelmintic resistance is, in some respects, inevitable, but indiscriminate and overzealous use of dewormers greatly hastens the process. Deworming your horse based on the calendar alone is an outdated and harmful habit. Instead, resolve to work with your veterinarian to develop a deworming program tailored for your property and the individual horses on it.

Keeping this resolution will require some work and investment. You’ll need to consult with your veterinarian and collect fecal samples for testing. Then you’ll have to craft a master deworming strategy specifically for your situation. In the end, you’ll likely find that you’ll be able to deworm your horses less often, and perhaps some of your horses will never need to be dewormed at all. It’s a nice bonus when doing right by your horse saves you money.

The second phase of this resolution involves managing your manure, specifically in pastures, to decrease the amount of parasite larvae your horses pick up as they graze. Spreading manure on pastures or dragging piles already there is a legitimate manure-management method, but if you’re doing either when environmental conditions favor egg hatching and larvae growth, you’re just seeding your pasture with parasites.

In general, spreading or dragging manure in hot (90 degrees Fahrenheit or higher), dry weather is safest, as the larvae will quickly be killed in the sun. Larvae are less likely to be killed in very cold weather, but prolonged periods of below-freezing temperatures can keep some larvae from maturing to the point they are infective. The worst time to spread and drag manure is in moderate (between 45 and 90 degrees Fahrenheit) temperatures, particularly after a rain. As appealing as outdoor work may seem in those conditions, resist the urge to hitch up the spreader. Instead, pick up piles in the fields and compost your manure to be spread only after it is thoroughly “cooked.”