17/11/2025
⚠ You might have heard the saying “worm after the first frost,” but while frost can help reduce bot fly activity, our milder UK winters mean this old advice doesn’t hold true when it comes to encysted redworm.
❄️ People can be eager to give their winter wormer, but one frost is not enough and as long as temperatures on the pasture stay above 6°C, redworm remain active which allows the potential for reinfection. For healthy adult horses, It’s best to wait until winter sets in (Dec–Feb) with temperatures consistently below 6°C for several days before tackling encysted redworm. At that stage, either blood testing or using an appropriate wormer is recommended.
🍂🔬 For now, we’re still in autumn, so if it’s been more than three months since your last worm egg count or six months since your last tapeworm test, it’s time to check in with your worm control plan. If your results show a need for treatment, it’s fine to treat now with the right wormer, then plan your encysted redworm control.
High risk horses that are either young, old or immune compromised may need extra consideration, so get in touch if you're not sure and undertake a risk profile so you know your individual horses risk level.
