Horse owners have been warmed that warm weather is linked to higher parasite risk, and are urged not to delay worm egg count testing.New analysis of more than 50,000 UK worm egg count results highlights the importance of sticking to 8 to 12-week testing intervals.Equine parasite specialists, Westgate Labs, said sustained high temperatures replicate the conditions that saw significantly more horses requiring treatment in 2025.One of the biggest misconceptions we hear is my horse looks fine, so I can leave it another month. Last years data showed that isnt always the case., said Kristy Hodgson, Director at Westgate Labs. Regular testing allows us to spot changes before they become a problem. If owners stretch the interval between tests, theres a greater chance that horses shedding higher numbers of parasite eggs will contaminate the pasture for longer, increasing infection pressure for the whole group.Testing every eight to twelve weeks means youre responding to whats happening now, rather than what happened three or four months ago. This intervention could easily prevent a bigger problem down the line.Significant resultsWith 2026 having already brought record breaking spring temperatures and repeated summer heatwaves, Westgate is encouraging owners to keep to the recommended testing intervals, even for horses that have historically returned low worm egg counts.Analysis of Westgate Labs autumn and winter worm egg count results showed that around27% of horses exceeded the treatment threshold during 2025/26, compared with21% during 2024/25and18% during 2023/24. After allowing for the normal seasonal rise in egg shedding through autumn and winter, the increase remained statistically significant.The small redworm has a fast lifecycle of around 4-6 weeks. Experts have summarised that the warm weather accelerates the larval development phase of the parasites, allowing horses to become more readily infected as they graze. This, combined with burnt off paddocks and low grass growth means reduced opportunity to rest and rotate grazing. With less forage available, horses have been cropping the grass closer to the soil and dung piles, further increasing infection potential.Horse owners are encouraged to review when they last tested. If it has been eight weeks or more, Westgate said it is time to collect fresh samples before heading into the autumn.More from Your HorseEssential horse worming schedule and management tips from a vetWhich parasite and why: essential seven-step worming planFaecal worm egg counts for horses explainedResistance to horse wormers: action every owner must take now or horses will dieThe post Warm weather warning: Owners warned of increased risk of parasites and urged to test appeared first on Your Horse.