CONTROLLING worms in horses used to be so easy we would regularly give our horses a wormer (anthelmintic) every few months, changing the type of anthelmintic each time in the misguided belief that this would eradicate the worms. Sadly, this wasn't the case and each treatment merely provided selection pressure for a sub-group of worms that were more resistant to the effects of the wormer.
As with antibiotics, horse worm populations have adapted over time, and we now are left in the bleak situation that there is widespread anthelmintic resistance among the common worms that affect horses with no new medications on the horizon. This is a global problem the tsunami of resistance is recognised worldwide.
Every horse that grazes pasture will have worms. This is inevitable, and also completely normal. It is likely that maintaining a low level of worm infestation is beneficial and helps the horse sustain a healthy balance of "good" bacteria in its intestine. Since we started worming horses in the 1960s, the large redworm (Strongylus vulgaris), previously a common cause of life-threatening colic, has become rare in regions where modern wormers are used regularly.
However, the most common type of worm that mature horses harbour is the small redworm (cyathostomins), and anthelmintic resistance is common in these parasites. Large numbers of small redworms in the intestine can result in poor performance, diarrhoea, weight loss and colic, especially in younger horses up to around five years of age.
Denne historien er fra January 18, 2024-utgaven av Horse & Hound.
Start din 7-dagers gratis prøveperiode på Magzter GOLD for å få tilgang til tusenvis av utvalgte premiumhistorier og 9000+ magasiner og aviser.
Allerede abonnent ? Logg på
Denne historien er fra January 18, 2024-utgaven av Horse & Hound.
Start din 7-dagers gratis prøveperiode på Magzter GOLD for å få tilgang til tusenvis av utvalgte premiumhistorier og 9000+ magasiner og aviser.
Allerede abonnent? Logg på
'Sorry, but I wasn't feeling it'
Fresh from the opening meet, Tessa Waugh hasn't quite yet been bitten by the hunting bug. Without the crisp autumnal air and cheek-pinching cold she hoped for, it's a sluggish start
New pair pull off a win
A former European Championships pony is on form with his new rider, while elsewhere former showjumpers and eventers take ribbons
Lording it over the rest
Horses who have returned from injury, a second generation homebred and a long format specialist score on the final weekend of the British season
Smith hits flying form
A \"her way or no way\" mare helps Zoe Smith to an impressive ribbon haul and a rider beats his own boss to the top spot
Jankorado hits the jackpot
Paul Sims is triumphant despite his interrupted jump-off preparation and a borrowed horse comes up trumps
Peanut
From \"dangerous, scary\" to hedge-hopping brilliance, hunting has been the making of this unstable but very lovable equine character
She's a corker
Communication, says long-standing and highly respected Belvoir master Lady Sarah McCorquodale, is the key to all, as Catherine Austen discovers
Access all areas Cavalier Centre
The Cavalier Centre is a fully accessible, state-of-the-art equestrian centre designed to improve lives through horse-based activities. Ellie May Forrester pays a visit
'Use it or lose it'
Not everyone wants to reach for the pipe and slippers at a certain age. Becky Murray speaks to some veteran horse-and-rider combos for their secrets of human and equine longevity
A new way forward
Worm control in horses is vital, but established methods will not remain effective for much longer. Tim Mair FRCVS explains why and how we need to change