Do combination wormers cause abscesses? I described in a previous blog
how we operate a targeted equine worming programme based on Faecal Egg Counts and saliva tests for Tapeworm.
The reasons for this, briefly, are
1) the national problem of increasing resistance to anti-helminthic chemicals with no new drugs in the pipeline
2) a general desire to limit the herd’s exposure to synthetic and possible toxic chemicals
3) a sneaking suspicion that worming can cause systemic upset in sensitive horses
Do combination wormers cause abscesses?
Now I’m not advocating letting the worms flourish. I completely understand how dangerous worm infestation can be for our fragile equines. I have close friends who have lost horses to worm disease. I also have friends whose horse had a terrible reaction to a commonly used wormer. So I’m just trying to minimise the amount of worming doses I have to use for my horses, to be a good citizen and decrease the spread of resistance for all of our sakes and to reduce the chance of bad reactions in my own precious herd.
Do combination wormers cause abscesses?
So after testing for redworm and tapeworm in October, I had 4 horses needing 3 different treatments. I went to the farm shop and bought the wormers and labelled them carefully with each horse’s name so I wouldn’t get too confused. The 4 horses came down to the house for hoof trimming and I took the chance to do a worming round. And got confused.
The short non profane version is that Cal, the most systemically sensitive horse, needed worming for tapeworm and didn’t get the Equitape he was meant to. After I’d jumped around swearing a bit I thought never mind, he’s only mildly positive for Tapeworm, I’ll do a combined dose in winter and cover tapes and encysted. It’ll be OK.
Do combination wormers cause abscesses?
So on the 3rd Jan I wormed them all, 3 with Equest for encysted redworm and Cal with Pramox to cover both encysted redworm and tapeworm. 8 days later he was really quite lame.
Do combination wormers cause abscesses?
Both front feet had palpable digital pulses and both front hooves were warm to touch. The other three horses were all fine. We had had a touch of frost and one of the bales of haylage smelt a bit ripe so I didn’t immediately connect the situation to the wormer…after all it was a good few days later. I cursed the frosty grass, cut back on Cal’s bucket feed and kept him turned out for movement. A couple of days later I brought him down to the house to have a good look at the still sore feet- the pulses were less bounding, there were no obvious boggy bits or sore spots in the sole and no signs of an abscess ready to burst so I painted his soles with frog oil and back down to the field he went.
The sore feet and the palpable pulses lasted about 10days in total. The left forefoot did smell of pus for a couple of days, although I could never find a convincing egress wound. The frog was a bit spongey but he didn’t mind me prodding it and there was no visible punctum. The right forefoot didn’t smell of pus or thrush but was on off sore for that time and had a variable pulse.
After about ten days I was doing night time bucket feeds and noticed he was moving better (charging around the field with his tail flagged out). Saturday came and I marched him down to the house, picked out his feet without any problem, tacked him up, hacked around the corner on the stony tracks and worked him in the neighbour’s arena. He felt amazing, strong and willing and almost better for a couple of weeks off.
I checked his feet again and there was a small divot in the sole of the left forefoot, as if a small solar abscess had burst or a bit of sole exfoliated, but there was no other sign of what might have caused the lameness.
It was a few days later when I remembered we did have a similar episode two years ago. The last time he abscessed was when were still at livery. That year at the livery yard was a foot- related nightmare. Cal had a few months of constant abscesses and went around his hooves twice; I seem to remember 7 consecutive abscesses. Even Paddy the invincible barefooter had an abscess whilst there. The forage analysis showed their hay to be very high in iron. Because we had so much trouble with abscesses at the livery yard, the various episodes all merged into one. The information did percolate through to my brain though that the last time Cal had a combination wormer was that last winter in livery.
Since moving the horses to our own land we had not had any trouble with abscesses in nearly 2 years…until now.
So I did some Googling: Do combination wormers cause abscesses?
There is plenty of anecdotal evidence on the internet about horses becoming footsore after combination wormers. It seems to be more of a problem in horses with Cushing’s disease or hind gut problems.
There are numerous stories of colic too, but the toxicity there seems to be associated with high worm populations being exterminated quickly and releasing endotoxins into the gut as they die. Cal’s tapeworm test was weakly positive and his redworm count negative in October so I don’t believe the worm burden was the problem in our case. He has tested negative for Cushing’s to date. However he always looks and feels better when he is on regular treatment for hindgut issues.
Do combination wormers cause abscesses?
Other possible causes of this footsore episode include ripe fermented haylage and frosty grass. We have had both these situations occur again since Cal became sound again and he hasn’t missed a step.
Will I give him a combination wormer again? I have to say that I will do my best not to. If he needs covering for both tapeworm and encysted redworm in the future I will dose separately a couple of weeks apart.
I have never tried non-chemical or natural wormers. I’m too much of a doctor there- I think that if worms are detected they need eradicating and then the horse needs re-testing to check eradication has occurred. If there are no worms on testing then the horses shouldn’t need anything other than a balanced species -specific diet.
I know people report egg count success with regular use of herbal wormers but I do cynically wonder if their horses are all non shredders? Paddy has only tested weakly positive for redworm twice in the last 5 years.
I am really looking forward to the promised ELISA test for encysted redworm becoming commercially available.
Once we have reliable affordable tests for common equine parasites, there will be some calendar years for my boys where no chemical worming is necessary. It isn’t cheaper than worming blindly every few months, but my recent experience suggests it may well be safer for horses to test before dosing unnecessarily, both in the short and the long term.
Soil analysis digging done today -year 2- I’ll keep you posted.
