WORMING
Sadly, all horses have worms, and many worms are becoming resistant to the wormers available. There are many ways we can cut down the worm burden by good stable management.
Worm all new horses when they arrive during their isolation process.
Keep to the same field companions and worm as regularly as needed (about every 8-12 weeks if their worm count is high) all at the same time with the same wormer.
Poo pick the fields regularly and rest and harrow them as often as possible.
Alternate the chemical base of the wormer every 2 years (more detail below).
Make sure you give a wormer that covers tapeworm in spring and autumn.
Signs a horse may have worms
Loss of weight.
Dull, listless coat.
Big belly but no fat covering over back.
Colic or general signs of discomfort in the stomach.
Itching tail.
Coughing.
Constipation or diarrhoea.
Many places are now recommending that you send a poo sample off so they can worm count before you worm. I am interested to see how this goes as it does seem to be making them quite a lot of money, but I can see it may be necessary to halt the immunity the worms are getting to our chemicals.
Wormers
There are many different types of wormer that can be given in the feed or as a syringe. I prefer the syringe as there is nothing worse than having feed that is spat out, or some left, and not knowing how much they have had.
The different chemical base in wormers is:
moxidectin (Equest, Equest pramox) and ivermectin (Eqvalan, Eraquell, Equimax) both considered to be the same base;
fenbendazole and mebendazole both considered to be the same base (Panacur, Telmin);
pyrantel embonate (Strongid P, Pyratape, Exodus, Embotape ).
As I have said previously, I select a wormer, use this for 2 years, then change to a wormer with a different chemical base.
Different Types of Worms
Worm pictures with thanks from Pen Llyn equestrian Tack Shed.
Small red worm
Up to half an inch long, thin and red in colour.
These are one of the most deadly worms causing severe damage to the gut wall. Symptoms include colic, loss of weight and diarrhoea.
The eggs pass out in the dung. In a week, if it is warm and damp, the larvae hatch and are eaten by the horse and then burrow into the intestine wall causing much damage. Some larvae cling to the gut lining in an encysted state emerging in early spring en masse, others develop within 6 weeks and continue making swiss cheese out of your horse’s gut wall. Some wormers do not get rid of the encysted state, so check on the package to make sure in autumn, after the first frost, you are dealing with this issue.
Large red worm
Up to 3 cm long, red in colour.
These also cause severe damage to your horse.
Eggs pass out in the dung and are eaten by the horse. The larvae eat through the gut wall and head to the blood supply, this can cause blood clots and blockages. The larvae then return to the gut to mature to adults and attach to the lining to suck blood. The female then lays eggs to start the cycle again. It is important to use a wormer that covers the larva stage in autumn, again, after the first frost.
Roundworms
White stiff worms, up to 30 cm in length.
The eggs pass out in droppings. The horse eats the eggs which then hatch and go through the wall of intestines into the blood supply. They then migrate to the liver, then lungs and lastly into the airways where they are coughed up and swallowed. The last part of their journey is to the small intestine where they mature to egg-laying adults.
Foals are particularly prone to these, and will show signs by coughing and general poor growth and development.
In large quantities they can cause blockages and intermittent colic.
Pinworms
About 6 cm long and thin, these are one of the most common seen, and one that most wormers do not treat.
The adult female worm lays its eggs just outside the rectum.
causing severe itching of the tail with a sticky discharge visible.
The larvae get eaten by the horse where they go to the large intestine to finish their development.
A lot of the wormers do not act against these worms. We found embotape wormer to be the most effective and given as an extra wormer in our programme.
Tapeworm
These worms look like long chains of segments that resemble pumpkin seeds. They can grow to about 20 cm in length.
They can inflame the intestinal wall where they attach themselves, and can absorb some of the goodness of the food the horse eats.
A lot of wormers do not get rid of these worms so make sure you use a wormer that does in spring and autumn.
Bots
These are the larvae of the gadfly.
In summer the gadfly, which is a large, brown fly that seems to terrify the horses, lays eggs on the horse’s coat, especially on the sides of the cannon bones and fetlock. They are the small yellow eggs that you can see and easily pick off, or you can use a bot fly knife to scrape them off. The horse licks the emerging larvae who then burrow into the mucous membrane of the tongue and gums. About a month later they will migrate to the stomach where they will attach to the intestinal wall until spring, when they will be expelled in the dung to emerge as a gadfly after about 10 weeks.
In spring, they can cause colic and blockages if enough have been ingested, so in December your wormer should tackle this issue.
Sample Worming Program
Before introducing a horse to your herd, in the isolation period, give a 5 day course of Panacur granules then:
spring – Equest
summer – Equest Pramox
autumn -Equest
winter – Equest Pramox
repeat the following year, then on the third year
spring-Strongid P
summer-Embotape (for the pinworms)
autumn-Strongid P
winter– Eqvalan Duo (to kill the bots)
repeat the next year, then continue this 4 year cycle.
How To Give A Worming Syringe
Put a headcollar on your horse and make sure you are in a safe environment so the horse can not run away.
Put your finger in the corner of his mouth so he spits out any unwanted food.
Insert the syringe as far into the horse’s mouth as you can, pointing it towards the back of the tongue.
Squeeze the syringe as quickly as you can.
Remove the syringe.
Hold the horse’s head up so he cannot spit any out.
TIP- Some horses hate this so it is a good idea to have an empty syringe, fill with crushed apple and practice with that. You will soon have a horse that loves the sight of the worming syringe.
Final Thoughts
Worms are a big problem for horses and, as their keeper, it is your responsibility to make sure you are tackling this issue.
You can not control what others do but for the good of the horses it is an excellent idea for each yard, as a whole, to decide how they are going to combat this problem.
Worm counts seem a very good way of seeing how big the issue is for your horse and will stop you worming unnecessarily.
Again do not feel intimidated by the yard “know it alls”, do what needs to be done for your horse’s health.
Update- it has now been seen that many horse’s that have not been wormed after a low worm count, have subsequently had a very high worm burden. There have also been many examples of people who have had low worm count result, but wormed anyway. Afterwards they have seen lots of worms in the manure.
At present I have not seen enough reports to make an informed opinion on this and understand the cases that have worked well do not get media coverage. I do understand the need to stop the overuse of chemicals and hope this is the start.