Do worms shed eggs in winter?

DD

DD

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have had an email from westgate saying its time to worm count. But assuming the horse has mature worms, do they shed eggs in winter? I'm sure I've read somewhere that they dont as the conditions for them hatching arnt suitable and cold weather will kill them so its not in the interests of the worm to shed its eggs at this time of year. Maybe Borderreiver could help?
 
If a horse ingest eggs in winter that have been exposed to cold weather they are encysted within the gut wall and not shedding eggs but this does not account for active worms within the horses gut. This year the only true frost was last weekend so expect things to be extended. Any active worms will shed eggs irrespective of the time of year as they are in a stable environment that is not affected by weather or day length.
 
Hello, a good question! Of course we all know that a proportion of redworm worm larvae can burrow into the gut wall to hibernate in less favourable conditions. This is why we suggest that for most horses a winter dose is a good idea to target these stages.

However we still carry out a lot of worm counts in the winter quarter of the year and still see high egg counts eg results as high as 7000 epg in tests last January. If you get a new horse, have a less than well horse who reacts badly to dosing or are monitoring a wormy one then there are good reasons to test.

A few people test all year round and don't give a winter dose if they are in a very low risk situation.

Some people will be worming and then using the winter special offer resistance test a couple of weeks later to make sure there are no worm eggs present. This is especially important if you rely on Panacur 5 day (lots of resistance) but still helpful to monitor moxidectin.

If in doubt ring the lab to discuss your situation. 01670 791994 or ask on Westgate FB page for a personal reply.
 
Borderreiver said:
Hello, a good question! Of course we all know that a proportion of redworm worm larvae can burrow into the gut wall to hibernate in less favourable conditions. This is why we suggest that for most horses a winter dose is a good idea to target these stages.

However we still carry out a lot of worm counts in the winter quarter of the year and still see high egg counts eg results as high as 7000 epg in tests last January. If you get a new horse, have a less than well horse who reacts badly to dosing or are monitoring a wormy one then there are good reasons to test.

A few people test all year round and don't give a winter dose if they are in a very low risk situation.

Some people will be worming and then using the winter special offer resistance test a couple of weeks later to make sure there are no worm eggs present. This is especially important if you rely on Panacur 5 day (lots of resistance) but still helpful to monitor moxidectin.

If in doubt ring the lab to discuss your situation. 01670 791994 or ask on Westgate FB page for a personal reply.
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so if you want to do equest in say a fortnight (resistant to PG so no choice) and whilst horse has had and could be expected to have a <50 count you are worried about using equest for that particular horse (PPID) will a count now make it a bit safer. (presuming of course it shows <50)
thanks
 
Borderreiver said:
(Snipped) Hello, a good question! Of course we all know that a proportion of redworm worm larvae can burrow into the gut wall to hibernate in less favourable conditions. This is why we suggest that for most horses a winter dose is a good idea to target these stages.
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As Popsdash asked, how do the worms know it is winter? I can accept that worms do not lay eggs at a regular rate, like battery hens, but the triggers for an egg laying spree will surely be things like a change of diet, not the temperature/humidity of the external environment which does varies. The temperature of the horse should remain stable if it is otherwise healthy.
 
Downton Dame said:
have had an email from westgate saying its time to worm count. But assuming the horse has mature worms, do they shed eggs in winter? I'm sure I've read somewhere that they dont as the conditions for them hatching arnt suitable and cold weather will kill them so its not in the interests of the worm to shed its eggs at this time of year. Maybe Borderreiver could help?
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With our weird climate - yes they WILL shed eggs in winter. TBH we don't really have proper winters in the UK anymore, apart from the highlands of Scotland and maybe Northern England, last year we didn't have a single frost on the south coast, and due to the constant mild winter we had plenty of positive WEC's back from customers horses (tested by Westgate) I would carry on testing as normal. If we do get a frost it may kill a few but not all of any eggs shed and as long as it is warm enough (16 degrees in November!!) larvae will develop, and keeping stringent records of WEC's really helps build up a good picture of your horse's health status and allows you to cut down chemical use = good.

I saw a cloud of mosquitos today while filling the trough - great......
 
Dry Rot said:
As Popsdash asked, how do the worms know it is winter? I can accept that worms do not lay eggs at a regular rate, like battery hens, but the triggers for an egg laying spree will surely be things like a change of diet, not the temperature/humidity of the external environment which does varies. The temperature of the horse should remain stable if it is otherwise healthy.
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There are theories that they can detect hormonal changes within the horse, caused by the shortening and lenthening of daylight hours... maybe this would explain why cushings horses tend to be susceptible to higher than normal worm burdens.
 
maisie06 said:
There are theories that they can detect hormonal changes within the horse, caused by the shortening and lenthening of daylight hours... maybe this would explain why cushings horses tend to be susceptible to higher than normal worm burdens.
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Ah yes. Theories!

To a self declared sceptical cynic, that is waving a red flag! Not sure whether I should stop or charge now.... :)
 
There are many areas of research which would be of benefit to our knowledge of parasite behaviour. I was talking to an 'expert' in the field of horse worming yesterday and we were discussing encysted worms. Of course the worms don't know when it is winter. At present the thought is that day length may be an important trigger but not enough is known. A natural part of the redworm's life cycle is a ten day 'rest' in the gut wall. The longer spell of encysting or more correctly inhibiting, may last all winter or even two or three years but not all worms do this. Perhaps it depends on the numbers of parasites present. Until more is known we could not say.

But what IS important for most horses is that we only worm them if they need it for most of the year, NO random doses, use the tests available. Then as a back up, most horses should have that winter dose just in case of underlying problems, so as to prevent any chance of larval cyathastomiasis in spring. This can kill, but is rare and is not really likely with healthy well kept horses. We all want the best for our horses so we try to get it right with present knowledge available. :)
 
In mares their cycles are prompted by light levels, so there may well be something in the hormone theory - not sure about geldings or entire males though, I thought their hormones were prompted by in season mares, which might again trace back to light levels.
Borderreiver do you know if there is any particular time in winter for that one annual dose? An Equest rep once told me after the first frost, and someone else who has reason to know said that red worms cease encysting when spring arrives. Some local horse owners have already done theirs
 
Well after having a worm count done it came back at medium burden so have wormed with Pramox. So yes, they do shed eggs in winter.
 
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