Sudden extreme exercise, muscle fatigue i.e. unfit horse asked to do too much or is high spirited and doesn't no when to give up. Too much hard feed with starch in.
I think the textbook would say that it is overfeeding and underworking or insufficient cool off/warm up when working.
However some horses just seem more prone to it than others.
Overfeeding, but feeding the wrong - or unsuitable - things particularly.
Excess starch that can't be processed by the body is a big cause.
Also, stressy horses seem more susceptible as their digestive systems can't cope.
lots of possible reasons:
over-working an unfit horse
insufficient warming-up/cooling off
de-hydration
electrolyte imbalance
high cereal diet or diet that is not appropriate for workload
stress
horses with muscle myopathies (such as EPSM)
warm- and hot- bloods are more prone
The reason I ask is that I was talking to a friend out hunting the other day and his wife has trained pointers and under rules on a permit for 20years and he said that they were always tying up, the frequency got me thinking, was it something that they were doing?
TBH I don't know enough about it so will probably be talking out of my @rse but I'd imagine TB's racing/pointing/hunting would be near the top of the list as susceptable candidates due to the high grain feeding and the type of work they do.
Would be interesting to see what your friends call frequent and how this compares to the incident rate among similar types of horse. If it is higher maybe it does have something to do with the management systems they have in place.
I ride a mare now and again, for a lovely lady, she (the owner) is quite elderly and is of a fairly old fashioned hunting school of thought. From what I have seen she overestimates how fit her horse actually is and feeds it far more than is needed for it's workload, lo and behold the horse is prone to tying up, unfortunately she doesn't believe me when I tell her the horse doesn't need buckets of hard feed to go for a hack.
Only thing I can add is cold.
I used to look after a hunter who would be guaranteed to tye up during the week after a hill meet (cold and blustery). Also, washing young fillies off with cold water is a very bad idea.
Have known loads of people that go mad for turnout with a horse that tyes up - they chuck it out in high winds and rain and they wonder where they have gone wrong (dimwits). I never ever take a full clip off a young filly or a horse that is prone, always leave the backs on.
True! Mine has had episodes after sweating on cold days when out riding, so I always use an exercise sheet and make sure she is fully dry before I turn her out afterwards.
It's referred to as Monday Morning disease because of when and how hunters would get it.
Fed high grain/cereal diets, worked particularly hard one day of the week, likely to be stabled the next day, and TB types - hence the hunting on the Saturday followed by Sunday possible spent indoors with little forage and big hard feeds, they would then tye up on Monday morning.
They could inestigate a Selenium deficiency, it can have similar symptoms and is made worse suddenly when the horse is working hard and needs additional minerals.
We have pony that baffled vets at liphook by having chronic aorturia as opposed to acute. It lasted 22 weeks and to be honest they never found the cause depsite numerous blood test, muscle biopsies etc. He now has a sugar/cereal free diet and selenevite and so far so good.
Mine had shortness of breath after light exercise a few years back, despite being warmed up in the same way as he always had. Blood tests showed he'd tied up. He is a laid back ISH who was out 24/7 at the time, being fed nothing extra to the grazing he was on. Following year almost to the day (October), he showed similar symptoms but didn't tie up. Have mananged to avoid it this year but I'm inclined to think he's pre-disposed to it and that something environmental/seasonal knocks his system out of kilter that makes him prone. He doesn't seem a textbook case at all.