Do I really need to worm my horse?

Endoparasites the gutwrenching villains that terrorise our horses from their tums to their bums but how big an issue are they for the average horse? Which worms do we need to be aware of? Is wormer resistance really that big an issue? So many questions so many drug names.
What is a worm?
A worm or an endoparasite is an organism that lives inside of your horse to your horses detriment. We have all seen the adverts for good bacteria this is known as a synergistic relationship where both host and occupier benefit. With parasites only the parasite gains.

Cyathostomes. Why did the cyathostome always get what he wanted? Because he was so encystant Excuse my awful jokes its been a long day. Cyathostomes are a type of nematode or round worm known as small encysted redworm. The adults when in the large intestine produce eggs that the horse will excrete onto their pastures the eggs then hatch and the larvae are eaten by the horse. It is also the larvae that are capable of encysting hiding in the walls of the large intestine. So the saying really is true dont eat where you These nasty critters can encyst in the mucosal lining of the large intestine of horses the larvae are capable of hypobiosis they stay in a state of arrested development a bit like hibernation.  It is when they emerge that they can cause potentially fatal damage and diarrhoea known as larval cyathostomosis.
Strongyles large redworms. These nematodes are detrimental to your horse in a different way than their smaller namesakes. Eggs in the pasture have a moult phase referred to as Larval stage 1 L1 and moult to form logically L2. The L3 are consumed by an unwitting grazer it is the L4 stage that migrate from the gut to the arterial supply of the intestine the cranial mesenteric artery if you are curious. This can cause a compromised blood supply to the large intestine with inflammation of the arteries known as verminous arteritis and can cause the dreaded colic.
Parascaris Equorum ascarids another nematode. Are you the owner of a young horse? This one is for you sorry!.  Thankfully our equid amigos develop a resistance to these worms however youngstock in the 6 month 2year old bracket are highly susceptible. The eggs are passed out in excrement and moult to L1 and then L2 unlike large redworms it is the second larval stage