Toxic Residues From Parasites In Horses And Cattle

Parasites are a major threat to the health of livestock. Although we use the example of a horse thoughout, the worms and parasites written about apply equally to other cattle.

A single horse can be at the mercy of over 60 kinds of parasite and may harbor one or two different kinds of worms at any one time. The results of internal bugs are considerably more evident in young and seemingly undernourished animals.

Egg Count

A horse with an egg count of 2,000 eggs per gram of faeces — not a uncommon amount — can discharge up to 25 million eggs a day. You read that right twenty five million. This creates an immediate source of infection for other close by horses in the pasture or the stables. Although the eggs are invisible to the human eye, a proper microscopic investigation of a horse’s fecal droppings may evidence more then you bargained for. Confirming the presence of parasite eggs can determine what parasite types are present and establish the state of the infestation.

Many of the commercial products used to eliminate internal and external parasites in animals have become redundant through overuse and misuse. Fear of the detrimental impact that parasites can bring about could cause an over-reaction that is counter productive.

Life Cycle

Most worms begin their lives as eggs, quiclky maturing into larvae. Young parasites can within weeks become adults that lay eggs, starting this life cycle again. As an egg or larva, once inside the horse’s digestive organs, each adopts a unique pattern of migration, essentially ending up in the digestive tract. The great majority of worms are defecated in the horse’s manure; other, nearby grazing horses will likely ingest those eggs.

Of the many signs that substantiate parasitic activity, colic can suggest a major infestation as can underweight, poor growth or coat shine.


The Parascaris equorum or roundworm is one of the first worms that infect young foals. Growing anything up to 12-15 inches long, they typically remain as eggs until ingested. Found anywhere in the surrounding environment they are lined with an adhesive protein that helps them stick to all kinds of surfaces – barn walls, buckets, troughs, a horse’s mane and even a mare’s udder if she lies down on the dirt. A foal can become infected by eating hay, nursing or just brushing up against a fence post.

Once ingested, the eggs hatch inside the small intestine. Larvae penetrates the stomach tissue and enters the bloodstream travelling to any part of the horse’s body. Much damage is wrought during the migratory process itself. From the liver they reach the heart, enter the lungs then the windpipe where they’re coughed up before being swallowed into the gut. Pneumonia often takes place in a compromised lung. It takes 10 to 12 weeks for roundworm to finish this cycle . Most foals become overrun by larvae fairly quickly after birth; most worms are maturing when foals are two to three months of age.

A heavy infestation of roundworm often causes constrictions in the bowel, leading to obvious digestive difficulties.


In certain countries blood worms are thought to be the most hazardous worm to horses. The abundant nature of blood worms makes them seem to resist the application of standard de-worming drugs. As adults, blood worms become voracious blood suckers causing anaemia, diarrhoea, and damage to the intestinal lining at the same time settling in the lower bowel and surrounding arteries where they inflame and irritate, causing parasitic aneurysm. The blood flow is usually diminished often resulting in a rupture or in intense cases, the horse’s untimely death from internal bleeding. Lameness is an indication of blood clots from parasites lodged in the arteries of the hind legs.

It takes roughly 6 months for the maturing worms to complete their migration before settling in the large intestine. Foals less than 6 months old will give sanctuary to blood worms as they migrate.


Adult pinworm live in the rectum of horses. Female worms migrate to the anus to deposit eggs in a cement-like deposit. This “egg-cement” dries, cracks, and together with the eggs, detaches from the outer skin in flakes causing irritation, dreadful itching and restlessness.

The affected horse rubs its tail on any nearby object, causing a characteristic “rat-tail appearance.” Severe rubbing may result in further irritation and secondary infection of the anus, tail and surrounding skin. Pinworm are rather more a nuisance than a threat. As horses rub their rear ends and tails on nearby objects, the eggs are deposited to await another horse that licks the object, swallowing the egg.


Tapeworm are different to other internal parasites. Female tapeworm do not lay eggs. Instead , tapeworm segments containing eggs break off inside the digestive tract which are then passed in the fecal matter.

Second, tapeworms have an indirect life cycle. Before they become infective to a host, they develop from an indirect host. For example a horse passes eggs in its dung; mites in the pasture ingest these eggs. The eggs hatch and grow into larvae that are infective to horses. As the horse is grazing, the mites containing the infective larvae are ingested after which they migrate to ileocecal valve. After 6 to 12 weeks the mites start shedding segments full of eggs. If not eliminated, chronic conditions could lead to surgery.


Threadworm essentially affects foals, usually ingested from larvae present in a mare’s milk. Threadworm larvae are found in mare’s milk from 4 to 40 days after foaling; foals may become badly infected by 2-3 weeks of age, evidenced by dysentery and indigestion.


Bots are the larvae of flies that have become highly specialised as parasites of horses. Female flies lay up to 900 eggs in as little as 3 hours, gluing them to the hairs of the horse’s mane or body. Horses can sense when flies try to lay eggs and react by constantly moving and throwing their heads violently. Riders have commented that during this phase, horses can become temporarily unmanageable.

Although there are many different sorts of bot fly, the common bot lays its eggs on the hairs of the horse’s front legs. Hatching happens when they are rubbed by the moist lips of the host. The larvae emerge during this process and fasten to the mucous membrane in the mouth, afterward penetrating the mouth, lips, gums and tongue before migrating to the colon.

The presence of significant numbers of bot flies cause damage to the lining of the stomach, with a resultant deprivation of nutrition. In cases of heavy infestation, death may happen.

On any farm, ranch or estate Pareto’s law applies – 20% of the horses shed 80% of the bugs. If you can identify the hosts, you can create an effective de-worming schedule. Instead of de-worming every horse more often than is required you can de-worm the animals that shed the most eggs. This practice will save everyone a substantial outlay of time, effort and money.

Strongly recommended for getting rid of parasites from animals of all shapes and size is Critter Cleanse, a five hundred year old broad spectrum herbal formula originating in Ancient Phoenicia.

From a family of Clydeside Scots, Graeme was born and brought up in Hong Kong. He lived for 35 years there, as well as in Borneo and Indonesia. Intrigued by the way in which the different Asian cultures approach their health and welfare, he studied aspects of Traditional Chinese Medicine and became familiar with many other time-honoured healing methods, from the traditional Jamu herbal medicine healers of Java to the body balancing mechanisms of Jin Shin Jyutsu, from Japan. Together with his wife Phylipa, Graeme runs Resources For Life, a natural health business in Chichester, West Sussex. Much of what is available on their website has origins steeped in ancient wisdom.

For more information on Critter Cleanse, a broad-spectrum, anti-parasite natural herbal formula click here.

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