Wild equines such as zebra, American mustangs, Mongolian Wild Horses, wild donkeys or Burros, etc., live in grasslands, also known as prairies, steppes, etc. They spend much of every day grazing the plant life, which is green part of the year, and dry for another part of the year. These species evolved to inhabit such an environment.

Most animal species are parasitized by a variety of parasites. These parasites rarely destroy their equine hosts, because to do so would constitute a loss of a key vital to their survival.

For example, all wild species of equines, such as those mentioned above, are invaded by intestinal parasites, which permanently occupy their hosts. The most common examples in wild equines are roundworms (Ascarids) and bloodworms (Strongyles). They live within the animal’s digestive tract throughout the host’s life.

Until modern anti-wormers (vermifuges) came into use, the parasitized equines usually survived their affliction (as did other creatures including humans).

When I was a veterinary student only two drugs were available for worming horses: Phenothiazene and Carbon Disulfide.

More recently, a variety of “wormers” have been available for equines. Unfortunately, resistance to many of these anthelmintic products has, thanks to evolution, become a problem.

In their natural environment equines avoid grazing near manure deposits. It is as if they seem to instinctively know that each ball of manure is contaminated with the eggs of parasitic worms. That’s why they survive despite perpetual parasitic infestation.

Domestic equines living in large pastures also separate the grazing areas from the areas where they deposit manure, thus minimizing the chances for reinfestation.

However, domestic equines kept in small enclosures such as stalls, small pens, corrals, and even small pastures cannot so limit the areas where they deposit manure. Therefore they cannot avoid contaminating their feeding areas with worm eggs.

That’s why removing fresh manure from equine living areas (stalls, small pens or corrals or even smaller pastures) is important for parasitic worm control.

Even when using Fly Predators, an important factor in controlling another form of pest (flies), fresh manure should be stacked in order to minimize its exposure to the animals we are trying to protect.

That’s what I do.

My horses and mules, on my five-acre home property, are kept in stalls with year long open gates allowing them to go out to fenced pens any time they want to.

Thus, they rarely defecate in the stalls where they feed. Their manure piles are out in the pens where they can be cleaned up and regularly stacked in a separate area that the animals cannot get into.

The manure, thus gathered, serves periodically to fertilize our pastures, but also where we use our Fly Predators to minimize the population of insect pests, which are a year round problem in our Southern California climate.

We supplement the control of these inevitable pests in two ways: 

  1. At least once a year we run microscopic fecal exams on fresh manure (one ball of manure from each horse or mule). If positive for worm eggs, we worm each animal appropriately.
  2. We use Spalding’s Fly Predators regularly, plus repellent fly sprays on the animals, daily, during the warmer months when the flies are at their worst.

Every horse and mule we have owned (most of them born on our property) has lived into its thirties, with one 28 year old exception.

Parasites, both internal, like worms, or external, like flies, ticks, etc., are a part of life, part of nature, part of the miracle of evolution. It is mankind’s obligation to use our gifted intelligence and creativeness to control those parasitic organisms, which endanger the quality of life for us, or for the animals we have domesticated and cherish.