A skinny horse is not a pretty sight, and sometimes it can be tricky to find out why the horse can’t maintain its condition or why it is losing weight. “Weight loss” is the term or phrase that I will use for this article. Strictly speaking, though, “loss of body condition” is not only more applicable, but also easier to measure (by sight and touch) because few people are able to weigh their horses on a regular basis.

Physiological weight loss refers to weight loss that is to be expected (i.e. normal) under a specific set of circumstances such as the first few months of lactation (nursing a foal-producing milk taps a lot of nutrients and energy from a mare), and high levels of exercise or work where simple mathematics states that energy output is more than energy input.

Another circumstance to consider is the latter part of pregnancy in the mare. This is an example of where a horse will weigh more than before (because of the foal growing rapidly inside the mare), but will look thinner. This is because a huge quantity of nutrients is being channelled to the uterus in order to sustain the massively rapid growth of the unborn foal.

Lastly, weight loss can also take place during the breeding season. This is especially applicable to colts and stallions whose focus, energy and time are spent on other things!

Pathological weight loss refers to weight loss that is not “intentional”, normal or to be expected. The majority of conditions that result in weight loss, are the fault of the owner (or guardian) and not of the horse or nature itself! The list of causes of weight loss in horses is as long as my arm – you won’t know how long that is, but it’s long!

Feeding is very important. This sounds obvious, but you will be surprised at how much variation there is between different feeds and different feed companies, and you will be alarmed at how much junk there is in some feeds – especially the cheap ones.

Because feeding a 450 kg athlete is expensive, this is where people take short cuts. Firstly, owners (or guardians) take short cuts, because it costs them less. Secondly, some feed manufacturers do the same. The demand is there for cheaper feeds, so they tend to leave out important ingredients which add to their costs and reduce their profitability. Strong words, but I must make it clear that this may only apply to a handful of feed companies, and is not a generalisation.

If you stable your own horse/s, then make absolutely certain that the quality and quantity of feed being fed is correct. Get an unbiased, professional opinion from someone who is qualified to advise you about equine nutrition. By this I don’t mean the guy or girl at the local feed or tack shop – unless of course he or she is qualified. Representatives from feed companies have a wealth of knowledge, but always insist on the analysis of the feed and do some research yourself.

If your horse/s are stabled elsewhere you have all the right in the world to insist that your horse gets fed correctly, once again get an unbiased opinion … please! For a stable owner, especially in and around cities, feed costs are their highest expense because of restricted grazing space.
And this is where short cuts are taken. Again, this may only apply to the minority of stable owners.

The parasite problem

By parasites I refer primarily to worms, but other parasites may also contribute to equine weight loss. Parasites can cause weight loss in a number of different ways: They can compete for ­nutrients whilst “lying” in the gastrointestinal tract and absorbing the food that should be ­absorbed by the horse, e.g. tapeworms and some roundworms.

They can also suck enough blood to cause the animal to lose weight. Blood requires energy and nutrients to replace, and blood carries nutrients to different parts of the body. The irritation that worms cause in the intestine as well as the stomach (such as bots), can be enough to negatively affect the horse’s appetite (due to discomfort) and the digestion and absorption processes

Small strongyle worms (cyathostomes) affect the large intestine. Bearing in mind that a horse is a hind-gut fermenter, most nutrients are digested and absorbed in the large intestine. So a slightly (or very) skinny horse with a constant loose stool, may indicate a cyathostome infection, and often the immature stages of the small strongyles embed themselves in the wall of the large intestine. By doing this they evade regular deworming remedies.

Implement a complete, strategic (i.e. timing) deworming programme. But once again, get the correct advice from a qualified person, especially in terms of strategic deworming. Deworming three times a year can be more effective and cost-effective than deworming six times a year at the wrong times with cheap products!

Other parasites such as flies, midges and the larvae of certain worms can cause so much itching and irritation, that the horse either has less time to eat, or just doesn’t feel like eating. In the July issue of SA Horseman I will discuss the role that teeth, liver failure, cancer and lameness can play in weight loss and the “skinny horse”.