A skinny horse is not a pretty sight. With ribs protruding, and hip bones threatening to serve as a hat rack for the next passerby, he gives an immediate impression of ill health... and it's no illusion. A too-thin equine is one who has no energy reserves on which to draw, and when push comes to shove, will not be able to perform to the best of his ability. At the very least, he'll be easily fatigued; at worst, his every system is compromised, and he'll be vulnerable to injury and disease.
A very thin horse. Animal emaciated, very minimal fat covering. Spine visible but ends feel rounded; tailhead and hip bones obvious. Ribs prominent with slight depressions between them.
Many of these reasons are the result of neglect, but it's important to point out that some horses seem determined to resemble Humane Society cases regardless of the good care they receive. Often (but not always), these are "hot" horses, built for speed rather than comfort; and while the Thoroughbred breed seems to include an inordinate number of these individuals, the syndrome is by no means limited to Thoroughbreds. Think of these horses as genetically programmed to be "hard keepers." Their DNA predisposes them to a nervous temperament, extreme sensitivity, and a tendency to stay "lean and mean."
The fast and efficient metabolisms of "hot" horses might make it an uphill battle to achieve a plump outline, since they tend to burn calories at a rate some would compare to a hummingbird. But it is possible to help even a "genetically" skinny horse maintain a healthy weight--and a few simple nutritional strategies (coupled with comprehensive veterinary care) can help restore some needed flesh to a horse which has lost too much due to some sort of trauma in his life.
What's A Healthy Weight?
Since horses, like humans, come in all shapes and sizes--from the "gets-plump-on-nothing" type (think Shetland pony) to those who can eat you out of house and home and never get those ribs covered, researchers have come up with a classification system called "condition scoring" to help us better describe our horse's physiques. The chart on page 82 gives descriptions of the nine categories; a quick glance should tell you that, ideally, you want your horse to be a five (although anywhere in the four to six range is healthy and might be appropriate for the type of lifestyle your horse has).
Assessing your horse's body by this condition scoring chart can give you a more accurate perspective on his health than actually weighing him. While we can make estimates on a horse's ideal weight based on his height, the reality is that horses come in so many types--from the fine-boned Saddlebred to the Schwartzenegger-esque Belgian--that such estimates are practically useless. The old horseman's rule that you should be able to feel the ribs, with a firm press of the hands on the barrel, but not see them protruding through the coat, is a good axiom, although it doesn't tell the entire story. If your horse displays any of the characteristics of categories four through (heaven forbid) one, it's likely desirable that you help him gain some weight.
Step one in achieving that goal is to assess his physical health from top to bottom. He'll never be able to devote any effort to storing food energy if he is battling an infection, is worn down by chronic pain from an injury or a debilitating arthritic condition, or if parasites are robbing him of the nutritional value of his feed. Nor will he be able to extract any goodness from his diet if his teeth make chewing so painful that he dribbles large chunks of poorly-ground grain and forage from his mouth in quids, or simply decides it's not worth the discomfort. Any number of dental conditions--from caps (lingering baby teeth that sit atop erupting adult molars and make chewing difficult) to abscesses (usually from food particles or foreign objects, such as wood splinters, which get lodged in the gums) to sharp dental hooks that develop when regular floating is neglected--can make correct grinding of his feed practically impossible.
For a horse with a chronic condition, such as COPD or arthritis, anorexia (loss of appetite) can come with the territory. Controlling the symptoms of the condition with medication will likely make your horse more comfortable, and thus more interested in his food. (Unfortunately for horses which need daily assistance from a nonsteroidal anti-inflammatory such as bute, the drug which helps relieve his discomfort might eventually result in gastric ulcers, which make it difficult to maintain a healthy weight.) Bear in mind that loss of appetite can be a first hint of disease; for example, it can signal that an EIA (equine infectious anemia)-positive horse is suffering an active bout of the infection and is running a fever.
A thorough physical by your veterinarian is the first step when you notice a horse has lost condition, and addressing any health concerns that surface as a result is absolutely necessary before you begin to improve his condition. And if you haven't already, institute a program of regular dental maintenance and de-worming for every horse in your care, skinny or not.
In addition, take a moment to assess your management program, particularly if your horse is the hot or nervous type. Are his surroundings, or his care, exacerbating stress and making it impossible for him to relax and put on weight? For example, is he stabled next to an aggressive horse which makes him perpetually nervous? Is he being shipped all over the countryside to a different show every week? Is he in a high-pressure training program? Does he get limited turnout--or none at all? Perhaps a change of scenery or routine--even just moving him to a stall in a quieter part of the barn or altering the time of day you work him--would make a difference in his NQ (neurosis quotient). It's possible he's a square peg in a round hole, as well; perhaps he'll never make a Western pleasure horse, but would be happy running and jumping around lower-level event courses. Consider giving your horse a companion, such as a goat or a pony, which might serve to soothe a nervous temperament and provide some healthy competition for dinner; this is a tried-and-true trick at the racetrack.
And take heart as you assess him--even most hot horses do eventually experience a leveling out in their metabolism as they age. Horses which were bone racks at five might become positively easy keepers as they mature.
Feeding For Weight Gain
Next, it's time to examine your feed program. In order for your horse to gain weight, he must take in more calories than he burns. But as always, you must be careful not to deliver a diet so energy-dense that his system overloads and triggers colic or founder.
Grains, such as oats, corn, and barley, are calorie-rich, and it's tempting just to alter the diet of a thin horse to include large quantities of these carbohydrate-loaded feeds in the hope of quickly covering those protruding ribs. But the equine digestive system handles a carbohydrate-dense diet poorly because horses are designed to eat and digest forage, first and foremost. So forage is where we'll begin.
Let's start with your pasture. Does your horse have access to quality grazing? It might look green out there, but depending on the plants that are growing, the time of year, and the acreage available, your horse might not be getting the nutritional value from his pasture that you think he is. On closer examination, his paddock might be mostly carpeted with inedible weeds, rather than nutritious grasses and legumes. In times of summer drought, even good pasture can become dormant, with the plants ceasing growth and turning yellow; and in the fall and winter, there can be little nutritional value in the tough, fibrous grass that remains. Often, horses are kept in pastures too small to support their grazing habits, with the result that the field gets cropped to the ground and plants are not able to recover. So, if you're depending on your pasture to provide the bulk of your horse's daily dietary needs, assess it honestly; if your horse is ribby, the field is probably not up to the job.
That's not to say that turnout is not valuable. Whether or not your field provides good quality grazing, your thin horse is probably better off on a regular turn-out routine than confined to his stall (perhaps in a mistaken effort to help him keep from burning calories away by running and playing). Frequently, a thin horse is also a hot horse, the type which will fret and fuss when kept locked inside--and the development of stable vices, such as weaving, stall walking, or cribbing, can make it even more difficult to keep weight on his frame. A program that allows him plenty of time to wander and socialize with other horses in a field will be good for his peace of mind--and that, in turn, will help him to gain weight (or, at least, not lose any more).
But if your field doesn't provide sufficient nutrition on its own, it's time to supplement the amount of forage your horse receives. Good quality--but not necessarily high-protein--hay is the best addition to his diet that you can provide. And when the aim is to help your horse gain weight, you can provide forage free-choice (in other words, as much as he can eat).
If you feed your horses outside, keep in mind that pecking order in the herd has an impact on how much your skinny horse gets to eat. If he is not one of the "alpha" horses, it's possible that his more dominant herdmates are stealing much of his breakfast and dinner. In this case, your best bet is to separate your weight-gain candidate from the herd at feeding time; either put him in a stall, or in a separate paddock, so that he can focus his undivided attention on his meal. This will have the added advantage of reducing the amount of stress he experiences.
It's possible that you are faced with a horse which, despite his protruding ribs, is an indifferent eater, nibbling halfheartedly at his meals and leaving half of it untouched, or trampled into the bedding. Tempting the appetite is the trick here--and a frustrating trick it can be. It might take considerable experimentation to discover what suits such a fussy palate, so be prepared to try different feed formats--from sweet feed to pellets to extruded kibble shapes, and top dressings, such as molasses, corn syrup, or even raspberry jam--to see what tickles his fancy. You might wish to try moistening his grain with warm water to see if that suits him better (it can particularly enhance the appeal of his feed in the winter months). Don't top-dress his feed with loose salt, though, or leave a salt block in his grain bucket; a grain ration that's too salty will be immediately rejected. (Instead, make sure loose or block salt is available separately in his stall or pasture.)
With a fussy eater, freshness is imperative. Feed in small quantities, and be prepared to remove any feed that isn't consumed within an hour or so before offering more. (You can often offer the leftovers to an enthusiastic eater elsewhere in your barn.) Scrub out the feed tub on a daily basis. Try offering his hay in a haynet rather than on the floor of his stall (where he'll be tempted to trample it). And of course, make sure that he has a constant supply of fresh, clean water available. Even a horse with a good appetite will decrease his feed intake if his access to fresh water is restricted.
Generally speaking, legume hays, such as alfalfa and clover, are more palatable than grass hays; so while most adult horses don't need the high protein content of a 100% legume hay, it might be worth seeking out a mixed hay with a relatively high alfalfa or clover content to tempt your poor doer (balance it with a grain ration on the low-protein side). Likewise, sweet feeds are considered more palatable to most horses than plain grains, pellets, or extruded rations, but individual equines do vary in their preferences. Other choices likely to tempt the palate include processed "crunch" feeds (which often have a high level of apple or other flavoring to heighten their appeal), and the standard trick of adding carrots, apples, turnips, or other treats to the grain ration.
The traditional bran mash also gets a big thumbs-up from most horses, particularly when delivered warm and steaming, with a dollop of molasses and some goodies stirred in. To tempt the appetite, there's probably nothing tastier. But because of its extremely inverted calcium/phosphorus ratio, bran should never be fed on a daily basis. One or two bran mashes can, however, serve very well to jump-start the appetite of a horse convalescing from injury or illness, a stressed traveler, or a tired mare who has just given birth.
Packing In The Calories
Even a horse with an enthusiastic appetite is limited in his feed intake by the relatively small size of his stomach and the evolutionary inefficiencies of his digestive system. So, it's worth finding feeds that deliver good caloric value per pound when you're trying to put weight on a skinny horse.
One favorite feed additive is sugar beet pulp, a traditional choice in many Thoroughbred stables. Despite its name, sugar beet pulp contains almost no sugar--it's what's left of the sugar beet after the sugar has been extracted. It is an excellent source of highly digestible fiber, low in protein (averaging about 8%), and, to most horses, highly palatable once soaked in water for a few hours. For horses which pick at their hay, beet pulp is an excellent choice: it supplements the fiber content of the diet, and because it's fed in the grain bucket rather than on the floor of the stall, it's far less likely to be trampled into the bedding. Stir it in with the normal grain ration and your horse gets increased digestibility of the whole mix. And unlike grain, it's safe to work up to feeding relatively large quantities of the stuff; its starch content is very low and its negligible vitamin and mineral content means that it won't upset the nutrient balance of your overall ration.
Beet pulp also is a terrific choice for older horses which might have very few teeth left with which to chew; its soft consistency makes it easy to swallow and even an old and inefficient digestive system can make good use of it. For horses which can no longer manage hay, it can be fed in sufficient quantities to provide all the fiber they need.
Another fiber option for horses whose dental health won't allow them to grind hay properly is chopped hay (either done on-farm with a heavy-duty leaf shredder, or purchased in a bagged format) or hay cubes, soaked in warm water for a few hours to make a mush. For old horses whose lifespans have outreached their teeth, a pelleted grain ration, soaked in water to the consistency of gruel, is also a good bet.
One feed additive that delivers excellent caloric value for the money is fat. Readily digested by the horse, fat (usually in the form of vegetable oils such as corn or soy oil) delivers concentrated energy--almost 2 1/2 times as much as the same quantity of carbohydrates. And just as in humans, any fat that is not burned by the horse in exerting himself is readily converted to fat in his tissues. Despite its not being a natural part of a horse's diet, studies have demonstrated that horses have excellent tolerance for dietary fat making up as much as 15-20% of the total ration. Fat is a safer energy supply than carbohydrates, since it doesn't tend to ferment in the gut and overload the digestive system as can large quantities of grain. Interestingly, horses have the capacity to digest easily both animal fats (lard) and vegetable fats (usually liquid), but vegetable sources definitely have the edge in palatability.
There are a number of ways to add fat to the diet, ranging from a simple top-dressing of vegetable oil (gradually working up to about 1 1/2 to two cups per day in total), to high-fat supplements such as rice bran or even sunflower seeds (which most horses relish). Several feed companies now manufacture added-fat rations for performance and breeding horses, and if your horse has a fussy palate, these might be the best choice, as the fat is camouflaged within the mix and harder to taste. Any ration which lists a fat content over about 3.0% probably has fat added to it. Some, such as Purina's Athlete, have a fat content higher than 13% and are designed to be fed as a supplement to your regular grain, while others are meant to be complete feeds, with a fat content ranging up to about 10% as a rule.
A final suggestion: consider adding a digestive-enhancing supplement to your skinny horse's diet. Brewer's yeast is an inexpensive and readily available supplement that provides a natural source of B-complex vitamins, and also seems to encourage the proliferation and activity of the beneficial microflora inhabiting the equine digestive tract. The result often is an improved utilization of the nutrients the horse's diet provides. There are also acidophilus supplements, such as Ration Plus, which promote friendly microorganisms in the gut; either of these can be a good choice for a skinny horse, particularly an older one whose digestive system just isn't as good as it used to be at extracting nutrients. Some people also have reported improved feed utilization when feeding a daily deworming supplement such as Strongid; this is a side-effect that has not been documented directly by research, but is probably a result of a reduced parasite load.
Faced with a skinny horse, you'll probably want to try several, if not all, of these approaches to his diet to effect a change. Keep in mind, however, that at first visible change might be slow in coming. As one sage horseman once observed, "You've got to fill up the inside before you see a difference on the outside." But some perseverance, coupled with lifestyle changes to minimize stress, eventually will yield results.
General Condition Description
1 -- VERY POOR
Animal extremely emaciated: no fatty tissues can be felt. Spine bones easily visible, ends feel pointed; tailhead and hip bones prominent, ribs visible and skin furrows between them.
2 -- VERY THIN
Animal emaciated, very minimal fat covering. Spine visible but ends feel rounded; tailhead and hip bones obvious. Ribs prominent with slight depressions between them.
3 -- THIN
Fat buildup halfway on vertical spines, but easily discernible; flat spinal bones not felt. Tailhead prominent, hip bones appear rounded, but visible. Slight fat covers over ribs, but rib outline obvious. Withers prominent but with some fat cover.
4 -- MODERATELY THIN
Withers not obviously thin; neck carries some fat. Slight ridge along back. Fat felt on tailhead. Faint outline of ribs.
5 -- MODERATE
Neck blends smoothly into body; withers rounded over top. Back is level-spine neither protrudes nor is "burned." Fat around tailhead begins to feel spongy. Ribs not seen but easily felt.
6 -- MODERATELY FLESHY
Back may have slight inward crease. Fat around tailhead feels soft, as does fat over ribs. Fat layer visible over shoulder.
7 -- FLESHY
Visible fat deposits on neck and behind shoulder. Firm fat covering over withers. Slight inward crease down back. Individuals ribs can still be felt.
8 -- FAT
Noticeable thickening of neck; area behind shoulder filled in flush with the body. Crease flown back quite evident. Tailhead fat very soft and flabby. Difficult to feel ribs.
9 -- EXTREMELY FAT
Bulging fat on neck, shoulder, and withers. Obvious deep crease down back. Patchy fat over ribs. Fat along inner hind legs may rub together. Flank filled in flush
Body Conditioning Scoring System For Horses
[adapted from Henneke et al. (1983), Equine Vet Journal pg. 371-372]
About the Author
Karen Briggs is the author of six books, including the recently updated Understanding Equine Nutrition as well as Understanding The Pony, both published by Eclipse Press. She's written a few thousand articles on subjects ranging from guttural pouch infections to how to compost your manure. She is also a Canadian certified riding coach, an equine nutritionist, and works in media relations for the harness racing industry. She lives with her band of off-the-track Thoroughbreds on a farm near Guelph, Ontario, and dabbles in eventing.
POLL: University Equine Hospitals