The Hard Keeper: Horse Weight Gain Tips

Posted by Gabby Gufler, Fri, Oct 23, 2015

As horse owners, most of us have struggled keeping weight on that one “hard keeper” in our barn at one point in our lives. You try giving them the same ration of grain and quality hay on which the other horses are thriving, they are on a regular de-worming schedule, and you even had their teeth checked. What could you be doing wrong? Sometimes achieving horse weight gain is simply a matter of increasing their caloric intake. Other times, their diet may need to be higher in calories because of a medical or environmental problem.

What is Thin?

The first step to solving your horse’s weight problem is to determine how thin your horse really is. The use of body condition scoring will provide the best guide to your horse’s overall body condition.

This technique assesses flesh coverage on the tail head, rump, back, withers, ribs and neck using a scale of 1 through 9. A body condition score (BCS) of 9 indicates obesity. The ideal BCS for your horse is related to their breed or discipline, but typically a BCS of 5–6 is ideal. CLICK HERE for your free body condition poster.

You should regularly asses your horse’s BCS to help you determine your dietary strategies.

What makes a horse a hard keeper?

The metabolic rate determines whether a horse is an easy or hard keeper. Metabolism is the speed at which the body burns fuels for energy in order to maintain normal body function. A slow metabolism can function on less input of fuel energy. Conversely, a fast metabolism needs a higher caloric intake in order to function properly. (Kentucky Equine Research)

Thin horses require enough energy (feed) to fuel their body functions and build fat deposits. Calories can be contributed by carbohydrates, fats or proteins. When a horse does not have enough calories or protein in their diet, the body will deplete much of the adipose tissue or fat and even break down its own muscle tissue. (Kentucky Equine Research) Typically (although not always), the solution to weight gain is to increase your horse’s caloric intake while ensuring that they receive adequate protein.


When your horse simply cannot maintain their weight on hay or grass alone, the addition of a starch in the form of grains will help increase the number of calories in their diet. The trick is to select the feed or equine supplements that will allow you to feed fewer pounds of feed to supply more energy to the horse. Although grains are an excellent source of starch, they can also be hazardous to their digestive tract if fed in excess. Balance is key!

A long-standing recommendation is to feed a horse a minimum of 1% of its body weight in forage each day. The rest of the diet should be designed around the minimal forage requirement.

When looking for a feed or equine supplement, look for one that uses processed grains for optimal digestion.

Manna Pro® recommends Calf-Manna® Performance Supplement, which contains quality digestible carbohydrates and is “energy dense,” meaning it delivers more calories per mouthful. Calf-Manna also contains Brewer’s Dried Yeast to support the digestion of other nutrients.

Does your horse suffer from starch sensitivity? Max-E Glo® Stabilized Rice Bran is high in fat and digestible fiber while being relatively low in starch, making it an ideal choice for weight gain in the starch-sensitive horse.


Carbohydrates, including starch (mostly from grains) and digestible fiber (mostly from hay and pasture), are the primary energy source for horses. Although some horses can maintain their weight on hay and pasture alone, the hard keeper will (of course!) not maintain their weight on forage. However, there are fiber feeding strategies that can increase the horse’s ability to derive energy from forage.

A horse can more easily digest high-quality, early-harvest hay over mature hay. So, when going to purchase your hay in the spring, be sure to look for leafy soft hay versus stalky stiff hay. Maximizing your horse’s forage quality should be your first strategy when trying to achieve horse weight gain.

Max-E Glo is “cool” nutrition. The high fat and fiber content in Stabilized Rice Bran maintains energy without high-starch hyperactivity, providing your horse with a safe diet. How cool!

Did you know? Pasture is an excellent source of fiber with a typically higher digestibility factor than hay, as the curing process of haymaking results in digestible fiber losses.


Horses of all ages require adequate amounts of protein for maintenance, growth, reproduction and work. Proteins aid in maintaining the structural tissues of the body and are also involved in metabolic stability by contributing to the level of balance in the body’s many enzymatic and hormonal functions.

Providing thin horses with high-quality proteins that contain amino acids such as lysine and threonine may help improve their muscle mass. Lysine also supports weight gain as well as skeletal and muscular growth in horses. Horse supplements such as Calf-Manna that contain soybean meal are ideal for thin horses because of their great amino acid profile.


Gabby Gufler

Gabby Gufler graduated from Truman State University in 2013 with a BS in Animal Science & Nutrition and a minor in Equine Science. Gabby currently works on Manna Pro’s marketing team, and enjoys competing regularly with her six horses.