Feeding for weight gain: Hygain Nutrition series

How to feed horses for weight gain is a commonly-asked question. Some horses do not maintain their bodyweight easily and it can be a challenge to keep them at an ideal level.

Ultimately, your horse’s ribs should not be visible, but they should be easily felt if you run your hand along his side. A common complaint from horse owners is that their horse hasn’t got enough topline. This is achieved by working the horse in a manner that strengthens muscles in the back, along with the correct diet of quality protein to help build muscle.

Regularly monitoring your horse’s weight with a weigh tape or livestock scale will allow you to identify fluctuations and help you make corrective actions quickly.

What causes weight loss?

This can be due to a number of non-feed-related factors. Once these have been eliminated and your horse is still not gaining weight, the next step is to evaluate his diet.

  • Dentition. The condition of your horses teeth is the first factor that should be checked when assessing causes for weight loss. Proper dentition is essential due to the nature of its diet; plant materials require thorough grinding by the molars to break down the particle size of the food.
  • Parasites. Poor worming regimes can cause weight loss regardless of what and how much you are feeding. Parasites compete for nutrients inside the digestive tract and can damage the intestinal lining, making it difficult for nutrients to be absorbed. 
  • Stress. If your horse is a chronic weaver, stable-pacer or fence-runner, he is burning calories needlessly. Simple management changes, such as daily turnout or the addition of a buddy, can help.
  • Grain. High grain, low roughage diets can cause stress as a result of painful gastric ulcers and may discourage horses from eating.
  • Disease or illness. Sickness can decrease appetite or affect nutrient absorption within the digestive tract.

What should I feed?


Of the three major energy sources (fibre, carbohydrates and fat), fibre is the most important and is the major component of pasture and hay. Some horses can maintain weight on fibre sources alone. For the poor doer, however, fibre alone will not be enough, but there are fibre sources with higher energy content and digestibility than others. For example, lucerne hay can provide a horse with more energy than grass hay of similar quality. However, low-quality lucerne hay (more stem than leaf) is not a rich source of energy. When quality pasture or hay is not available, or if the horse does not readily eat hay or have access to pasture, there are alternative fibre sources available. The most common are “super-fibres” such as beet pulp, and legume hulls (soy or lupin hulls). The fibre in beet pulp is about 80% digestible (as compared to 50% for average hay). Soy and lupin hulls are the skin of the bean (not the husk or pod) that is removed prior to processing. The energy content of legume hulls is close to that of oats. HYGAIN MICRBEET and HYGAIN FIBRESSENTIAL are excellent sources of super-fibres and can be added to the diet to increase weight. Certain additives such as yeast may help with fibre digestion if the horse has a problem with the balance of microbes in the large intestine. Yeast has been researched and found to improve fibre digestibility. Live cell yeast culture is added to many of HYGAIN’s feeds.  Maximizing forage quality should be the first dietary adjustment when trying to achieve weight gain.


Carbohydrates, specifically sugar and starch found in grains, have been a traditional method of increasing the diet’s energy density. Obtaining energy from sugar and starch is very efficient due to its simple enzymatic process. While grain is a concentrated source of energy, complications can result from feeding it in large quantities. The small intestine can easily become overloaded with sugar and starch, causing an overflow into the large intestine. This can lead to gas colic, colonic ulcers and even laminitis. Also, if too much grain is fed, the delicate microbial population in the large intestine gets disturbed; this causes most horses to lose their appetite, and the situation worsens. Care should be taken not to feed any more than 2kg of grain in a single meal. When large amounts of grain are needed, it should be divided equally over three or more meals throughout the day. It is also important to make sure the grains you feed are processed: processing makes the nutrients more available to the horse and ensures proper digestion in the small intestine. HYGAIN utilises micronizing technology which is a “short time, high temperature” patented process, during which the grain becomes soft and pliable, causing the reconfiguration of the starch structure (gelatinisation). Immediate flaking further gelatinises the starch to significantly enhance the digestibility and nutritional value of the feed. Make sure the horse is always getting at least 1.5 to 2% of their bodyweight in the form of fibre and a good rule of thumb is to try to stick to a roughage-to-grain ratio of around 70:30.


Fats and oils are commonly used to increase the calorie content or to replace the calories supplied by grains. Fat supplementation has many benefits, including providing calories for weight gain, and essential fatty acids to improve skin and coat condition. Fat sources such as rice bran oil or soybean contain 2.5 to 3 times more energy than grains on an equal weight basis. Increasing the fat level of the diet is the easiest and safest way to increase its energy density. Higher energy levels can be obtained by feeding a lesser amount of a high-fat concentrate mix compared to a concentrate mix containing lower-energy grains. Research has indicated that adding 5 to 10% fat to the total diet has maintained the bodyweight of horses with a 21 to 25% decrease in concentrate intake. Adding fat to a horse’s diet permits safe weight gain while reducing the chance of colic or founder. Digestion of fat also yields less internal body heat when compared to other diets. Thin horses will gain weight and do so without having to eat as much grain if the diet is fortified with additional fat. HYGAIN offers several high fat feeds such as HYGAIN SHOWTORQUE, HYGAIN GROTORQUE and HYGAIN RELEASE as well as fat supplements HYGAIN TRU GAIN and RBO Equine Performance Oil.

How long will weight gain take?

It is safe to assume a healthy horse can gain one condition score every two months. Research suggests it takes 16 to 20 kg to change a horse’s body condition score by 1 unit (based on a 500 kg horse; 1 to 9 scale). Therefore a horse with a body condition score of 2 would need to gain around 60kg to increase its condition score to a 5, and this would take around 6 months.

Feeding, management & prevention

It’s important to evaluate your horse’s condition regularly, as old age, environmental changes and workload will have an effect on weight. Addressing unwanted fluctuations before they become potential health risks is the key to maintaining optimal bodyweight. After addressing all possible causes for weight loss, the first point of call is to increase the amount of quality fibre, followed by an increase of the energy density of the concentrate portion of the ration. It is essential that owners follow feeding directions on the back of feed bags to ensure their horses will maintain or gain weight as desired.

Weight Gain Feeding Plan

Diet for a 500kg horse in light work needing to gain weight on 24/7 average quality pasture:

•1.5kg lucerne hay (1 biscuit)




The amounts of HYGAIN TRU GAIN can be reduced once the horse’s desired weight is achieved.