There are a number of reasons why a horse might not be able to consume traditional forages such as hay or pasture. These include heaves (sensitivity to dust or mold in hay), allergies, or due to poor teeth often found in older horses. The first thing a horse owner should try in these cases would be products such as haylage (fermented hay), hay cubes (cut and cubed hay) or roughage chunks (cut hay processed into cubes, often fortified with vitamins and/or minerals). In cases where horses cannot eat any of the above, they still need to obtain sufficient fibre elsewhere to maintain digestive tract health. While the actual amount of fibre required per day is not known, it is generally accepted that if horses do not consume sufficient fibre, they risk digestive problems such as colic, gastric ulcers, or behavioral issues.
Non-forage fibre sources include beet pulp, soy hulls, wheat bran, rice bran, and sunflower seed hulls. Beet pulp is the byproduct of the sugar industry and may be found pelleted or flaked, with or without a coating of molasses. Beet pulp may be included in equine diets at fairly high rates – up to about 50% of their intake by weight. Beet pulp is thought to be highly digestible by horses and while the book values for digestible energy of beet pulp is about 2.8 mcal/kg, nutritionists believe the true value of beet pulp to be a little higher. Therefore, beet pulp is a moderate source of energy compared to cereal grains such as oats or corn (3.2-3.8 mcal/kg) and hay (about 1.8 – 2.2 mcal/kg). Also, beet pulp has a decent amount of protein (10%) and lots of calcium (0.8%).
Beet pulp is an excellent feed for horses who can’t consume hay or pasture, but it is also useful for those who need to gain weight through added calories to their diet, without the extra starch or sugar found in cereal grains. For those with horses that are sensitive to sugar, the beet pulp should be soaked and the extra water drained off, as the molasses is water-soluble. While flaked beet pulp does not need to soaked (although it may be recommended for some horses), pelleted beet pulp should be.
The recommended amount is about four parts water for one part of beet pulp. Other pulps, such as citrus pulp, may also be fed to horses. Soy hulls are the byproduct of the soybean industry and may be included in equine diets at rates of up to 75% of the total diet. Soy hulls have about 2.2 mcal/kg, but again this may be underestimated.
Similarly, oat, almond, cottonseed or sunflower seed hulls may be fed, although less research has been conducted on these feeds. When fed intact (i.e., whole oats, whole sunflower seeds) the internal parts of the kernel where most of the nutrients lie are available to be digested by the horse, causing these feeds to be higher in digestible energy and therefore categorizing them as ‘energy feeds.’
Bran from rice or wheat is derived from the outer layer of the kernel. Rice bran has substantial fat in it (15%) and therefore it is a higher-energy feed (3. 35 mcal/kg). Wheat bran has lower amounts of fat and is therefore slightly less (3.2 mcal/kg). Both contain good amounts of protein (15 and 17%, respectively). Unfortunately, both have inverted calcium-to-phosphorus ratios (we prefer Ca:P ratios of about 2:1) – wheat bran is 0.11:1 and rice bran is 0.04:1. Therefore, if you aren’t careful and ensure extra calcium is included in the diet, the overall dietary Ca:P ratio may be negatively affected. Further, rice bran should be ‘stabilized’ (treated with an antilipase enzyme by the manufacturer) to ensure the fat within it doesn’t go rancid.
In some instances, these non-forage feeds can be fed in addition to hay or pasture, and even alongside some commercial concentrates, in order to get some extra calories into the horse if offering additional grain isn’t warranted. These situations would include a sensitivity to starch and sugar in the diet, fear of digestive upset, etc. Caution should be used when horse owners take such steps, however, as commercially-made concentrates are designed and formulated to complement the nutrient composition of hay or pasture. Thus, if feeding large (or even small) amounts of these non-forage fibre sources, it is strongly recommended that you consult an equine nutritionist to ensure that all your horse’s nutrient requirements are being met, and that important ratios are not being disrupted.