The following information from Kentucky Equine Research can help us understand why molasses is used in livestock and horse feeds, what nutritional effects molasses might have and bust some of the myths about molasses in horse feeds.
Molasses is the liquid residue left after condensing the juice of sugar cane or sugar beets until sugar crystals precipitate. When all the crystals that can be formed have been centrifuged off, the syrup can be as high as 85% dry matter. This syrup is too thick and sticky to be handled by ordinary feed mill equipment, so it must be diluted somewhat before it is used at a feed mill.
Even though sugar is the primary material extracted from the condensed cane syrup, a great deal of unextractable sugar is left in molasses. There is a small amount of natural protein in cane molasses (about 3%) and a slightly larger amount in beet molasses (8%). In some cases, depending on origin and processing, cane molasses can contain as much as 10.6% protein. There is essentially no measurable fiber (crude, ADF, NDF) in molasses. Low levels of fat may be found in molasses, on the order of 1-2%. The mineral matter in molasses commonly amounts to about 6-10% of the dry matter.
Some early digestion trials with high levels of molasses resulted in low digestibility values due to the laxative effects of feeding impractical levels of molasses (more than 20%). This led to incorrect energy values for molasses early on. More recent metabolism work in ruminants has shown that at normal inclusion rates (4-10%), the organic matter in molasses is almost completely utilized. Equine studies indicate that nonstructural carbohydrates are well utilized by the horse, but there is very little information on the energy value of molasses in the horse.
Molasses is the primary liquid ingredient used in feed mill liquids, but the majority of mills use blends instead of straight cane molasses. These ingredients have become popular because the blends have a lower viscosity and are easier to handle. They require less energy for mixing, and result in less buildup on equipment than straight cane molasses. Lignin sulfonate and whey are used in blends to aid pellet binding. Corn steepwater adds some natural protein to the mix. Brewers and distillers solubles and some of the condensed molasses solubles are derived from fermentation processes and are high in B-vitamins and amino acid precursors.
Mold inhibitors can be included in the molasses blends, although they should be considered to be only part of the mold inhibition program. Flavors, vitamins, phosphorus and trace minerals can be added if desired. Fats are being added to some mill blends more for the effect they have on the appearance and handling characteristics of finished feed than for nutritional benefit. Texturized feeds retain a moist feel and appearance when treated with a molasses blend containing as little as 3% fat. Cold weather handling of texturized feed is dramatically improved by using a fat-containing blend.
Molasses and liquid blends are used in animal feeds for a number of reasons. These include improved palatability, reduction of dust and sorting, better mixing integrity and ease of pelleting, and enhanced moistness. Feeds containing molasses may have an extended shelf life, better winter handling and the ability to carry additional nutrients.