Feeding small amounts of bran on an infrequent basis will not cause major mineral imbalances, but as we all seem to appreciate that new feeds should be introduced gradually, why make an exception for bran? In fact, some researchers believe that this could have a negative effect on the hindgut microbes responsible for fibre digestion. Research has also shown than bran does not act as laxative, regardless of whether it is fed wet or dry. Instead, any ‘laxative effect’ is likely to be the caused by the mild disturbance or irritation resulting from the sudden introduction of a new feed.
For people, fibre (including bran) can increase the bulk of stools by helping them to retain more water and consequently make them easier to pass. However, fibre requirements in horses are much higher and whilst bran does contain fibre, the content is much lower (10-12%) than in sugar beet (20% - unmolassed) and hay. In fact even as a source of water, the benefits of a bran mash may be questionable when you consider the small amount of water actually consumed in comparison to the horse’s daily requirements.
Many of us reach for a mug of hot chocolate or soup in colder weather and whilst a feeding a warm bran mash may be a comforting thought, it will not continue to keep your horse warm after he has eaten it. As a result of fermentation in the large intestine, the digestion of hay and other forages produces heat (regardless of the weather) and therefore nutritionally, feeding additional hay is more likely to help keep your horse warm.
Whilst feeding bran will not always result in serious harm, particularly if properly balanced and fed in small amounts to adult horses; reported benefits are based largely on tradition. Consider whether adding bran to your horse’s diet is really necessary as unfortunately, it is one feeding tradition that may potentially cause more harm than good.