Are live strains of the yeast, Saccharomyces cerevisiae, are used in animal nutrition to enhance fiber digestion in both ruminants and non-ruminants. These strains have the ability to metabolize nutrients in an anaerobic environment and promote the growth of beneficial bacteria, including those that can utilize lactic acid.
Beneficial effects have also been seen in mares during gestation with regard to milk quantity and quality, resulting in faster growing foals. As the fetus grows in size during the 3rd trimester of gestation, the room available for food in the mare is significantly reduced, which can result in loss of body condition. Improving nutrient digestibility at this stage is important to minimize loss of condition of the mare.
Yeast also increases efficiency of energy production in animals like cattle and horses that ferment fiber via microbial breakdown. Although the exact mechanism remains elusive, one theory is that the yeast feeds the beneficial bacteria that convert fiber into energy in the cow’s rumen and the horse’s hindgut.
Although all horses can benefit from more efficient energy production, this is of extra importance to senior horses, whose ability to break down fiber eventually decreases, sometimes resulting in declining body condition.