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ES Epigenetics: equine nutrition programs the foal of the future.
November 30, 2023
What does the science say about forage-force feed ratio in horses?
The basis of a healthy horse's ration is not in a bag of concentrate, but in the field. Or in the hay rack. Roughage is the foundation of every horse's diet - and that is not just a tradition, but a scientifically based necessity. Research by Zicarelli et al. (2020)1 emphasizes how crucial the ratio of forage to concentrate is to the digestibility and degradability of the diet in horses. What exactly does that mean, and why should we always use roughage as a starting point?
Forage - such as hay, grass or alfalfa - does not just provide fiber. It plays an active role in the horse's intestinal health and metabolism. Fiber stimulates chewing activity, saliva production, and most importantly: microbial fermentation in the large intestine. Without this fermentation, the horse's energy supply is compromised, especially in horses that do not digest large amounts of starch. And therein lies just the crux: the more concentrate feed, the greater the risk of fermentation problems, such as acidosis and colic.
In the study "Forage: Concentrate Ratio Effects on In Vivo Digestibility and In Vitro Degradability of Horse's Diet," Zicarelli and colleagues examined what happens to the digestibility of the ration when the ratio of forage to concentrate changes. They found that:
Diets with a higher proportion of roughage were significantly better digested;
Fermentation was more efficient at a high-fiber ration;
The transit time through the digestive tract was better regulated, which is crucial for stable nutrient absorption;
The microbial balance in the colon was better maintained at a high forage ratio.
These results underscore a core principle: roughage promotes more efficient, stable digestion, while excessive concentrate feed can actually cause disturbances in the digestive tract.
In addition, inclusion helps regulate the rate at which feed passes through the digestive tract. The fiber content adds volume to the diet, slows the transit time and improves nutrient absorption. It also helps maintain a healthy balance of gut bacteria, preventing problems such as colic and acidosis in the colon.
Many owners turn to concentrate feed to supplement extra energy, protein or vitamins. But without a solid forage base, that supplementation often becomes a burden rather than a solution. Horses evolved as continuous grazers, not meal eaters. So replacing roughage with concentrate feed means not only a change in composition, but also in feeding behavior - with all its consequences.
Forage is not an optional supplement - it is the core of every healthy horse's ration. Both practical experience and scientific literature point in the same direction: the higher the forage ratio, the better the digestion, intestinal health and nutrient utilization. The study by Zicarelli et al. provides valuable confirmation of what we intuitively already knew: Horses are made for fiber. Not for kibble.
Whether you are working with sport horses, austere breeds or rehabilitating animals: start with the basics. Start with the roughage.