Brewers' grain for horses: benefits and risks

What exactly is brewers' grain?

Brewers' grain is the wet pulp that remains after barley and other grains have been used in the brewing process. It consists largely of the husks and indigestible cell walls of the grain kernel. Fresh brewers' grain contains around 75 to 80 percent moisture, which means it spoils quickly. However, the dry matter contains substantial amounts of crude protein — on average 25 to 30 percent on a dry-matter basis — and a considerable crude fibre content of around 20 percent. At first glance this makes it an interesting product, but the high moisture content also means that you need large quantities of fresh product to deliver any nutritional value at all.

Benefits of brewers' grain as a supplement

• High protein content (approx. 25–30% on a DM basis), useful for growing horses or sport horses with higher protein requirements
• Good palatability: most horses eat it eagerly, which helps with reduced appetite
• Relatively low starch content (< 5% on DM), suitable as an energy source for insulin-resistant horses when fed in small amounts
• Contains B vitamins such as niacin and thiamine, which are beneficial during exercise
• Often available free of charge or very cheaply from local breweries

Disadvantages and risks not to ignore

The disadvantages are at least as important as the benefits. Fresh brewers' grain spoils within one to two days at room temperature, quickly developing moulds and bacteria that are dangerous for your horse. Furthermore, the composition varies between breweries and between batches, meaning you never know exactly what you are feeding without a laboratory analysis.

• Perishability: at temperatures above 20°C fermentation begins within 24 hours
• Variable composition: phosphorus content can be high (up to 0.5% on DM), which disrupts the calcium-to-phosphorus balance
• High protein load: overfeeding leads to increased ammonia production and extra strain on the kidneys
• Not suitable for horses with liver disease or kidney insufficiency
• Freezing as a storage method changes the texture and reduces palatability

How much brewers' grain is a safe amount?

If you decide to feed brewers' grain, keep the quantity limited. A common guideline is a maximum of 1 to 2 kg of fresh product per 100 kg of body weight per day. For an average warmblood of 600 kg, that means a maximum of 6 to 12 kg of fresh brewers' grain per day. Spread this across multiple feedings and only feed it when the product is at most one day old. Store it in the fridge or a cooled space to slow down spoilage. When introducing it, always allow an adjustment period of at least seven days to prevent disruption of the gut flora. Record it in the horse profile in EquiSight so that your supplier, vet and farrier always have a clear view of the full ration.

Which horses is it suitable for?

Brewers' grain fits best in the ration of horses with an increased protein requirement or horses that are hard to keep weight on. Think of:

• Young growing horses (2 to 4 years) that need extra protein for muscle development
• Intensively working sport horses with recovery needs after hard training sessions
• Underweight older horses in whom other protein sources are poorly absorbed
• Horses with a sensitive gut that are prone to high starch levels

Storage and practical tips

• Never collect more than you can feed within two days; ordering in a planned way helps with this
• Store fresh brewers' grain between 2 and 7°C and seal the container tightly
• Always check the smell: sour or spoiled brewers' grain is immediately noticeable
• Have a feed analysis carried out once every six months if you feed it on a regular basis
• Use EquiCoach in EquiSight to check the protein balance of the total ration