Are Spent Grains Good for Farm Animals?

We have taken a look at whether spent grains are good for dogs. Today, we will examine the reasons behind the suitability of spent grains as supplemental feed for other animals including ducks, chickens, pigs, cows, goats and horses.

To sum it up, here is a summary of whether spent grains are good for certain animals:


Are spent grains good for chickens?

Yes. Spent grains are high in amino acids, carbohydrates and fibre, making them a suitable supplement at 10 – 20% of the regular feed.

In general, these are the dietary guidelines for chickens, taken from the publication titled:”Nutrition for the Backyard Flock”, published by Justin Fowler, an assistant professor of Poultry Science from the University of Georgia. 

Most chickens need about 16-22% of protein, 4-6% of fat and 2.5-4% crude fibre in their diet. Spent grains are able to meet these dietary requirements as they contain “approximately 20% protein and 70% fibre”. 

As a farmer, you will find that chickens are able to make some of the ”10 amino acids from other compounds” but they need to derive some others from their food. Thus, this is where spent grains are useful: they are high in amino acids which makes it a good supplementation source. In addition, spent grains have a very high moisture content which helps with their water intake. Spent grains are also a good source of carbohydrates as well as they are made from “cereal grains such as corn, wheat, sorghum, barley, rye, millet, etc.”. Moreover, they provide a good source of fibre as well as they contain cellulose, a non-digestible compound found in plants. Important minerals such as Vitamins and Phosphorous can also be found in spent grains.

Furthermore, studies have shown that chickens which had their regular feed supplemented with 10-20% dried spent grains gained more weight. 

Moreover, interesting insights from the Brazilian Journal of Poultry Science showed that Brewers Spent Grain(BSG) did not affect the egg quality or the chicken’s metabolism adversely.

On the contrary, by substituting 40% of the chicken’s diet with BSG, you will get to save money. 

Nevertheless, it is not advisable to substitute 45% of your chicken’s diet with BSG, as it might result in weight loss.  

If you have access to special enzymes such as beta glucanase, it may result in better outcomes.

Are spent grains good for ducks?

No. While spent grains can help to meet the dietary requirements of duck, they can cause digestive problems.

These are the nutritional requirements for ducks and geese, taken from Metzer Farms, a family-owned farm with many years of expertise in Ducks and Geese:

The table shows that most ducks will need about 14.5-22.5% protein, 4-6% of fat and 4-5 % of crude fibre throughout their lifetime. Spent grains are able to meet these dietary requirements as they contain “approximately 20% protein and 70% fibre”.

Just like chickens, ducks also have complex nutritional needs, and spent grains are very high in vitamin B which will be able to supplement their diet. 

On the contrary, one study found that the addition of BSG(Brewers Spent Grain) in ducks resulted in digestive problems for ducks, especially when their diet was completely substituted with spent grains.

Are spent grains good for cows?

Spent grains can be good for cows. Spent grains can help to meet the cows’ protein requirements. Spent grains can also help in milk production and coat quality. However, spent grains do not have sufficient carbohydrates.

Based on the table below, pregnant cows need about 7.6% to 8.2% of protein daily, as compared to other animals. In terms of protein content, spent grains which  “approximately 20% protein” will be able to meet these needs.

Credit: Iowa Beef Center | Iowa State University | Beef Quality Assurance Sessions

Due to their massive size, they also have higher energy requirements. According to the University of Florida, cattles should consume about “30 to 50 pounds(wet weight)” of spent grain a day and calves should consume about “20 pounds(wet weight)” of spent grain a day–the equivalent of “8 to 13 pounds per day dry weight for cattle” and “2 to 5 pounds dry weight per day for calves”. Optimally, a diet which comprises of 15-30% spent grains was promising when it comes to bulking up cattle.

Spent grains have resulted in increased milk production as well as better coat quality in cows. On the contrary, the carbohydrate content is lacking. 

Moreover, the 70% fibre content in spent grains means that they might be “less digestible than those high in starches and sugars”.

Are spent grains good for pigs?

Spent grains can be good for pigs. Spent grains can help to meet the pigs’ protein requirements at 17 – 25% for weaning pigs and growing pigs respectively.  However, spent grains have too much fibre and could affect pigs’ digestions and cause weight loss.

These are the dietary requirements for pigs:

Life stage/
Nutritional values
PigletGrower PigsBreeder PigsLacatating Sow
Energy / kcal2400 – 26002400 – 25002400 – 25002400 – 2600
Crude Protein (CP) / %1814 – 1616 – 1814 – 16
Fat / %333 – 43 – 4
Crude Fibre / %3 – 44.5 – 53 – 43 – 4
Calcium / %0.450.4 – 0.50.4 – 0.60.4 – 0.6
Phosphorous / %0.30.450.4 – 0.50.3 – 0.5
Credit: values taken from

Hence, on average, pigs need about 14% to 16% protein, 3-5% crude fibre and they have very high energy needs. Spent grains would be suitable for them as they contain “approximately 20% protein”. However, the “70% fibre content” might be a bit excessive as research showed that the crude fibre content affected the pig’s ability to digest food which resulted in weight loss. 

If you are thinking of adding spent grains to your pigs’ diet, it is best to include “17% for pigs which have finished weaning” and ”25% for growing pigs”, due to the economical cost per weight gain.

Are spent grains good for goats?

Spent grains can be good for goats. Spent grains can help to meet the pigs’ protein and fibre requirements. At 5-6% supplementation, spent grains can help with goats’ weight gain.

The table below shows that most goats need about 10% to 14% protein, and spent grains which contain about 20% protein” will be able to meet their needs nicely. As for their fibre intake, they need “a minimum of 12 percent crude fiber in the diet” which makes spent grains suitable for them, as they contain “70% fibre”. 

Credits: Nutritional Feeding Management of Meat Goats | NC State Extension Publications (

In fact, a recent study showed that adding 5-6% of spent grains resulted in a weight gain of 130% and a weight gain of 30% to those goats which were fed cassava foliage and water spinach respectively.

Are spent grains good for horses?

Spent grains might be good for horses. Spent grains can help to meet the horses’ protein and fibre requirements. However, there is no evidence to support or discourage its use to feed horses.

Table taken from: Introduction to Nutrition for Horses (

Horses need anywhere between 7.2% to 13.1% of crude protein a day, as well as 35% to 80% roughage. Hence, spent grains are extremely suitable for them as they contain approximately 20% protein and 70% fibre. Research-wise, there hasn’t been much evidence to support/discourage the use of spent grains. 


Spent grains can be beneficial to the diet of many animals, but too much spent grains in the diet might have an adverse effect on them.

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