Cereal crops belong to the grass family Gramineae and are grown for their edible grain. Botanically that grain is a caryopsis, made up of endosperm, germ, and bran. Cereals carry more energy per hectare than most other crops, which is why they dominate global agriculture, and it is also why they matter so much in livestock feeding.
For farmers, the interesting question is not what cereals do for human health. It is what they contribute to a ruminant ration, and which ones are worth ensiling as whole crop. This guide covers the main cereal crops from that angle.
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Why Cereals Matter in Livestock Feed
Cereals are energy crops. Their value in a ruminant diet lies in starch, which supplies the energy that forage alone often cannot.
This is what makes them so useful alongside grass silage. Grass silage tends to be relatively high in protein but limited in energy, particularly in fermentable carbohydrate. Cereals bring the opposite profile: plenty of starch and energy, comparatively little protein. Fed together, the two balance each other, which is the real reason cereals are used to complement a grass-based diet.
Whole crop cereal silage takes this further, preserving the entire plant, grain and straw together, at a stage where both energy and fiber contribute to the feed.
The Main Cereal Crops for Livestock
| Cereal | Feed Value | Whole Crop Silage Suitability |
|---|---|---|
| Maize | Highest energy density; very high starch; low protein (8 to 9% CP) | Excellent. The benchmark whole crop silage worldwide |
| Wheat | High starch and energy; generally the highest feed value among small-grain cereals | Very good as whole crop, fermented or urea-treated |
| Barley | Good energy; high beta-glucan; widely used in concentrate rations | Good whole crop option, earlier harvest than wheat |
| Oats | More fiber and less starch than wheat or barley; high beta-glucan | Useful where a higher-fiber, safer-fermenting crop is wanted |
| Rice | Grain is high energy; rice straw is a major low-quality roughage in Asia | Grain rarely ensiled; straw used widely as roughage |
Maize
Maize is often called the queen of the cereals, and by production volume it now exceeds both wheat and rice. Beyond direct human consumption, it feeds into ethanol, animal feed, corn syrup, and cornflour.
For livestock, maize is the energy crop. Its very high starch content and consistently high energy value are why maize silage anchors so many dairy rations. The trade-off is protein, at only around 8 to 9% crude protein, so the ration needs balancing with a protein source. Maize is also low in calcium, phosphorus, zinc, magnesium, and copper, so mineral supplementation is standard practice.
Wheat
Wheat is the most widely grown cereal in the world, with many variants including durum, spelt, emmer, Kamut, and einkorn.
As a livestock feed, wheat generally offers the highest value among small-grain cereals, ahead of barley and oats. It is high in starch and carbohydrate, low in fat, and contributes useful levels of phosphorus, magnesium, zinc, iron, and selenium along with B vitamins. As whole crop silage it performs well, and it can be preserved either by fermentation or by urea treatment, which raises the crude protein figure by supplying non-protein nitrogen for the rumen microbes.
Barley
Barley originated in Asia and was among the first cereals brought into cultivation. It is a mainstay of concentrate feeding for cattle, valued for its energy content.
Barley is notably high in beta-glucan, a soluble fiber. One point worth correcting: barley is sometimes described as low in gluten, but it does contain gluten proteins (hordein) and is not suitable for anyone avoiding gluten. The reason it is less used in bread-making is that its gluten does not form the elastic dough structure wheat gluten does, not that it lacks gluten.
For whole crop silage, barley is harvested earlier than wheat and is a solid option where the growing season is shorter.
Oats
Oats are typically processed with the bran and germ retained, which is why oat products are usually whole grain. Oats are naturally high in beta-glucan, and the oat bran in particular is rich in soluble fiber.
In livestock terms, oats carry more fiber and less starch than wheat or barley. That makes them lower in energy density, but it also makes them a more forgiving crop in rations where too much rapidly fermentable starch would risk acidosis. Oats suit situations where a safer, higher-fiber cereal is preferable.
Rice
Rice is the world’s most important staple food crop by population dependence, with more than half the global population relying on it.
In livestock feeding, rice matters less for the grain than for what is left after harvest. Rice straw is one of the most widely used roughages in Asian livestock systems, available in enormous quantities as a by-product. It is low in protein and low in digestibility, so it needs supplementation to be useful, but as a fiber source and a way of extending scarce forage it plays a genuine role, particularly for maintenance feeding of dry cattle.
Cereals as Whole Crop Silage
Because of their consistent yield and reliable energy content, cereals have become one of the most dependable feed crops for intensifying livestock production. Preserved as whole crop silage, the entire plant is ensiled together, capturing both the starch in the grain and the fiber in the stem.
The preservation method changes the composition significantly:
- Fermented whole crop: approximately 35 to 40% dry matter, 7 to 9% crude protein, 15 to 25% starch.
- Urea-treated whole crop: approximately 50 to 65% dry matter, 14 to 20% crude protein, 25 to 30% starch.
The higher protein figure in urea-treated crop comes from the urea itself, which provides non-protein nitrogen that rumen microbes convert into microbial protein. Urea must be applied at the correct rate, as excessive urea is toxic to cattle.
Whichever route you take, the fermentation only holds if the seal does. Silopak has manufactured silage film since 2011 from premium virgin resin, with a service life of 18 months or more under real weather conditions. Standard sizes are 750 mm x 1,500 m, 500 mm x 1,800 m, and 250 mm x 1,800 m at 25 micron thickness.
Frequently Asked Questions about Cereal Crops as Feed
Q: Why are cereals fed alongside grass silage?
Because the two have complementary nutrient profiles. Grass silage is relatively high in protein but limited in fermentable energy. Cereals are the reverse: rich in starch and energy but low in protein. Feeding them together produces a more balanced ration than either could provide alone. The value cereals add is energy, which is what grass-based diets most often lack.
Q: Which cereal makes the best whole crop silage?
Maize is the benchmark, delivering the highest energy density of any common cereal and ensiling readily thanks to its high sugar content and low buffering capacity. Among small-grain cereals, wheat generally offers the highest feed value, followed by barley, with oats lower in energy but higher in fiber. The right choice depends on your climate and growing season: maize needs sufficient heat to reach maturity, while barley suits shorter seasons and is harvested earlier than wheat.
Q: Is barley gluten-free?
No. Barley contains gluten proteins, specifically hordein, and is not safe for anyone avoiding gluten. It is sometimes wrongly described as low in gluten because it is less commonly used for bread, but the reason for that is functional rather than compositional: barley gluten does not form the elastic dough structure that wheat gluten does. The gluten is present regardless.
Q: Is rice straw good cattle feed?
Rice straw is a widely used roughage, particularly across Asia where it is abundant as a harvest by-product, but it is low quality on its own. It is low in protein and low in digestibility, so cattle fed rice straw need protein, mineral, and vitamin supplementation to maintain condition. It is best suited to maintenance feeding of dry cattle rather than growing or lactating animals, and it works better when treated or supplemented rather than fed alone.
Reviewed by Sue Su, Marketing Director of Silopak, on 20 August 2026. This guide has been rewritten to focus on the livestock feed value of cereal crops rather than their human dietary properties.
