What’s the Deal with Feeding Grain to Livestock?

Susan Kerr

WSU NW Regional Livestock and Dairy Extension Specialist

Livestock do not have a requirement for grain. They require a certain amount and balance of nutrients, and some of these nutrients can be provided by grain. Or not. Should you feed grain? Maybe. It all depends on your goals.Definition of Grass Fed: “Grass and forage shall be the feed source consumed for the lifetime of the ruminant animal, with the exception of milk consumed prior to weaning. The diet shall be derived solely from forage consisting of grass (annual and perennial), forbs (e.g., legumes, Brassica), browse, or cereal grain crops in the vegetative (pre-grain) state. Animals cannot be fed grain or grain byproducts and must have continuous access to pasture during the growing season. Hay, haylage, baleage, silage, crop residue without grain, and other roughage sources may also be included as acceptable feed sources. Routine mineral and vitamin supplementation may also be included in the feeding regimen.”—USDA Ag Marketing Service


For various reasons, you may have decided to raise and/or finish livestock on grass (see the USDA’s definition of grass-fed in text box). It is possible to meet livestock’s nutritional needs with very well-managed pasture and/or high-quality hay, particularly adult animals just maintaining themselves. However, it is challenging to meet the increased nutritional requirements of some classes of animals—such as those that are lactating, growing, extremely active, heavily pregnant, or ill—with grass alone. Legume forages generally provide more protein and energy than grasses, so grass-legume mixes meet grazing livestock’s nutritional needs better. WARNING: fresh legumes can cause fatal bloating in ruminants (especially cattle) if certain precautions are not taken.


How Much Forage is Needed?

Grass-fed animals on pasture need access to a LOT of fresh forage. The grass in Photo 1 will not support any rate of growth or production level in any species of livestock. Photo 2 shows timothy grass at a more appropriate height for grazing. Many producers who want to raise grass-fed animals simply don’t have enough pasture to accomplish this for more than a few animals a year, unless hay is fed. How much pasture is needed for pasture-based production? Here’s an example:


A 660# Angus steer expected to finish and be ready for slaughter at 1173# with a small amount of marbling will consume about 2.5% of his body weight in dry matter every day. Fresh forage is about 20% dry matter and 80% water. Let’s do the math: 660# x 2.5% = 17.2 # dry matter intake daily17.2# dry matter with 20% dry matter = 86# fresh forage intake needed daily 

Do you have 86# of forage per animal per day throughout the finishing period? If not, you’ll need to lease more pasture, purchase hay, or feed grain. The amount of forage also needs to increase as an animal’s weight increases. Optimally, a forage analysis should be conducted on fresh forage or hay to quantify its nutritional composition so supplements can be provided if needed for a balanced diet that will promote optimal health and growth.



Photo 1. Grass-fed is fine, but where’s the grass? Sufficient grass quality and quantity are needed to support grass-fed animal health and growth. (Photo by Susan Kerr).



Photo 2. Timothy field ready for re-grazing. Plants are at least 9” tall and can be grazed down to 3-4” without harm to plants. The sugars in the remaining stem will be available to fuel re-growth of leaves for the next harvest via grazing or haying, or ensure a healthy crop next spring. (Photo by Susan Kerr).









Pros and Cons of Grass Fed

Finishing meat animals on grass is an art and a science. Animals gain more slowly and take longer to reach slaughter weight, which can affect cash flow and product availability. They need careful monitoring to ensure daily gain of at least 1.5#/day (beef) for optimal meat quality. Animals are more active so nutritional requirements are increased and feed efficiency is decreased. On the plus side, production costs might be reduced. Also, the market for grass-fed meat is currently very strong and supply does not meet demand, so grass-fed producers can usually command above-retail prices through direct marketing to consumers. Despite the lack of consistent and irrefutable evidence of the health benefits of grass-fed meat (see references 3 through 7), some red meat consumers perceive health benefits and are willing to pay higher prices for grass-fed products. High-quality, tender, and flavorful products can be produced through grass fed systems, but care must be taken to ensure animals reach full bloom and are truly finished, among other concerns.


“At this point, there is no scientific evidence to support the claims that ground beef from grass-fed cattle is a healthier alternative to ground beef from conventionally raised, grain-fed cattle.” --S.B. Smith, meat scientist, Texas A&M University.


Why Feed Grain?

Grains are used as concentrated sources of nutrients, typically energy. If a ration lacks sufficient protein to meet animals’ needs, high-protein supplements such as peas, alfalfa pellets, brewers’ grains, soybeans or other oilseed meal, etc. can be included to balance the ration. If the ration is low in energy, though, grains such as corn, barley, oats, etc. are often included to boost the level of this essential nutrient.


Remember the Bottom Line

Before adding grain to a diet for more energy, always compare the financial cost of adding grain vs. meeting nutritional needs with just feeding more or better hay. Forage is usually the least expensive way to deliver nutrients, but not always. Also, sometimes an animal’s maximum physical capacity for forage intake and digestion is reached before its nutritional requirements are met, so a more energy-dense feed such as grain is needed.


If you’ve determined you must add grain to a ration to meet an animal’s requirements, compare grains on a cost-per-pound-of-nutrient basis. This will equalize seeming price disparities between grains with varying nutritional composition. For example, as shown in Table 1, the Total Digestible Nutrient (TDN) percentage (a measure of energy content) of oats is much less than that of corn, so oats would have to be much less expensive per ton to compare favorably with corn as an energy source.






























Table 1. Comparison of some nutrient levels in various whole grains. Columns 3-6 are percent of dry matter. Numbers are averages only and chemical analysis of specific grain lots should be performed for accurate ration balancing. Source: National Academies Press and others.


If You Choose to Feed Grain…

Grains can be processed from whole into cracked, rolled, steam flaked, etc. Processing increases digestibility by 5 to 10% and increases costs. It is usually unnecessary for sheep and goats because they grind their feed quite thoroughly; however, processing benefits horses, cattle, and pigs. A caveat: Figure 1 shows that as feeds are processed more finely, speed of digestion increases. Finely-ground grains can cause acidosis, a drop in intestinal pH and death of beneficial microbes due to increased rate of fermentation secondary to increased surface area of grain. Severe livestock illness and even fatal consequences can result.



Figure 1. Acidosis risk associated with various types of grains and degree of processing.


Feeding Grain Safely

• Make all rations changes gradually

• When adding grain meals to a ration, divide the day’s allotment into multiple meals a day—the less at one time the better

• If hand feeding, feed forage before grain. If on pasture, feed grain after foraging time. Forages help prevent the pH drop that follows a grain meal

• Keep grains in safe, clean, dry, and vermin-free storage and protect from accidental access by livestock

• Monitor grains for evidence of mold, toxins, contaminants, etc.; do not feed any of this dangerous grain

• If hand-fed animals bolt their grain, they are at risk of choke from grain impaction. Large rocks can be placed in the feed manger or bucket of such individuals. This slows down the rate of grain intake

• As shown in Table 1, cereal grains are relatively low in calcium and high in phosphorus, so supplemental calcium may be needed to keep the ration’s calcium-to-phosphorus ration at the recommended >2:1. This is especially important for growing and lactating animals and in species prone to urinary stones (sheep and goats, especially wethers).


Strategic Uses of Grain

Including grain in livestock diets can help control feed costs when hay prices rise. A low-quality and less expensive forage such as local grass hay or straw can be the fiber foundation of a diet, with concentrates included to meet protein, energy, vitamin, and mineral requirements. Commercial grain products often have added vitamins, minerals, and a molasses binder, which increases palatability and makes feeding minerals easier. Producers can order customized supplements from feed mills but should work with a nutritionist to create the product they need.


Creep feed is a good way to help youngstock grow faster and deliver certain medications and minerals if needed. Creep feeds are high in nutrients and are usually expensive, so adult animals need to be physically excluded from the creep feeding site. Supplementing growing animals with creep feed may or may not pay for itself in all situations, but is something to consider in cold weather, for high-value animals, early marketing, rate-of-gain contests, show animals, and if nutrient intake from milk is insufficient.


Pigs and Poultry on Grass

It is critical to note that grass, no matter how fresh, immature, and nutritious, cannot meet the nutritional needs of growing pigs and poultry. As monogastrics, these species are unable to fully utilize the nutritional content contained in the structural carbohydrates of forages. Growing animals have high protein requirements, a nutrient in which grasses are often deficient. Adult pigs at maintenance can meet some of their nutritional requirements on pasture, but even these will need supplements for a complete and balanced diet. Pigs and poultry are not ruminants.


Full Circle: Learning from Bison

Some “anti-grain” voices cry “This country’s thundering herds of bison in the mid-west didn’t eat grain!” That is true. However, if native grasses did not provide these free-roaming ruminants with the quality and quantity of nutrients they needed, bison reflected these deficiencies in poor reproductive rates, low milk production, high calf mortality, slow growth, increased susceptibility to disease and predators, and so on. Few livestock producers are willing to let the health and productivity of the animals in their care rely on the whims of weather and other forage production variables. To maximize the genetic potential and growth performance of improved domesticated species, most of today’s livestock producers like to include grain in their feedstuff armamentarium. Some breeders are developing lines of animals that perform well in grass-fed systems; such breeding programs should enable more grass-fed producers to finish out livestock more quickly and with better carcass traits in the future.


Grains are not inherently good or bad. They are simply a tool livestock producers can choose to use when needed to help animals grow, produce, maintain themselves, and stay healthy. Economic advantages to feeding grain can be realized through faster rates of gain and access to markets that prefer grain-fed products, but grass-fed marketing options may be just as lucrative. As always, pay attention to sources of information, triple-check “facts,” and base decisions on credible research results and your livestock production goals.

When Forage Is Not Enough: Lessons from a Meat Goat A true story: an inexperience meat goat producer had a weaned Boer goat kid that weighed 40# lbs. and 60 days later weighed 41 lbs. The average daily gain was 0.017 lbs. per day. At this rate, the goat would have been almost 13 years old when it finished at 120 lbs. What was the problem? The kid was turned out on dryland range and not supplemented. He had to work very, very hard for that one pound of gain. Due to carcass characteristics that change with age, it is impossible to overcome the detrimental effects on meat quality that result from such a growth delay. This goat was unable to meet his genetic potential for growth and meat quality due to an inadequate forage-only diet. 

References and Selected Resources

1. Stock, R. A., and R. A. Britton. 1993. "Acidosis in feedlot cattle." Scientific update on Rumensin/Tylan for the professional feedlot consultant. Elanco Animal Health, Indianapolis, IN. p. B 1 (1993).

2. www.ext.colostate.edu/pubs/livestk/01615.html. Nutritional requirements and feed composition.

3. www.sheepandgoat.com/#!truthgrain/cjjy. Feeding grain to sheep and goats.

4. http://animalscience.tamu.edu/2013/12/07/ground-beef-from-grass-fed-and-grain-fed-cattle-does-it-matter./ Human health benefits of grass-fed vs. grain-fed beef.

5. http://extension.psu.edu/animals/beef/grass-fed-beef/articles/telling-the-grass-fed-beef-story. Grass-fed vs. grain fed claims.

6. https://extension.usu.edu/files/publications/publication/AG_Beef_2011-01.pdf Grass Fed vs. Conventionally Fed Beef.

7. www.csuchico.edu/grassfedbeef/research/Review%20Grassfed%20Beef%202010.pdf. A review of fatty acid profiles and antioxidant content in grass-fed and grain-fed beef.