When it comes to feeding cattle, most people focus on protein, energy, and minerals, but roughages are just as important. They are a crucial component in ensuring a balanced diet for cattle. Without enough roughage, a cow’s digestive system—specifically the rumen—can’t function properly. Roughages help break down food and allow cattle to absorb the nutrients they need to stay healthy and productive. Simply put, they’re the foundation of a well-balanced diet.
The rumen is home to millions of microbes that work to break down complex plant fibers and turn them into usable nutrients. But just like the cattle themselves, these microbes need to be fed. Without enough roughage, the rumen can’t do its job, and the cow’s overall health and productivity can take a hit. Keeping the rumen in good shape means ensuring cattle get enough fiber in their diet.
Not all roughages are created equal, however. Factors like rainfall, plant maturity, and how the forage is managed can all affect its quality. The quality of roughage directly impacts cattle productivity. Low-quality roughage won’t provide the same benefits, which can lead to nutritional gaps. That’s why paying attention to the type and availability of roughages is key to running a successful cattle operation.
What Exactly Are Roughages?
A general definition of roughage is a feed ingredient with a high concentration of slowly degradable fiber. The tradeoff here is that roughages are low in total digestible nutrients because they are high in fiber. Roughages include the vegetative part of plants such as grass, hay, and silage, as well as feeding stuff of low total digestible nutrient content on a dry matter basis.
For a ruminant, the term roughage is any feed ingredient that has what is called ‘long roughage’. Long roughage contains particles that are from 3/8in to 1 1/2in or longer. This means that the feed ingredient has long, coarse fibers that require the animal to re-chew them. The length is significant because the longer fibrous material will need to be re-chewed by the animal. They will remain in the rumen for a more substantial period of time than the shorter material.
The crude fiber content will also determine whether it is roughage. According to the National Research Council, roughage feedstuffs have a minimum crude fiber content of 18%. The maximum total digestible nutrient of the feedstuff should also be 70%.
Why the Rumen Needs Roughages
Cattle may be the ones eating, but it’s actually the microbes inside their rumen that do most of the work. These tiny organisms break down the tough fibers found in plants, turning them into nutrients the cow can use for energy, growth, and milk production. Without enough roughage, the rumen doesn’t function properly, and digestion slows down. This problem can lead to poor nutrient absorption, weight loss, and even health problems in the long run.
Think of roughage as fuel for the microbes—if they don’t get enough, they can’t do their job. Unlike grains, which digest quickly, roughages provide a steady, slow-burning energy source that balances the rumen. When cattle don’t get enough fiber, their digestion can become too acidic, which throws the whole system off. Keeping the rumen healthy isn’t just about feeding the cow; it’s about feeding the microbes that keep everything running smoothly.
Not all roughages are created equal, however. Factors like rainfall, plant maturity, and how the forage is managed can impact its quality. Poor-quality roughage won’t provide the same benefits, leaving cattle without the nutrients they need. That’s why paying attention to the type and availability of roughages is crucial for maintaining a healthy, productive herd.
What do roughages do?
Roughages provide for what is called the “roughage effect.” This effect means that the long, coarse fiber materials rub against the wall of the rumen. By doing this, the muscles in the wall of the rumen expand and contract. This expansion and contraction stir and mixes the food that is in the rumen.
Mixing the material allows the microorganisms to break down more food. The more contact the microorganisms make with the mix, the more completely they can break down the food. Breaking them down more allows more nutrients to be absorbed and used by the animal.
Another benefit of roughage in the diet is that the coarse material has to be regurgitated and chewed again to be metabolized by the microorganisms. This action is commonly known as the animal “chewing its cud.” Along with breaking the material down more, producing more saliva is also beneficial.
A ruminant’s saliva contains buffers that help keep down the rumen’s acidity. An animal’s stomach should have some acidity, but too much can be harmful and even fatal. The fiber-digesting microorganisms in the rumen work best in a neutral to slightly acidic environment. This change is typically a problem with animals fed an all-concentrate diet. The saliva produced during the chewing of roughage helps maintain this optimal pH level in the rumen.
How Much Roughage Do Cattle Need?
The amount of roughage that a ruminant requires will depend on the species. For example, a cow with a larger rumen capacity and a slower process time will require more than a goat with a smaller rumen. It would be best to look at which animals you will be feeding to determine the amount you need.
When it comes to measuring the amount of roughage, there are two ways to go about it: Acid Detergent Fiber or Neutral Detergent Fiber. The Acid Detergent Fiber, or ADF, measures a feed’s cellulose and lignin content. Cellulose is a digestible form of fiber, while lignin is an indigestible form. ADF is a good test for measuring the energy value of forages. In contrast, the NDF is superior in valuing a feed’s roughage effect. This reason is because this test measures the cellulose and hemicellulose, which are poorly digestible materials, and the lignin content of the feed.
The minimal NDF values for cattle have been studied extensively, mainly by the dairy industry. The minimum recommended NDF level here is 25%; below this, the rumen environment can become very volatile and potentially dangerous to the animals’ health. The minimum amount for sheep and goats has yet to be studied. There is a consensus that they can tolerate between 20% and 30%.
There is a difference between a ruminant selecting a diet in the pasture that is 25% NDF and one that you are feeding them. When animals are in a native pasture grazing forage each day, they can manipulate their diet as needed. If they eat something one day that makes their rumen more acidic than the next day, they can search for another forage higher in fiber to balance it out.
Where Do Cattle Get Roughage?
There are three types of roughages that you can feed your animals. Grazed roughages (such as pastures and rangelands), preserved roughages (hay and silage), and crop residues or by-products (straw and hulls) are all available. A producer can feed them in either a fresh, dried, or ensiled state.
If you have to provide roughages in a supplement, it is essential to look deeper than what will be on the feed tag. The crude fiber listed on the feed tag does not represent the ADF and NDF values. It would help if you did more digging to find that out.
The higher the crude fiber, the more roughages that should be in the ration. Animals are on a feedlot-type ration and are fed hay along with it. They should have a feed that is at least 16% crude fiber for cattle and 14% for smaller ruminants. Cottonseed hulls, soybean hulls, and rice hulls are excellent sources.
A Texas label must list the percentage of roughages in the ingredients section. If the roughage level is low and the crude fiber content is high, the fiber is from a source that will probably give little of a roughage effect. I go into a little more detail on what to look for in a previous post, “How to read a feed tag.”
When Roughage Is Hard to Find: Alternative Options
There are sometimes certain conditions that make traditional roughages unavailable. Situations like drought conditions can affect the quality and, in many cases, the quantity of forages that are present. In addition to that, there is the possibility of there not being enough hay for this winter, and producers may have to get creative when supplementing roughages for their cattle. Here are some options that you can consider.
Droughts or poor growing conditions can limit roughage availability, forcing producers to find alternatives. Here are some common roughage substitutes:
- Cottonseed Hulls—Common in the southern U.S., these are high in fiber (44%) but low in protein (3.7%), calcium, and phosphorus. When mixed with grain-based diets, they provide bulk and improve digestion.
- Corn Stalks – The leftover plant material after harvesting corn. While great for wintering non-lactating mature cows, younger heifers and fall-calving cows may need additional energy and protein.
- Soybean & Rice Hulls – Used as fiber sources, though their effectiveness depends on processing and inclusion rates.
When feeding roughage alternatives, be mindful of potential digestive issues. For example, cattle consuming too many downed ears of corn may develop acidosis or founder due to excessive starch intake.
Leave a Reply