Roughages, often overlooked but crucial, are an essential part of a cow’s diet. While the focus is usually on crude protein, energy, and mineral content, understanding the role of roughages is equally essential. A certain amount of roughage is necessary to keep the rumen functioning and aid in the digestion of protein, energy, and minerals, contributing significantly to cattle’s overall health and production. This knowledge empowers you, the reader, to make informed decisions about your cattle’s nutrition.
The rumen, particularly its microbes, is a key player in cattle production. Its primary function is to break down complex structural fibers found in plants, metabolizing them into the nutrients that the animal needs. To keep this process going, the microbes need to be nourished just like the animals themselves, highlighting the intricate and fascinating nature of cattle nutrition. This intricate process is a testament to the fascinating world of cattle nutrition, sparking your curiosity and interest.
The quality and availability of roughages can directly impact a cattle ranch’s success. Many factors, such as rainfall, stage of maturity, and management, can affect the quality of roughages. As a cattle rancher, understanding and managing these factors is crucial for the success of your operation, making you feel responsible and proactive in your approach to cattle nutrition.
What are roughages?
Roughages are feed ingredients with a high concentration of slowly degradable fiber. Examples of roughages include pasture grass, hay, and straw. While this high fiber content is beneficial, it also means that forages are low in total digestible nutrients. Roughages encompass the vegetative parts of plants as well as feeding stuff with low total digestible nutrient content on a dry matter basis, providing a clear understanding of this essential component of cattle nutrition.
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 contains long, coarse fibers that require the animal to chew them again, aiding in more efficient digestion.
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%.
How Roughages Benefit Cattle
Roughages provide what’s known as the ‘roughage effect’ in cattle, which is essential for good digestion. When cattle eat roughage—those long, coarse fibers—it’s like giving their stomachs a little workout. As these fibers rub against the rumen’s walls, they trigger the rumen muscles to expand and contract. This constant movement stirs and mixes the food inside, helping to break it down, which is the ‘roughage effect. ‘
Why is this mixing so important? It gives the microorganisms in the rumen a better chance to reach and break down more food. The more contact these microbes have with the food, the more completely they can digest it, which means more nutrients are available for the cattle.
Another reason roughages are so beneficial is that they encourage cattle to “chew their cud.” When they bring up this material and chew it again, it does two things: it helps break down the food even more and makes them produce more saliva. Cattle saliva is actually critical because it acts as a natural buffer, helping to control the acidity in their rumen.
While some acidity is normal and necessary, too much of it can harm the microbes and even make the animal sick. Those fiber-digesting microbes work best in a primarily neutral environment or just a little acidic, which is often a problem when cattle are on a low-roughage, high-concentrate diet. So, by keeping plenty of roughage in the diet, cattle stay healthier, digest their food better, and get the most out of their feed.
How much do they 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, say, a goat with a smaller rumen. It would be best to look at which animals you would feed 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 superiority is because this test measures the cellulose, hemicellulose, which is a poorly digestible material, and the lignin content of the feed.
The minimal NDF values of 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 animal’s health. The minimum amount of sheep and goats has yet to be studied. But it is believed that they can tolerate somewhere in the 20%—30% area.
There is a difference between a ruminant selecting a diet in the pasture that is 25% NDF over the one that you are feeding them. When animals in a native range select forage each day, they can manipulate their diet as needed. If they eat something one day that makes their rumen more acidic one day than the next, they can search for another forage higher in fiber to balance it out.
How can animals get roughage?
There are three types of roughages that you can feed your animals. They have grazed roughages (such as pasture and range), Preserved roughages ( hay and silage), and crop residues or by-products ( straw and hulls). A producer can feed them in either a fresh, dried, or ensiled state.
If you have to provide roughages in a supplement, you must look deeper than what is on the feed tag. The crude fiber listed on the feed tag does not represent the ADF and NDF values. You will have to do a little more digging to find that stuff out.
The higher the crude fiber, the more roughages that should be in the ration. Animals that are on a feedlot-type ration and are being fed hay along with it should have feed that is at least 16% crude fiber for cattle and 14% for smaller ruminants. Cottonseed hulls, soybean hulls, and rice hulls are some excellent sources to use.
Here in Texas, the percentage of roughage must be listed on the label in the ingredient 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 more detail on what to look for in a previous post, “How to read a feed tag.”
Some alternatives to roughages
There are sometimes certain conditions that allow traditional roughages to be available only occasionally. Things like the current drought that is going on in most of the country forages need to be improved in quality or just missing altogether. 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 it comes to supplementing roughages for their cattle. Here are some options that you can consider.
Cottonseed hulls are considered an excellent source of fiber for cattle diets. They are used mainly in the southern U.S., where cotton production is most common. They are low in protein (3.7%), calcium, phosphorus, and energy but high in fiber (44%). Cottonseed hulls are very palatable and are used as roughages in areas where forages are very scarce. Usually, they are included in grain mixes to increase the bulk density and crude fiber content.
Corn stalks are another alternative that is used. Stalks are what is left over after the grain has been harvested. It can winter non-lactating mature cows very effectively. However, suppose you will be grazing first-cow heifers and fall-calving cows. In that case, you will need to provide additional energy and protein alternatives. Too many downed ears per acre can lead to excessive grain consumption. This increase can lead to digestive disturbances like acidosis and founder.
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