Tips for improving forage digestion in beef cattle
In the cow-calf production system, forage is the primary source of feed and plays a significant role in cattle health and productivity; however, forage digestion is limited by the interaction of different fiber components. Nevertheless, fiber contributes a major source of energy, regulates feed intake, and stimulates chewing, salivation and gut motility (Adesogan et al., 2019). Fiber is digested by rumen microbial populations that are responsible for breaking down digestible fiber, hemicellulose and cellulose, then converting those to energy. However, fiber digestion can be limited by the associations between hemicellulose, cellulose, lignin, and other acids in the plant cell wall.
Additionally, forage type, quality and length can have an impact on fiber digestibility, depending on the amounts of cellulose, hemicellulose and lignin the plant contains. Different approaches can be taken to ensure that cattle are digesting the maximum amount of forage.
Providing a balanced diet
Understanding how forage matures is fundamental in making sure a balanced diet is provided year-round. Young, growing forages will typically provide enough protein and energy and require no protein supplementation. As the forage matures, however, its nutrient content and digestibility decline. This decline is associated with an increase in lignin, resulting in less digestible fiber available for use. Reduced fiber digestion will reduce feed intake, rumen microbial function and overall digestion, making less energy available to the cow. However, providing the correct amount of protein, an essential nutrient, will help to optimize rumen microbial function and increase fiber digestion.
Trace mineral sources have also been demonstrated to have an impact on rumen fermentation. Research has revealed that steers with sulfate sources of trace minerals added to their diets had reduced fiber digestibility and overall dry matter digestibility from their diets when compared to steers supplemented with complexed trace minerals (Guimaraes et al., 2022). Alltech’s Bioplex® offers proteinate trace minerals, a specific type of complexed trace minerals, as an optimal alternative to sulfate-sourced trace minerals. In a study comparing these two types of minerals, the authors suggested that rumen bacteria that ferment carbohydrates use more Bioplex trace minerals, at a faster rate, than sulfate-sourced trace minerals, thus maximizing rumen fermentation (Pino and Heinrichs, 2016).
The process of forage digestion starts with cattle chewing and breaking down forage. The act of chewing reduces forage particle size, resulting in a greater inside surface area for rumen microbes to attach to, which is important because the bacteria’s digestion process works from the inside out. Cattle further reduce forage particle size by chewing their cud, a process of regurgitating a bolus of forage and chewing it again; however, there is an energy cost associated with the process.
Chopping forage prior to feeding it is a cost-effective way for producers to increase fiber digestion. This process decreases the amount of time cattle spend chewing their cud, thus helping to increase feed intake. Producers need to be aware, though, that hay chopped too finely may have negative effects on rumen health. Therefore, the recommended chop length is no smaller than ½ inch. In situations where hay is fed on the ground, a longer chop length can be used to minimize waste.
Natural feed additives
Natural feed additives, including live yeast cultures and yeast fermentation products, have been around for several years and have been shown to have positive effects on animal digestion, health and performance. Yea-Sacc® 1026 is a live yeast culture by Alltech that has demonstrated the ability to stimulate the growth of rumen bacteria, resulting in a positive effect on feed intake, nutrient availability and rumen pH. More specifically, Yea-Sacc 1026 stimulates the growth of fiber-digesting bacteria. This leads to a more efficient breakdown of fiber in the rumen and an increase in the amount of nutrients available to the cow.
Fibrolytic enzymes are other feed additives that have shown positive results at improving fiber digestion. Based on fermentation extracts from fungal or bacterial sources, these enzymes provide high activity that breaks down cellulose and hemicellulose more efficiently (Mendoza et al., 2014). Fibrozyme®, a fibrolytic enzyme by Alltech, has been shown to support better fiber digestion and feed efficiency by promoting early digestion rates of fiber.
A producer can improve fiber digestion in many ways. It is important to investigate which method will work best for a particular operation to maximize animal health, productivity and profitability.
References are available upon request.