At the beginning of hay season, we often have high expectations about the upcoming year, with hopes for both good-quality and abundant forage yields. Unfortunately, as the season progresses, Mother Nature doesn’t always cooperate, and the result is often of lower quality — and sometimes quantity — than anticipated. Between price and availability, buying better-quality hay may not be an option. In most cases, grazing cattle are also consuming lower-quality forages during the fall and winter months. This is where the fascinating function of the rumen comes into play, specifically with the assistance of the fiber-digesting microbes in the rumen, giving beef cattle the ability to survive — and even thrive — on low-quality forage.
The feed value of low-quality hay is improved by digestion and conversion into microbial protein. As a rule of thumb, when the crude protein content of forages is less than 13-15 percent, ruminal protein output is greater than input. Over 60 percent of the protein that ruminant animals use when consuming low-quality hay comes from microbial protein. The microbes are being turned over and passed through the rumen in order to be absorbed by the small intestine. This means the more microbes that are grown and available, the better the ruminant does. In order to produce more microbes, they have to digest more hay.
With bulky, high-fiber, low-quality forages, intake is limited by the amount that can physically fit in the rumen at one time. Increasing the rate of passage of bulky forages increases the amount that can be consumed. A quicker passage rate is advantageous in that more microbes are grown, indicating more nutrients digested — thus improving overall animal performance.
Protein that is ruminally available is a limiting factor in fiber fermentation. Low-quality hay contains high amounts of hard-to-digest fiber, slowing the passage rate. To support the fiber digestion process, protein is needed for the microbes to bind to and begin breaking down the fibers in the rumen so that they can be utilized. Microbes not receiving adequate protein may result in a reduction in the animal’s overall consumption and appetite. Stimulating the rumen microbes through additional available protein unlocks more nutrition from the base forage.
The source of the protein, whether from natural protein sources or non-protein nitrogen (NPN) sources, isn’t much of a concern for the microbes. In fact, research suggests that microbes digest fiber in low-quality hay moderately better with the addition of NPN-containing protein supplements, such as urea, versus all-natural protein supplementation (Farmer et al., 2004; Cooke and Arthington, 2008). This is because 100 percent of NPN is ruminally available, as it is broken down to ammonia in the rumen, while this is not the case for all-natural protein. However, both NPN-containing and all-natural protein supplements improve fiber digestibility, compared to only offering hay alone.
In much the same way we are accustomed to eating three meals a day, research suggests that rumen microbes will be more efficient when small, regular doses of protein are provided, compared to slug feeding less frequently. Studies conducted at Kansas State University reflect this. In one study, reducing supplementation frequency resulted in cows losing more weight during winter (Beaty et al., 1994). In another, daily supplementation was shown to improve forage intake and digestibility, as opposed to twice-weekly supplementation. Additionally, supplementing with limited amounts of a high-protein supplement increased the digestibility and intake of lower-quality forages (Greenwood et al., 1998). These studies suggest that it doesn’t take much protein to enact a positive result.
Low-quality forages can be better digested when protein supplementation is managed to maximize the nutritional value provided to beef cattle. The additional protein available will improve the microbes’ ability to digest low-quality forages and has been measured to increase digestibility up to 10 percent. This allows for greater forage intake and increases the number of microbes available for digestion by the rumen, improving overall utilization and performance. Not only does the beef cow benefit from the additional supplemental protein, but recent research also suggests that the calf’s health and lifelong performance will also be benefited when the dam receives additional supplementation during pregnancy.
When it comes to providing supplemental protein to cattle for the purpose of stimulating microbial forage utilization and intake to improve performance, consider the use of self-fed CRYSTALYX® low moisture blocks. By consuming small, regular doses of ruminally-available protein throughout each day, cattle can achieve optimum fiber utilization and improve rumen turnover. Visit www.crystalyx.com to learn more about how CRYSTALYX fits into your operation.
Beaty, J. L., R. C. Cochran, E. S. Vanzant, J. L. Morrill, R. T. Brandt, D. E. Johnson. 1994. Effect of protein concentration in supplements and frequency of supplementation on the performance of beef cows grazing dormant bluestem range. J. Anim. Sci 72:2475-2486.
Cooke, R. F., J. D. Arthington. 2008. Effects of the protein source added to molasses-based supplements on performance of mature Brahman-crossed cows grazing winter range. Professional Animal Scientist 24:264-268.
Farmer, C. G., R. C. Cochran, T. G. Nagaraja, E. C. Titgemeyer, D. E. Johnson, and T. A. Wickersham. 2004. Ruminal and host adaptations to changes in frequency of protein supplementation. J. Anim. Sci. 82:895-903.
Greenwood, R.H., E.C. Titgemeyer, C.A. Loest, and J.S. Drouillard. 1998. Effects of supplement strategy on intake and digestion of prairie by beef steers and plasma amino acid concentrations. Professional Animal Scientist 14:56-61.