Many in the U.S. Midwest have had the luxury of increasing their forage inventory over the last couple of years, and this year continues to be on pace.
Dairy cows have the ability to transform fibrous plant materials and byproducts into high-quality milk, but the rumen microbes require available protein to perform these fiber digestion functions. Protein prices in the last month have continued to rise, and many dairy producers are now looking at ways to reduce their out-of-pocket costs and feed more of their housed forage, which typically represents 50 to 70 percent of the total mixed ration.
The rumen bacteria need ammonia-nitrogen
In order to keep the rumen bacteria working more efficiently, an effective source of ammonia-nitrogen (NH3-N) is needed to enhance fiber-digesting bacteria. Research has shown that the bacteria in the rumen primarily use NH3-N in the ruminal fluid, which is derived from a non-protein nitrogen (NPN) source in the feed.
Possible nitrogen sources in the dairy ration
Feed-grade urea is a common form of NPN used in dairy rations, but because of rapid ammonia release, it leads to nitrogen inefficiency and wasted energy in the dairy cow. Vegetable protein sources, such as soybean meal and canola meal, can also be a source of slow-release nitrogen, but these ingredients can have variability in nutrient composition and take up valuable space in the ration. Many producers are trying to find ways to make the ration more energy dense, especially during periods of heat stress, and feeding less bulky ingredients may help to achieve this goal.
Optigen® is a unique protein alternative that is 256 percent equivalent crude protein from NPN and provides a sustained release of NH3-N in the rumen. This slow release allows for better synchronization with microbial protein needs while dramatically increasing nitrogen efficiency in the dairy cow. The key is to synchronize the ruminal carbohydrate and crude protein degradability in the rumen to increase microbial protein production and energy derived from rumen microbes. A combination of effective protein sources available in the rumen and post-ruminally — matching essential amino acids in the small intestine — has the potential to increase the cow’s efficiency.
How does Optigen work?
Many rations can implement up to 6 ounces of Optigen and allow for some removal of protein from vegetable protein sources, such as soybean meal. For example, 6 ounces of Optigen provides 0.9 pounds of protein, which will replace 1.9 pounds of soybean meal, with space for 1.5 pounds of dry matter of corn silage. This will create space in the ration, which will allow the dairy producer to utilize more forage in the ration and to lower out-of-pocket costs.
In a recent trial done at the University of Wisconsin (Journal of Dairy Science 02, Suppl. 1, 290), 16 commercial dairy farms in Wisconsin incorporated Optigen into the ration and removed soybean meal. The space that it created was filled with corn or corn silage. The results show a 1-pound milk production response. You can find the full article on this research here.