Two research projects under way at the Consortium for Alfalfa Improvement (CAI) may have the potential to significantly decrease the need for purchased protein supplements.
Alfalfa has a high protein content, but rapid rumen degradation of alfalfa protein leads to inefficient use. Through the use of biotechnology, CAI is looking at ways to improve protein-use efficiency in alfalfa. The first research project is tannin alfalfa. Condensed tannins bind with plant proteins, slowing the rate of protein degradation in the rumen. Tannin-containing forages have a slower rate of protein degradation in the rumen and higher rumen-undegradable protein. Alfalfa produces condensed tannins in seed coats, but not in forage tissue. Scientists are working to modify alfalfa to produce tannins in leaves and stems.
Models estimate that alfalfa containing condensed tannins would decrease feeding of protein concentrates and reduce nitrogen losses on dairy farms by 40 percent. Post-harvest protein proteolysis is the focus of the second research project at CAI. Proteolysis of alfalfa protein during the making of silage often results in greater than 50 percent non-protein nitrogen in alfalfa haylage. Red clover, however, has significantly less post-harvest proteolysis during ensiling than alfalfa. Scientists have identified a key enzyme related to this benefit and have expressed this red clover gene in alfalfa. Further metabolic modifications are under way to replicate what is seen with red clover in alfalfa.
Animal feeding trials are still needed to validate in vitro research and to design feeding rations that optimize the value of these novel forages, Mark McCaslin told audience members at the California Alfalfa Symposium.