Location: Dairy Forage ResearchTitle: Protein and dry matter degradability of European- and Mediterranean-derived birdsfoot trefoil cultivars grown in the colder continental USA Author
|Griggs, T - West Virginia University|
|Min, D - Kansas State University|
|Macadam, J - Utah State University|
|Cassida, K - Michigan State University|
Submitted to: Crop Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 12/22/2014
Publication Date: 5/4/2015
Publication URL: http://handle.nal.usda.gov/10113/62844
Citation: Grabber, J.H., Coblentz, W.K., Riday, H., Griggs, T.C., Min, D.H., MacAdam, J.W., Cassida, K.A. 2015. Protein and dry matter degradability of European- and Mediterranean-derived birdsfoot trefoil cultivars grown in the colder continental USA. Crop Science. 55:1356-1364.
Interpretive Summary: Birdsfoot trefoil produces high quality forage that is often superior to alfalfa and other forage crops in terms of supporting live weight gains, milk yields, and wool growth from cattle and sheep. Superior animal performance observed with feeding of birdsfoot trefoil is related to the presence of modest amounts of condensed tannin (CT) in its herbage. Birdsfoot trefoil is, however, a minor crop in the United States and its production is often limited by poor persistence and relatively low dry matter yields compared to alfalfa. Commonly grown North American cultivars of birdsfoot trefoil such as Norcen also have relatively low CT concentrations compared to European and Mediterranean derived cultivars from which the greatest benefits of tannin have been observed. Because of the limitations of current cultivars, we conducted a multi-year field study in four states in order to identify European- and Mediterranean-derived birdsfoot trefoil cultivars with higher CT concentrations that would be suitable for forage production in the colder continental USA. In our first publication, we reported the dry matter yield, morphological characteristics, and chemical composition of herbage produced by 13 foreign-derived birdsfoot trefoil cultivars relative to Norcen birdsfoot trefoil and ‘Spredor 4’ alfalfa when harvested under a two- or three-cut management. In the current paper, we assessed the digestibility of protein and dry matter in these birdsfoot trefoil cultivars, examined how protein and dry matter digestibility was related to the concentrations of CT and other chemical constituents in birdsfoot trefoil herbage, and made recommendations and highlighted further research needs for developing improved birdsfoot trefoil cultivars for use in the colder continental USA.
Technical Abstract: Recent work suggests several European- and Mediterranean-derived cultivars of birdsfoot trefoil (BFT, Lotus corniculatus L.) are well adapted to the colder continental USA and produce forage with greater condensed tannin (CT) concentrations, but comparable neutral detergent fiber (NDF) and slightly lower crude protein (CP) concentrations than the commonly grown cultivar Norcen. In the current study, thirteen of these foreign-derived cultivars and Norcen were harvested under two- or three-cut management during 2006 in MI, UT, WI, and WV and analyzed in vitro for rumen degradable and undegradable protein on a CP and dry matter (DM) basis (RDPCP, RDPDM, and RUPDM) and for rumen degradable and true degradable DM (RDDM and TDDM). Foreign-derived cultivars usually produced forage with greater RUPDM and lower RDPCP, RDPDM, RDDM, and TDDM than Norcen. The low NDF cultivar Bokor uniquely combined high CT and RUPDM with high TDDM. The high yielding, persistent cultivar Lotar also produced herbage with moderate to high CT, RUPDM and TDDM. Concentrations of CT and CP both influenced RDPCP, RDPDM and RDDM, while CT affected RUPDM, and NDF influenced TDDM; relationships were greatly influenced by growth environment. Reductions in RDPDM exceeded gains in RUPDM as CT increased, thus feeding of high CT cultivars should mainly curb urinary N excretion from excess RDPDM rather than boost amino acid supply from potentially digestible RUPDM. Additional work is needed to improve the nutritional consistency of harvested BFT across environments and to develop high yielding cultivars with optimal RDPDM and RUPDM, and high TDDM for maximizing livestock performance.