|Cassida, Kim -|
|Griggs, Thomas -|
|Min, Doo-Hong -|
|Macadam, Jennifer -|
Submitted to: Crop Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: February 18, 2014
Publication Date: June 23, 2014
Citation: Grabber, J.H., Riday, H., Coblentz, W.K., Cassida, K., Griggs, T., Min, D., Macadam, J. 2014. Yield, morphological characteristics, and chemical composition of European- and Mediterranean-derived birdsfoot trefoil cultivars grown in the colder continental United States. Crop Science. 54: 1893-1901. Interpretive Summary: Birdsfoot trefoil produces high-quality forage that is often superior to alfalfa or other forage crops in terms of supporting liveweight gains, milk yields, and wool growth from cattle and sheep. The superior animal performance observed with the feeding of birdsfoot trefoil is related to the presence of modest amounts of condensed tannin in herbage. Tannins in birdsfoot trefoil also reduce the incidence of intestinal parasites and the production of environmentally malevolent forms of nitrogen and methane from livestock farms. Despite its desirable nutritional, health, and environmental benefits, birdsfoot trefoil is a minor crop in the United States and its production is often limited by slow establishment, poor persistence, and relatively low dry-matter yields compared to alfalfa when grown on well-drained fertile soils. Commonly grown North American varieties of birdsfoot trefoil also have relatively low tannin concentrations compared to European and Mediterranean derived varieties, from which the greatest benefits of tannin have been observed. Therefore, our objective was to evaluate the forage production and forage quality of European or Mediterranean derived varieties of birdsfoot trefoil in order to identify productive higher tannin genotypes that would be suitable for cultivation in the colder regions of the United States. We found the variety Lotar, with intermediate tannin levels, appeared particularly well-suited for the Eastern and Midwestern United States where poor stand longevity hinders birdsfoot trefoil production. A wider array of intermediate to high tannin varieties such as Bokor, AU Dewey, Georgia 1, and Lotar warrant further evaluation in arid Western states under irrigation. While several higher tannin varieties show promise for production in the United States, additional studies are needed to identify optimal tannin levels for ruminant livestock. Further work is also needed to develop management strategies for dealing with environmentally-driven shifts in forage quality so that forages with desired nutritional characteristics can reliably be produced, conserved, and fed to livestock.
Technical Abstract: Commonly grown North American birdsfoot trefoil (BFT, Lotus corniculatus L.) varieties, such as Norcen,0 produce forage with insufficient condensed tannin (CT) concentrations to maximize ruminant livestock performance. Our objective was to identify European and Mediterranean genotypes with higher CT concentrations that would be suitable for production in the colder continental United States. Fourteen BFT genotypes were grown for three years under a conservation cutting management in Michigan, Utah, Wisconsin, and West Virginia. Variances in dry matter yield (DMY), crude protein (CP) and fiber components were mainly associated with growth environment while CT and protease-degradable protein (PDP) were equally influenced by genotype and environment. The ranking of genotypes for most traits, however, remained fairly consistent across environments. Earlier-maturing genotypes had higher CT and lower PDP but not undesirably low CP or high fiber concentrations. The variety Lotar with intermediate CT levels appeared particularly well suited for the Eastern and Midwestern United States where poor stand longevity hinders BFT production. A wider array of intermediate-to-high CT varieties, such as Bokor, AU Dewey, Georgia 1, and Lotar, warrant further evaluation in arid Western states under irrigation. While several higher CT genotypes show promise for production in cold temperate regions, additional studies are needed to identify optimal CT levels for ruminant livestock and to develop management strategies for dealing with environmentally driven shifts in forage quality.