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United States Department of Agriculture

Agricultural Research Service

Title: Research Observation: Cattle Preference for Lambert Locoweed over White Locoweed

Authors
item Ralphs, Michael
item Greathouse, Gary - COLORADO STATE UNIVERSTIY
item Knight, Tony - COLORADO STATE UNIVERSITY
item James, Lynn

Submitted to: Journal of Range Management
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: July 8, 2000
Publication Date: January 1, 2001
Citation: Ralphs, M.H., Greathouse, G., Knight, T., James, L.F. 2001. Cattle preference for lambert locoweed over white locoweed. Journal of Range Management.

Interpretive Summary: White and Lambert locoweed grow together on the foothills of the Rocky Mountains from southeastern Wyoming to northeastern New Mexico. Lambert locoweed matures later and flowers about 3-4 weeks later than white locoweed. Previous research on cattle grazing white locoweed on short- grass prairies suggest cattle will cease grazing white locoweed as it matures and warm-season grasses begin rapid growth in early June. Since Lambert locoweed matures later, cattle may continue to graze it after white locoweed matures and increases the critical period of poisoning when livestock graze areas infested by both species. Lambert locoweed was preferred over white locoweed in the season-long grazing trial in 1998, and in each of the r intensive grazing trials in 1999. The cows consumed white locoweed as availability of Lambert locoweed declined in 1998, but little white locoweed was consumed in the 4 intensive grazing trials in 1999. The etoxic locoweed alkaloid swainsonine was not detected in Lambert locoweed i this study.

Technical Abstract: White (Oxytropis sericea Nutt. In T. & G.) and Lambert (Oxytropis Lambertii var. biglovii Pursh) locoweed grow together on the foothills of the Rocky Mountains from southeastern Wyoming to northeastern New Mexico. Lambert locoweed matures later and flowers about 3-4 weeks later than white locoweed, thus potentially increasing the critical period of poisoning when nlivestock graze areas infested by both species. The objective of this study was to evaluate the relative palatability of these two species as they mature through their phenological growth stages. In 1998, 15 Hereford cows grazed a 32 ha pasture infested with both species from the time white locoweed flowered in mid June until both species were mature and senesced in August. In 1999, 4 cows were placed in a 5 ha pasture infested with both species for 4 days in each of the following periods: (1) flower stage of white locoweed, (2) flower stage of Lambert locoweed, (3) immature pod stage of Lambert locoweed, (4) mature pod stage of both species. Diets were estimated by bite-count. Lambert locoweed was preferred over white locoweed in the season-long grazing trial in 1998, and in each of the 4 intensive grazing trials in 1999. The cows consumed white locoweed as availability of Lambert locoweed declined in 1998, but little white locoweed was consumed in the 4 intensive grazing trials in 1999. The toxic locoweed alkaloid swainsonine was not detected in Lambert locoweed in this study. Some Lambert locoweed populations do contain swainsonine, and observations suggest that cattle grazing Lambert locoweed have become poisoned, yet with different symptoms.

Last Modified: 7/31/2014
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