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ARS Home » Pacific West Area » Dubois, Idaho » Range Sheep Production Efficiency Research » Research » Publications at this Location » Publication #111151
Title: GENETIC AND PHENOTYPIC PARAMETERS FOR DIETARY SELECTION OF MOUNTAIN (ARTEMISIA TRIDENTATA SSP. VASEYANA) IN RAMBOUILLET SHEEP

Author
item Snowder, Gary
item WALKER, JOHN - TEXAS A&M UNIV.
item LAUNCHBAUGH, KAREN - UNIVERSITY OF IDAHO
item Van Vleck, Lloyd

Submitted to: Journal of Animal Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 9/6/2000
Publication Date: 3/1/2001
Citation: Snowder, G.D., Walker, J.W., Launchbaugh, K.L., Van Vleck, L.D. 2001. Genetic and phenotypic parameters for dietary selection of mountain big sagebrush (Artemisia tridentate Nutt. Spp. vase yana [Rydb] bettle) in Rambouillet sheep. Journal of Animal Science 79:486-492.

Interpretive Summary: The objective of this study was to determine if genetic mechanisms influence diet selection in sheep grazing western range, particularly for sagebrush, a common woody brush. Diet preferences in a very large number of Rambouillet sheep was determined by modern technology using near- infrared spectroscopy. The heritability or genetic influence on diet selection was estimated at .25 to .30; therefore, heritability has a moderate effect on diet selection for sagebrush. This is encouraging and suggests that ruminants can be selected for diet preferences. These results further infer that range improvement and utilization, management of noxious plants, and animal performance may be improved by selecting animals for their diet preferences.

Technical Abstract: The heritability of diet selection for big sagebrush (Artemisia tridentata ssp. vaseyana Nutt.) by grazing sheep was estimated from fecal samples from a total of 549 Rambouillet ewes. Fecal samples were collected in September and October during 1996 and 1997 from free-grazing ewes on intermountain sagebrush-bunchgrass rangelands at the U.S. Sheep Experiment Station in Idaho. The total number of fecal samples was 1,949. Fecal samples were evaluated for composition of big sagebrush by near-infrared spectroscopy. Big sagebrush consumption was less in September than October (21.6 vs 31.7%, respectively). Single trait and bivariate derivative-free REML analyses were performed to genetically compare big sagebrush consumption between September and October. Heritability estimates were similar between September and October sampling (.25 and .28, respectively). The genetic correlation between September and October diet preference was high rG = .91), inferring that there is strong genetic similarity between September and October measurements. These results contribute to a greater understanding of dietary preferences in free grazing sheep, and suggest opportunities to improve production efficiency and forage management through selection for dietary preferences.