The effect of feeding ewe lambs a 15% tarbush (Flourensia cernua DC) pellet pre- and post-weaning on the subsequent diet selection of tarbush

The shrub Flourensia cernua (tarbush) has rapidly increased in dominance wi thin Chihuahuan Desert grasslands, and is comparable to alfalfa in nutrient content. Increasing tarbush in livestock diets may improve diet quality, b ut reduces tarbush dominance. We examined dietary selection for tarbush by sheep, and the effect of previous exposure on selection. Thirty-eight ewe l ambs received either tarbush or alfalfa in a sorghum-based pellet 120 days postparturition, after which dietary selection was assessed. Previous expos ure to tarbush deterred lambs from tarbush consumption. Lambs without previ ous exposure maintained greater intakes initially, but this declined with t ime, which corresponds with the onset of tarbush toxicosis. (C) 2000 Academ ic Press.