Intake of Bitterweed by Dorper-cross and Rambouillet Sheep Both With and Without Supplementation
Keywords:Onions, Soybean meal, Intake, Toxicity
Bitterweed (Hymenoxys odorata, DC.) toxicity continues to threaten sheep production in west-central Texas. Strategic protein supplementation, by providing higher levels of certain amino acids, may provide some protection from toxicity. For instance, the amino acid L-cysteine, which is found in onions (Allium cepa, L.) and other protein sources, may reduce the likelihood of bitterweed poisoning. The objective of this study was to determine if the supplementation of onions or soybean meal would increase the consumption of bitterweed without increasing the incidence of toxicity. Trial 1 used Dorper-cross rams and Trial 2 used Rambouillet lambs. Sheep were randomly allocated into three treatments. Treatment 1 was supplemented with onions, Treatment 2 was fed a protein supplement containing soybean meal, while Treatment 3 received alfalfa pellets. Sheep in all treatments in both trials received alfalfa pellets (2% body weight), fresh water, and a calcium/phosphorus mineral supplement to meet maintenance requirements. Intake of onions, supplement, alfalfa, and bitterweed were measured daily. Bitterweed intake was higher (P < 0.05) for Dorper-cross sheep fed onions but was similar (P > 0.05) among treatments with Rambouillet wethers. The hypotheses that supplementation with onions or with a supplement containing soybean meal would improve bitterweed intake were not confirmed.