Thesis (MSc (Paraclinical Sciences)--University of Pretoria, 2006. / Includes bibliographical references.

Thesis (Ph. D.)--Swedish University of Agricultural Sciences, 2000. / Errata tipped in. Includes bibliographical references.

The following work was conducted at the Agricultural Experimental Center under the title of : Apparent digestibility in llamas feed with stipa ichu (Peruvian feather grass) treated with urea and molasses, for which 3 assays were performed in reference to the study : 1) percentage of assimilation of the treated and non- treated grass, 2) apparent digestibility of fiber and protein after and before feeding, and 3) determine the adequate levels of urea and molasses for the chemical treatment of the grass (Stipa ichu). For the first assay, the greater consumption was obtained at the level of 3 (3% of urea) reporting a consumption index of 1895.67 gr, the least amount of consumption was found to be 0(0% of urea) reporting a consumption index of 1450.93 gr. The administered food prepared with (grass + urea + molasses) at the different levels of 3%, 2%, and 4%, we had a variability coefficient of 12.56%. The highest index of water consumption was obtain with the 0% untreated grass with a volume of 882.12 ml, and the least was found at level 2 (2%) with a volume of 335.71 ml, with an average of 424.27 ml/day with a variability coefficient of 77.02%. The amount of excreted feces were found to be produced in a greater amount when fed with grass with at 3 (3%) type of treatment with a total of 1059.8 gr, and the least amount of excretions was shown when fed with treatment 4 (4%) with 60.8 gr, with an average of 826.51 gr/day with a variability of 22.35%. For the second assay, we found that the apparent digestibility of fiber at the 3 different levels of treatment , the greater percentage of fiber assimilated by the organism was with those that received food at level 3 (3%) with a 76.78%, and the least with a 0 (0%) in relationship to the other treatments. The greater percentage of protein was obtained at level 4 (4%) with 49.48%, decreasing the protein level 2%, 3%, and 0%, we can say that the difference is due to the different levels of urea found in the treatments. For the third assay, the most consumed was level 3 (3%) of urea with an average of 94.83%, the second one is level 2 (2%) with an average of 85.71%, followed by level 4(4%) with 74.59%. We concluded that 2.6% of urea is acceptable for the supplementation of stipa ichu (Bolivian feather grass) for the feeding of llamas.

Leafy spurge (Euphorbia esula L.) is a costly noxious weed to manage in the Northern Great Plains; it invades rangelands and displaces native and desirable vegetation. Our first objective was to test the recommended full rate and half rate of selected herbicides applied in September following a spring burn on a leafy spurge invaded plant community. Our second objective was to determine if raffinate (desugared beet molasses) applied to leafy spurge invaded rangeland would attract cattle to consume leafy spurge. The aminocyclopyrachlor with chlorosulfuron treatment had the best leafy spurge control at the full rate, with stem density reductions of 95 percent for both sites nine and twelve months after treatment. The salt block treatment had the best success at reducing leafy spurge stem density. Herbicides can be the most common and effective type of management; however, manipulating livestock to graze noxious weeds converts a weed into a useable forage.