Thesis (M.Inst. Agrar.(Animal Production))-University of Pretoria, 2006. / Includes bibliographical references. Available on the Internet via the World Wide Web.

The objective of the study was to evaluate the dry matter production, intake and the nutritive value of Indigofera species. The dry matter yield, leaf:stem ratio, chemical composition, voluntary intake and digestibility of Indigofera species were determined. The leaves as well as the leaves and stems (<3mm) of five different Indigofera species (I. amorphoides, I. cryptantha, I. costata, I. viciodes and I. arrecta) were harvested. There was a greater total dry matter yield during autumn 2004 from I. amorphoides. However, no significant differences were obtained between all the species over the seasons. There were significant differences between all the species in autumn with a lower proportion of leaves than in spring, except for I. arrecta, which had the same leaf: stem ratio in both seasons. During spring, I. amorphoides and I. cryptantha generally had a higher proportion of leaf material than other species. There were significant differences between all the species for the leaves as well as leaves and stems (<3mm) as a result of advancing maturity and decrease in leaf: stem ratio with respect to ash, crude protein (CP), neutral detergent fibre (NDF) concentration and in vitro digestibility of organic matter (IVDOM). Despite a decrease in leaf: stem ratio, all the species had an adequate CP concentration for optimal animal production. All the minerals (macro and micro elements) found in this study, in both years, will satisfy the nutrient requirements of sheep. However, all mineral elements in this study appeared to decrease with ageing of the plants and decline in leaf: stem ratio, except for Mn concentration, which increased with ageing of the plants. Lucerne, which was used during the intake study as a control, had a significantly higher organic matter intake (OMI) and digestible organic matter intake (DOMI) than Indigofera species and Leucaena leucocephala. However, there were no significant differences between Indigofera species and L. leucocephala. Intake levels in this study for L. leucocephala and Indigofera species would be insufficient for maintenance requirements of grazing sheep. The relatively lower IVDOM for Indigofera species and L. leucocephala compared to that of lucerne was because of a higher NDF concentration. Despite the relatively high NDF concentration, Indigofera species appeared to be a good fodder because of its high CP and Ca, P, Mg, Cu, Zn and Mn concentrations. / Dissertation (M Inst Agrar ( Animal Production))--University of Pretoria, 2007. / Animal and Wildlife Sciences / unrestricted

In aerial seeding of clearcut-logged sites above 1000 m elevation near Kamloops, British Columbia, mixtures of 5 forage species have been applied; orchardgrass (Dactylis glomerata L.), timothy (Phleum pratense L.), smooth brome (Bromus inermis Leyss.), alsike clover (Trifolium hybridum L.), and white clover (T. repens. L.). Seeding has been done by the B.C. Ministry of Forests during winter when such sites are snow-covered. A survey of stand establishment on operational winter seedings resulted in survival estimates for orchardgrass (2.3%), timothy(1.2%) and bromegrass(1.3%),in contrast to the 0.1% survival observed for clover species. On operational spring seedings, grass survival was 1.3%, 0.5% and 1.9% respectively for the above three species, while clover survival was 2.6%. In high elevation date-of-seeding trials established on a new clearcut winter mortality of clover seeds occurred after all seeding dates. First and second year clover plant establishment averaged 1.5% and 0.2% respectively for winter seedings (Nov. 11 to Mar. 22) compared to 20.5% and 13.2% for the May 2 seeding. Orchardgrass seeds were not damaged during the winter and first and second year survival of winter seedings was 43.8% and 21.9% compared to 37% and 12% for the spring (May) seeding. When broadcast from an aircraft, seed of the five species became lodged in the upper snowpack and soon after deposition were able to imbibe melt water. A model snowpack was developed in the laboratory to show that when the snow melted, pack shrinkage was localized at the top and that grass and clover seeds did not sink into the pack. In the field a similar pattern was observed; shrinkage was localized in the top of the pack so that seed was eventually exposed on the surface of the remaining pack. Therefore, seeds broadcast on any date in winter would eventually be located on the pack surface, regardless of the occurrence of post-seedng snowfalls. Field measurements showed that rapid freezing and thawing could occur in the upper layers of the pack. Laboratory simulation of such freeze-thaw cycling caused significant reductions (r₂=0.71;P<0.05) in alsike clover viability while not apparently affecting that of orchardgrass (r₂=0.10;NS). The effects on viability could not be explained by changes in seed moisture content of the two species. It is concluded that no date during winter is suitable for snow seeding of alsike and white clover on high elevation clearcut sites at Kamloops. / Land and Food Systems, Faculty of / Graduate

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