Thesis (PhD (Forest and Wood Science))—University of Stellenbosch, 2007. / Sustainable livestock production in semi-arid Botswana could be improved through tree planting on-farm to provide much needed protein and shade. Such action can be encouraged if the growth, productivity, nutritional value of trees and their contribution to mass gain of livestock are known.. A study at Malotwana investigated two indigenous species, Acacia galpinii and Faidherbia albida, and two exotic species, Leucaena diversifolia and L. leucocephala, at three spacings in a randomised complete block design replicated five times. The three spacings represented 400, 317 and 241 trees per hectare. The study was conducted over 6.5 years. Indigenous trees were sampled biennially and exotics annually to evaluate crown width, height, stem diameter, stem number and stem volume index. Complete plant harvesting of exotic trees at 2.5, 4.5 and 6.5 years evaluated agroforestry production. Leaves from all four species and pods of exotic species were analysed for chemical composition. Two groups of eight lambs were balanced for mass at selection for an on-farm feeding trial. Browse from exotic trees, comprising a 2:1 ratio of pods to leaves, was fed at 30% as supplement to hay to one group whose mean mass was contrasted with that of the control group fed sorghum bran at 30%. A. galpinii was a promising species, adaptable to planting away from its origin. Its crown width ranged from 5.86 m in high density plots to 6.08 m at low density and was significantly different among stands (p = 0.0406) at 6.5 years. Diameter at breast height (dbh) was significantly different among stands aged 6.5 years (p = 0.0003) and ranged between 10.38 cm at high density to 12.48 cm in low density plots, demonstrating a capacity to provide both shade and poles on-farm. At 4.5 years, F. albida attained a mean height of 4.5 m and 4.5 cm in dbh but suffered 67% mortality during a severe drought. Annual fodder production of 0.647 and 0.996 metric tonnes ha-1 for leaves and pods of L. diversifolia and 1.237 and 1.431 for L. leucocephala was recorded in years of average rainfall. Yields of 0.3 and 0.59 metric tonnes ha-1 were recorded for both species in the driest year. Equally good agroforestry production was obtained from both low and high density stands suggesting that low density plantings, which foster higher plant survival and reduce disease incidence, are best suited to the semi-arid conditions of Botswana. The crude protein of leaves ranged between 16.26 (L. diversifolia) and 25.25% (F. albida). They were highly digestible with more than twice the calcium content livestock require. Crude protein and digestibility measures were significantly different among leaves and varied significantly at different spacings (p<0.0001). Pods of the exotic species contained significantly more protein than the leaves (p<0.0001). Lambs supplemented with browse gained 102.33 g per animal per day while the control group gained 83.95 g. There were significant differences between groups during growth (p<0.05). Growing of A. galpinii, complemented with L. diversifolia and L. leucocephala, can supply short and long term feed, and greatly enhance livestock production while diversifying farm feed sources

This study attempts to identify factors responsible for determining differences in the productivity of cattle managed by communal and private livestock farmers in the southern region of Botswana during 1999/2000. It is hypothesised that herd productivity and investment in southern Botswana are higher on private ranches than on open access communal grazing land. This study is important because livestock, especially cattle, contribute significantly to the livelihood of farmers in Botswana. Cattle are a major source of meat, milk and draught power, and provide a store of wealth that protects against inflation and which can easily be converted into cash. Cattle production is also an important source of employment in the rural economy of Botswana. Furthermore, the export of beef is a major source of foreign exchange earnings, and cattle account for 80 percent of agriculture's contribution to Botswana's gross domestic product. A stratified random sample survey of communal and private livestock farmers was conducted in the southern region of Botswana from August 1999 to May 2000 with the assistance of four enumerators. The sample survey data were used to compute descriptive statistics and to estimate the parameters of a block recursive regression model. The model postulated relationships between agricultural credit, investment in fixed improvement, investment in operating inputs and herd productivity. Some of the equations are estimated with Ordinary Least Squares (OLS) and some with Two-Stage Least Squares (2SLS) to account for likely correlation between endogenous explanatory variables and the error term. Descriptive statistics show that levels of investment and herd productivity are higher on private farms than on open-access communal grazing. Private farmers are also better educated, more liquid, and have larger herd sizes, but do not differ from their communal counterparts in terms of age, gender, race or household size. The regression results show that (a) respondents with secure tenure and larger herds use more agricultural credit than those who rely on open access communal grazing land to raise cattle; (b) secure land tenure, higher levels of liquidity and use of long-term credit promote investment in fixed improvements to land; (c) liquidity from short-term credit and wage remittances supports expenditure on operating inputs; and (d) herd productivity increases with greater investment in fixed improvement and operating inputs. Herd productivity is therefore positively (but indirectly) influenced by secure land tenure. It can therefore be inferred that government should (a) uphold private property rights to land where they already exists; (b) privatise open access grazing to individual owner operators where this is politically, socially, and economically feasible; and (c) where privatisation to individuals is not feasible, government should encourage users to convert the grazing into common property by subsidising the costs of defining user groups and the boundaries of their resources, and enforcing rules limiting individual use of common property. This first-step in a gradual shift towards more secure tenure should be followed by the conversion of user groups to non-user groups organized along the lines of investor-owned firms where members exchange use rights for benefit and voting rights in a joint venture managed by an expert. / Thesis (Ph.D.)-University of KwaZulu-Natal, Pietermaritzburg, 2006.