Production objectives and breeding practices of urban goat and sheep keepers in West Africa: regional analysis and implications for the development of supportive breeding programs

To better understand the relative importance of the multi-purpose functions of small ruminants for their urban owners and related breeding practices including selection criteria, we undertook a comparative analysis across the West African cities of Kano (Nigeria), Bobo Dioulasso (Burkina Faso) and Sikasso (Mali). Semi-structured questionnaires were used to collect the required information from 301 sheep farmers (100, 102 and 99 in Kano, Bobo Dioulasso and Sikasso) and 306 goat farmers (100, 99 and 107 in Kano, Bobo Dioulasso and Sikasso). Sheep and goats were kept for a variety of reasons including income generation, insurance (sale for cash to meet unexpected expenditures) and economic security (sale for cash to support foreseeable expenses), social/religious functions and prestige in ownership. The relative importance given by respondents to the different functions varied significantly (p < 0.001) across cities and between species within a city. However, irrespective of city, both species were primarily kept for their financial functions whereby sheep were perceived as having higher economic value. Although breeding practices were very similar in many respects (low practice of castration, culling and replacement strategies, uncontrolled mating, no record keeping and selection criteria), the emphasis put on each selection criteria varied across cities and between species. Irrespective of city, most of the goats were of the indigenous type while keeping crossbred animals and/or maintaining more than one genotype in the same flock was more commonly practiced by sheep keepers. This points to a higher motivation for strategic breeding among sheep than goat keepers and indicates that the former might be interested in joining carefully designed participatory flock improvement programs

Nutrient requirements of exotic tree species in Zimbabwe

Pot and field experiments were conducted in the greenhouse and at three field sites (Marondera, Domboshawa and Makoholi) in Zimbabwe to examine the effects of soils and fertilizers on nutrient uptake and growth of 6 exotic tree species (Eucalyptus camaldulensis, E. grandis, E. tereticornis, Leucaena leucocephala, Casuarina cunninghamiana, and Acacia holosericea). Plant growth, N and P contents of all species were increased by the application of N, P, K and micronutrient fertilizers. The effect of individual nutrients (N, P, K and micronutrients) and their combination on Eucalyptus species was further investigated in a pot experiment using soil from Domboshawa. Eucalyptus species responded only to N application and no significant interactions were found between N and the other elements. Nutrient uptake results showed that E. camaldulensis and E. tereticornis removed more cations than the N-fixing trees but only in the fertilized treatments. L. leucocephala and C. cunninghamiana were higher in P, but no clear trends were observed for N. Plant growth and nutrient uptake by E. camaldulensis. C. cunninghamiana and A. holosericea were assessed in the field at the three sites. Plant species grown in the Marondera site had greater height and diameter at breast height (DBH) than those in the two other sites. These results followed trends in soil nutrient contents. The analysis of foliage revealed differences in the nutrient concentration of leaves from different trees, but no effect of site was found. The interrelationships between plant characteristics, soil and foliage nutrients were examined. In a pot experiment, mineral N was the only variable correlated with growth response and nutrient uptake, while in the field the only significant correlation was obtained with soil pH