Perspective: Animal-vegetation relations which optimise production, utilisation and protection of natural resources: an African experience

Abstract

The broad objective is to improve the standard of living of farmers/herders through identification of complementary vegetation-use under mixed animal species grazing. This paper aims to (1) review mixed-grazing research and development carried out in Ireland and in the semi-arid Senegalese Sahel; (2) evaluate results in relation to other grazing lands; and (3) identify research and development strategies for the future with emphasis on Africa. A systems approach is suggested as the best model. The strategy for the semi-arid area is to measure dietary selection by cattle, sheep and goats when grazed separately and mixed, and to select mixes and overall grazing intensities which would satisfy the objectives of combining productive and protective vegetation resource-use. New methodology was developed. Under temperate conditions mixed sheep/steer grazing increased animal growth rate by 7–10% or stocking rate by 13%. Benefits were also obtained using mixtures of suckler cows and sheep and using lambs grazing dairy pastures in early winter. Roundworm burdens in lambs were also reduced. In semi-arid range sheep diets were intermediate between widely differing cattle and goat diets. The herbaceous layer dominated sheep and cattle diets, and woody species the goat diets. Large between-year and season variations occurred. It is necessary to select the correct animal mix and grazing intensity to combine efficient and ecologically balanced use of vegetation. Vegetation dry matter availability was of little use in estimation of pasture value. It appeared that the critical stocking rate or grazing is that which gives the optimum use of the most vulnerable vegetation fraction and for sustainability the application of this to all vegetation fractions. Within-plot vegetation state, dietary origins from a common vegetation menu and patterns of herds and individual animal uses of spatial and temporal variation are essential. Use of mixtures increases options to improve resource use, maintain a more balanced subclimax vegetation and to build improved grazing ecosystems.

Keywords: africa; cattle; cattle diets; condition; cows; dairy pastures; dietary selection; dry matter; ecosystems; goats; grazing; grazing ecosystems; grazing intensity; growth rate; herbaceous layer; ireland; lambs; methodology; mixed-species grazing; model; natural resource use; natural resources; pastures; range; senegal; sheep; stocking rate; sustainability; systems approach; temporal variation; vegetation; vegetation use; woody species

African Journal of Range & Forage Science, 13(1): pp. 42-48