Utility of Acacia karroo for beef production in Southern African smallholder farming systems: A review

Acacia karroo is one of the most widespread and abundant indigenous tree legume species in Southern Africa. The tree possesses positive attributes such as high growth rates, drought tolerance, adaptation to acidic infertile soils and resistance to large temperature variations. In the recent past, A. karroo was deemed to be a severe encroacher, which adversely affected land utilisation and rangeland productivity. Research attention has been diverted from its riddance as a weed to its utilisation as an animal feed. Widespread adoption of feeding strategies based on A. karroo was mainly impeded by the presence of thorns and tannins. Opportunities to minimise the adverse effects of these anti-quality factors are now well documented. A. karroo leaves have desirable fatty acid profiles, high N and mineral concentrations. At present, utilisation of A. karroo for beef production on rangelands is restricted by limited evidence regarding its feeding value. The current paper, therefore, demonstrates the potential of A. karroo to reduce worm burdens, and improve growth rates, carcass traits, beef quality and fatty acid profiles of cattle on rangeland. Economics of feeding A. karroo, strategies for incorporating it into feeding regimes for beef cattle and its relevance to sustainable livelihoods in low input production systems are outlined. (C) 2011 Elsevier B.V. All rights reserved.