Pure and mixed swards of Centrosema pubescens (centro), Pueraria phaseoloides (puero) and Brachiaria mutica (para grass) established under a 12-year-old mango plantation were sampled at 6-week intervals for 2 years to determine crude-protein (CP) content, dry-matter (D.M.) and CP yields and apparent digestible energy and apparent digestible crude-protein (DCP) contents. Daily dry-matter intake (DMI) and apparent digestible energy and digestible crude-protein intakes (DEI and DCPI), as well as live-weight gain (LWG) by 11·5 kg penned West African cross-bred weaner lambs, were also determined.
The pure legumes were better than the mixed swards in respect of CP (mean: 22·1, 18·8, 14·4 and 13·8% for centro, puero, centro-para grass and puero-para grass respectively) and DCP (mean: 16·2, 13·4, 10·4 and 10·0% respectively) contents, and daily DMI (mean: 50·8, 49·7, 41·8 and 41·3 g/kg W0·75 respectively), DEI (mean: 562, 531, 418 and 410 kj/kg W075 respectively) and DCPI (mean: 8·09, 6·55, 4·04 and 3·94 g/kg W0·75 respectively). On the other hand the legume-grass mixed swards, especially puero-para grass, were superior to the corresponding pure-legume swards with regard to D.M. yield (mean: 11·90, 7·69, 7·13 and 4·54 t/hafor puero-para grass, centro-para grass, puero and centro respectively) and CP yield(mean: 1·62,1·09, 1·32 and 0·99 t/ha respectively). The pure-legume stands gave the highest LWG per lamb (mean: 45·7, 3·89, 2·63 and 25·3 g/day for centro, puero, centro–para grass and puero-para grass respectively) but it was estimated that the legume-grass mixed swards would give higher returns in terms of lamb LWG on forages harvested per unit sward area than the corresponding pure-legume cover.
It was concluded that legume-grass covers would be preferred to all-legume covers if livestock were to be integrated into tree crop farming systems. However, the choice of companion grass would have to be given proper consideration as shade-intolerant grass species, such as para grass, would detract from profit maximization.