Six pairs of Mashona oxen ploughed dry, red clay soils in August (winter) and in mid-November (spring). Between September and November the oxen were randomly assigned to 3 feeding groups: no supplement (control), 400 g/head per day of cobsheath-groundnut stover for 70 days and 800 g/head per day of the same supplement for 35 days. Cobsheath-groundnut stover was fed in order to determine its potential as supplementary feed for draught oxen during the dry season. The liveweight (LW) lost by heavy oxen during winter ploughing was lower (P < 0.001) than that of light oxen. During spring ploughing heavy oxen again lost less (P < 0.001) LW than light ones. In addition, non-supplemented oxen lost more LW than those supplemented. Therefore feeding strategies for Mashona draught oxen should aim at providing adequate nutrients to at least maintain LW during the dry season. Heavy oxen outperformed (P < 0.001) light ones during winter ploughing. Work output of supplemented oxen in spring was also significantly greater (P < 0.05) than that of non-supplemented ones. This result demonstrated the benefits of supplementary feed during the dry season. Concentrations of lactate and free fatty acids in plasma, heart rates and rectal temperatures increased (P < 0.05) markedly during work. The increases were higher (P < 0.05) for light oxen, particularly those not fed supplement.