Two experiments designated A and B were conducted to evaluate the effect of supplementing napier grass with lucerne on dry matter intake (DMI) and weight gain(ADG) of Friesian and Sahiwal heifers. In experiment A which lasted 92 days, 24 heifers from each of Sahiwal and Friesian breeds were blocked by breed and randomly allocated to the following treatments: young napier + 0 kg lucerne (T1); young napier + 1.5 kg lucerne (T2); old napier + 0 kg lucerne (T3); old napier + 1.5 kg lucerne (T4); old napier + 2.5 kg lucerne (T5); old napier + 3.5 kg lucerne (T6) heifer‾¹.day‾¹. Supplementation significantly (p < 0.05) increased DMI from 4.3 to 6.7 kg.day-l in Sahiwals and 5.2 to 7.8 kg.day-l in Friesians (p < 0.05). Similarly. supplementation positively influenced ADG which significantly (p< 0.05) improved from 0.29 to 0.64 kg.dayl for Sahiwals and 0.30 to 0.65 kg.day-l for Friesians. In Experiment B, diets from experiment A were incubated in the rumen for 0, 3, 6, 12, 24, 48, 96 and 336 h using four steers to estimate degradation. The rumen degradation of lucerne-containing diets were significantly (p < 0.05) higher than those with napier grass alone. It was concluded from the study that lucerne has a great potential to improve animal performance in smallholder dairy farms.