Much of coastal Kenya has a subhumid lowland climate with proven potential for small holder dairy production. Establishment of dairy units to realise this potential is taking place and is being stimulated by a large unsatisfied demand for milk and dairy products. The units use crossbred cows with the recommendation that feeding is zero-grazing based on Napier fodder (Pennisetum purpureum). Napier fodder usually contains insufficient protein to meet the requirements of lactating animals so there is a need to feed a by-product or forage which is rich in protein. The legume shrub Leucaena leucocephala grows well in the subhumid tropics and it has been established already on many smallholder farms. The aim of this study was to compare the performance of lactating dairy cows given Napier fodder only cut at two different stages of growth (1.0 or 1.5 m in height) or supplemented at two levels with freshly cut Leucaena.