<p>Leucaena planting on private land is increasing due to declining carrying capacity of native pastures in Timor Leste, and feeding 100% leucaena to cattle have started to be a common practice. However, feeding 100% leucaena for cattle fattening may not be economical, therefore it should be combined with crop residues such as maize stover, the most commonly available energy source in Timor Leste. The aim of this experiment was to determine feed intake, feed digestibility, rumen ammonia concentration and live weight gain of fattening Bali bulls feed different combinations of leucaena and maize stover. 12 male Bali cattle were allocated based on body weight into three treatment groups and each group fed either 100% leucaena, 75% leucaena and 25% maize stover or 50% leucaena and 50% maize stover. <br/>
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Feed intake (g OM/kg BW) was significantly higher in the bulls fed 100% leucaena compared to those fed 75% leucaena and 25% maize stover or 50% leucaena and 50% leucaena and 50% maize stover (26.8±1.1, 24.9±1.2 and 22.6±0.2 respectively). Digestibility of organic matter did not differ significantly with declining level of leucaena in the diet (60.6±1.6%, 58.8±2.4% and 53.1±10.2% for diets with 100%, 75% and 50% leucaena respectively). Rumen ammonia concentrations significantly decreased with decreasing level of leucaena in the diet (222±33, 169±5 and 157±24 mg N/L respectively). Live weight gain (kg/d) was significantly higher in bulls consuming 100% leucaena (0.50±0.08) than those fed 75% (0.46±0.07) and 50% leucaena (0.39±0.05). The lowest live weight gain recorded in this experiment was higher than the 0.2 kg/d for growing bulls fed grass only (Dahlanuddin et al 2012). Feed conversion ratio was lower (6.8±0.6 kg DMI/kg ADG) when maize stover was fed at 50% of diet, compared to 6.5 ± 0.6 and 6.2 ± 0.7 for the bulls fed 100% Leucaena and 75% Leucaena + 25% maize stover respectively. The minimum level of leucaena inclusion needed in the leucaena: maize stover combinations was 55% allowing up to 45% maize stover to gain a moderate growth rate.