Pasture scarcity and limited availability of year round feed resources during the prolonged dry season is a hindrance to ruminant production in Nigeria. Silage production is very essential in order to salvage the situation. This experiment was designed to investigate the nitrogen balance and apparent nutrient digestibility of West African Dwarf sheep fed Brachiaria decumbens ensiled with grain by-products using a completely randomized design. B.decumbens was ensiled with grain residues to produce four treatments consisting of the following: TR1 (80% B.decumbens + 20% white maize by-product), TR2 (80% B.decumbens + 20% yellow maize by-product), TR3 (80% B.decumbens + 20% guinea corn by-product), TR4 (100% B.decumbens). After 42 days of fermentation, the silage quality, proximate composition and nutrient digestibility were determined. All the treatments had silages that were firm and had olive green colour with patches of the by-products except in TR4 where light green colour was observed. All the treatments also had a pleasant odour and pH ranging from 3.2 to 3.9. The results showed that TR2 contained the highest crude protein (18.50%) which is enough to meet the nutrient requirement of ruminant animals while TR1 had the highest digestibility values. Dry Matter Intake significantly ranged from 267.37% to 450.70%. Variation occurred in Dry Matter Digestibility among the sheep ranging from 60.32% to 81.50%. Crude Protein Digestibility ranged from 72.52% to 86.25%. Animals fed TR2 had a significantly higher (p<0.05) Nitrogen Intake (13.13%), absorption (11.03%) and retention (10.88%) compared to other experimental silages. Nitrogen absorption expressed as percentage of intake (86.25%) and Nitrogen Retention expressed as percentage of Intake (84.91%) were significantly higher (p<0.05) in animals fed TR1 compared with other experimental diets. The positive N-balance observed in all animals suggested that Nitrogen absorbed was well tolerated and utilized by the animals. Results showed that silage quality, proximate composition, dry matter intake and digestibility were better in silages with grain by-products. It was also observed that the inclusion of the residues had significantly improved the nutrients and nitrogen balance of the experimental animals, therefore, ensiling B.decumbens with grain residues is sufficient to meet the nutritional requirements of ruminants’ for optimal productivity.

            Keywords: Silage, Dry Matter, Crude protein, Ruminants, Proximate composition