Dry matter intake, nutrient digestibility and nitrogen balance in growing Red sokoto bucks fed <i>Sorghum bicolor</i> hay supplemented with concentrate

Abstract

During the dry season, forages are low in quantity and quality; hence lacks the essential nutrients that are prerequisite for growth in ruminants,  suggesting a supplemental feeding. Thus, this study was conducted to investigate the dry matter intake, nutrient digestibility and nitrogen balance in growing Red Sokoto bucks fed Sorghum bicolor hay supplemented with concentrate. Eight growing Red Sokoto bucks with average body weight of 15±1.0 kg were randomly allotted to two dietary treatments containing S. bicolor hay/concentrate mixture (100:0 and 60:40). The bucks were individually fed at 3.5% body weight daily for a period of 21 days in a completely randomised design with four replicates per treatment. The  parameters measured were dry matter intake, water intake, amount of faeces voided, volume of urine and costs of feeding. Total dry matter intake (424.64g/day) was significantly (p<0.05) higher in 60:40 dietary treatment than 100:0 treatment (353.57g/day). The digestibility coefficients of
crude fibre (92.34 %), acid detergent fibre (71.46 %) and neutral detergent fibre (69.77 %) were significantly (p<0.05) higher in Red Sokoto bucks fed Sorghum bicolor hay:concentrate ratio of 100:0 compared to bucks fed 60:40 diet with crude fibre (87.25 %), acid detergent fibre (59.67 %) and neutral detergent fibre (60.08 %) digestibility coefficient values. However, crude protein (78.49 %) and ash (70.04 %) digestibility coefficients in bucks fed 60:40 diet were significantly (p<0.05) higher than those fed 100:0 diet with 38.14 % crude protein and 21.45 % ash digestibility coefficients. There was an increasing trend (p<0.05) in all parameters measured when concentrate was supplemented. The nitrogen retained (7.55 g/day), nitrogen retained as % intake (68.76 %) and nitrogen absorbed as % intake (78.46 %) were significantly (p<0.05) higher in Red Sokoto bucks fed 60:40 diets when compared with that of 100:0 diet which recorded 0.69 g/day nitrogen retained, 23.87 % nitrogen retained as % intake and 38.15 % as nitrogen absorbed as % intake, respectively. Total costs per kg of feed (N78.13K) and costs of feeding per buck (N696.72K) were significantly (p<0.05) higher for 60:40 diet than 100:0 diet with N45.83K total costs per kg feed and N340.29K costs of feeding per buck. It is therefore, concluded that concentrate supplementation on Sorghum bicolor hay enhances its utilisation by growing Red Sokoto bucks in terms of increased dry matter intake,
nutrient digestibility and nitrogen retention in Northern Guinea Savannah of Nigeria.

Keywords: Intake, digestibility, nitrogen balance, Sorghum bicolor hay and concentrate