Nutrient utilization in sheep fed sorghum silage

A study was conducted to evaluate the fermentation characteristics and nutritional worth of sorghum (sorghum bicolor L. (Moench) forage ensiled either alone (C), with 0.5% urea (T₁) or 30% poultry litter (T₂). Each of the above silages was prepared in 5 metal drums (210 kg capacity) double lined with polyethylene bags for 60 days. The CP was higher (P<0.01) in the T₁ than T₂ silage. The cell wall components (NDF and hemicellulose) were lower and lignin content was higher in T₂. Decrease (P<0.01) in pH, water soluble carbohydrates and an increase in lactic acid (P<0.05) was observed in T₁ silage than T₂ silage (8.61% Vs 6.47%).

A metabolism trial was conducted using 18 crossbred wethers (averaging 39 kg BW). The sheep divided by weight into six blocks were randomly allotted to the three experimental silages within each block. The data were analyzed by randomized block design. The apparent digestibility of DM and OM was statistically comparable in all the groups but that of CP, NDF, ADF and cellulose was higher (P<0.01) in T₁ and T₂ silage. Total N intake, excretion and retention were higher (P<0.01) for sheep fed T₁ and T₂ silage than for sheep fed the control silage. Among sheep fed treated silages, those fed T₂ silage had higher (P<0.01) N intake, excretion and retention than those fed T₁ silage. No significant differences were observed for ruminal pH among sheep fed different diets, but ruminal NH₃-N was higher (P<0.01) in sheep fed treated silages. Sheep fed urea-treated silage showed higher ruminal NH₃-N (P<0.05) concentration than those fed poultry litter-treated silage. Total VFA and valeric acid concentrations were higher (P<0.05) for sheep fed treated silages that those fed control sorghum silage. It was concluded that the nutritive value of sorghum forage can be improved considerably by ensiling with either urea or poultry litter.