Digestibility and nitrogen balance of Sudan goat ecotypes fed different energy/protein levels

Abstract

Goat (Capra hircus) as small ruminants is reared in Sudan for its milk, meat, skin and wool. The present study was conducted to evaluate the effects of different levels of energy/protein on apparent digestibility coefficients and nitrogen balance of different Sudan goat ecotypes (Nubian, Desert and Swiss Nubian). Nine male goat kids (2-3 months and average weight 9.23 kg) of either ecotypes were used in a 3×3×3 arrangement, fed three experimental diets A (control), B and C, with varying energy: protein 1:0.14, 0.16 and 0.18, respectively. Animals were housed in metabolism cages and diets were fed for a 3 day adjustment period followed by a 4 day collection period. Feed, feed refusal and feces were taken daily to measure digestibility. Urine was collected daily and measured in mL and preserved with sulfuric acid. Then urinary nitrogen was analyzed. The study showed a significant difference (p<0.05) between species only for Ether Extract (EE), Nubian kids recorded best digestibility of Digestible Dry Mater (DDM), Digestible Organic Mater (DOM), Digestible Crude Protein (DCP), Digestible Ether Extract (DEE) and Digestible Nitrogen Free extract (DNF) Effect of ration was significant (p<0.05) for DDM, DOM, DEE and DNFE. The highest values of apparent digestibility coefficient of Dry Mater (DM), Organic Matter (OM), Ether Extract (EE) and Nitrogen Free Extract (NFE) were observed in ration B and C. Nitrogen balance was not significantly varied for treatment. Animal species were in positive N balance for all three experimental diets. Nitrogen retention and nitrogen retention percentage was highest in ration B and C. The digestibility of nutrients of experimental diets indicated that the digestibility increased significantly (p<0.05) with increasing energy: protein in the test diets. Therefore, increasing energy protein levels gave better results, with overall higher nitrogen retention in Nubian goats than the other two ecotypes which were similar. It is likely that Nubian goats are well adapted to be raised under intensive condition due to their efficient utilization of nutrients. © 2012 Knowledgia Review, Malaysia.