Nutritional parameters of lambs fed extruded ration with different roughage to concentrate ratios

Abstract

The objective of our study was to compare the intake and digestibility of dry matter and nutrients, and the nitrogen balance, of lambs fed extruded ration with different roughage (R) to concentrate (C) ratios. The experiment was carried out at the Federal University of Uberlândia (UFU), Experimental Farm Capim Branco, from 7 December 2016 to 6 January 2017. Ten lambs (Santa Inês × Dorper) aged between four and five months, and with a mean weight of 25.9 ± 2.8 kg, were used. The animals were placed in metabolic cages equipped with a feeder, drinking fountain, and salt shaker, and which had a wooden slatted floor. The treatments consisted of extruded ration with 30R:70C or 70R:30C. Treatments were distributed in a randomised, complete block design, with each treatment being performed twice and with ten replications. The experiment was carried out in two blocked stages. Differences in the means of treatments were evaluated by Tukey’s test at a significance level of 5%. Intake and digestibility of dry matter and nutrients, water intake by animals, and nitrogen balance were also analysed. The 30R:70C treatment resulted in a lower intake of dry matter, crude protein, neutral detergent fibre, acid detergent fibre and hemicellulose, and caused higher dry matter and neutral detergent fibre digestibility. The 30R:70C treatment also resulted in a lower intake and faecal excretion of nitrogen, consequently establishing a higher ratio between retained and ingested nitrogen. In conclusion, the ration with 30R:70C results in lower intake, and better utilisation of nutrients by the animal.