Resíduo da agroindústria de girassol e algodão em substituição à silagem de milho na dieta de ovinos

Abstract

Sunflower and cotton are among the main Brazilian commodities. In the processing of these crops residues are generated that can be used in the formulation of diets for ruminants. For chapter I, an experiment was conducted to evaluate consumption, digestibility, nitrogen compounds, blood parameters and urinary parameters in lambs fed with diets containing 0; 13.3; 26.7 and 40.0% of sunflower residue as a substitute for corn silage, with 40% of hay and 60% of concentrate. Twenty uncastrated, mestizo sheep of the Santa Ines breed were used, with an average weight of 21kg ± 2.4. The inclusion of sunflower residue did not affect (P>0.05) the consumption of MS, FDN and PB, with estimated averages of 4.02, 0.72 and 0.70% of PC. An increasing linear effect (P<0.05) was observed for consumption of MM and EE. The increase of 2.82 to 8.47% in the energy fraction of rations with sunflower residue was not sufficient to alter the intake of DM. There was no difference (P>0.05) for the digestibility coefficients (DC) of DM, DFN and BP, with estimated averages of 73.08; 45.19 and 66.71%. There was alteration (P<0.05) in the CDEE, with estimate of increase of 0.51 percentage units for each residue unit. There was no effect (P>0.05) of sunflower residue on ingested N, fecal N, absorbed N, urinary N, with mean values of 24.31; 8.55; 15.77 and 13.17 g day-1, respectively. The inclusion of sunflower residue did not influence blood and urinary parameters (P>0.05). The use of sunflower residue (300 g kg-1 MS) is recommended to replace corn silage in the diet of confined lambs, because it does not cause negative alteration on the consumption and digestibility of nutrients. For chapter II, two consecutive experiments were carried out in order to evaluate consumption, digestibility, nitrogen compounds, blood parameters, urinary parameters and ingestive behavior in sheep fed with diets containing residues from the cotton agroindustry. In experiment I, the inclusion of 0; 13.3; 26.7 and 40.0% of cotton delinting residue was evaluated in substitution of corn silage in diets with 40% of hay and 60% of concentrate. In experiment II, the inclusion of 0; 12.5; 25.0; 37.5 and 50.0% of cotton delinting residue was evaluated to substitute corn silage in diets with 50% of hay and 50% of concentrate. In each experiment, 20 uncastrated, mestizo Santa Ines sheep were used, with an average weight of 25kg±2.67 in experiment I, and 30kg±3.0 in experiment II. In experiment I, the inclusion of cotton delinting residue did not influence (P>0.05) the CMS, registering a mean value of 4.07% PC. Consumption of PB, EE and MM were influenced (P<0.05), with estimates of additions of 1.67; 0.68 and 1.52 g day-1 for each percentage unit of added cotton waste. The DCs of MS and PB presented quadratic behavior (P<0.05), with estimates of minimum values of 66.11 and 59.67% for the levels of 25.88 and 19.85% of residue inclusion. It was verified effect for the fecal N (P<0.05), with estimate of maximum value of 13.11% with the inclusion of 27.09% of residue. There was influence (P<0.05) on ingestion time (TI) and idle time (TO), the maximum value of TI was 4.3 h day-1 with the inclusion of 17.63% of residue, and the minimum value of TO of 13.93 h day-1 was obtained with the inclusion of 17.27% of cotton residue. In experiment II, the inclusion of cotton delinting residue influenced (P<0.05) the consumption of MS and FDN, with increases of 0.010 and 0.009 in %PC for each unit of cotton residue. PB consumption was influenced (P<0.05), with 1.668 g day-1 addition for each residue unit. There was influence (P<0.05) of CNF contents, with decreases of 1.68 g day-1 for each residue unit. The CDFDN was altered (P<0.05), with additions of 0.288 percentage units for each residue unit. A decrease in the EDC was observed, with an estimate of a minimum value of 66.83%, including 19.72% of waste. The metabolism of nitrogen compounds, blood and urinary parameters were not influenced (P>0.05). There was no effect (P>0.05) for IT, TR, TO and TMT, and EIMS, ERMS, TMTMS, EIFDN, ERFDN and TMTFDN. The inclusion of cotton delinting residue influences consumption, digestibility and ingestive behavior of confined lambs. Still, the blood metabolites were not altered and the diets promoted a positive nitrogen balance. Further research is needed to determine the best levels of inclusion of this residue in the diet of confined lambs.