Grãos de girassol peletizados e/ou tratados com lignosulfonato na dieta de vacas leiteiras confinadas : ingestão, digestibilidade e parâmetros ruminais

Abstract

This study aimed to evaluate intake, digestibility and in vitro and ruminal characteristics of Holstein cows fed diets containing grain, sunflower meal (GM) grain sunflower pellets (GMP), sunflower grain treated with lignosulphonate (GML) or grain sunflower pellets treated with lignosulphonate (GPL). For the study of intake, digestibility and ruminal parameters there were used four multiparous cows, lactating 60+20 days of lactation, mean weight 569.25±63.39 kg in a feedlot, the experimental design was a 4x4 Latin square of 21 days. There were evaluated intake and apparent digestibility of dry matter (DM), organic matter (OM), ash, crude protein (CP), neutral detergent fiber (NDF) and acid detergent fiber (ADF). There were no differences (P>0.05) for intake (% BW) of DM, OM, ash, CP, NDF and ADF. The apparent digestibility of DM, OM, CP, EE, NDF, ADF and CNE were similar (P>0.05) for all diets, with a tendency (P=0.06) of a lower CP digestibility for pelleted treatment (65.79%) compared to not pelleted treatments (69.66%). The pellet only decreased the concentration of acetic acid (55.95 mM vs. 58.82 mM) in rumen fluid. There was no treatment effect on the pH (6.17) and NH3-N (18.19 mg / dL). To perform the in vitro test was used a Holstein cows fitted with rumen fistula who received the basic diet of corn silage, corn and soybean meal. IVDMD, IVOMD IVNDFD and corn silage were 58.60%, 60.21% and 68.68% respectively. There was a negative effect (P=0.05) of lignosulphonate on diets in vitro digestibility (DIV). The addition of lignosulphonate reduced IVDMD and tended (P =0.06) to reduce IVOMD. However, the pellet did not affect IVDMD and IVOMD. The heat treatment of the pellet and chemical of lignosulphonate used in the evaluated diets did not promoted the protective effect of the grain as expected. Both treatments did not affect the intake of diets, the parameters of rumen fermentation and apparent digestibility of nutrients, except for CP with decreased with the pelletization process. In the DIV test the lignosulphonate showed a negative effect on IVDMD. Considering all the parameters evaluated in this study, the use of both treatments is dispensable in diets containing sunflower grains, being more viable supply grain just ground.