Banca de DEFESA: ANTONIO LEOPOLDINO NETO

STRATEGIES FOR ELEPHANT GRASS ENSILAGE: PLANT SIZE, CUTTING FREQUENCY AND INCLUSION OF LEGUMES

Size, elephant grass, cutting frequency, additive, Sábia

The aim was to evaluate ensilage strategies for different heights of elephant grass subjected to cutting frequencies and the inclusion of Sabiá. The experiment was conducted at the Experimental Farm of the Federal Rural University of Pernambuco (UFRPE) in Garanhuns, Pernambuco's Agreste region. Treatments were distributed in a randomized block design in a factorial scheme (4×2), with four elephant grass genotypes: IRI 381 and Elephant B, tall genotypes, and Taiwan A-146 2.37 and Mott, short genotypes, and two cutting frequencies, 60 and 90 days. For the experimental trial with Sabiá inclusion, the same experimental area and the same genotypes at 90 days of age were used, with the inclusion of 0 and 20% Sabiá in green matter. Effluent losses showed different behavior in tall genotypes, increasing in the Elephant B genotype with a 90-day cutting frequency and decreasing in the IRI genotype at the same frequency compared to 60 days. The DM and CP content in Mott genotype silages are not altered when the cutting frequency decreases, but in the other silages, there is an increase in DM content and a decrease in CP content as the interval between cuts increases. Differences in DM and NDF content between genotypes only occur when managed with a 90-day cutting frequency, and in this case, the Mott genotype has lower DM and NDF content than the others. The NDF content only increases in Elephant B genotype silages when managed with a 90-day cutting frequency. Fraction A protein is higher in the Mott genotype compared to the IRI genotype, while fraction B3 is higher in the Taiwan genotype compared to tall genotypes, and higher in silages produced from elephant grass managed with a 60-day cutting frequency. Total carbohydrate levels are higher in silages of short genotypes compared to tall genotypes. Regardless of the genotypes, digestibility decreases when the cutting frequency decreases. Plant height and cutting frequency influence the quality of elephant grass genotype silage. When using 20% Sabiá, no significant effect was observed for genotypes and Sabiá inclusion levels and their interactions for the variables gas loss with an average of 24.42%, dry matter recovery, average pH of 4.5, and ammonia nitrogen N-NH3. The inclusion of 20% Sabiá provided a higher fermentation coefficient. Among the genotypes studied, Mott had the highest effluent production, and the 20% Sabiá inclusion level reduced effluent production with an increase in dry matter. The inclusion of 20% Sabiá resulted in increased CP, condensed tannins, and lower NDF, ADF, IVDMS, and total soluble carbohydrates. The loss of stability in all silages was recorded 48 hours after the silos were opened. The increase in CT led to a reduction in IVDMS; however, further investigation is needed to determine the optimal CT concentrations for ruminant diet inclusion