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Whole-plant soybean silage management and its use in dairy cow`s diet

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Author(s):
Lucas Ghedin Ghizzi
Total Authors: 1
Document type: Doctoral Thesis
Press: São Paulo.
Institution: Universidade de São Paulo (USP). Faculdade de Medicina Veterinária e Zootecnia (FMVZ/SBD)
Defense date:
Examining board members:
Francisco Palma Rennó; Luiz Felipe Ferraretto; Jefferson Rodrigues Gandra; Mikael Neumann; Patrick Schmidt
Advisor: Francisco Palma Rennó
Abstract

The objectives of the present study were: experiment 1: determine the effects of phenological stage (ST) on morphological and chemical composition of soybean plant (WPS), and on losses, fermentation and chemical profile of SS; experiment 2: evaluate the effects of addition of molasses and microbial inoculation on losses, fermentation and chemical profile of SS; and experiment 3: evaluate the effects of increasing level of SS on dairy cow`s diet on feed intake, ruminal profile, feeding behavior, and milk yield. For experiments 1 and 2, 200 mini silos were used. The experiment 1 was carried out in a complete randomized design to evaluate the effect of 8 ST (R1 to R8) on WPS variables and a in a complete randomized block design (CBD) considering the effects of 5 ST (R3 to R7) as treatments and the additive combination for blocking (4 blocks) on SS variables. Increasing PS increased dry matter (DM), organic matter (OM), crude protein (CP), and ether extract (EE) contents, decreased non fiber carbohydrates (NFC) content and showed higher neutral detergent fiber (NDF) content at R4, R5, and R6 along with acid detergent fiber (ADF) content at R3, R4, and R5. Ensiling at R6 and R7 decreased acetic and lactic acids, and ethanol contents as well as buffering capacity (BC) and increased ammonia nitrogen (NH3-N) content of SS. Butyric acid content was decreased with increasing ST with lower value at R5, R6, and R7. There was no ST effect on SS pH values, however, increasing ST increased DM, OM, CP, and EE contents with highest values at R7, decreased ADF and NFC contents with lowest values at R7 and tended to decrease NDF and lignin contents of SS at R5 and R7 respectively. The highest NDF ruminal disappearance was observed at R7. The best combination among forage mass yield, fermentation profile and higher digestible fraction among evaluated ST in the present study suggests R6 and R7 for WPS ensiling. The experiment 2 was carried out in a CBD with a 2 × 2 factorial arrangement of treatments, to evaluate the addition of molasses (MOL; 0 and 40 g/kg fresh forage) and microbial inoculation [INO; 0 and 105 CFU (Lactobacillus plantarum and Pediococcus pentosaceus)/g fresh forage] on WPS ensiling. The ST from R3 to R7 were used for blocking (5 blocks). Inoculant increased DM recovery in MOL-treated silage. Molasses decreased losses, whereas INO tended to decrease gas losses. The addition of molasses increased lactic acid and reduced other organic acids, ammonia (NH3-N), and ethanol concentration, pH, and BC. Inoculant increased NH3-N, while decreased OM concentration. Molasses increased the concentration of CP, NFC, and decreased OM, NDF, ADF, lignin, and EE contents, besides improved ruminal disappearance of DM and NDF. The use of INO didn`t provided positive results if not associated with MOL, while MOL improved SS quality, reduced losses, improved fermentative profile and chemical composition, might be used as additive at WPS ensiling. For experiment 3, 24 Holstein cows (8 of which were rumen cannulated) were enrolled in a replicated 4×4 Latin square experiment (21 d-periods) and arrangement of treatments of levels: control diet with 480 g/kg dry matter (DM) of corn silage as only forage source and SS replacing CS at 16, 33, and 50 g/kg DM. Soybean silage linearly decreased DM intake and digestibility, and intake of feed particles shorter than 4 mm. Cows fed SS had a linear increase in ruminal pH and ruminal concentrations of butyrate, branched-chain fatty acids, and NH3-N. Soybean silage linearly decreased milk and solids yield. Dietary inclusion of SS at the expense of CS linearly increased milk fat concentration of unsaturated (C18:1 and C18:2) and long-chain fatty acids (>C16). Microbial protein synthesis was linearly decreased, and blood urea nitrogen concentration was linearly increased by SS treatments. Soybean silage had a positive quadratic effect on periods of rumination and chewing (min/d). Replacing CS with SS ensiled at R5,5 phenological stage decreases feed intake and performance of cows, without affecting milk fat content. Dietary SS, however, can be used to modulate ruminal fermentation and increase long-chain fatty acids (>C16) and unsaturated fatty acids proportion on milk fat. (AU)

FAPESP's process: 16/23132-8 - Forage soybean silage (Glycine max L. Merrill) on feeding lactating dairy cows
Grantee:Lucas Ghedin Ghizzi
Support Opportunities: Scholarships in Brazil - Doctorate