Management practices associated with physical, chemical characteristics and fermentation quality of whole-plant corn silage in dairy farms

Abstract

This study compared the physical characteristics, fermentation profile, and chemical composition of whole-plant corn silage (WPCS) produced on technologically advanced dairy farms in Brazil and evaluated the associations between production and ensiling practices and key silage quality indicators. Ninety-two dairy farms in Minas Gerais, Brazil, were evaluated. Information on herd characteristics, production systems, and corn silage harvest and ensiling practices was collected through structured questionnaires administered to farm managers. Silage density was determined by sampling 12 points across the silo face using a probe attached to an electric drill. Samples were analysed for physical characteristics (kernel processing score - KPS, density, and particle size - sieves 19 mm, 8 mm, 4 mm, and pan), chemical composition (DM, OM, CP, ether extract, starch, neutral detergent fiber corrected for protein and ash – apNDF, undigestible neutral detergent fiber – uNDF, and in vitro digestibility of NDF and OM – IVNDFD and IVOMD, respectively), and fermentation profile (pH, lactic acid, acetic acid, 1,2-propanediol, 1-propanol, propionic acid, butyric acid, ethanol, and NH-N). Data were analysed using Spearman partial correlations and principal component analysis (PCA). Farms were grouped according to PC1 and PC2 scores (explaining 35.5% of the total variance) and compared using nonparametric one-way ANOVA, whereas milk production and composition variables were analysed using one-way ANOVA and management variables were analysed using generalized linear models (SAS 9.4; = 0.05). Farms in Q1 had higher density than those in Q3. Low variability in fermentation profile was observed among quadrants; however, farms in Q1 had lower pH and higher concentrations of lactic acid, acetic acid, and propionic acid than farms in Q3 and Q4. Regarding chemical composition, farms in Q4 had higher starch concentrations and higher IVOMD than the other quadrants. For the fibrous fraction, farms in Q1 and Q4 had the lowest uNDF values. Kernel processing score did not differ among quadrants. Regarding production performance, farms in Q1 had higher mean milk production per cow across the herd and within the highest-producing group. For WPCS production and ensiling practices, only land management and harvest equipment differed among quadrants, with farms in Q4 more frequently adopting no- till planting, self-propelled forage harvesters, andkernel processors. Overall, quadrants showed low variability in silage characteristics, production performance, and WPCS production and ensiling practices. However, Q1 farms had better preservation indicators and higher milk production, whereas Q4 farms showed more desirable nutritional characteristics. Keywords: density; fermentation profile; in vitro digestibility; survey.