Características de fermentación, composición química y evaluación in vitro de ensilados de excretas pecuarias mezcladas con tres fuentes de carbohidratos fermentables
Abstract
The inadequate management of livestock excreta and agro-industrial by-products generates negative environmental impacts, but their processing and utilisation through silage is a strategy to use their nutrients in animal feed and thus reduce this impact. The objective was to evaluate the effect of the inclusion of non-conventional sources of non-protein nitrogen (N) and rapidly fermentable carbohydrates (C) in silage on fermentation characteristics, chemical composition and degradability of dry matter (IVDMD) and neutral detergent fibre (IVNDFD). A Completely Randomized Design with factorial arrangement of four N sources (PL, dehydrated poultry litter; QM, dehydrated quail manure; PM, fresh pig manure and AU, agricultural urea) × three C sources (CM, cane molasses; BBP, bakery by-product and OP, orange pulp) plus ground corn stover and water was used, for a total of 12 treatments with 4 replicates each. The ensiling process lasted 30 d and then the fermentative qualities, chemical composition, DIVMS and DIVFDN were evaluated. The interaction between N and C influenced the final composition of the silages (P<0.05). The QM+CM silage and those with PL and AU had the most pleasant odours (P<0.05). Butyric and manure odours were common with PM and QM. Treatments with OP showed higher pH (P<0.05), affecting their quality. Including PL favoured silage compaction (P<0.05). The highest crude protein (CP) content was found in QM+CM and the lowest in PM+OP, the treatment with the highest NDF (P<0.05). IVDMD and IVNDFD values were higher (P<0.05) in PL-based silages and lower in PM+OP. In conclusion, ground whole orange pulp in the amount included negatively affected the fermentative, nutritional, dry matter degradability potential and neutral detergent fibre characteristics of the silages and those made from dehydrated poultry litter had the best results for these variables.