Resumen de Principios nutritivos y fermentativos de ensilados de hierba en función del tipo de pradera y del aditivo empleado en su elaboración. Poder contaminante de los efluentes generados

Adela Martínez Fernández, Alejandro Argamentería Gutiérrez, María Begoña de la Roza Delgado

• español

  Con el fin de analizar los principios nutritivos y fermentativos de los ensilados de hierba más frecuentemente elaborados en la Cornisa Cantábrica, el efecto contaminante de los efluentes generados y la eficacia que sobre estos parámetros muestra la adición de distintos aditivos comerciales, se elaboraron ensilados de hierba a escala de laboratorio utilizando siete forrajes: dos prados, dos praderas de Lolium perenne- Trifolium repens y tres cultivos forrajeros de Lolium multiflorum, sin aditivo o con adición de: ácido fórmico 85% (3,5 ml/kg de forraje), Morasil (melaza + propilenglicol) a 6 ml/kg, Ecosyl (bacterias lácticas) a 2ml/kg y Folia (bacterias lácticas + enzimas) a 3 ml/kg. En cuanto al valor nutritivo y contenido energético en MJ/kg MS, todos los aditivos fueron efectivos cuando los ensilados se elaboraron con forrajes de baja ensilabilidad (p

• English

  In order to study the effect of different additives on nutritive and fermentative silage quality and on the effluent pollution index, laboratory silages were made using spring grass from seven grasslands located in the Northwest Spain: 2 of permanent pastures, 2 of perennial ryegrass-white clover pastures (Lolium perenne-Trifolium repens) and 3 of Italian ryegrass swards (Lolium multiflorum), with different dry matter contents. Each of the grass types was treated with each one of the following additives: formic acid 85% at 3.5 ce kg-' of grass, Morasil (molasses with minerals and propylenglycol) at 6 ce kg1, Ecosyl (lactic acid bacterias) at 2 ce kg1 and Folia (lactic acid bacteria, cellulases and hemicellulases) at 3 ce kg'or no additive (control).

  In grasses with low ensilability valúes, all additives were effective. The nutritive parameters and metabolizable energy content (MJ/kg MS) were improved (p<0.05). In silages with dry matter content lower than 18 %, the formic acid gave the best results (p<0.001).

  Comparing with control, all additives were effective in decreasing the pH (p<0.05).

  As a whole, the better results were obtained with formic acid and Morasil additives Concerning to effluent polluting effect of grass silages, to reduce or stop effluent production and to minimize the nutrient losses is necessary to obtain an initial dry matter content above 250 g kg1. In general, to minimize the nutrient losses and the effluent pollution environmental effect is necessary to increase the dry matter content. BOD and COD index in Italian ryegrass swards were higher than other grasses tested.

  The inoculants are able to reduce the BOD and COD levéis. However, the biological additive with enzymes used (Folia), increased the total silage effluent production. As a result, the global contamination rate with Folia was higher than other additives tested