Chemical composition and voluntary intake of effluent as affected by silage additive and time of flow following ensiling.

摘要

The influence of 9 commercial silage additives on the composition of effluent tapped from silages at various stages of fermentation was investigated. In late August 1990 (experiment 1) and early October 1991 (experiment 2), a total crop mass of 400kg containing timothy (Phleum pratense), meadow fescue (Festuca pratensis) and red clover (Trifolium pratense) was added to each 1-m3 silo in experiment 1, and 330 kg in experiment 2. Silos were kept indoors at 15-20degC and 10-15deg in experiments 1 and 2,respectively. In experiment 3, 40 t of a crop consisting of timothy and meadow fescue were ensiled in each of 3 wooden tower silos with the silage additives Natuferm 3.7 litres/t, Foraform 4.0 litres/t and Maxgrass 5.3 litres/t, respectively. Effluents from silages treated with Natuferm (lactic acid bacteria and Pediococcus) or Maxgrass (formic acid, propionic acid, caprylic acid and ammonia) were fed ad libitum to 12 dairy cows for 6 weeks. Although all silages were well-fermented, considerable variation was observed in the chemical composition of resulting effluents. Effluents from silage treated with inoculants or Howden (molasses, potassium chloride, sodium chloride, sodium benzoate, malt extract), as well as those from untreated silages, exhibitedthe highest lactic acid concentrations, whereas silages treated with formic-acid based additives yielded effluents with the highest sugar content. Sugar and ash content decreased with time following ensiling, while DM, CP, organic acid and ethanol content increased. Daily intake in cows fed on effluent from Natuferm-treated silage was 43.6 kg, compared with 57.4 kg in cows fed on effluent from Maxgrass-treated silage. Effluent intake decreased rapidly with time following ensiling. A positive correlation was observed between effluent sugar content and feed intake.