Quality of preservation and feeding value of direct cut silages. A comparison of permanent pasture silages made without or with three different additives

Abstract

Two trials were carried out to study the effects of addition of preservatives on preservation quality and feeding value of direct cut permanent pasture silages for one year old dairy heifers. The silage samples were prepared from the same fields either without preservative (SC) or with addition of either a mixture 70/30 formic acid-formalin (AFF) or 40 % sulphuric acid (ASd), or Lithioxine (L), a mixture of calcium formiate, sodium nitrate and hexamethylene tetramine, or Caylasil (CAY) based on lactic ferments and cellulolytic enzymes. The silages were fed ad libitum with 100 g of minerals/ day/animal to groups of 12 loose housed heifers. AFF clearly improved preservation quality, with L at a very similar level. ASd gave an intermediate quality between SC and AFF. CAY showed almost no improvement compared with SC, but it should be noted that the fresh forage had a low soluble carbohydrate content (6,5 % dry matter). The addition of preservative cause little change in organic matter digestibility (measured on sheep) of the silage, nor of its intake by heifers, but significantly increased live weight gain (on average by 275 g / day) with by an insufficient supply of nitrogen (PDI = Protein Digested in the small Intestine) and depend mainly on the proportion of ammonia nitrogen in the silages samples that were distributed.