Survey of Fungal Diversity in Silages Supplied to Dairy Cattle in Belgium Over a Two-Year Period

Abstract

The fungal diversity in silages for dairy cattle feeding has been assessed by purification and identification of 966 isolates collected in silages during the two 2006 and 2007 winter storage/feed-out periods from farms localized in various geographic regions in Belgium. The relevant fungal species in silos were P. paneum and P. roqueforti (18.2 % and 14.5 % of total isolates, respectively). The proportion between the two species varied significantly from 2006 to 2007 (P<0.05) depending on the type of forage crop. The prevalence of P. paneum in Belgium compared to results in other countries is of major importance due to the mycotoxigenic capacity of this species. Information on numerous aspects of silage making process and silo management showed that neither the crop rotation, the date and weather at harvest, the use of additives, the feeding rate, the type and dimension of silo, the covering used nor the forage chopping length at ensiling could be significantly correlated to the fungal species composition isolated in farm silages. There were also no significant relationships between the chemo-fermentative parameters tested (dry matter, pH, NH3 content, concentration of lactic, acetic and butyric acids) and the fungal species composition in silages. The prevalent fungi were tolerant of the wide ranges of conditions found in the farm silages with year-to-year variations.