An Investigation into the Coliform Growth of Digested Manure Solids on a Large Commercial Michigan Dairy

Abstract

Anaerobic digesters are a potential solution for increasing sustainability while reducing the environmental impact of dairy farms. Many farms utilize the digester's solid waste product as freestall bedding. It provides good cow comfort and is readily available at a low cost to the producer. However, concerns have been raised about the relationship of this bedding to udder health and milk quality. Currently, little is known about the ideal management of digested manure solids, its use as bedding, and its influence on environmental mastitis. We set out to qualify and quantify the levels of coliform bacteria in the bedding, as well as aspects which would influence management in the freestall by measuring changes over time, surface and deep differences, composting and influence of the cow (i.e., inoculation of the bedding).