Microbial Population Changes and Fermentation Characteristics of Ensiled Bovine Manure-Blended Rations

Abstract

Manure from beef steers confined on concrete was blended with a basal ration at 20, 40 and 60% and ensiled at 25.degree. C. The moisture content of the rations increased with manure added. The rations with higher moisture developed a lower pH and higher lactic acid during the 10 day ensiling. Coliform bacteria were not detected in rations with 40% and 60% manure after 5 days ensiling and after 10 days in the 20% manure-blended ration. Coliform count of the basal ration (no manure) remained constant at .apprx. 104/g. When pH dropped to 4.4-4.7, coliforms died in all manure-blended rations. Salmonellae were isolated twice from 66 samples of the manure-blended rations and ration constituents (basal ration and manure) prior to ensiling. Salmonellae were not recovered from the salmonellae positive manure-blended rations after 3-days ensiling. The total bacterial count, numbers of acid-producing bacteria and numbers of yeasts and molds decreased in the manure-blended rations after 10 days ensiling. Sporeforming bacteria survived but did not proliferate in the ensiled rations. The predominant acid-producing bacterium in the manure-blended rations prior to ensiling was Streptococcus faecalis. After 10 days ensiling Lactobacillus plantarum was the predominant type.