Animal Industry Report

Extension Number

ASL R2321



Summary and Implications

This summary provides data regarding characteristics (dry matter content and environmental mastitis pathogen counts) of separated manure solids following anaerobic digestion and usage in freestalls on 3 Iowa dairy farms (separated and used on 1 dairy, transported and used at 2 other dairies). Dry matter content of fresh separated solids was 28-40%. Dry matter content of separated solids once in stalls increased to 60-80% (50-60% during winter). Anaerobic digestion (once properly achieved) resulted in coliform bacteria levels < 10 2 (detection levels) but levels of all bacteria were elevated to baseline stall values following < 12 hr. time in stalls. Cow comfort, cleanliness, and feet and leg health were excellent on the bedded manure solids in all 3 herds. SCC remained constant or decreased following use of separated with no associated increases in clinical mastitis. This data shows that composted manure solids can provide a comfortable, effective bedding source if a consistent product is generated and managed properly, and stall, alley, and milking management areas are optimized. However, presence of other organisms (Johne’s and salmonella) in separated materials should be evaluated and taken into consideration if separated solids from one dairy are used by other dairies.

Copyright Holder

Iowa State University