This research was published and written by Eric Hatungimana, Ph.D., and Pete Erickson, Ph.D., Extension Dairy Specialist, University of New Hampshire.
Treating wet brewer’s grains (WBG) with salt would be an easy strategy to improve the shelf-life of WBG at the farm. Brewer’s grains can be marketed as WBG or dried brewer’s grains (DBG). While DBG is easy to store because of its low moisture content, drying incurs additional high costs. The moisture content of WBG ranges between 65-80 % making it very difficult to be stored for a long time. In order for WBG to work economically for dairy producers, there is a need to preserve the feed quality.
Our project evaluated the effect of storage on WBG treated with salt or a commercially available preservative on preventing spoilage caused by mold and yeast development. It also evaluated how this treatment affects dry matter and protein digestibility. Three levels of salt (1.4, 26, and 3.8%) and 3 levels the commercial preservative (PRES: 0.05, 0.10, and 0.15%) on a fresh basis, were used to treat WBG for 28 days.
This research was conducted at the New Hampshire Agricultural Experiment Station at the University of New Hampshire Fairchild Dairy Teaching and Research Center and was led by experiment station researcher Peter Erickson, Ph.D., and Eric Hatungimana, Ph.D.
Hatungimana and Erickson found that WBG treated with 3.8% salt or 0.15% commercial preservative had the least mold counts, indicating the prevention of spoilage. While treating WBG with the commercial preservative at 0.15% considerably decreased both molds and yeast development, salt treatment was effective against mold development.
Additionally, this research showed that apparent dry matter and protein digestibility were greater in WBG treated with 2.6% salt. This suggests more potential nutrient availability to support growth and production of dairy cows.
To be more effective against mold growth, salt can be incorporated in WBG by using a mixer wagon. It can also be sprinkled on the surface, especially during hot days when mold grows rapidly. It is recommended to store WBG in a shed to mitigate high environmental temperature effects.
While the lowest mold count was observed with WBG treated with 3.8% salt, and greater DM and protein digestibility was obtained with 2.6% salt, we would recommend treating WBG with 2.6% to avoid potential excess of salt when WBG is incorporated in diets. Preserving WBG with salt would be less expensive ($0.12/lb.) than the commercial preservative ($2.30/lb.) and is easily accessible to farmers who feed WBG to their herds.
This research was published in the Journal Applied Animal Science (DOI: https://doi.org/10.15232/aas.2019-01857).