Soaking forage for 24 hours may reduce its hygienic quality, according to Swedish researchers.
The research team from the Department of Clinical Sciences at the Swedish University of Agricultural Sciences found that soaking forages in water for 24 hours increased counts of yeast and enterobacteria.
Silage and haylage contained lower mould counts than hay both before and after soaking, they reported in the Journal of Equine Veterinary Science.
Cecilia Müller and her colleagues said soaking hay in water before feeding had become common practice among horse owners to reduce the number of particles that could be inhaled and/or to reduce the content of non-structural carbohydrates.
However, it was not known if soaking may increase general microbial loads in different forages.
The researchers undertook a study in which the microbial composition of silage, haylage and hay was analysed before and after soaking in water for 24 hours.
They acknowledged that storage times may influence microbial composition, so the soaking procedure was evaluated after two different storage periods for the forages.
Results showed that soaking increased counts of yeasts, enterobacteria and lactic acid bacteria, and decreased mould counts.
“Although mould counts in hay decreased with soaking, soaked hay still contained higher numbers of moulds compared to silage and haylage pre-soaking,” they said.
“Counts of enterobacteria increased with soaking in silage and haylage, but not in hay.”
Counts of yeast and lactic acid bacteria generally increased with soaking, they reported.
“Soaking forage for 24 hours may therefore reduce the hygienic quality of forage,” the researchers concluded.
Increased storage time, from 3 to 12 months, resulted in decreased counts of moulds in hay and decreased counts of lactic acid bacteria in silage, as well as in haylage.
Microbial counts in forages for horses – effect of storage time and of water soaking before feeding
C.E. Müller, K. Nostell (Associate professor), J. Bröjer (Associate professor).
The abstract can be read here.