Effects of inclusion of red clover silage on the carriage of gut pathogens in steers

Summary

Eight Hereford x Friesian steers prepared with rumen and duodenal cannulae were offered increasing proportions (increase of 33% each period) of red clover to grass over four periods with grass silage fed throughout to 4 steers as an experimental control. Numbers of Escherichia coli and Listeria were enumerated in silage from rumen, duodenal digesta and faecal samples at time points throughout each period. The results indicated that no silage contained E.coli whilst all silages had high populations of Listeria. Pathogen populations were lowest in the duodenum and highest in the rumen, although large populations were also found in faeces. The populations of E.coli were generally 10 fold lower than those of Listeria. Feeding red clover appeared to reduce pathogen loading but this was confounded by variation in the pathogen populations in the feed. Thus in conclusion, further research is required to elucidate the different effects of red clover and feed pathogen load on the gut and faecal pathogen populations.