Effect of ruminal mechanical stimulating brushes on the performance of lactating Holstein dairy cows

The aim of this study was to confirm the hypothesis that artificial brushes administered to the rumen can partially replace the function of structural fibre, and increase milk production or quality. To mitigate the risks of feeding low levels of physically effective neutral detergent fibre (peNDF) to cattle, the administration of ruminal mechanical stimulating (RMS) brushes was examined in 22 high-yielding lactating Holstein dairy cows. The cows were divided into an experimental group equipped with RMS brushes and a control group without RMS. Cows were fed four experimental total mixed rations (TMR) consisting of fixed amounts of alfalfa silage, maize silage, rush corn cob mix silage and different proportions of brewer's grains, concentrate and wheat straw. The TMRs had the following 4 peNDF contents: 10.9%, 13.0%, 12.6% and 14.0%. The duration of the experiment was 18 weeks. All cows were fed TMRs with a low structural fibre content near levels associated with a risk of subacute ruminal acidosis (SARA). For the RMS brush group, 3 RMS brushes were inserted orally into the rumen using a special applicator. The effects of RMS brushes on feed intake, rumen fermentation and milk production were evaluated. Ruminal fluid (250 mL) was taken using a stomach tube for pH, volatile fatty acids and ammonia nitrogen analysis. A significant increase was found for the feed intake and milk yield of the RMS group fed the TMRs with 13.0% peNDF although no relationship between peNDF content and RMS TMRs was found. No significant increase in milk quality, rumen pH or rumen fermentation metabolites was declared for the group with RMS brushes. Although RMS brush technology only partially reduced the requirements for peNDF, it may decrease the risk of SARA.