Review: Effect of flavonoids on ruminant productivity

Flavonoids are a class of polyphenols known to have anti-inflammatory and anti-oxidative functions. Supplementation with flavonoids appears to be most beneficial during periods of stress. In growing ruminants, flavonoid supplementation did reduce the severity of pathogenic and nonpathogenic diarrhoea and had little impact on metabolism, health status, or growth parameters. Flavonoids lessened the drop in ruminal pH and reduced the inflammatory state of cows fed a high grain diet and during induced subacute ruminal acidosis.

Milk yield was increased in most studies over the transition to lactation, but milk component responses were varied. Milk somatic cell concentration was often reduced by dietary flavonoids, and they have been effective at suppressing inflammation and apoptosis in pathogen-induced mouse mastitis models. Further research is warranted to investigate the potential of flavonoids to reduce mastitis in dairy cows. In addition, several studies showed that supplementing different flavonoids to dairy cows during the transition period had potential to reduce postpartum inflammation, endoplasmic reticular stress, and hepatic lipid accumulation.

Overall, flavonoids can increase ruminant productivity with beneficial effects exhibited under a variety of stressful conditions; however, unexplained variability in response to flavonoid supplementation is likely due to differences in dose, specific compound efficacy, and mode of action.