A primary condition for successful production, optimal ruminal health requires an optimum pH and high bacterial count in the rumen. Indicators of optimal rumen health are a physiological ruminal pH (pH 5.8- 6.8) and high commensal bacteria count that result in high microbial protein production. Securing optimal rumen health leads to higher digestibility and feed intake. Improved ruminal health and fermentations will be reflected not just in improved milk yield, but also in better general health and reproduction, with a positive impact on the cow’s lifespan and productivity. This review provides insights into the role of and gives practical hints regarding diet balancing efforts and feeding management strategies targeting rumen health and cow health.