This editorial innovatively establishes circadian timing of rumen fermentation properties as a natural probiotic and modulator of nutrient efficiency and microbial-host health in food-producing ruminants. Inspired by nature, circadian availability of differently nutritious plants is a major driving factor in maintaining near-to-optimal rumen conditions and microbial health and integrity [60-66]. Short-chain organic acids also occur as inhibitory compounds in industrial fermentation processes, for example the detrimental effect of acetic acid and on the production of bioethanol from lignocellulosic material in a fermentation using Saccharomyces cerevisiae