Impact of diet on odor

North Carolina State University Swine Nutrient Management Research from 2003. Although odors have always been associated with animal production, only within the last decade has the interest to control them resulted in extensive research. Because odors are difficult to measure, this research has not achieved much more than suggestions as to what may work. What is known is that odors are predominantly the result of anaerobic fermentation of feed waste, indigested feed, and secretions by the animal. Although sulfur compounds are extremely malodorous and of concern for health, their role in odor sensation is controversial. Phenolics such as skatole and indole and volatile fatty acids are typically the compounds most highly correlated with odor sensation. Ammonia is derived from cleavage of urinary urea by fecal/bacterial urease. Ammonia is of health and environmental concern and should be reduced for those reasons. However, its correlation with odor sensation is mediocre and strategies effective at reducing ammonia may not positively affect odor.