Composition and method for promoting growth of microbes that are capable of degrading animal waste. The method includes applying a nontoxic composition to a bedding substrate that is disposed to receive animal waste. The composition comprises a carboxylic acid, preferably the carboxylic acid is a fatty acid, and more preferably a combination of a saturated fatty acid and an unsaturated fatty acids. Specifically, a preferred composition comprises a saturated fatty acid having from 12 to 22 carbon atoms and an unsaturated fatty acid having from 12 to 22 carbon atoms. A still more preferred composition used both saturated and unsaturated fatty acids having from 16 to 20 carbon atoms. Optionally, the composition may include or encapsulate nutrients, an oxygen-releasing compound, or microbes.