Ureolytic and urease-activating properties of commercial laboratory animal bedding

Five types of commercial laboratory animal bedding were assessed for endogenous ureolytic activity using a sensitive method which measures the rate of evolution of 14C-carbon dioxide from 14C-urea. On a weight basis, the highest levels of urease activity were found in heat-treated hardwood chips and a regular grade of crushed corncobs. A deodorant-treated type of crushed corncobs had a moderately high level of activity, while pelleted corncobs and pelleted alfalfa were almost devoid of urease activity. A heat-stable activator of bacterial urease was found in hardwood chips and crushed corncobs.