Abstract: A composition for slowly releasing a veterinary medicament in a ruminant animal is described. The composition comprises a water-insoluble and water resistant binder a therapeutically active substance and a critical water-insoluble controlled release agent. The process of the invention includes the steps of adding a solution of a water-insoluble binder dissolved in an organic solvent to a mixture of a therapeutically active substance and a water-insoluble dense filler, stirring the mixture until free flowing granules are formed, drying the granules, blending the dried granules with a lubricant and a water insoluble controlled release agent and compressing the mixture into convenient veterinary dosage forms. When the veterinary composition is orally administered to a ruminant animal it remains in the animal's body for a desired period of time and the therapeutically active substance contained therein is released in a predictable and controllable pattern.