my cats and dogs

lately, all my cats have been disappearing. my black lab is nice to the cats and the cats like him too because he is sweet. i have a German Shepard, and she likes to eat cats. Either my cats are in poor health, or they just keep getting eaten. The other day, I saw my dog playing with a cat's dead body. Last night, i saw one of my rotting cats laying in the yard. it was pretty sad. but now we dont have to buy as much cat food!