Published on Saturday, May 9, 2009 by admin Spay and Neuter Your Pet * Number of cats and dogs entering shelters each year: 8-12 million * Number of cats and dogs euthanized by shelters each year: 4-6 million * Number of animal shelters in the United States: Between 4 and 6 thousand * Average number of litters a fertile cat can produce in one year: 3 * Average number of animals in an average feline li...