For female puppies, spaying before first heat cycle is especially important in preventing mammary cancer, which statistics say will strike one in four un-spayed females. (caninejournal.com)
Some pet owners believe that it is best to wait until after their pet's first heat cycle prior to sterilization. (caninejournal.com)
But a lot of cats are pregnant by 6 months old, and now people are encouraged to avoid the first heat cycle. (tulsapetsmagazine.com)