When to neuter or spay?

First of all let me say that I am the first to agree there are too many unwanted puppies and kittens in this world already.  Responsible pet ownership is of highest priority.  The standard recommendation for years has been to neuter/spay your pet at 6 months of age.  The reasoning behind this is that this is generally before the pet is capable of having  or producing young (although some  pets are fertile before 6 months).  This obviously would reduce the number of unplanned puppies and kittens.   Many humane societies, low cost spay neuter services are sterilizing pets as young as 8 to 12 weeks with out regard to health concerns this may pose later in that animals life.  Neutering pets as these very young ages  prevents the urinary tract (urethra primarily) from reaching full size and in many cases this can lead to urinary tract disease/blockage, especially in male cats.  Additionally, the hormones of puberty (estrogen/testosterone) play a vital role in signaling the growth plates of the long bones in the legs to close thus stopping the lengthening of these bones.  Recent research suggests that pets neutered prior to going through puberty experience longer growth in these bones without an increase in their density thus the bone is abnormally long.  What does this harm?  There is evidence that pets neutered  before puberty experience a higher rate of osteosarcoma , bone cancer, later in life.  In addition, there is also evidence that when pets go through puberty that this has an effect on their brain/behavior and helps them to mature mentally.  My current recommendation is to not neuter male toy breed dogs and cats  until after 7  months of age.  For medium breeds I would wait until at least  12 months of age, large breed 18 months and giant breeds at least 24 months.  For all female  pets there is the question do I let them have their first estrus (heat cycle) or not.  Obviously there is the need to strictly control your pet while she is in season so as to not let her get pregnant.  Estrus will last 3-4 weeks and the female pet must be strictly monitored and kept away from the males.  There is also the added mess that this presents and some people do not want to deal with this.  The advantages are the same for the female dogs/cats.  If you are willing and able to deal with a female pet in season then I recommend  letting them go through their first cycle and then spay them as soon as this is over.  For toy dogs and cats this is somewhere around 6 months of age.  Medium to large breed 7 to 12 months of age and giant breeds 9 to 18 months of age.  Always keep in mind that pets are  individuals and these time frames are only guidelines.   Responsible pet ownership is about reducing the number of unwanted puppies and kiteens as well as proper training, feeding, health care for your pet.  Look at the whole picture when it comes to your pets’ health needs.


  1. It’s a pleasure to find such rtaioantliy in an answer. Welcome to the debate.

Speak Your Mind