People always ask me when is the best time to neuter or spay their new puppy. My recommendation based on experience and the research I’ve done on the subject is between 4-6 months old. I do not recommend waiting longer because of the unwanted behaviors that can come along with the unneutered male dog after puberty… but don’t just go on what I say.. do your own research and make your educated choice.
Here is some advice from two doctors on the subject.
In general, reducing the reproductive drive of an animal diminishes roaming for mates, reducing the chance of being hit by a car and the chance of being injured in a fight with another animal. Lowering reproductive hormones decreases urine marking, decreases aggressiveness between animals, and sometimes, decreases aggressiveness with people. The earlier spaying or neutering is done, the earlier this will happen.
The spayed or neutered animal won’t develop uterine cancer, ovarian cancer, and testicular cancer. Its risk of mammary cancer, uterine infection, and some forms of prostate disease are also decreased.
But, we’ve now learned that intact animals with normal reproductive hormones have decreased risks of some forms of cancer, such as blood, bone, prostate and bladder cancers. Intact animals have lower instances of urinary tract infections, diabetes mellitus, hypothyroidism and cruciate ligament injuries.
These are all very confounding. For some problems there is benefit from spaying and neutering at the earliest age possible. For others there is benefit from waiting and even not spaying or neutering.
For example, the benefits noted as far as cruciate ligament injuries go applies when the animal is growing. Once growth stops being intact doesn’t matter.
The beneficial effect from spaying for prevention of mammary cancer declines as the patient ages, so the earlier a pet is spayed the better.
The beneficial effect from neutering for prostate disease is more important with the older dog. Prostate disease is very uncommon in young dogs.
So in the final analysis the proper time to spay or to neuter an animal depends on a lot of things. Spend some time with your veterinarian talking about your goals for your pet and your personal concerns. Then you’ll know what should be done.
Dr. Harmon Rogers
I was writing to ask about the right time to neuter a Lab male. When he got his annual exam and shots, the vet said to leave him unneutered until he was two years old as “large-boned dogs get cancer if they are neutered before then.” I had never heard of this before and have always been a proponent of early neutering, but since this has come up, I am now unsure what to do. Is there any truth to this? What is the best time to neuter/spay a dog?
Dr. Sherry Weaver’s advice.
I would start by saying that there are many different vets with as many different experiences and opinions. In these articles, I try to express my personal experiences as well as current research. No research is perfect, and no experience is absolute. In reality, there are very few definite “right” answers. The best answer to most questions is to find a vet who you trust to tell you the whole story and make your decision based on that information.
Early neutering is a controversial topic. A very few uncontrolled studies have shown a link with early neuters (before 14 months of age) and some forms of cancer and joint problems. Both the joint problems and the cancers that they have linked are relatively common in large-boned dogs, so the challenge is to prove whether the early neuter actually caused an increase in the incidence. There have been no studies that prove this.
On the other hand, there have been several good studies done to look at different potential complications from early neutering (as early as 6 weeks of age) that have found no adverse effects other than slightly longer legs and less “masculine” muscle development. These pro-early neuter studies were not carried out long enough to evaluate the risk of cancer.
In my experience, dogs neutered under 6 months develop less obesity and don’t establish some of the “male” behaviors that neutering is meant to treat. They are also less likely to jump a fence, fight, or get hit by a car. With no true proof of the risk of increased cancer–and the very real risk of bad behaviors or even physical injury from running away or fighting–I am letting my clients make their own decisions based on a debatable risk of cancer vs. the very real behavioral risks.
Spaying females before 6 months is less controversial than neutering; preventing the first heat nearly eliminates the risk of breast cancer which is much more common than bone cancer.
So all of that being said… the best advice is to do your research. Talk to your vet and make an educated choice for you and your dog.
Location: Woodland, Washington State