the thing about spays…
What is a spay?
When we refer to a “spay” in the United States, we mean an ovariohysterectomy. This means that both ovaries and the uterus are removed.
Let’s talk anatomy. The ovaries sit up next to the kidneys and are anchored in place by taught ligaments. The uterus extends from the ovaries all the way to the cervix, which is basically the junction between the vagina and the uterus in the inguinal abdomen. This is the one surgery where an organ is removed that goes from the front of the abdomen all the way to the back of the abdomen.
The complicated parts of this surgery are making sure all the blood vessels that go to those organs get tied off completely. The vessels that go to each ovary come directly off the aorta, the largest vessel in the body. Making sure they are completely tied is basically life or death. The vessels that supply the uterus are further away from the aorta and are much easier to see than the ovarian vessels, but all the same, very important to make sure they will not bleed. Remember this anatomy – more on this later!
When should I spay my dog?
This is a hot topic! In the not-to-distant past, the answer was always “at 6 months”. From your veterinary surgeon’s point of view, this is a no brainer. The surgery is WAY easier the younger and smaller the dog is. There are a few reasons for this:
The distance from the front part of the abdomen to the back part of the abdomen is shorter, so this means less suturing time.
The vessels are smaller. It is a lot easier to tie off tiny vessels than large, Great Dane sized vessels.
The older a dog gets, the more fat she accumulates around her ovarian vessels. The more fat that is around them, the more difficult it gets to completely tie them off. If you think of a flexible tube, it is a lot easier to tie a rope around it and constrict the lumen when that is all you’re tying around than if there is a bunch of cotton padding around it.
The more heat cycles a dog has, the more blood supply gets trained to go to the uterus and ovaries, the more tying off that needs to happen during the spay surgery.
In the last 5-10 years there has been more investigation into spay timing and its relationship with joint disease, certain cancers, urinary incontinence and pyometra (infection of the uterus) incidence. The research began with identifying specific problems within specific breeds of dogs of performing early spays and neuters. There is a caveat to all this “investigation”. Many of the studies were done using surveys or retrospective data. This means the researchers looked back through patient charts for their data. Prospective studies, those that eliminate as much variability as possible and are usually double blinded, meaning the researchers aren’t biased by knowing a dogs history or spay status. So while there is some information out there, we are very far away from having expert knowledge on spay timing.
Below is a table of timing for spaying of specific dog breeds based on the studies that have been done so far. Please note that there is information on this table regarding neutering male dogs as well – we will do a blog post on them as well! For now we will focus on the right side of the chart below. “Choice” means that there has been no association between spay timing and joint disorders and cancer rates. “Beyond 6 months” means that there has been an association between spaying prior to 6 months and joint disorders and cancer rates. “Beyond 11 months” and “beyond 23 months” imply the same association as previously mentioned but at 11 and 23 months respectively. “Leave intact” means that regardless of spay timing, that breed has an increase in joint diseases and cancer if she has been spayed.
You can see here that for most dog breeds, there is no increase in their risk for joint disease or cancer based on spay timing. Australian Cattle Dogs, Rottweilers and Saint Bernards should wait until after 6 months to spay. Border Collies, Collies, English Springer Spaniels and Labradors should wait until after 11 months to spay. Boxers, Cocker Spaniels, Dobermans, German Shepherds, Shetland Sheepdogs and Shih Tzu’s should wait beyond 23 months to spay. Finally, Golden Retrievers have an increased risk of joint disease and cancer if they get spayed any time in their lives.
This table is great if your dog is a purebred dog, but what about all the mixed breed dogs out there? Some information has come out recently on mixed breed dogs and spay timing based on weight. The most recent study basically found that for mixed breed female dogs under 42lbs, spay timing does not change their incidence of joint disease or cancer. In mixed breed female dogs over 42lbs, they found that delaying the spay to over 11 months of age decreases the likelihood of joint disease and cancers.
What does it mean for my dog and my pocketbook to wait to spay?
Great question! As you remember from above, there are difficulties with the surgery when we wait to spay. The larger a dog is, the harder the surgery is and the longer it takes. This means that it should definitely be more expensive.
There is another side of this as well! Veterinarians have been subsidizing spay surgeries for decades. That’s right, they have been giving lower prices for spays in an effort to get more people to spay their dogs. Currently, if you were to bill based on the cost of performing abdominal surgery for duration of a typical spay, the cost of a spay should be about $1000. You read that right: $1000. Now most veterinarians don’t charge that much for a spay, so they each basically figure out how much money they can and are willing to lose on spay surgeries. Many have also tried to find short cuts to making them more affordable, and these short cuts usually involve either compromising how much the veterinarian is compensated OR the patient’s safety.
Also, when a dog is in heat, she has more blood supply going to her uterus and ovaries. The uterus is about triple to quadruple the size it normally is. Both of these factors make the spay significantly more difficult and dangerous, thus costing you more.
After all this, when should I spay my dog?
This is a very individual decision that should be made between you and your veterinarian. Here are the following considerations:
Breed and size – is there overwhelming evidence to support waiting to spay. We also have to keep in mind that much of the information we have is retrospective and could change after more studies come out.
Surgical timing – remember that the longer we wait, the more difficult and dangerous the surgery is.
Possibility of your dog being bred – the more heat cycles we allow a female dog to go through, the higher likelihood she has of being bred. Male dogs will travel miles and jump very high fences to get to a female dog in heat. Accidental breedings happen all the time. If your dog gets bred, are you capable of going through with a litter, taking care of those puppies, finding them homes, or potentially getting her a cesarian section if she needs one? If the answer is no to any of these, it would be worth having your dog spayed prior to her first heat cycle.
Ultimately, there are lots of considerations and personal preferences in these decisions. There are pros and cons to all aspects of spay timing. We recommend you discuss this decision with your veterinarian to come up with what works best for you and your dog.
