My Abby came into heat at 6 months and is now heading into her second cycle. She turned 1 on the 9th of February.

I've been doing a bit of research and a vet on-line said small dogs should not be spayed (my Teddi is female) until they are 9 months and have had their first heat..She also claims that i should allow Teddi 6-9 weeks to recover from the 'heat' before spaying....medium sized dogs 12 months and large dogs 15 months and always allow the time of recovery after the 'heat'...She said it is to allow the female to internally mature and early spayng can cause problems with bladder and kidneys later n their life....I thought it made sense, so im leaving Teddi until she has had her first heat and 2 months recovery.....:animal36

Mammary Cancer in Dogs
Spaying greatly reduces the chances of a female dog developing mammary cancer. In those females spayed prior to their first heat cycle, mammary cancer is very, very rare. The risk of malignant mammary tumors in dogs spayed prior to their first heat is 0.05%. It is 8% for dog spayed after one heat, and 26% in dogs spayed after their second heat. It is believed that the elimination or reduction of certain hormonal factors causes the lowering of incidence of the disease in dogs that have been spayed. These factors would probably be, a similar hormone or possibly a combination of two or more of these. All my passed females were spayed BEFORE first heat, appox. 6 months old, none of them had problems with bladder and / or kidneys. They lived to be 13 plus years. My last girl was 17 y/o when she had to be put down. All my females were 10 lbs and over. I would check with your own vet and not take advise from an on line vet that has not seen your baby, just my opinion.

That can increase the risk of cancer. Early spay would be before 6 months but there is no real science that it causes any problems. It is better to spay before the first heat.

Sorry Matese... said vet...I looked the article again....Her name is Michele Welton..She has 35 years experience as a dog breed adviser, obedience instructor, canine phychologist and author of 17 books....She has trained and shown dogs in competitive obedience, agility, herding, tracking and schutzhund....Her work has been featured on The Orange County TV News Channel and in the Orange County Register Newspaper in Southern California....her web site is http:/www.yourpurebredpuppy.com...I have one of her books and i thought it very interesting.... :confused:

I would still speak to your vet about proper time to spay.
Your Dog
Your call

I agree with her. I have read that it's best to wait until after the growth plates close, most likely around eight months old but easily confirmed by an x-Ray. At the same time as a spay, all retained baby teeth should be pulled, as well. I would wait until several weeks after the first heat.

There is no study's on this but there are several articles that say growth plates still close even after being spayed.

You are right that there are no studies on small dogs. However, it's not a question of whether growth plates will close. It's a question about how early removal of the sex hormones affects bone growth and bone density if spaying/neutering is done before the growth plates have closed. There are numerous studies and articles about this about dogs in generals. This is only one.
EARLY SPAY-NEUTER IN THE CANINE ATHLETE, by Chris Zink, DVM, PHd

Early is generally before 6 months. Larger breed dogs are very very different then small breed dogs so all these study's on larger breed dogs are useless to smaller dogs.

The rate at which they grow is different, so they may need to be modified a bit, but they are far from useless. We extrapolate information on smaller animals (such as mice) used in medicine, and use these studies as a basis for human beings. Small dogs and big dogs are the same genus and species; therefore what we learn about variations within the dog world we can extrapolate and modify the studies to apply to our small dogs. For eqxample, in Yorkies growth plates generally close around eight months; in larger breeds they close at approximately fourteen months.

The idea of eradicating mammary cancer is very important to you, so you dismiss these studies about larger dogs. However, there is a very small chance of developing mammary cancer if spayed after the first heat. Have you seen studies about small dogs and mammary cancer, and can you link them? I'm curious why you believe what they say about mammary cancer in the larger dog studies, but you don't believe the other studies? If we follow your Logic that these studies about Yorkies are useless, why do you believe the studies about mammary cancer?

I prefer to weigh all of the health risks and benefits, and then I will choose a time to spay that would be best for my females in the future. I have always hadspayed females, never had mammary cancer, and I've never believed in spaying early.

Thank you everyone for the wonderful knowledge her on YT.....I simply don't have a lot of knowledge about spaying/neutering....but thanks to you all...im learning :aimeeyork

Research on spaying is cyclic....like kids and putting tubes in their ears or removing tonsils, it changes about every 8-10 years! The latest research I have been reading, has swung the other way....for the last couple of years, the "old wives tale" about allowing dogs to have their first heat before spaying, has come back around again, and what was old is now new again! For years, I advised getting females spayed before their first heat, because that was what was being promoted by vet schools and text books. Then it began to swing the other way, and now, it seems to validate it is best to let the female have her first heat cycle and then spay her.....because of the effect of the developing/mature hormones on every body system. So now, that is what I tell my new owners....wait about 2 months post heat and then spay. This is based on research and not any agenda for spay/neuter for population control ideology.

Thank you Yorkiemom1...decision made :)

I can tell you just from comparing two dogs one who was spayed before their just heat and one who was not by flipping them on there back with out any studies you can see that the mammarys are developed in the non spayed before first heat female and they are not in the female that was fixed before her first heat. With no developed mammarys there is a much less of a chance of mammary cancer. I have heard and seen many cases of mammary cancer. Of course every one needs to read and do there own research but upon doing mine it is simply a personal choice there is no science to back up that waiting is best. The growth plates still close and so on after being spayed. Although I do not recommend spaying before 6 months the younger they are the faster they heal and recover. I personaly have not seen anything that would make me sway from getting them fixed before there first heat.

That is quite true about the delayed closure of the growth plates.


I think that dogs just like humans are part of the same genus, and there is value to looking to large or medium breed studies for many conditions. Certainly hormones tend to act very similarly across all sizes of dogs. And an internal organ is an internal organ in all sizes of dogs.
But for osteopathic conditions it seems logical to conclude osteo configuration problems are more severely felt by large breed dogs. In fact they can be life - threatening - and certainly have severe quality of life implications.


And a Mammary Gland is the same Mammary Gland across all breeds of dogs - and there is no grand increase in this cancer with delaying a spay for one or two heats. The often quoted statistics are quite wrong - cancer mammary does not increase to 8% after even spaying after second heat. I will need to look up once again the often mis-understood and quoted study - but first only 50% of all mammary tumors are cancerous - and 50% are benign. Cancer risk does increase very very slightly after delaying one or two heats - the increase might be 8% on the .01% spaying before first heat. That means the increase is measured like this .01% goes up by 8% for simplicity at 10% increase the incident rate would go from 1% to 1.10% - a really really neglibile factor.

But there IS an increase .. For me, I prefer NO risk at all. 50% are cancerous...enough for me.

I am not a breeder and there is no reason for me to have intact dogs in my home. My dogs are in great shape and I don't for one minute buy into this whole thing about the growth plates. Maybe there is some slight difference, but it is obvious to me that it is not a huge one. I will continue to spay before the first heat. I will not put my dogs at any risk of cancer that can be avoided....that information is backed by research.

For anyone else, I would hope you would speak with your vet and get his/her feedback on this topic.

I rely on what my vet advises me. Again, I suggest you speak to your own vet before making your final decision.