"spaying a dog before her first heat cycle will decrease her chances of mammary cancer by over 98 percent."
although it is the job of the veterinarian to educate his clients and portray the pros and cons of surgery, as clients to that veterinarian, it is also our responsibility to make informed decisions and educate ourselves. Veterinarians cant make a decision for you, but they can answer questions you may have. There is a wealth of information out there. Just as you educate yourself before you purchase a new car (vs allowing the car salesman to pick the vehicle for you).
Dont base a decision on one article or study, because there are many great studies out there that look at multiple things (for instance, the UC Davis study reporting a 6% case rate of mast cell tumor in dogs that were neutered vs a 98% increase in mammary tumor rate in females spayed after their second heat cycle. In females spayed before their heat cycle, likelihood of getting mammary tumor is approx 0.05% (I couldnt find the primary article on this one, but was told this by my vet, I learned about it in my oncology course, and the link above discusses it).
thanks to everybody who shared information on this post! the UC Davis study is very interesting!
So a 98% increase over .05% would give you and actual rate of 0.1% for mammary cancer in late spay vs. a 6% rate of MCT in early spay. If you include the increase risk of orthopedic injuries in early spaying it would seem that late spay makes more sense.
How much would family history play a part if available?
Curious if this is the case across all breeds or just specific breeds?
Originally Posted by jecartag
so I did not word that correctly, thanks for catching that! It depends on what is meant by late spay. If it means at 12 months of age like what UC Davis study described "late spay" as, then that may make sense...but, spaying your dog after 2.5 years of age to decrease chance of mammary tumor has not been shown to decrease this risk. However, there are, of course, other benefits.
Originally Posted by Buck Mann
Here is another quote taken straight off of Veterinary Society for Surgical Oncology website....
•ovariohysterectomy reduces the risk of mammary neoplasia with an incidence of 0.5% if before neutered before the 1st estrous, 8% before the 2nd estrous, 26% after 2 ovarian cycles, and no protective effect after 2.5 years
•ovariohysterectomy is not indicated if > 2.5 years as does not affect biologic behaviour
And what about an unspayed female who develops pyo cause she is not spayed or being breed?
Originally Posted by wheelhorse
Yes for sure to do that.
Originally Posted by rbr
In regards to mammary cancer (MC) in intact females; a quote from the discussion of the results:
"This is the first study of the effects of neutering on an array of joint disorders and cancers in the same breed of dog, using a single database and examining the variables of gender and early and late neutering versus leaving the dogs gonadally intact. No cases of MC were diagnosed in intact females in this study. This finding is partially explained by the relatively low frequency in which MC is diagnosed in Golden Retrievers . While this finding contrasts with the general concern expressed about the risk of MC in gonadally intact females , , , it is consistent with the recent findings from a systematic meta-analysis finding a weak link, if any, between neutering and reduced risk of MC ."
Source (13): Beauvais W, Cardwell JM, Brodbelt DC (2012) The effect of neutering on the risk of mammary tumours in dogs – a systematic review. J Small Anim Pract 53: 314–322. doi: 10.1111/j.1748-5827.2011.01220.x. Find this article online
You can read the entire UC Davis study:
I spayed my dog before her first heat and she ended up with thyroid problems which caused her to have seizures. It took awhile to find out what was causing the seizures but once we did and got her on the proper meds she was fine. I heard that spaying them early can cause thyroid problems.
Here are a couple interesting articles on early spay/neuter and the health effects that go along with it.
This one is quite a bit older, but still raises some interesting points....http://www.thedogplace.org/Spay-Neut...elete_zink.asp
This one is a great comparison of the pros and cons of early spay/neuter...http://www.naiaonline.org/pdfs/LongT...uterInDogs.pdf