First off I don't think lots of Vets are in the know on this subject. I think they are just trying to avoid owners of unwanted litters. Because yes in the U.S. there is a problem with unwanted and euthanized pets.
The fact is being a responsible pet owner.
Male or Female these are very important sex hormones. They help with Muscle and Bone Growth.
Medium to large breed dogs have not completed growth and development by one year.
Early spay/neuter can prevent some cancers. But also early spay/neuter can increase the chances of some aggressive cancers.
Early spay/neutering could cause joint and hip issues. Also not having these hormones down the road can increase chances of Endocrine issues.
Having early spay could cause incontinent at a fairly young age.
Here is a lot of info on the subject.
Best times:
Never or unless having an issue.
Look into these alternatives which they get to keep these important sex hormones. For females a Modified Spay Or Ovary Sparing Spay. For males look into a Vasectomy.
For a larger breed dog. Wait until Bone Growth Plates have closed. Which is between 14-16mo.
Most people wait until 18-24mo to spay/neuter. But I would wait longer at least 2yrs before doing anything. Then look into these other options of Ovary Sparing Spay for Females or a Vasectomy for Males.
Ovary-Sparing Spay - Parsemus Foundation
Projects Archive - Parsemus Foundationovary-sparing-spay
Ovary-sparing spay is a way to
spay female dogs without the
increased cancer risk and health impacts from
hormone loss.
Effects of Neutering on Dog's Health and Behavior
https://
healthypets.mercola.com/.../archive/2016/10/16/effects-neutering-
dogs.aspx
Oct 16, 2016 · In a desexed
dog, it’s
important to check all
hormone levels if one is out of whack. Another example Valente cites is a
spayed female dog who becomes incontinent at a fairly young age. This is usually the result of an
estrogen deficiency, and if so, normalizing the
estrogen level may resolve the incontinence.
A Modified Spay Procedure Preserving Female Dog Ovaries
https://
healthypets.mercola.com/.../archive/2013/09/23/
modified-spay-procedure.aspx
Sep 23, 2013 ·
Dr.
Michelle Kutzler believes that modified spay procedure, which preserves the ovaries of female dogs, is a better option than surgical sterilization. Call Toll Free: 877-985-2695 Free Newsletter
Ovary sparing spay
Image: petguide.com
Ovary-
sparing spay may be a way to have one’s cake and eat it too: a way to
spay female dogs (thus addressing population concerns), without the increased cancer risk and health impacts from hormone loss (particularly in large and giant breeds) that are only recently beginning to be understood.
Ovary-
sparing spay is approved by the
AVMA.
Age To Spay Or Neuter, Ovary Sparing Spay, Vasectomy ...
https://www.
dogsnaturallymagazine.com/age-to-
spay-or-neuter-
ovary-
sparing-
spay...
For bitches, the ideal procedure is an
ovary sparing spay. This
surgery removes the entire uterus and cervix, leaving the
ovaries. The bitch can then no longer become pregnant or develop uterine diseases. A
tubal ligation should never be performed on a female
dog.
Long-Term Health Risks and Benefits Associated with Spay ...
https://www.
dogsnaturallymagazine.com/long-term-health-risks-benefits-
spay-neuter-
dogs
- Summary
- Findings from Studies
- Conclusions
- An objective reading of the veterinary medical literature reveals a complex situation with respect to the long- term health risks and benefits associated with spay/neuter in dogs. The evidence shows that spay/neuter correlates with both positive AND adverse health effects in dogs. It also suggests how much we really do not yet understand about this subject.On balance, it appears that no compelling case can be made for neutering most male dogs, especially immature male dogs, in order to preven...
What is the effect of sex hormones on dog development ...
https://
www.petplace.com/.../vet-qa/what-is-the-effect-of-
sex-hormones-on-dog-development
Mar 02, 2015 · Bone and muscle growth are the two things that I would like to hear discussed. Although a lot of research has not been done in the important role of the
sex hormones play from birth to old age in a dog, it's in any physiology book on canines and anyone with a knowledge base to understand it will understand it.
Effect of Hormone on Dog Aggressive Behaviour - Daily Dog ...
https://www.dailydogdiscoveries.com/tag/effect-of-
hormone-on-dog-aggressive-behaviour
Dec 17, 2016 · A
dog’s endocrine system is composed by several glands that are meant to produce
hormones which are then transmitted through the bloodstream where they have several effects on the
dog’s body and mind. The
hormone testosterone, in particular, is secreted by the male
dog’s testes and is known for producing several physiological and ...