I have typed out a lengthy response three times, but I keep losing them, so this will be my last attempt. Half of my last post disappeared, as well. There are many factors if one wants to read the entire, well researched article. It’s just not a black and white issue. In terms of orthopedics, it talked about the closing of growth plates being
delayed when removing the sex hormones before they reach maturity. A Yorkie’s growth plates generally close by eight months, but a simple X-ray will verify that. It doesn’t mean we can’t use these results knowing a Yorkie reaches puberty before a Golden and extrapolating the results.
I will respectfully disagree and choose to spay a female after the first or second heat. Dr. Zink recommends waiting until after the second heat because of the incidence of other cancers and the orthopedic considerations in pups that were spayed early .
In response to mammary tumors, she wrote, “ One study indicated a slightly increased risk of mammary cancer in female dogs after one heat cycle (8% increase), greater risk with two heats (26% increase) and increased risk with each subsequent heat.(19) However, a recent systematic review of the publications that advocate neutering to reduce the risk of mammary tumors in dogs indicated that 9 of 13 reports had a high risk of bias and the remaining 4 had a moderate risk of bias. This study concluded that the evidence that neutering reduces the risk of mammary cancer is weak and do not constitute a sound basis for firm recommendations.(20) Additionally, at the time when several of these studies were conducted (late 1960s). . .”
Pyometra is a real threat, so I will always chose to spay my females or leave the ovaries intact and do a tubal ligation. All of my dogs love walking, and I won’t walk a pup in heat, so that is another factor for me. I don’t like to deny them something they love. Katie was spayed at three, since she was with her breeder until then. She was bred after she had attained her championship and then retired early. Her breeder prefers that her pups be spayed after their first heat. Katie has well defined nipples, so we routinely examine them.
We have a huge overpopulation problem and too many pups are being euthanized, and because of this, I advocate spaying and neutering. To say that there are only pros and no cons is wishful thinking. This well-documented article by an esteemed veterinarian shows that.
http://www.caninesports.com/uploads/...tions_2013.pdf
Dr. Zink’s credentials
From Wikipedia: Christine "Chris" Zink DVM, PhD, ACVP, is the director of the Department of Molecular and Comparative Pathobiology at the Johns Hopkins School of Medicine. She also holds professorships in the Department of Pathology at Johns Hopkins and in the Department of Molecular Microbiology and Immunology at the Johns Hopkins Bloomberg School of Public Health. Zink researches the response of the immune system to retroviruses such as HIV and is currently investigating an animal model of antiretroviral therapy[1] and the potential of a common antibiotic to prevent HIV-associated neurocognitive disorders.[2][3][4]
As a veterinarian, Zink is known for consulting and writing on canine athletics[5] and is an expert on stem cell therapies for dogs.[6] She was named Outstanding Woman Veterinarian of the Year at the 2009 meeting of the American Veterinary Medical Association (AVMA).[7] Her books include Peak Performance: Coaching the Canine Athlete, Dog Health and Nutrition for Dummies, The Agility Advantage, and Jumping from A to Z: Teach Your Dog to Soar and Building the Canine Athlete: Strength, Stretching, Endurance and Body Awareness Exercises.[5] Zink is a Toronto-born Canadian[6] and has won several awards for her photography.