Labrador spay timing: balancing growth plates and mammary tumor risk

Hi Donna,

Stella’s size at six months, approaching 60 pounds, puts her firmly in the large breed category, and that makes this decision more nuanced than a simple “spay early” recommendation. Both your breeder and your veterinarian are working from legitimate concerns, but they are focusing on different risks. Given your family’s experience with Labradors and orthopedic problems, I think it is especially important to consider Stella’s skeletal development when deciding when to spay her.

The concern about growth plates is legitimate. Estrogen contributes to normal growth plate closure, so removing the ovaries before skeletal maturity can prolong growth plate activity and alter the proportions of the developing bones. In large breed dogs, this is particularly relevant because their skeletons mature considerably later than those of small breeds. Think of Stella’s skeleton as a house still being framed. The structure may look nearly finished from the outside, but some of the most important work is still happening inside. Studies in Labrador Retrievers have found increased rates of certain joint disorders in dogs spayed at younger ages, although the evidence does not mean that every early spayed Labrador will develop orthopedic disease, nor does it establish that waiting causes cancer.

Your veterinarian’s concern about allowing heat cycles is also valid. Spaying before the first estrus provides the greatest reduction in mammary tumor risk, and that protective effect decreases as the number of estrous cycles increases. However, allowing Stella to mature for additional months does not mean accepting an inevitable cancer problem. For a large-breed female, a reasonable compromise is often to allow additional skeletal maturation and plan the procedure around 12 to 14 months, typically 2-3 months after the first heat, depending on her individual growth, orthopedic health, household circumstances, and your veterinarian’s assessment. I would be more comfortable with that individualized approach than choosing either six months or 18 months as an absolute rule. Preventing accidental breeding during this period is extremely important.

Laparoscopic ovariectomy is certainly worth investigating if it is available to you. It is a surgical approach that removes the ovaries through small incisions and generally results in less tissue trauma and a comfortable recovery, but it does not change the hormonal consequences of removing the ovaries, so it does not make early spaying equivalent to waiting for maturity. It is best thought of as choosing a gentler surgical route, not as a solution to the timing question. For Stella, I would discuss a plan centered around allowing more growth, closely monitoring her orthopedic development, preventing pregnancy, and considering laparoscopic surgery when the timing is appropriate.

Given her size, breed, and your previous experience with Labradors, I think your instinct to slow down and make this a thoughtful decision is entirely appropriate. The other thing I would mention is that, as you’re probably aware, spayed females are often more prone to becoming overweight, due to the effects of hormones on the metabolism. Given that Stella is already quite a large girl, I would want to be sure that her weight is appropriate for her body size. Your vet can help you with this, or you can use body condition scoring to see if any adjustments might be needed.

Best wishes,

• Dr. Paola

This article is a part of our weekly Ask Dr. Paola series

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Dr. Paola Cuevas is our Senior In-House Veterinarian at Dogster and Pangolia. She has over 19 years of experience working with an array of species and loves sharing her knowledge and experience with our readers and aims to provide assistance with any issue presented by your non-human family members. She received her degree from the University of Guadalajara, Mexico.

Her passions are animal welfare and preventive medicine, and has skills in the fields of nutrition, microscopy, clinical pathology, diagnostic imaging, and endoscopy. Paola frequently contributes pet care insight to various media outlets like PetMD, The Daily Record, Parents.com, etc.

Paola is also an animal behaviorist with extensive experience in positive reinforcement animal training.