Stephen J. Birchard DVM, MS, Diplomate ACVS

Sunday, March 2, 2014

Should We Stop Spaying and Neutering Vizslas? Read on!

Evaluation of the risk and age of onset of cancer and behavioral disorders in gonadectomized Vizslas
M. Christine Zink, DVM, PhD; Parvene Farhoody, MA; Samra E. Elser, BS; Lynda D. Ruffini; Tom A. Gibbons, MS; Randall H. Rieger, PhD

JAVMA, Vol 244, No. 3, February 1, 2014

Commentary: Vizslas born between 1992 and 2008 were surveyed by an online questionnaire; 2505 dogs were included in the study. Dogs that were spayed or neutered were more likely to develop several types of cancer (such as mast cell tumor, lymphoma, and hemangiosarcoma) compared to in tact dogs. Behavioral disorders, such as storm anxiety, were also more common in gonadectomized dogs. The younger the dogs were spayed or neutered, the earlier they would develop the above problems.

The authors felt that more studies are needed to confirm their findings, but that owners should be made aware of these adverse effects of spay and neuter in addition to the benefits.

In the Discussion section of the paper, the authors cite other studies in animals associating gonadectomy and increased incidence of cancer. They also postulate on the mechanism of the association, including studies showing that sex hormones may play a role in maintaining immune surveillance for cancer cells.

Of course the benefits of spay and neuter, such as controlling dog and cat populations and the many other medical benefits currently outweigh the adverse effects. But this study shows that we need to maintain a healthy level of surveillance of the potential adverse effects of gonadectomy and attempt to determine: is this association between cancer and spay/neuter true for all breeds, even mixed breeds, and what is the pathophysiology behind it.

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