A viewer asks: “My female puppy is now 6 months old and lives with her father and me. He is unsterilized and we met with the veterinary surgeon to discuss options ranging from vasectomy for him, to full spay for her, to my preference, which would be ovary sparing hysterectomy. I ran across a popular alternative veterinarian who points to research that shows there are issues with cancer, and so forth, in females whose gonads are entirely removed. She says, like us, that dogs need the endocrine hormone system in order to function properly. The surgeon, is able to do these other options, but has seen issues with pyometra and mammary tumors (50% malignant) in female dogs that have had ovary-sparing spay (OSS).” What can we tell him?

This is a complicated business that will be variable as no two dogs are alike, just as no two people are alike. All have a karmic history and varying degrees of vulnerability to developing maladies of all kinds. There are arguments on both sides as you are pointing out. In general, we favor avoiding surgical alteration for the most part. There are as many negatives as positives, and this is an example as well. It is true that the hormonal cycles, and biochemical effects of the gonads, contribute to healthy well-being. In a significant percentage of cases, this becomes more difficult a situation to manage because animals will have behavioral changes in response to surging hormones—they will want to wander; they will want to have contact with others for breeding. This is all instinctual but it is a powerful behavioral influence and can lead to much frustration, and even incompatibility with particular households in terms of what can ensue with animals wanting to roam and having a more highly charged interaction when they meet other dogs, and so on. So we think this is something you need to research about the pros and cons and make a decision based on your own circumstances and what you feel is your responsibility in providing a safe and comfortable environment for your pets.