We offer both ovary sparing spay for females and vasectomy for males as a way for certain dogs to retain the sex hormones without being able to reproduce.
Current evidence indicates that, at least in large breed dogs, the health benefits of keeping the hormones may outweigh the health risks. A recent publication from U.C. Davis (de la Riva, Hart et al, 2013) looked at two joint disorders (hip dysplasia, cranial cruciate ligament injury/tear) and three cancers (lymphosarcoma, hemangiosarcoma and mast cell tumor). It was determined that for all five diseases analyzed, the disease rates were significantly higher in both males and females that were sterilized either early or late compared with intact dogs.