What’s become of greater interest to me of late are several studies showing the ill effects of surgical gonadectomy, or instant hormone-pause.
A study done in UC Davis and published in February 2013 revealed some startling health consequences of neutered animals, both male and female. The research tracked 759 Golden Retrievers, and looked at early neuter (less than one year of age) vs later neuter (12 months or older) vs intact dogs and five common diseases:
- Hip dysplasia (HD), the arthritis of the hip joint common to dogs
- Cranial cruciate ligament (CCL) damage, the “football injury” of dogs’ knees
- Hemangiosarcoma (HSA), a type of cancer that can be fatal
- Lymphosarcoma (LSA), immune system cancer, usually fatal
- Mast cell tumors (MCT), yet another cancer that can kill dogs
To summarize the researchers’ findings:
- Neutered animals fared significantly worse in all five diseases.
- Early neuter of males doubled the rate of hip dysplasia compared to intact males.
- None of the intact animals had cruciate ligament disease. Zero. It only appeared in the neutered animals.
- Early neutered males had three times more LSA than the intact males, while late neutered males had no LSA.
- The percentage of HSA was four times higher in late neutered females than in either intact or early neutered females.
- MCT was absent in intact females but present in neutered females. In males, neutering status made no difference.
So, in dogs of both sexes, neutering had significant ill effects in this large study, though it wasn’t uniform across the board.