In an attempt to stem the production of unwanted dogs that are put down each year, the desexing of puppies prior to sale will soon be mandatory in South Australia. However many studies show sterilisation of young puppies puts them at substantially higher risk of a range of serious health and behavioral issues.
Concerns raised by the Australian Veterinary Association point to the dangers of infection and anesthesia posed by surgery at such a tender age, but this barely scratches the surface of the negative consequences that owners and their unfortunate dogs may face.
Mandatory puppy desexing prior to sale will interfere with development of good social skills during the most critical period of social development.
Though (technically) puppies can be spayed or castrated (neutered) from the age of 6 weeks, in small breeds in particular it is prudent to delay the procedure until a minimum body weight safer for surgery is attained. This is to avoid complications posed by low body weight such as hypoglycemia and hypothermia. So by the time the stitches are removed – in all but the largest breeds – the puppy will already be 10 to 12 weeks old before it is ready for the new owner to collect.
Given that the puppy experiences its most intense ability to bond to humans between the ages of 6 and 8 weeks, such a delay not only deprives it of the opportunity to be thoroughly socialized by its new owner – you – but also may reduce its ability to attach emotionally to you and your family. And the timing of such a traumatic veterinary intervention during the heightened fear phase of development of the young pup – between the ages of 8 and 10 weeks – can imprint a lifelong fear of many events associated with the trauma such as riding in cars, meeting new people, being handled, and visiting the veterinarian.
Environment Minister Ian Hunter seems to think that the rising number of people hospitalised in South Australia due to dog attacks is very strong case for mandatory desexing of animals. However, research suggests that sterilization does not always improve dog conduct, and is often associated with worse behavior.
Reviewing owner-reported behavior of a random sample of 1552 dogs, Serpell and Duffy discovered that, contrary to popular opinion, there’s little evidence that castration is an effective treatment for aggressive behavior in male dogs, and may exacerbate other behavioral problems. Castrated dogs are in fact about 30% more likely to show aggression to their owner and other dogs and spayed female dogs are about twice as likely to be aggressive toward their owners and to strangers than intact females.
Further they found that sterilisation doubles the likelihood that a dog of either sex will be sensitive to handling and dislike being touched, particularly bitches. Of additional concern, sterilised dogs (especially males) of either sex are about 40% more likely to be fearful than their more confident, intact brethren, with important negative implications for their sociability and likelihood to fear-bite.
Other Unwanted Behaviors
Looking specifically at males, on the positive side, early neutered dogs have a lower incidence of escaping, separation anxiety and inappropriate urination when frightened. Other undesirable male dog behaviors such as roaming, inter-male aggression and urine marking in the house is often (but not always) effectively curbed by castration but its success in this regard is not influenced by the age this is done. If castration is going to be useful to reduce these unwanted behaviors, it will be useful at any age.
On the negative side, castrated dogs are more likely to suffer from noise phobias and unwanted sexual behaviors (such as inappropriate humping).
What about the health benefits of sterilization? Yes, there are some, but also some serious negative impacts, particularly from early sterilization. Once aware of these, veterinarian Dr Karen Becker was full of remorse for the needless suffering she unwittingly inflicted on the dogs of responsible owners she had previously advised to neuter early in life. In this video she weeps for what she put them through:
Looking at general issues common to either sex, the most significant of these with respect to the number of dogs affected are cancer and orthopedic issues.
Sterilisation is sometimes justified to protect dogs from reproductive cancer. But it’s a weak reason because the risk is very low – under 1% for males (testicular cancer) and only around 0.5% for bitches. Mammary cancer however is very common in some breeds and spaying bitches before the age of 2 ½ years has been shown to reduce the risk significantly.
Early sterilization on the other hand appears to increase the risk of other common cancers as it shuts off the proven protective effect of sex hormones.
Take bone cancer (osteosarcoma). It’s a common cause of death in many medium sized and larger breeds, and the earlier sterilization occurs, the more likely it is to occur. Even the old protocol of neutering before one year of age has been shown to multiply the risk three (in bitches) to four (in male dogs) fold. For example, in a group of Rottweilers sterilized prior to one year of age one study found osteosarcoma struck 25% of bitches and 28% of dogs.
Another one is hemangiosarcoma, a cancer of blood vessel cells. Comprising around 6% of all canine cancers, it’s fairly common. Early sterilisation increases the risk by 60%, and research shows that the most protective strategy for your dog, especially if it is a bitch, is to delay the operation until after puberty.
Basically, the longer a dog has normal levels of sex hormones, the safer it is from most cancers.
Further, the known influence of sex hormones on skeletal development has raised concerns that early prepubertal or “pediatric” spaying might predispose dogs to weak bones and joint problems.
Some research suggests there is merely a delay to closure of bone growth plates resulting in slightly taller adult size in dogs sterilized at a young age. However, since growth plates close at different times in different bones, neutering when some bones have completed development and others have not could result in a misaligned skeletal structure with sub-optimal performance and durability. In keeping with this theory, one study of almost 2000 dogs found a 70% greater risk (but reduced average severity) of hip dysplasia in dogs spayed or castrated before 5 ½ months old. A sterilized dog or bitch is also twice as likely to suffer rupture of the cranial cruciate ligament, contributed to no doubt by their greater propensity to also be obese or overweight.
Other Health Issues
The earlier a bitch is spayed, the more retarded the development of its external genitalia, predisposing it to an increased risk of vaginal dermatitis, inflammation and infection. In addition, spayed bitches are three to four times as likely to suffer from chronic bladder infections, especially those sterilized before 5 ½ months of age.
All of these behavioral and health effects of puppy desexing prior to sale will amount to higher veterinary expenses for owners and reduced satisfaction with dog ownership – known triggers for having dogs put down or surrendered to shelters. Given this and the deleterious welfare implications of neonatal sterilisation, the fact that the chief bodies who have been pushing for compulsory desexing prior to sale of puppies have been peak welfare organisations such as the RSPCA and the Animal Welfare League is nothing short of ironic.
 Deborah L. Duffy, Ph.D., and James A. Serpell, Ph.D., Non-reproductive Effects of Spaying and Neutering on Behavior in Dogs, Center for the Interaction of Animals and Society, School of Veterinary Medicine, University of Pennsylvania
 Long-Term Health Risks and Benefits Associated with Spay / Neuter in Dogs (Literature review) Laura J. Sanborn, M.S. May 14, 2007