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Neutering- the number one cause of aggression problems in dogs.

Yesterday someone reached out for help with an adolescent male German Shepherd that had launched at someone and bitten a person. When I gave her a possible date to come over for an evaluation she mentioned that on that day the dog would get neutered, an advice she got from her veterinarian to reduce and avoid any aggressive behaviors in the future. 

I was very disappointed to hear that as over the last 15 years research has proven that neutering and spaying have the opposite effect. Neutering male dogs causes more behavioral problems. ( Dr. Coren 2018) Unfortunately veterinarians today still advice this very outdated procedure to “solve” aggression and over-excitement based behavioral problems. I believe the reason for that is two fold. The main reason is outdated schooling at the current Vet-University programs who often still teach practices and protocols established in the 1960s. Another reason is the money, neutering and spaying is an easy and quick buck in their pocket. 

Veterinarians - outdated information and false statements

The problem in today’s society is that the internet is full of false statements about neutering and spaying. Some of these websites are professionals such as large groups of Humane societies and many veterinary groups. Almost every member of these groups talks about responsible dog ownership and that the responsibility we have as humans is to spay and neuter our animals. They will give outdated statements like:

  1. Spaying and neutering makes dogs more affectionate

  2. Neutering reduces sex hormones that contribute to stress and aggression 

  3. Most aggression problems are avoided by early neutering 

Beside the above statement some veterinarians will also state that neutering a male dog will reduce the risk of prostate-cancers, which is absolutely false, the opposite is actually the truth. Neutered males have a much higher risk of developing prostate cancer. Dr. Smith a highly renowned reproductive specialist here in Washington State said to me: “ In my 33 years of reproductive medicine I have not seen one intact male with neoplasia (prostate cancer), all neoplasia cases were neutered males.” She also stated that unfortunately still many veterinarians today have outdated and false information on spaying and neutering. Dr. Smith is a Member of the Society for Theriogenology (since 2000) and a regular attendee to educational conferences on the topic of canine reproduction.

Another leading veterinarian is Dr. Karen Becker, she is a proactive and integrative wellness veterinarian. Here is what she has to say about spaying and neutering: 

Dr. Karen Becker about spaying and neutering dogs.

New Research proof that spaying and neutering increase aggression

In Europe spaying and neutering practices are completely different. In some countries, like Norway, it is even against the law to neuter or spay dogs unless there is a medical reason. 99% of the Swedish dogs are in-tact. One of the reasons for this phenomenon is that the European universities update their programs a lot quicker with new information gained from the latest research. 

One of the fist studies conducted to address the issue of behavioral change as a result of spaying and neutering was a study published in the Proceedings of the Third International Symposium on Nonsurgical Contraceptive Methods for Pet Population Control*, by Dr. Deborah Duffy and James Serpell. The second was a master's thesis at Hunter College in New York which was submitted by Parvene Farhoody**.  Both studies used C-Barq method as there base for assessment. To read more about the c-barq method follow this link : https://vetapps.vet.upenn.edu/cbarq/

If you are interested in all the details of the study and you have access to scholar libraries I highly recommend looking it up. The main outcome of both studies is that spayed and neutered dogs show considerably more aggression than intact dogs. For both male and female dogs the increase of aggression varied from 20% to almost double the aggression. 

My own experiences

As data is continuously being collected the evidence of negative effect on behavior due the spaying and neutering increases. In my personal experiences and observations 99% of the severe aggression cases I deal with as a behaviorist are neutered or spayed dogs. Also neutered and spayed dogs show more fear related behaviors and have more anxiety. They will response to loud noises by showing avoidance behavior or excessive barking. When these dogs are exposed to an unfamiliar situation, like being approach by a stranger they often bark excessively or growl. The same with dog reactivity, neutered and spayed dogs are more dog reactive and show aggression to other dogs. The younger the dogs are spayed or neutered the greater these fear based behaviors are observed. As a behaviorist it is very clear for me, I see this on a daily basis. It is my hope that via continued research society led by veterinarian groups, they will change their practices and so contribute to more balanced dogs. 

Bart de Gols