A Link Between Desexing and Reactivity

ResearchBlogging.orgWhile desexing bitches is a common surgery, I was pleased to see Kim et al. take note that “the side effects of the operation, particularly any changes in behaviour, have been quantified in only few studies”.

That is to say, despite us commissioning vets to take the ovaries and uterus out of a great many bitches, we don’t really have much research about it. It’s a pretty scary state of play.

This particular study took 14 healthy German Shepherd bitches, between 5 and 10 months old. Half of these dogs were spayed, and the other half left entire. (The bitches were assigned to each group randomly, except for litter sisters, which were assigned opposite groups.)

After the spay, and having been given 4-5 months to recover from the surgery, the bitches were filmed in their kennel as a stranger and a dog approached. This footage was then scored based on how reactive the bitch was. A score of ’3′ indicated severe reactivity, and a score of ’0′ indicated no reactivity. The scorer was unaware of whether the bitch was spayed or not.

Photo courtesy of Rachel Willis.

Photo courtesy of Rachel Willis.

The reactivity of each bitch was recorded several times, and the reactivity of each bitch declined over the study. It’s likely that the bitches habituated to the novel stimuli. However, despite this affect, bitches in the ovary-hysterectomy group scored higher throughout the study.

Before generalising these results, there are some matters to consider:

  • Reactivity was only measured in a kennel setting, and how these dogs react in the ‘real world’ may be different. We can’t suppose that our pet dogs are going to respond in the same way as kennel dogs.
  • The reactivity of these dogs was not measured at the start of the study. While it is unlikely, perhaps more reactive dogs happened to fall into the treatment group by chance. Without a ‘before desexing’ score, we cannot be sure of this.
  • The authors make note that these results are for German Shepherd bitches aged 5-10 months old. We can’t assume dogs of all breeds and ages would respond this way to spays.
  • Further, the bitches in this study are working lined German Shepherds, which may be more reactive than the typical pet dog.


However, this study notes that other studies on bitch spays have shown that as a group spayed bitches are:

  • More likely to gain weight
  • More aggressive than prior to spay (if they were aggressive prior to spay)
  • More active
  • More likely to have urinary incontinence
  • More likely to be reactive after surgery


The authors recommend:

[V]eterinary practitioners should inform owners that a bitch may become more reactive after spaying either because they have lost the calming effects of progesterone or because elevated gonadotropins stimulate release of adrenal androgens.

Kim HH, Yeon SC, Houpt KA, Lee HC, Chang HH, & Lee HJ (2006). Effects of ovariohysterectomy on reactivity in German Shepherd dogs. Veterinary journal (London, England : 1997), 172 (1), 154-9 PMID: 16772140

Further reading:
Desexing: It’s bad for Vizslas too
Is desexing a cult?
Desexed dogs – 2.6 times less likely to bite!
Why would you NOT desex your dog??
Golden Retrievers: Cancer if you do, cancer if you don’t


Research Finds: Hungry Dogs are Hungry

Some Thoughts About Dogs welcomes guest blogger Michael D Anderson from NerdWallet.

Photo © Ruthless Photos.

Biologists at the University of Vienna published a study last month about dogs’ temperament in relation to their owners. The study hypothesized that without their owners, dogs would be more likely to view ambiguous events as negative ones. This is a common feature of human cognition – you’ll often hear that depressed people “see the glass as half-empty.”

The abstract of the study is available here.

The Vienna researchers found that, unlike in humans, when presented with ambiguous stimuli, dogs don’t have a negative judgment bias when they’re in distress. This is a jargon-loaded, awkward way of generalizing on the following: These scientists found that, when hungry, dogs don’t become emotional if their owners are absent—they go right to the bowl of food because, following one of the experiment’s stipulations, these dogs hadn’t eaten in at least three hours.

Experimenters measured how long it took each of 24 dogs to approach a bowl—the study had initially included 32 animals, but the scientists decided to exclude dogs that had unusually extreme separation anxiety.

In training—before the two testing days—the biologists conditioned the dogs to identify one side of the testing room as positive—where a bowl had food—and the other side as negative—where a bowl was empty.

On testing days, they refreshed dog’s memories about the room, but then they changed up locations a bit. They established near-negative (i.e. closer to the original negative location), middle and near-positive locations. At the beginning of each test, they approached one of these new locations with a bowl.

The experimenters then tested for “latency,” or long it took the dogs to approach the bowl, when the owner was present and when he or she was absent. The owner, they said, had an effect. The dogs took longer to approach the near-negative location and shorter to approach the near-positive; in tests without the owner, they approached at the same rate to each respective location.

What I don’t understand is how the biologists so tightly connect dogs’ approach to food—which they measure as “latency”—to their mood. The idea, I think, was that dogs should take longer to approach a bowl—even if the location is near-positive—when the owner isn’t there. The idea is that the dog is distressed without the owner around—they’ll start barking, toileting, or whatever else instead of going right to the bowl.

But these dogs were hungry: as I mentioned at the beginning of this piece, owners were asked not to feed their dogs in the 3 hours before the study.

The whole premise of this experiment is odd. What they pose is that dogs are less temperamental than humans: emotional distress or not, they’ll logically discern where the food is. What I think they meant to ask is whether or not dogs behave any different after domestication: Are they still primal? The answer, I think, didn’t even require extensive experiments: yes, they’re hungry, owner be damned.


Further reading:

“Animal Behaviour: Cognitive Bias and Affective State”

“Bias in Interpretation of Ambiguous Sentences Related to Threat in Anxiety”

“Dogs Showing Separation-Related Behavior Exhibit a ‘Pessimistic’ Cognitive Bias”


This article comes from NerdWallet, a consumer-focused, analysis-driven website dedicated to dissecting the data behind the story.


McGreevy’s Thoughts on Dog Science

This post is part of the McGreevy seminar series. Click here for the index.


Paul McGreevy spoke a lot about research, and basically reaffirmed my points in my post Paucity in Dog Science.  McGreevy believes that ‘the times are turning’ and dogs are beginning to be a legitimate research topic. There is a lot to be learnt about dogs.

In my post ‘Paucity in Dog Science’, I identified three reasons that dogs are rarely scientifically studied.  Firstly, expense. Secondly, that dogs do not have an official academic field of study. And finally, because humans are self centred and only interested in themselves.

Paul McGreevy identified different issues hindering the research of dogs. Continue reading


Belyaev’s Fox Experiment – Index

After frequently finding myself encountering references to Belyaev’s fox experiment in a number of dog-related texts, I felt the need to investigate his experiment more thoroughly.  This has resulted in a lot of reading, but a lot of new found knowledge.  From this reading, I hope to have a better understanding of the connection dog-authors are trying to make between dogs and the fox experiment. I hope it also proves useful for my readers.

Part I – Introduction
A summary of the work of Belaev in his ongoing experiment with foxes.

Part II – Changes
Description of the changes observed in Belyaev’s fox experiment.

Part III – Answers
Possible reasons for the changes seen in the foxes in Belyaev’s experiment.

Part IV – Dogs?
Why does the Belyaev fox experiment matter to dogs?

I hope this series has been of interest, as I thoroughly enjoyed researching.  I did cut out some bits and pieces, so please feel free to comment if you feel I haven’t answered a burning question for you! Additionally, if you would like in text referencing, I can provide such.

References: Continue reading


Belyaev’s Fox Experiment – Dogs? – Part IV

This post is part of the series on Belyaev’s fox experiments.
(index | part I | part II | part III | part IV )

You may have read my previous three posts, which have explained details of Belyaev’s fox experiment.  And you may have wondered the relevance of studying foxes on a blog about dogs.

Obviously, foxes are not dogs. They’re not even wolves. However, they aren’t far off it.  Regions of fox chromosomes correspond with those of the dog (to be specific, fox chromosome 1 seems to indicate a fusion between chromosomes 1, 33 and 12 as we see today in the dog).  That means that we should not disregard this research because it is a different species.

Chiefly, this study can be used to examine the process of dog domestication. Because domestication and associated variability seemingly occurred relatively quickly, there have been doubts that Darwinian theories are applicable. However, this study shows that significant changes can be seen in a brief period of time and generations. Coppinger (in his book Dogs) uses this study to show how quickly a significant change can take place – in the foxes here, significant morphological and physiological changes were seen in just 8-10 generations. This all occurred with just one selection pressure – selecting for ‘tameness’.

Dogs are very different to wolves.

This is surprising on a surface level, but when considering the causes of these changes it is not so remarkable.  Indeed, these changes have been seem occur in a similar way in terms of wolf’s domestication to dogs.  For example, dogs play as adults while wolves do not, and dogs carry many other juvenile-wolf characteristics.  Furthermore, dog puppies respond to human cues like fox domesticated pups and indeed are ‘dog like’ in many behavioural ways.  It is likely that the causes of the foxes changes are also the reason the wolf is the dog we know today.

On a larger scale, this research shows that we can select for nature.  Consider that these dogs were never trained, but were selected on their genetic amicability to humans.  This is a loud message on how we should be selecting dogs to breed from.

I hope this series has been of interest, as I thoroughly enjoyed researching.  I did cut out some bits and pieces, so please feel free to comment if you feel I haven’t answered a burning question for you! Additionally, if you would like in text referencing, I can provide such.

References: Continue reading