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


Vaccinations Last At Least Three Years

ResearchBlogging.orgWhen reading Terrierman he made reference to the work Schultz has done on the duration of vaccines. Intrigued, I decided to read one of his articles. I dug up a review Shultz wrote on the duration of vaccines. It looks at available research on vaccines and their ‘duration of vaccinal immunity’ (i.e. how long they last).

Whether a dog has immunity can be determined either by antibody titres (a ‘titre test’) or a challenge study (e.g. deliberately exposing the dogs to the pathogen).


For distemper, parvovirus, and adenovirus the published data suggests an immunity period of 3 years or longer minimum.

Using blood products to test immunity, it seems that vaccines last 3 years or longer.  When using challenge studies, dogs that were vaccinated 11 years ago did not contract the virus.

According to this article, if a cat or dog is:

  • Vaccinated with core vaccines at 12 weeks of age or older,
  • Is revaccinated at 1 year old, and
  • Receives a vaccination “not more often than every 3 years”

then this would be as protective to the pet as annual vaccination.

However, non-core vaccinations last a year or less.

Table 1 shows estimated minimum duration of immunity for the 4 core canine vaccines.

How long does a dog vaccination last?

Shultz concludes, “Extending the revaccination intervals for canine and feline core vaccines does not place the animal at increased risk to developing vaccine preventable disease, but it does reduce the potential for adverse reactions”

He also recommends using titre tests to ensure that a puppy’s final vaccine enduces an immune response – and to revaccinate if the titre does not indicate that an immune response was produced.

Oh, and on cats? According to this paper, feline vaccines less researched, but feline parvovirus, calcivirus and herpes seems to last at least 7.5 years. Exception is feline leukemia which provides immunity for 1 year or less.


Ronald D. Schultz (2006). Duration of immunity for canine and feline vaccines: A review Veterinary Microbiology, 117 (1), 75-79 DOI: 10.1016/j.vetmic.2006.04.013


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


“From fork to friend”

Recently, I attended an Adelaide University event called Research Tuesdays, where one receives a free ‘crash course’ of sorts, with the university promoting their recent research projects.  The hour-long session was called “Animals in Society – from fork to friend”.  It basically was a brief consideration of research being undertaken regarding many facets of animals.  The professor running the topic was Gail Anderson, from the school of veterinary science.

She explained how research on animals has taken place mostly concerning the human benefits involved. Production animals (such as cattle, pig, alpacas, etc) have a financial appeal to people.  Animals have also been useful as models for human disease, and studying therapies for those diseases. Research concerning wild animals often has an overarching environmental aim. There was also a mention of animals used in ‘recreation’, such as racing animals.  Finally, the category of companion animals was considered, and that this was an expanding field as there are ongoing discoveries regarding the human-animal bond.

I will briefly summarise the other categories before considering the companion animals in more detail.

Firstly, production animals need to be as profitable as possible – so research is ongoing into the best way to increase profits from animals.  Additionally, there is increasing concern regarding animal welfare and sustainability of practices.  All of these are research pressures in the production animal industry.

Animal welfare allows for the use of animals in experimental conditions, such as testing human treatments.  There are obviously ethical issues concerned, and there is concern from animal rights groups, as well.

Research into wildlife seeks to maintain environmental populations, discover “extraordinary metabolic pathways”, and otherwise use animals (such as frogs) as environmental indicators. Emerging diseases may also be found in wildlife.

Recreational animal research is often centred around welfare, but also ‘increasing speed’ (and so financial gain).  In terms of dogs, there are studies being commenced that attempt to measure heat stress, and its implications, on racing groups. Particular, methods of ‘cooling’ after racing will be considered. The ultimate aim of this research is to establish welfare protocols – so potentially establish a ‘too hot to race’ policy, and a universally effective method for cooling animals down.

Companion animals, admittedly, were a small segment of the talk. Anderson explained how 63% of Australian households (and 62% of USA households) have pets. As many pet owners place their animal’s health before their own, and prefer their pet’s company to people, then this poses ‘risks’ to people that risk their own well being for the sake of their pet.

We also need to consider the therapeutic value of companion animals – with proven studies shown that touching animals reduces blood pressure, and that caring for animals empowers people.  There was also mention made to the fact that there is a strong relationship between harm to animals and harm to children.  (That is, if a vet sees animals being harmed in a household with children, serious consideration should be given to the wellbeing of those children.)

Companion animal treatments are becoming increasingly specialised.  Vets are becoming specialists in fields or in particular animal species.  Animals that are of particular benefit to people, such as guide dogs, are privy to methods to determine hip dysplasia and arthritis earlier, prevent its onset, and also prevent its occurrence by genetic screening.

This is a brief overview of what was overall a brief session, but I hope it is of a small interest to those involved in animals in some way.

(On a side note, question time revealed that cortisol levels are reflective of stress, but that handling of animals in order to obtain samples can increase the stress of animals and so also cortisol levels.  This has implications for the changes seen in Belyaev’s fox experiment, as the difference between the domesticated and undomesticated foxes could have been exaggerated due to undomesticated foxes being more stressed from handling, and so revealing a higher cortisol level.)