So, I'm chatting to you today about neutering and behaviour. And I've titled this webinar when, why and how to Keep or cut. So a little introduction about myself.

I'm a practising veterinary surgeon at the Amazing Veterinary Hospital in Lincoln. I'm a new mother, so everything in my life is pretty crazy at the moment, and I'm a veterinary behaviourist. So I did the master's in clinical animal behaviour at Lincoln University, then went on to obtain my CCAB qualification for dogs and partnered with the wonderful Lynn Heerson to launch petha company.

Today we're going to talk about neutering, specifically focusing on neutering and behaviour. We'll discuss the pros and cons of neutering, the balanced decision making process, and I hope that the evidence will convince you that for some dogs, particularly nervous dogs, it may be better to wait. A quick summary of what we're going to cover today.

We'll briefly touch on brain development. We'll then move on to look at females, starting with health considerations for neutering, then behaviour considerations, and then a little dive into false pregnancies and timing the bay correctly. Then we'll look at males, again, starting with health considerations and then behaviour considerations.

We'll discuss supraorin implants as a non-permanent means of assessing the likely behavioural response to castration. And finally, we'll consider protocols that we might use if we are going to go ahead with neutering in a nervous patient. Regarding canine brain development, the brain undergoes many changes during development, including cell death, the formation of new neural pathways, and the garden pruning, so getting rid of those unused pathways.

The most effective brain areas are those involved in emotional regulation, behavioural inhibition, and risk reward judgement. And that's the reason why adolescents of all species, humans, canine, and others are more prone to taking big risks than adults. You can think of the adolescent brain as like a building site.

There's a lot there, but still a lot of work going on. And hormones play a key role in guiding this. If we neuter dogs or bitches during adolescence when the brain is still developing, it's possible that we may interfere with brain development and prevent full behavioural maturity.

A study in humans by Sisk and Za in 2005 showed that a lack of gonadal hormones during puberty results in permanently impaired spatial cognition. A similar study in dogs shows that intact dogs perform better than neutered dogs in spatial learning and memory tasks, and this is true of both dogs and bitches. So in this study, 81% of entire females successfully completed tasks using a team maze compared with only 56% of spayed females.

62% of entire meals were successful, compared with only 50% of castrated meals. We know that brain development in dogs continues until at least 2 years of age, so we need to consider the potential impact on the developing brain when weighing up decisions about neutering, particularly neutering before full social maturity. Although this webinar is mainly about behaviour, I am going to consider the health impacts of neutering as well, because at the end of the day, each decision has to be made on a whole patient basis.

Now, I don't really need to remind this audience about the medical reasons for spaying. We've all seen more than enough paos at 6 on a Friday night, which is typically when they always come in, isn't it? So pao's been reported to affect 1 in 4 entire bitches by the age of 10.

Spontaneous pao is most common after 6 years old, and the mean age is 7.25%. So pao is a strong incentive to spay, but not before full social maturity.

Population control and the inconvenience of seasons pretty much speak for themselves. I just wanted to add a quick note about spaying to decrease the risk of mammary tumours. So there is some evidence that spaying is beneficial, but that initial paper that we all remember from vet school has since been subject to a systematic review which found that the evidence that agent neutering has an effect is judged to be weak and not a sound basis for recommendation.

There's also conflicting evidence about the benefits of spaying at the same time as performing a memory strip when tumours are identified, but there is evidence from a study of 225 bitches that disease-free survival time is longer for bitches that had an ovarectomy as well as a mastectomy compared to those that were left intact. So personally, I would still recommend spaying bitches that present with mammary tumours unless there's a strong reason not to. However, recently there's been this seminal paper by Harter To reviewing the evidence around neutering of specific breeds, and this has highlighted a significant increase in joint disorders following early neutering of many large breed dogs.

Small breeds are generally OK from a joint perspective, but some smaller breed dogs such as shih-tzus have a significantly increased risk of developing neoplasia if they're spayed around one year old. In cocker spaniels, spaying between 1 to 2 years old has been associated with a massive increase in the risk of developing mast cell tumours. And so it's advised to spay later than 2 years old in cocker spaniels.

So this table summarises the recommendations from the hard to tell paper for some specific breeds based on the evidence. This isn't a hard and fast rule though, and the decision for each individual dog should always be based on their individual history and circumstances. For example, the paper suggests we should consider avoiding spaying altogether in golden retrievers, but this isn't a practical option for guide dogs or other golden retriever service dogs.

Nor would it be practical in households with entire male dogs or densely populated areas with a potentially high number of entire males living locally. The postulated reason for avoiding neutering in female golden retrievers is the increased risk of neopasia, . For golden retriever bitches that are spayed, even if they're spayed later on in life.

There's also an increased risk of joint disorders if golden retrievers are spayed at less than a year old, but no increased risk of joint disorders with later pas. One of the key papers looking at the risks in golden retrievers analysed necropsy results from 1989 to 2016. Although they found that a greater proportion of spayed females died of cancer than intact females, they also found that intact females had significantly shorter life spans than spayed female dogs.

The median age of dying from anything other than cancer was 6.9 years, whilst the median age of dying from cancer was 9.8 years.

And actually, being spayed did not affect the risk of cancer-related death, but increasing age did. So, while there are increased risks of neoplasia in spayed golden retrievers, this study suggests that it's still beneficial for the longevity to to go ahead with the spade. So What about the behavioural implications of spaying?

Well, there are clear benefits in cases where unwanted behaviour changes only occur during a season, but not at other times during a bit's cycle. In these cases, problem behaviour will be reduced or alleviated by neutering as we are then removing that hormonal fluctuation. Similarly, behaviour changes that occur only during a pseudo pregnancy will be helped by spaying.

But we'll touch on pseudo pregnancy in more detail later on. What do we know about other behaviours? Some of the most comprehensive evidence that we have on this comes from a study by a large group at Sydney Vet School in 2018.

A similar study design was followed for female and male dogs, so I'm going to go through the study design and the results now, and then just look at the results when we get onto male dogs later. This study looked at owner responses to the CBA questionnaire, which is a validated online assessment tool available through the University of Pennsylvania. Owners can choose to log in and submit their details.

The questionnaire is still available live online, so if you're interested, you can Google it and complete it for your own dogs now. These are the results for my little rescue terrier, who features on quite a few of these slides. There are some limitations to the CA questionnaire though, so it is just a snapshot in time.

These are the results from my terrier now, but if I'd filled this in when he first came home 3 years ago, all of the fear categories would have been well into the red. This chap was absolutely petrified of life. We've done loads of work to make him the happy chap he is now, but the questionnaire has no way of knowing this.

Also, there's likely to be some selection bias in the owners who are completing this questionnaire. There are likely to be owners who have an interest in bug behaviour, and that may impact the results. So, back to the study, this group looked at responses for over 3000 entire females and over 11,000 spayed females.

They assessed differences in behavioural traits according to what they called the percentage lifetime exposure to gonadal hormones, or the PLGH. And this was in order to take into account the age of neutering. Percentage lifetime exposure to gonadal hormones was calculated as the age when the dog was spayed, divided by the age of the dog when the owner completed the questionnaire, multiplied by 100.

So a 10 year old dog spayed at 9 years old would have a higher percentage lifetime exposure to gona adult hormones than a 10-year-old dog spayed at 1 year old. A confusing factor is that this paper did not control for the age of dogs at the time the owner completed the survey, so a bitch spade at 2 years old, whose owner completed the questionnaire 6 months later, would have a higher PLGH than a bitch spade at 3 years old, whose owner completed the questionnaire when their dog was 6. The authors recognise this but highlight the financial and ethical challenges of a prospective case control study.

So there are some issues with with this study, but the evidence that they found is still really interesting and worth considering. And they did look at age of spay as well as percentage lifetime exposure to gonadal hormones. So we'll go through that in a minute as well.

So this research found that spaying is likely to help decrease a couple of very specific behaviours. The only two behaviours that were not related to seasons that improved with spaying were howling and chewing. By contrast, several behaviours were likely to have been made worse as a result of neutering.

They found that a lower percentage lifetime exposure to gonadal hormones was likely to worsen fear, aggressive behaviours, and excitability in a range of contexts. More specifically, with a lower PLGH, they found increased fear responses when barked at by unknown dogs. Increased aggression when delivery workers approached the home.

Increase aggression when approached by an unfamiliar dog when on the lead. Increased aggression when barked at by an unknown dog, and increased excitability in response to the doorbell and car trips. The authors looked at age of spay as well, and they found that whilst aggression towards other dogs was correlated with PLGH but not age at bay, aggression to delivery workers was significantly higher with a lower age at spay as well as with a lower PLGH.

I just want to highlight something quickly about most of the papers we'll consider in this webinar. So many of these papers discuss aggression as the outcome variable, but as a term, aggression is not that useful because it's so non-specific. So thinking about actual dog cases, we don't just need to know whether or not a dog sometimes shows aggressive behaviours, but we really need to find out what specific behaviours these are so bark or growl, or air snap or bite or something else, and what context they're seen in.

So to children, or just to dogs, or just to the postman or to everyone. Or only when trapped, or only when outside, or only when inside, there's just so many variables to explore here. A dog that growls whenever she's slightly uncomfortable, but would give a lot of warning before a snap is actually far preferable to a dog that rarely growls but would bite if past a certain threshold.

The seatbelt questionnaire is quite good for the context, asking specific questions such as when approached directly by an unfamiliar adult, but it's much less specific on the behaviour shown, simply asking owners to score on a like scale from no visible signs with growling or barking as a proposed midpoint, up to the maximum snaps, bites, or attempts to bite. So we have to be mindful of this limitation in what exactly increased aggression means through all the research in this area. Several of the studies have found a higher proportion of neutered than entire females amongst dogs with bite histories.

It's difficult to interpret the significance of this without much control groups or detailed information on the ratio of spayed and entire females in the general population at that time and location. There has also been one prospective case control study performed on spaying female dogs, and this was published in JSAP in 1990. This study asked owners of 150 dogs to complete questionnaires about their dog's behaviour at the time of spay and again 6 months later.

The same questionnaire was completed twice by owners of 150 controlled dogs, again with a 6 month interval. The control dogs were successfully matched for age and breed. Significant increases in indiscriminate appetite and what the authors describe as dominance aggression towards family members were seen in spade bitches when compared with controls.

The increase in appetite is something we're all familiar with now following neutering, and it probably fits more into the health aspect of decision making. But perhaps if we know an owner's been prone to having overweight pets in the past, this might be a reason to advise against neutering. Certainly if we're going ahead with neutering, we should be advising owners of the reduced calorific needs post-op, but that's a whole other webinar.

The increase in aggressive behaviour was looked at in more detail by the authors, and it was found that the greatest difference between experimental and control groups was in the youngest age group. Spade bitches most likely to show increased aggression were less than a year old, and had already shown some signs of aggression at the time they went in for spay. The authors use the term dominance aggression towards family members, and from analysis of the questionnaire they used, this includes any threatening behaviour, so presumably includes growling or snapping, in the context of being disturbed when resting toward family members in general, when groomed or when objects are removed.

Looking at the stats from this paper, the authors calculated that if a puppy showing some aggressive behaviour is spayed, there's a 50/50 chance that her use of aggressive behaviours will increase post spay. If she's not spayed, the chances are 6 to 1 that her aggressive behaviours will decrease. So it's quite clear that it is better not to spay a young female that has already shown some concerning behavioural signs.

Spaying an adult bitch with no history of aggression would have no impact on the likelihood of her showing aggression in the future. So No problem whatsoever spaying an adult female with no behavioural concerns, but really think very carefully about preseason stays. And if you are thinking about doing a pre-season stay, please, please do ask the owner about the dog's behaviour before going ahead and booking in.

There are a few more breed specific papers looking at the impact of spaying on behaviour as well. So a 2006 study showed increased reactivity of spayed German shepherd dogs in comparison to their entire counterparts. It was only a small sample size, so only 14 dogs involved.

They were randomly assigned to either neutering or non-neutering groups. After this, video footage was assessed on the approach of an unknown person and dog, and that was done at 5 months post treatment. The dogs in the study were only 5 to 10 months old, so it was a really, really early neutering.

But there was a significant increase in reactivity in those neutered dogs. A 2005 survey of springer spaniels also found neutering to be consistently associated with an increased risk of what they describe as owner directed aggression. So the take home message when it comes to staying females is that if we have a female dog with any behavioural concern that is not season specific, so a dog that's anxious, a dog that's barking at strangers, avoidant or showing aggressive behaviours, then we're likely to want to wait until they are fully sexually and socially mature.

So over 2 years old, before considering a spay. Now, I wanted to touch in a bit more detail on false pregnancy. So, this is something that's relatively common in the bitch, and it can present as physical signs only.

Which can include mammary enlargement, lactation, weight gain, anorexia, PUPD or vomiting and diarrhoea, or it can present as behavioural signs only, which can include nesting, digging, licking, carrying or mothering objects, lethargy, agitation, and aggression. And sometimes it presents as a combination of the physical and the behavioural signs. Owners will often present to the practise if their bitch is showing the maternal signs, so the nesting or the carrying toys around.

But often they may not realise that other behaviour changes such as the lethargy, the agitation, or the aggression, could also be hallmarks of a false pregnancy. It's likely that these dogs may not actually be presenting to the practise at all, and this can have a serious welfare implication for the dogs. Historically, the standard recommendation for spaying was 12 weeks after a season, but we know now that this is actually a little bit too soon.

So at the 12 week mark, there's too high a chance that a proportion of bitches will still be in Metis stress, and these bitches might then end up with a persistent false pregnancy after the spay. So we would now recommend to stay 16 weeks after the end of the season. So we want to stay 16 weeks after standing heat, but if we speak to owners, they often might not know exactly when this was.

Most owners will know roughly when the first day of bleeding was, and so the easiest thing to do may be to approximate the best time to stay as 19 to 20 weeks after the first day of bleeding in a bitch's cycle. If a bitch has milk or any nipple discharge when they come in for a spay, we should be sending them home. We shouldn't spay due to the risk of a persistent false pregnancy after the spay.

If the only sign that the bitch is presenting with is lactation, then it is absolutely fine to just wait it out and spay once the milk has dried up by itself. Alternatively, we can give a 4 to 6 day course of Cabergoline. So this is either Galistop or Finilla, and then we can stay 7 to 10 days after this.

There can sometimes be a recurrence, in which case the cabergoline course can be repeated. It's important to wait at least 7 days after finishing the Cabergoline treatment before surgery, and this is partly to see whether there will be any recurrence in clinical signs, and partly because cubergoline affects blood pressure and so general anaesthesia is not recommended whilst bitches are receiving treatment. Where a bit is showing significant behavioural concerns associated associated with a false pregnancy, a 4 to 6 day course of Cabergline is likely to be insufficient, and so a 14 day course is recommended.

We would then stay 2 weeks after finishing that course, as long as this fits in with the dogs into estress intervals. So the interval between seasons can vary from 4 to 12 months, and we don't want to stay as the bitch is coming back into season. So we want to look at their individual history and then assess the best time to spa when we have no nipple discharge.

When we should be in an stress and when we're not expecting the bitch to be sort of back in season any moment. The true expert in persistent false pregnancies is Sara Davies, who is another veterinary behaviourist, and she has kindly offered that any vets are welcome to contact her by email with queries regarding the timing of spa in specific cases. So I've included her email at the bottom of this slide here.

Because persistent false pregnancy can occur either days or sometimes weeks to months after staying, it's often a misdiagnosis in behaviour cases. In any bitch who's showing aggression which developed after neutering, we should be suspicious of the possibility of a persistent false pregnancy. It's worth trialling a 14 day course of cabergoline, as blood tests may not be representative and response to treatment is the best method for diagnosis.

If the bitch was in a persistent false pregnancy, then a 14 day course of Cabergoline should have a really obvious marked effect on their behaviour. And actually it's a bit of a miracle cure when this happens, so it's really, really. Really worth doing if you're suspicious that this might be the case.

So the take home message here is that the timing of spay is so important relative to the season to prevent persistent false pregnancy. So just to check that you're all still awake, how many weeks is that from the end of standing heat? And from the first day of bleeding.

We want to stay 16 weeks after the end of the season, and that is approximately 19 to 20 weeks from the first day of bleeding. Moving on to our male dogs, again, looking at health aspects first, there are still some health reasons for castration, including population control and the decrease of androgen dependent diseases. If we see cases of prostatitis or perineal adenoma in entire males, it is advisable to castrate to avoid recurrence, however.

As with the females, there's an increased risk of joint disease and neoplasia associated with early castration of male dogs. And these risks are very much dependent on breed. So this table summarises the recommendations for castration, according to breed from the Heart review.

It's recommended to delay castration to avoid an increased risk of joint disorders in Labradors, beagles, and German shepherds. While we typically think of joint disease as regards the larger breeds, delaying neutering in standard poodles, boxes, and Irish wolfhounds is actually to avoid an increased risk of neoplasia in these breeds. So, in male standard poodles neutered at a year old, the occurrence of neoplasia rose to 27% compared with just 4% in intact males.

In mailboxes, the occurrence of cancers was 17% in entire dogs, but neutering the mailboxes before 2 years old significantly raised the risk to 32%. And in Irish wolfhounds, castration at a year old increased the risk of cancer from 8 to 25%. So quite compelling evidence to delay castration in these breeds on health grounds, but what about behaviour?

Castration genuinely does improve some specific behaviour concerns. The main three classes of behaviour that will be improved by castration are behaviours driven by proximity to entire females, urine marking and howling. So directly related to the presence of entire females or the sort of the sexual behaviours, we have roaming, aggression towards entire male dogs, and sexually driven mounting.

But do be aware that mounting is also often seen due to frustration rather than sexual arousal. As regards urine marking, there is ample evidence that castration does genuinely help with this. So 60% of dogs show less than half as much urine marking following castration, and a quarter of dogs reduce their urine marking by 90% after castration.

If owners present requesting castration to resolve urination in the home, it is still really important to take a thorough history and perform a full clinical exam, including urinalysis and a prosthetic examination if possible. A sudden onset of urination in the home, laura, squatting to urinate, and reduced appetite can all be signs of a UTI or prostatitis, which could be misinterpreted by the owner as urine marking. Only if urinalysis is normal and the dog is fit and well should we go ahead with castration.

There is also some evidence that howling decreases following castration, and it's been suggested that separation related behaviour may may decrease following castration. But we don't know if this is a genuine improvement or simply a correlation with the howling. So it's not clear whether the dog is actually feeling less anxious and less distressed about being left home alone, or whether they feel the exact same way, but because the howling has decreased, the owner's perception and the neighbour's perception is that the separation related behaviour has improved.

It's an area that needs further research, and it will be interesting to see if there's more evidence coming out on this in the next few years. Another trait that we can be fairly sure is decreased by castration is called boldness. Boldness is considered to be a super trait consisting of high trainability and willingness to play with humans and a low frequency and intensity of fearful behaviour.

Now to me, these all sound like characteristics that I would quite like in my dogs, and we now recognise that in most cases, decreasing baldness is not a desired outcome. However, it's likely that the decrease of boldness following castration is behind the historical popular assumption that castration might decrease aggression. So why is this?

Where did it come from? And is there any truth in it? Well, male dogs are generally bolder than female dogs, and male dogs are also traditionally considered to be more likely to show aggression than female dogs.

Looking back at an old paper from 1982, researchers tested male dogs against female dogs and pseudo hermaphrodite dogs in an equal opportunities test, and they found that males won 78 out of 100 tests between males and females. This experiment would never have passed an ethics committee today, and for good reason. Two dogs were placed in an enclosure and had 1 bone thrown in between them, and researchers then recorded which dog won possession of the bone during a set time period.

The equal opportunities tests were also followed by established possession tests in which males were more likely than females to attack the possessor of the bone in order to gain possession. Looking at these results, we can imagine how experts in the field previously assumed that male baldness might be associated with an increased risk of aggression. And this authority consensus on sexually dimorphic behaviours was discussed by Hart back in 1997.

So this led to suggestions that castration of male dogs might reduce problem behaviours or reduce dog bites. There was historically a tendency to recommend castration of any dog showing aggressive behaviour. However, in light of newer evidence, the tide on this is turning.

Recent studies have found no difference in aggression in neutered male dogs compared to entire male dogs. In a study of free roaming dogs in Chile, surgically castrated dogs showed no reduction in aggressive behaviour from their pre-castration levels. We're still lacking enough robust evidence on the impact of sex and neuter status on the incidence of dog bites.

A 1987 study of 105 dogs found that intact males were the most likely demographic group to be referred for behaviour problems involving aggressive behaviours. But the majority of the baseline population, based on comparison with responses from a local vet clinic, also consisted of intact males. A 2001 survey of 227 dogs with a bite history found that the majority of male dogs with bite histories were neutered.

Although this study lacked a control group and there's no data provided on the percentage of neutered males in the baseline local population. Interestingly though, in this 2001 paper, any dogs who displayed what the authors described as dominant or possessive aggression differed significantly from the other biting dogs by having a higher fear score and by their owners listing them as being afraid of more stimuli. The Sydney group who looked at responses to the CBA questionnaire compared responses from over 3000 entire males and over 6000 castrated males.

So just as a refresher, as with the equivalent paper in female dogs, this group assessed the differences in behavioural traits according to percentage lifetime exposure to gonadal hormones. Percentage lifetime exposure to gonadal hormones was calculated as the age when the dog was castrated, divided by the age of the dog when the owner completed the questionnaire, multiplied by 100. 23 specific problem behaviours were identified for which there was a reduction in the behaviour associated with increased PLGH.

So results which indicated that we should advise against early castration include the association of lower PLGH with exacerbation of fear responses in a number of contexts. Fear of noises, fear of unfamiliar objects. Fear when lunged or barked at by an unfamiliar dog.

Fear when approached by a dog of a similar or larger size. Fear in unfamiliar situations. Fear when approached directly by a child.

Fear when having nails clipped by a family member, and fear when examined by a vet. This demonstrates that we don't just need to be delaying neutering in those dogs showing aggressive behaviours due to fear, but also those showing avoidant behaviours or those whose body language and posture displays that they're not comfortable in certain situations. A lower percentage lifetime exposure to canal hormones was also associated with increased scores for aggression in this study, although, as we discussed earlier, the CA questionnaire isn't very specific about the nature or the intensity of the aggressive behaviour seen.

Increased scores for aggression were seen when delivery workers approached the home, when passed by strangers or cyclists when the dog is outside the home, when approached by an unfamiliar female dog when on the lead, when an unfamiliar person approaches a family member in the home towards cats, squirrels, or other small animals in the garden. And to unknown visitors to the home. Some other undesirable behaviours were also increased with a lower PLGH and this included eating poo, rolling your poo, and barking excessively when excited.

In favour of neutering, the paper did confirm the expected decrease in indoor marking associated with the lower PLGH or age castration and also found that immediate recall and fetching were decreased with a longer PLGH. There were fewer associations when they looked at age castration rather than PLGH, but a lower age at castration was still associated with an increased fear of unfamiliar objects and increased aggressive behaviours in response to delivery people approaching and to strangers and cyclists passing the home, as well as an increase in excessive barking when alarmed or excited. In a study looking at over 2000 visitors, the odds of noise or storm phobia were significantly increased in neutered compared to entire males.

In the same study, all dogs, both male or female, neutered at less than 6 months old, had an increased odds of developing a behaviour disorder. I've already mentioned the study of over 1000 springer spaniels in which neutering was associated with an increased risk of owner-directed aggression. And finally, there has been a postulated link between neutering and the development of canine cognitive dysfunction in the older dog.

The authors postulated that neuting might increase the risk of cognitive dysfunction for both male and female dogs, but there were no entire females included in the study, so I didn't mention this one for the ladies. The authors looked at neutered males and females together, compared with entire males and found that entire males were less likely to progress from mild to severe cognitive impairment. It's an interesting area for further research, but currently the evidence is quite weak and unlikely to significantly affect our decision making.

So the take home message for castration. Please always ask about the dog's behaviour during a pre-castration check and advise the owners accordingly. We do want to castrate male dogs that are urine marking in the home, but only after ruling out a urinary tract infection.

We do not want to castrate fearful dogs, nervous dogs, or dogs that are showing aggressive behaviours to strangers. We want to encourage later castration where possible, aiming to castrate after sexual and social maturity for the majority of our male dogs. If in doubt about whether castration is likely to help or hinder a dog's behaviour, it's advisable to assess the response to a suprelain implant first.

In my capacity as a behaviourist, I've seen several cases where castration has helped to moderate the dog's behaviour, but I've also had so many neutered males present with owners reporting that their dog's behaviour became dramatically worse following castration, and they wish they'd never gone ahead with it. I'm hoping that this webinar will help to avoid us seeing too many more of them. I want to touch on how the suprearin implants work.

And by the way, I always thought that this was pronounced slurin, but the videos on the Verva website, it is actually suprearin, so there you go. Once we've done a surgical castration, there's no going back. So for a dog that we think might benefit from castration, but we aren't sure.

And from a behavioural point of view, of course we can never be sure how a dog will respond. Souprearin is a great way to assess the likely effect in a reversible way. The marketing on the Verbank website describes Suarin as a try before you buy option.

Cuprearin implants are desorolin slow release implants which block the release of FSH and LH and therefore decrease testosterone. They're available as either 6 or 12 month implants, and we'll generally want to use the 6 month implant, which is the 4.7 milligramme implant in those cases where we're using suprearin as an assessment tool.

The implant is loaded in a needle which is a similar size to a microchip needle. It comes in a seal foil packet and you open the packet and then screw the needle onto a plastic implantation device, so the whole setup looks a lot like a microchip implanter. Verbek recommend clipping and cleaning the implantation site before placing the implant.

I also recommend to the client that it can be a good idea to book two appointments 30 minutes apart so that EA cream can be applied to the area and given time to take effect before placing the implant. Placing the implant follows exactly the same procedure as implanting a microchip. Once the implant is in place, you'll see a little plastic spacer at the end of the needle.

Remember to unscrew the needle before placing it in the sharp's bin and to keep the plastic implantation device for the 2nd implant in the box. Usually we place the implant subcutaneously in the back of the neck, as this is the easiest place to do it in the conscious dog. But if you think there's an increased likelihood you might want to remove the implant before it runs out, it's recommended to place it subcutaneously near the umbilicus or in the medial thigh instead, so it's easier to locate.

If you're placing the implant under sedation or anaesthesia, then it's definitely worth going for the ventral abdomen or the medial thigh for this reason. The most important thing to remember about the suprearin implants and to discuss with the client in advance is that for about the 1st 2 weeks after placing the implant, the testosterone levels will actually increase. It's really important to understand that that initial behaviour change will be the opposite of what we would see after neutering, and if we suspect that a dog would benefit from neutering, then we should exercise caution in these first few weeks when behaviour may get worse before it gets better.

Testosterone then decreases to post castrate levels by around 4 to 6 weeks, with reliable infertility from 6 weeks to 6 months. And you can use a reduction of testicle size as an indication that the implant is effective. So we can assess the behavioural response from 4 to 6 weeks after implantation to make an informed decision about surgical neuring.

Of course, we still only want to use suprearin if we think it's likely that the dog will improve following castration. So I wouldn't recommend surgical or chemical castration in very fearful dogs. Do note also that the data sheet states that surgical or medical castration might have unexpected consequences, i.e., improvement or worsening on aggressive behaviour.

And so the data sheet says, thus dogs with sociopathic disorders and showing episodes of intraspecific and or interspecific aggressions should not be castrated either surgically or with the implant. Now, this is another issue where the common umbrella term of aggression is really not that useful, because what we really need to be considering is the behaviour shown, the motivation behind that behaviour, and the context it is shown in when we're making decisions about whether to trial a supreluin implant. It's important that we always advise owners that behavioural effects of castration can be unpredictable.

After all, that's why we're using a suprearin implant before going ahead with the surgery and that behaviour could deteriorate. So, in theory, we may be able to surgically remove the implant if we don't like the effect that we see. But the implant dissolves over time, so the longer it's been in situ, the lower the chance that we'll manage to successfully locate and remove it.

I always warn owners that they may just have to wait out that 6 month duration. But at least it's not forever. Now, having said that surgical castration is completely irreversible, there has actually been one case study from America in which hormone replacement therapy was used to reverse the effects of castration in a four year old dog.

This dog was castrated at 7 months old and presented at 1 year old with a number of problems, mobility issues, rapid weight gain, and an intense fear of unknown people, which all started after the castration. Several of the treatments were tried but were unsuccessful. It was therefore decided to trial weekly testosterone injections.

Testosterone was given subcutaneously and regular blood tests were carried out to assess the testosterone and minizing hormone levels. Testosterone concentrations were brought back up to precastrate levels by the regular weekly injections, but luteinizing hormone levels remained extremely high. And as a result, a soupfluorine implant was then given to reduce the luteinizing hormone levels.

But hang on, we gave a supraorin implant to an entire male to assess the likely effect of castration. But now we're giving a suprolorin implant to a castrated male to bring hormone levels back to more like an entire meal. What on earth is going on here?

Well, it's all about the HPA axis and gene expression. So the normal mechanism of the HPA axis looks something like this diagram on the left. JNRH is released from the hypothalamus in a pulsatile fashion.

And this pulsatile release is really, really important. So the pulsatile release stimulates the release of LH and FSH from the pituitary. And these stimulate the release of testosterone from the testes.

The testosterone then exerts negative feedback on the hypothalamus to reduce the release of GMRH. Following surgical castration, the testes are removed and so they're no longer present to produce testosterone. This means there's a loss of loss of negative feedback on the hypothalamus's production of GNRH, and as a result, the surgically castrated male will have a persistently elevated LH concentration.

It's actually about 30 times what we would see in an entire meal. Following chemical castration with suprearin, what happens is quite different. So suprearin is a GNRH supragonist, but unlike the sort of natural GNRH released from the hypothalamus, which is pulsatile, the suprearin implant gives a constant sustained release of Desloolin.

So we have an initial stimulation of GNRH receptors and that increase in LH and testosterone in the first two weeks. But then within 9 to 20 days, the sustained release of Desloolin results in an activation of a complex series of pathways involved in gene expression. There's a decrease in mRNA coding for specific subunits involved in gonadotrophin production, and that is why we have a decrease in LH following supraorin implantation.

The decreased LH reaching the testes results in decreased testosterone release. So, what's the significance of this? Well, what's the significance of this?

Well, it means that suprearin won't be exactly like a surgical castration, as luteinizing hormone is thought to have an important role in behavioural regulation. Testosterone levels are equivalent after a chemical or surgical castration, and this will result in similarities of behavioural effect. Testosterone is known to decrease fear through direct direct effects on androgen receptors and indirect effects on GAA receptors.

Androgen receptors have also been shown to be increased in the basolateral amygdala of dogs showing pathological levels of aggressive behaviour. However, after surgical castration, luteinizing hormone levels are much higher than in the entire male, around 30 times higher. Whereas after a chemical castration, LH levels will be lower than those seen in the entire male.

There are abundant LH receptors present in the hippocampus and the hypothalamus, and both of these brain areas are important in the regulation of fear and aggressive behaviours. So we can expect to see prearin implant given to an entire male for the purpose of chemical castration to result in similar but not identical behavioural change to that seen after surgical castration. But what about using a supraorin implant in a surgically castrated male to normalise the luteinizing hormone levels?

In the one case study mentioned earlier, there was a strong positive physical effect and a mode moderate positive behavioural effect, but it wasn't clear how much of this should be attributed to the weekly testosterone injections and how much to the suprearin implant. Verbach very kindly chatted to me about whether there would be any precedent for using suprearin implants in surgically castrated males who've shown a negative behavioural response to castration. They advised that we simply don't have the evidence yet as to what impact decreasing mutantizing hormone would make in these dogs.

We have a lot more information currently on the effects of testosterone, but research into the effects of luteinizing hormone is very much ongoing. No adverse health effects would be anticipated from using suprearin in a surgically neutered male. So if faced with a neutered male who's shown a marked deterioration post castration, it is something we could potentially try.

Obviously this would be off licence, and the limited information around this is something that we would have to discuss in depth with the owner. I haven't tried this yet myself, but I may well discuss the possibility with owners in the future. And if any of you do try it, I would be really grateful if you could please email me at [email protected] with the case details so that I can collate the evidence.

From a health perspective, it's been suggested that chemical castration may avoid some of the risks of physical castration because elevated levels of luteinizing hormone have also been implicated in hypothyroidism, reduction of satiety, and therefore weight gain after neutering, joint disorders, and neoplasia development after neuting. There are luteinizing hormone receptors in the thyroid, adrenal glands, gastrointestinal tract, cranial cruciate ligament and round ligament, and in lymphocytes. In addition, LH receptors have been found in several neoplastic tissues, including lymphoma, hemangiosarcoma, mastocytoma, transitional cell carcinoma, and osteosarcoma.

It's been suggested that research is needed to establish whether suprearin implantation might be beneficial in treatment of neutered dogs presenting with these types of neoplasia. So, assuming that we have decided to go ahead with neutering, we want to think about how we can make the procedure as pleasant as possible for everyone involved and reduce stress for both the staff team and the patient. We want to give some oral medication at home first for nervous dogs.

Then we want to pre-med the patient immediately on arrival and use Dom rather than ACP in the pre-med. Since meatomidine has anuallytic properties, but ACP does not. If the anaesthetic is stable and I'm happy with the patient, then I would actually avoid reversing the pre-med post-op and allow the dog to wake up gradually instead.

It's also worth considering additional analgesia postoperatively, as these patients may be more sensitive to pain and any unwanted behaviour will be exacerbated by pain. That's exactly the same as in humans, so if we're feeling a bit sore, we will be a bit crankier than we would have been otherwise. We also try to arrange an earlier discharge for our more nervous patients.

Obviously, as long as the owner is happy to keep an eye on them and call us if they have any concerns. Just to mention here as well, which is slightly off topic, erring on the side of sedation for other painful procedures in fearful dogs, for example, removal of torn claws. It can be really tempting at the end of a busy day to just pull a nail conscious, but this can be really aversive for the dog and can really affect future vet visits going forward.

We also want to encourage desensitisation and counter-conditioning visits before and after neutering where possible. The amazing hospital practise where I work offers free nurse consults for desensitisation and counter conditioning. It's a great way to reset expectations on entering the vet clinic and provide a positive experience for the dog and the owner.

It's also really important to think about the process for this. It wants to be a positive experience, and we don't want to push the dog outside of their comfort zone. So we're not trying to get a lot done in these visits.

We're just aiming to provide 5 or 6 positive experiences to offset any negative ones. The pace of this may be very different depending on the individual patient's needs. If we can get them in one when they like if we can get them in when they're puppies, it's a lot more fun for us and for them than when we're doing these on a a sort of an already really worried older dog.

So if we can encourage clients to come in with their puppies when they're young for these DSCC visits, it's great fun for us, but it also creates a lovely bond, a loyal client. And a dog that's a pleasure to see for years to come. So what about medication protocols?

We always advise to select medication protocols depending on the individual patient. In many cases, a gabapentin and trazodone combination the night before and morning of the procedure is a good option to consider. This is off-license use of human medication under the prescribed cascade, so something to discuss with owners.

Trazodone is classed as an atypical antidepressant which exerts its effects via moderation of serotonin levels. Unlike the SSRIs, such as fluluoxetine, which take 4 to 6 weeks to take effect, trazodone is a short-acting drug. So we see the behavioural effects very rapidly after administration.

And these effects will wear off after 8 to 12 hours. Trazodone is available as 50 milligramme capsules or 150 milligramme tablets, which can be quartered quite easily. It's a fairly inexpensive drug which is also beneficial for client concordants.

We'll sometimes use trazodone at moderate doses in a patient on a low dose of fluoxetine, but we would really advise to avoid using the higher end doses of both of these medications concurrently due to the risk of serotonin syndrome. It's also recommended to avoid trazodone in dogs with a seizure history, as this could potentially lower the seizure threshold. For preoperative trazodone, I typically use the doses as listed in the BSAVA formulary.

Another option we may sometimes recommend, for example, if a patient is already on the maximum dose of fluoxetine and we want to avoid the risk of serotonin syndrome, would be Dexamedatomidine gel, Celeo an hour prior to admin, or alternatively, clonidine for those dogs whose owners would struggle to administer Celeo. Again, this is off licence use, so something to discuss with owners. Clonidine is currently only available in very tiny 25 mcg tablets.

So if using this for a medium to large breed dog, you will need to give a large number of tablets. For example, at a dose of 0.01 milligrammes per kilo, which is the dose we would typically choose, a 25 kilogramme dog will need 10 tablets as a single dose.

But they are tiny and they don't taste offensive, so they're actually not that hard to administer in a tiny bit of food. Apotoin, soexian can also be really useful for fearful dogs that are avoidant and do not have a history of using aggressive behaviour to create distance. Pexian is a benzodiazepine partial agonist, which enhances the activity of GABA.

Again, the dose is as per the BSAVA formulary recommendations for behaviour. If using Pexium preoperatively, I may actually start this a few days in advance. So for example, a 10 to 20 MB per kg dose twice daily from 3 days pre-op and continue for 3 to 5 days post-op.

With any with any behaviour medication, we have to be aware of the risk of disinhibition, but this risk is considered to be greater for the benzodiazepines than other classes of psychoactive medication. So the concept with disinhibition is, if we have a dog that's considering biting but is holding back because they're worried, then relieving this inhibition could result in the dog going ahead and biting. It's thankfully not something I've observed with any of these medications in practise, but it is a theoretical risk, and we should discuss this with owners and implement risk management precautions accordingly.

So Pexian is actually a really, really wonderful dog for really, really wonderful drug for those dogs that are, just super duper fearful, but fearful and avoidant, not recommended in those dogs that have a history of using overt aggressive behaviours. Obviously, with any at home medication protocol preoperatively, we have to discuss administration with owners because we don't want our patients to eat preoperatively. I usually discuss the risk benefit analysis and advise using the smallest possible quantity of something super delicious like Arden Grange liver paste to get the tablets in.

For dogs that are totally comfortable with their owners handling them, but really nervous in the veterinary environment, it can also be beneficial and time efficient for us vets if the owners can clip the forelimb and apply MLA cream at home so that we can administer an IV pre-med painlessly on arrival. For other patients, either an IM or subcutaneous pre-med on arrival may be the best option depending on the specific patient circumstances. To keep clinic space free and the dog as relaxed as possible, we'll often do this at the car and then carry the dog in once they're asleep.

In the summer, we can also make use of outside space and bring a blanket out to the garden area of the practise if appropriate. Now, Before I finish, I just wanted to go through a couple of little case studies. First up, we have Nell, a gorgeous golden retriever who was spayed last year.

Nell's owner is really diligent and behaviour savvy, but unfortunately, lockdown struck when Nell was a young puppy. And as with so many lockdown pups, her early socialisation was really limited. So as an older puppy, Nell was really nervous.

She was fearful of unknown people, and she would largely show avoidant reactions, backing away and cowering. She was also fearful of unknown dogs, and this would normally display as aggressive lunging and barking towards them. To try and increase distance.

Nell was also petrified of the vets. So we discussed the pros and cons of neutering, and because Nel was a golden retriever, we discussed increased risk of joint disorders with early neutering. Increased risk of neoplasia with neutering at any age, but a longer median lifespan for spade than in higher golden retrievers.

And of course, we discussed the typical benefits of avoiding pyometra or unwanted mating. Nell's owner decided on balance that she would like Nell to be spayed. So when should we spay now?

Because of Nell's behaviour, we wanted to wait until Nell was over 2 years old to ensure that she was fully sexually and socially mature and to give her the behavioural benefit of a bit more exposure to gonadal hormones before neutering. We then booked her in for 16 weeks after the end of her next season. Before coming in for spay, she visited the practise several times for desensitisation and counterconditioning.

Because Nell was so nervous, she benefited the most from visits where she really had minimal or even no interaction from staff. Just getting used to the environment and occasionally having treats delivered from a distance. It's really important with these visits that we don't try to do too much because if we push the dog outside of their comfort zone, then we'll be having the opposite effect from what we're aiming for.

We want to avoid emotional conflict. So if we try to bribe the dog towards us with treats, they're faced with a conflict. I want the treat, but I don't want to be too close to the scary human.

And at some point, the scariness of the human will outweigh the appeal of the treat. This could decrease the value of the treat by giving it a negative association. Or in the worst case scenario, the dog may start to approach, then realise that she's outside of her comfort zone and show exactly the behaviours that we're trying to avoid.

So instead, we want to deliver treats to the dog from a distance by gently throwing them in the dog's direction, not at the dog though, and then move away. This teaches the dog that when they see us, good things happen and it's safe. So after a few of these visits, it's time for the big day for now.

Nell received trazodone at home preoperatively, and this worked really well for her. When she came in, she had a pre-med which contained meotomidine and methadone. After the surgery, Nell actually woke up really dramatically fast, so we gave her a little top-up to make her drowsy and relaxed until collection time.

She went home just a few hours post op, and there's a little picture of her hair when she'd just got in. Didn't even make it all the way onto her bed before having a little snooze. So, how's Nell doing now?

Well, heroin was so impressed by how she responded to the trazodone that we actually started Nell on fluoxetine. And this provided a greater window of opportunity for the owner to progress with her behaviour and training plan. With the combination of medication and ongoing training, she's made massive progress, so much so that we're currently in the process of weaning off the fluoxetine at the moment.

Next up we have Reggie. Now, Reggie had already been castrated before we saw him for a behaviour consult, but I just wanted to share this quote from his owners. So on their pre-consultation questionnaire, they put, Reggie was castrated at 10 months old, and I've never regretted anything so much.

He was always a nervous puppy, but at 6 months old, he was beginning to gain confidence and become more accepting of strangers, and he had never snapped at other dogs. After his castration, he's become less tolerant of dogs in his face and extremely nervous and fear aggressive with strangers. This is just one example of many, but I wanted to share this to emphasise that in these pre-castration checks, as well as listening to the heart and checking for two testicles, we should absolutely always be asking owners about their dog's behaviour.

And if they're nervous, whether that's displayed as barking and lunging, or displayed as avoidant behaviour, cowering, or moving away, we should proactively be advising the owners not to castrate, or at least not so soon. Reggie is also doing fantastically now. His owner has been really dedicated with his behaviour plan and recently they managed to take Reggie on holiday with them, staying in a B&B rather than having to have a private cottage.

Now, one final case study, we have Billy. Billy came in to see us primarily because of separation-related behaviours, struggling to cope even with his owners taking the bins out and requiring the owner's parents to come and sit with him every day while his owner did the school run. Billy also struggled with over arousal and humping of visitors to the home, and at daycare he'd shown some growling towards the entire male, but not the neutered male dog.

We felt that castration was likely to be beneficial, but as we can never be sure of the behavioural effects of castration, we advised to trial a supraorin implant first. Billy had 2 appointments booked at his local practise, 30 minutes apart, so that Emma could be applied in the first appointment and the suprearin implant placed in the second. We advised that Billy should not attend his daycare for the 2 weeks after the implant was placed, as we would expect increased testosterone during this initial period.

So if the growling towards the entire male dog was indeed sexually driven, we would expect this to be worse during this period. Billy showed a positive response to the suprearin implant with no further issues at daycare and reduced humping at home. He's since been surgically castrated, and he's also making good progress with his behaviour plan.

He still can't be left for long periods, but he can now relax at home alone while his owner does the school run each day. So That's it, folks. In overall summary, we should base neuting decisions on the individual.

In general, we should delay spaying bitches with any behaviour concerns that are not directly related to the season. We should ensure when we do spay that we time this to avoid persistent false pregnancy by spaying 16 weeks after the end of standing heat and not spaying if a bitch has any milk at all. Castration may be helpful to reduce some specific behaviours, particularly urine marking, but we should avoid or delay castration in fearful dogs.

And if we are at all unsure, we should assess response to a suprearin implant before performing an irreversible surgery. We should always ask owners about their dog's behaviour at pre-neutering checks. And if we do neuter a nervous dog, we should try to use a combination of medication and additional time to make the experience as a traumatic as possible.

I hope this has been useful for you all and thank you so much for listening. There are references here if you want to see any of the papers that I've used, putting together this presentation. More references here again.

And if you do have any questions, you're always welcome to drop me an email. Take care and enjoy the rest of your day. Bye.