Can we castrate a hippocampus?

The castration of male dogs from a behavioral point of view Sophie Strodtbeck & Dr. Udo Gansloßer

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1 The castration of male dogs from a behavioral point of view Sophie Strodtbeck & Dr. Udo Gansloßer Summary: The main behavioral endocrinological and ethological aspects of the castration decision are discussed. Already five to six hormonal systems (glucocorticoids, catecholamines, sex steroids, prolactin and the oxytocin / vasopressin system) can contribute to causing aggression problems. Other areas of behavior, such as hunting or stray, are also independent of the sex steroids. Finally, various options for chemical test runs are briefly discussed. The story of the male's castration is a story full of misunderstandings. Unfortunately, many veterinarians, as well as trainers and keepers, still persist in the belief that castration is a surgical miracle cure for a wide variety of behavioral problems. But castration can never replace sensible behavioral control, and many problems that are associated with sex hormones - in this case with testosterone - stem from completely different hormonal control systems and cannot be influenced by castration in any way. In this article we want to go into more detail on the behavior and the underlying physiological relationships, dispel many prejudices and try to provide a decision-making aid for or against castration. In advance it must be clearly stated that 6 of the Animal Welfare Act prohibits the complete or partial amputation of body parts or the complete or partial removal or destruction of organs or tissues of a vertebrate animal, except in the case of clear medical indications, which are not to be discussed here . To prevent unwanted reproduction, sterilization by vasectomy is the much more suitable method, since it does not interfere with the hormonal balance and is completely free of side effects for the male dog. This procedure is carried out as a routine procedure in zoo animal medicine, for example. 1 Early castration In general, it can also be stated that early castration, i.e. castration before puberty has subsided, is strictly to be rejected and has only negative consequences for the animals: they become more insecure, towards conspecifics and more aggressive towards same-sex dogs. The physical development is lagging behind, they remain child heads for life because their mental capabilities are not fully developed. This is due to the fact that the brain under the influence of sex hormones develops again during puberty, new synapses, axons and glial cells are formed, and superfluous cell areas are broken down (apoptosis). As a result, an improved stimulus conduction can be observed as well as a renewed consolidation of learned behavior, in particular through the imprinting of fixed behavior. The uncertainty that begins in dogs with the onset of puberty under the influence of strong cortisol fluctuations naturally correlates in the life story with the point in time at which more dangerous, because unknown regions are visited for the first time, so it makes biological sense. The

The remodeling processes mentioned in 2 have a strong impact on the prefrontal cortex, which is often referred to as the seat of social intelligence and competence. Finally, it must be emphasized that, just like us, puberty in dogs does not end with physical sexual maturity. As a guideline for both sexes, we assume the age at which the bitch would have lived through her third heat. 2 reasons for castration As the Bielefeld castration study [4] showed, the most common reason for castration of the male is the hope of being able to remedy undesirable behavior. A full 74% of those questioned stated this as the decisive argument in favor of the procedure, followed by 30%, the reasons for the holder, e.g. named male and female cohabitation in one household as an indication, medical considerations played a role in just 21% of dog owners. Since multiple answers were possible here, the total is more than 100%. 3 Not all aggression is the same thing with dominance One of the most frequently mentioned reasons that lead to behavior-related castration is the occurrence of dominance or aggressive behavior. This blanket statement can by no means be left as it is, but has to be viewed in a much more differentiated manner from a hormonal and behavioral perspective. The behavior of the male dog, which is often interpreted as dominance behavior, towards his owner can hardly be influenced by removing the sex hormones, as this usually conceals a lack of leadership skills on the part of humans and not a striving for dominance on the part of the dog. Dominance in the behavioral sense is not a property, but a relationship that is stabilized from the bottom up and not the other way around. An animal whose dominance is recognized is granted privileges voluntarily, i.e. it can assert its interests at any time without the use of force against the other. A really dominant animal is sovereign and does not need any aggression [1, 2] 3.2 Cortisol-dependent aggression, e.g. Anxiety gression In real aggression behavior, it is necessary to precisely determine the cause of the aggression. Aggression is physiologically and ethologically a multi-causal event that serves to regulate allostasis. There is no instinct to aggression and there is also no stagnation in aggression. And of the many forms of aggression, only a small part of competitive aggression, namely status and possibly territorial behavior as well as aggression in the direct sexual context, is regulated by sex hormones. In the case of fear aggression, castration is completely contraindicated in the male, the behavior will increase significantly after the procedure. This is because fear and panic reactions, which result from a loss of control, are under the influence of cortisol. Since testosterone inhibits cortisol and thereby also has an anxiolytic effect and creates self-confidence, the removal of the sex hormones will worsen the anxiety gression. This is due to special receptors for sex steroids in certain regions of the limbic system associated with fear reactions. And by the way, this is the reason why not every chemical castration is also suitable as a test run, see below.

3 The so-called self-defense aggression is controlled by adrenaline / noradrenaline. The problem for the dog owner is that through feedback loops between the hippocampus, amygdala, locus coeruleus and hypothalamus / pituitary gland, a behavior that has been tried and tested as a problem solution is learned very quickly, especially in fearful or frightening situations, and is saved as a problem-solving strategy. This learning from success is not related to the sex hormones and is reinforced by norepinephrine. Like the fear gression, the food defense is under the influence of cortisol and has no relation to the sex hormones. 3.3 Young animal defense and infanticide Defense of young animals (and also infanticide), on the other hand, is controlled by the pituitary hormone prolactin, the so-called parent hormone, which is also used in male dogs to care for and defend children or puppies in their own families [5]. In very many mammal species, including humans, it has been proven that the prolactin level also rises in males in the presence of young animals / children in the family and pregnant partners. This results in an aggressive defense of the individual distance of the pregnant owner or another pregnant caregiver. In addition, there is an increased tendency to be unfriendly to strange children or young dogs during this time. This behavior has also been demonstrated in castrated animals. In addition, at least in wolves, a seasonal increase in prolactin is known. High testosterone levels inhibit prolactin, so that even with this problem it is clearly not advisable to castrate the male dog. On the other hand, low testosterone levels, as they also arise from the adrenal gland in castrated animals, promote the effect of prolactin (Schradin, 2007) 3.4 Partner protection, status and competition aggression If the owner, or the male owner in particular, defends the owner, it is Partner protection behavior for which the vasopressin known as the jealous hormone is responsible. Together with the bonding hormone oxytocin, it plays a role especially in the early phase of newly formed relationships. Vasopressin is active as a co-transmitter of norepinephrine and ensures that uninvolved third parties are kept away during the relationship-building phase. In general, the vasopressin / oxytocin system has been shown to be involved in regulating social relationships in many vertebrates [1, 2]. This system cannot be influenced by castration. The situation is different with real status or competitive aggression, or with territorial aggression as long as the behavior is not yet learned, but actually hormone-controlled. In this case, neutering could possibly improve behavior. It must also be noted, however, that in many species (for example horses and monkeys, including humans) an increase in testosterone levels after the improvement in rank has been demonstrated, which calls into question the assumption of a lot of testosterone and many battles for ranking. In primates and laboratory rodents, in particular, it has also been proven that fluctuations in serotonin in the brain initially trigger the status aggression caused by ascension. Once the animal has reached the desired high status, the serotonin level remains constant, testosterone follows suit, and now there is often a rather calm, social status assurance. 4 Stray and hunting behavior

4 Straying and hunting behavior are often cited as further reasons for castration. In male mammals, including dogs, the tendency to use larger grazing areas and to control and mark them is created under the influence of sex hormones in the brain, but as far as is known today, this happens prenatally and can hardly be postnatally influence more. The situation is different when straying in the presence of bitches in heat in the neighborhood, which is directly sexually motivated and can possibly be influenced by castration. Hunting and prey-catching behavior is in no way related to the sex hormones; it is triggered by very simple stimuli: an object moving quickly away from the animal triggers a chase / prey catch. Which brain areas are responsible for this in canids has not yet been finally clarified, the limbic system may be involved (namely the lateral thalamus and the cholinergic system). It is noteworthy that in investigations on domestic cats almost all sex hormones, with the exception of folliculin, had a depressant effect on hunting and prey-catching behavior [3]. 5 Hypersexuality With the so-called hypersexuality of the male, it must be clearly differentiated from which behavioral group it originates. Frequent riding and mating movements often do not arise from sexual behavior, but have other causes. It can be movement stereotypes that serve to reduce stress and are reinforced by dopamine. If the behavior occurs between several dogs in an established group, it is usually game. In addition, when deciding whether or not to castrate this indication, it should be noted that even neutered males can show complete mating behavior, including hanging, in the presence of a bitch in heat, even for years after neutering. The reason for this is that sexual activities activate the dopamine system, which in turn has a self-rewarding effect and is also the trigger for many addictions in humans. Conversely, dopamine released for other reasons has also been shown to increase sexual activity; other endocrine feedback systems between behavior and sex hormones are also known, such as courtship and competitive behavior increasing the level of sex hormones. Also responsible for an increased testosterone release of the male is the noradrenaline, which increases the level of sex hormones within the active stress management axis, especially in fight-stressed individuals. In this context it must be emphasized again that all steroids of the adrenal gland, including the sex steroids, are under the influence of the ACTH, not the GnRH system. Only if it is actually a matter of sexually motivated behavior should a castration possibly be considered after weighing all the facts mentioned in this context, but this should definitely be clarified in advance with professional help through a precise analysis of the situations that arise in each individual case! 6 A sensible test run A reliable way to test the changes in behavior that a real surgical castration would bring with it is the use of a GnRH down regulation chip (Suprelorin chip from Virbac). A GnRH peak leads to a cessation of testosterone production for several months via negative feedback, the dogs then have the same hormone status as their neutered conspecifics. This principle has been used successfully in zoo animal medicine for several years. However, you should

5 Inform owners that there can be a significant increase in sex hormones in the first few weeks before the negative feedback process is started, which in turn can lead to a massive increase in the behavioral abnormalities induced by testosterone. In severe cases this can be counteracted with antiandrogens. The effect of the castration chip is completely reversible. In contrast, the earlier methods of chemical castration by injecting anti-androgens or estrogen analogues are not a reliable prediction system because of the above-mentioned connections with anxiolytic side effects should always carefully analyze the causes of the abnormal behavior in order not to exacerbate the problem presented. In individual cases, such as real status-related aggression, wandering around in the presence of bitches in heat, or even with real hypersexuality triggered by the sex hormones, a decision to castration can actually be helpful, but only if the behavior shown is not yet learned. Under no circumstances can castration be seen as a panacea for behavioral problems of any kind. Literature: [1] Gansloßer U. mammal behavior. Fürth: Filander; 1998 [2] Gansloßer U. behavioral biology for dog owners. Stuttgart: Cosmos; 2007 [3] Gansloßer U. behavioral biology of the house cat Fürth: Filander; 2010 [4] Niepel G. castration with the dog Stuttgart: Kosmos; 2007 [5] Schradin C. Biology of the father Fürth: Filander, 2007 Addresses of the authors: TÄin Sophie Strodtbeck Ringstr Hattenhofen web: PD Dr. Udo Gansloßer Bremer Str. 21 A Fürth web: