Variables neuroendocrinas y su relación con el comportamiento durante la lidia del toro bravo ("Bos taurus", L.)

Zusammenfassung

Fighting bull is a great interesting animal model due to its particular behavior in high stress inductor situations, as bullfighting is. This behavior is unique in animal kingdom and it appears as a consequence of the selection, during centuries, by cattle breeders. At the Animal Physiology Department of The School of Veterinary Medicine of Complutense University of Madrid, we have characterized this adaptative response to stress produced by ordinary and “recortes” bullfighting in the bulls. Moreover, aggression has an important role in this unique behavior of fighting presented by fighting bull; this aggressive component is very important for the development of the bullfighting. In this Doctoral Thesis we have analyzed the adaptative response to stress developed by the bulls during two different types of bullfighting, ordinary and “recortes” bullfighting; this response is mediated by sympathetic and medulla-adrenal systems and the hypothalamus-hypophysis-adrenal axis. Another aim of this work has been to characterize the aggressive behavior developed by bulls during the bullfighting and to describe the neurophysiological basis of this aggression. And, finally, we have studied the potential relation between these neuroendocrine variables and the aggressive behavior developed by the bulls during bullfighting. To carry out the study, epinephrine, norepinephrine, cortisol, ACTH, serotonin and testosterone serum levels have been determined in 143 fighting bulls in two different moments of life: branding (6-8 months old) and bullfighting (4-5 years old). Moreover, we have assessed the aggressive behavior developed by these animals during bullfighting and we have assigned a behavioral aggression mark that was related with neuroendocrine parameters studied. As conclusions, we can state that fighting bulls are able of developing an adaptative response to stress during the two different types of bullfighting. Regarding aggressive behavior developed by bulls during bullfighting, it was shown that serum level of serotonin is a good indicator of the tendency to show an aggressive behavior during bullfighting and, for this reason, serum serotonin level could be used as an orientative variable in the selection of fighting bulls. It would be especially useful in the identification of those animals with a predisposition to show a non-combative behavior. Otherwise, the serum level of testosterone did not work as a good indicator of aggressive behavior during bullfighting. In the same way, it was not found correlation between serum levels of catecholamines, cortisol and ACTH with aggressive behavior developed by bulls during bullfighting.