Krubbitning hos häst
implikationer på djurvälfärd och argument för en nollvision om förekomst av beteendet
Most descriptions of stereotypic behaviours have in common that these repetitive behaviours only has been observed in captive animals and therefore it has been proposed that stereotypies exist because we house animals in environments that are sub-optimal to them. Some scientists claim that performance of stereotypies in itself decreases the animal's welfare due to costs in time, energy and health and a poorer quality of life. Other scientists assert that individuals performing stereotypies may have a better welfare compared to the rest of the animals in the same environment, since these individuals have developed strategies to cope with stress. Studies have estimated the prevalence of abnormal behaviours in horses to 18-30 % of the population. Several studies on cribbing have revealed a prevalence of 4-5 %, although some results indicate that more than 10 % of the horse population performs this stereotypy. Today we keep horses in ways that differ markedly from the way horses evolved. We also tend to demand higher performance out of younger horses kept for sport and competition. Many traditional procedures in housing and training tend to push horses beyond their natural adaptable behavioural repertoire. This may lead to stress and cause some horses to develop stereotypic behaviours. The purpose of this essay is to investigate and discuss if today's level of knowledge is sufficient to argue for a zero vision in prevalence of cribbing, just like Mason et al. (2007) argues regarding stereotypies in zoo animals. Another aim with this work is to emphasize why prevention of the development of stereotypies is important in relation to animal welfare. The conclusion is that today there is immense knowledge about risk factors regarding the development of stereotypies in horses and most factors are related to our management procedures. Since the horse keeping is modifiable a zero vision in prevalence of cribbing should not be considered a utopia either if it is a matter of changes that horse owners implement themselves or if it is a question of more stringent legislations. An examination of the Swedish Animal Protection Legislation that regard horses reveals some shortcomings mainly regarding the demands on daily movement outside stalls and social contact. The most prominent argument why it is important to prevent development of stereotypies in an animal welfare point of view is that horses showing these behaviours should be taken as serious signs of management deficiencies. These deficiencies do not only affect horses displaying abnormal behaviours as a response to the difficulties they experience, but all resident horses. It is even possible that the individuals displaying stereotypies have a somewhat better welfare compared to other horses in the current environment, since they may have developed strategies to cope with the stress that our management may cause them.