Proceedings of the XLV Italian Society of Agricultural Genetics - SIGA Annual Congress

Salsomaggiore Terme, Italy - 26/29 September, 2001

ISBN 88-900622-1-5

Oral Communication Abstract

GENETICS, STRESS AND COPING MECHANISMS: EXAMPLES OF EXPERIMENTAL RESULTS IN DOMESTIC ANIMALS

VERGA M.

Istituto di Zootecnica, Facoltà di Medicina Veterinaria, Via Celoria 10, 20133 Milano

Marina.Verga@unimi.it

genetics, stress, coping strategy, domestic animals, welfare

Stress reactions and coping mechanisms have been studied for many years in domestic animals. The motivational basis to this research are related to the need of improving the quality of animals' life and thus their welfare. In farm animals this may improve the quality of the whole production system, which is considered an important issue by the consumers too; in companion animals this may lead to a better relationships with humans and avoid the appearance of some disturbed behaviours.

Although it is difficult to precisely define welfare, it is well known that the presence of stress lowers welfare levels, mainly when adverse environment induces a chronic activation of stress response, negatively affecting also growth, reproduction, behaviour and some aspects of disease resistance. The genetic traits of domestic animals, both from the evolution perspective and from each breed as well as individual point of view, have to be deeply considered, due to the fact that the survival and the fitness of these animals are completely controlled by humans. In fact individual variability leading to better or worse coping efficacy exists in nature but also in the same farming environment. Obviously the coping mechanisms are based both on genetic background and on the experience, i.e. learning. However, the basic reactivity, mainly related to the neuro-endocrine activation and to the response of the other behavioural and physiological mechanisms involved in the stress reaction, may differ according to the genetic selection, which may pre-dispose each organism’s sensitivity to stressors. To identify and select the individuals less stress prone may both improve welfare, and also positively affect other traits, for example: production, such as growth rate and feed conversion index; reproductive performance, such as fertility rate; reactivity in some immune systems. Many researches have been focused on the meaning and development of the responsiveness to acute and chronic stressors, which may be related to the genetic background. Although the process of domestication has been carried out for many species since thousands of years, nevertheless the rapid changes in the husbandry techniques, including the new recent biotechnologies, may represent challenges which negatively affect the animals and their adaptability to the environment.

With respect to the previous considerations, some experimental results of the effects of genetic selection on stress reactions in domestic animals are reported on three different domestic species: 1) poultry; 2) cattle; 3) domestic dogs. In the first example the genetic selection may contribute in reducing fear reactions, both towards new environment and human beings. The second example shows that both phenotypic and breed characteristics affect the ability to adapt to the environmental conditions. The last example indicates the possibility to identify stress prone and non stress prone dogs, analysing their behavioural and physiological reactions (heart rate) to a stressful environment.