BIOINDICATORS OF STRESS IN DIFFERENT WEANING SCHEMES IN CATTLE

DE FINO, F; ODEON, MM; MAIDANA, SS; VITTONE, S; ROMERA, SA

Mar del Plata

Congreso; V Congreso Nacional- V Reunión Científica Regional- II Simposio de Métodos alternativos- AACyTAL; 2016

The agricultural sector is changing rapidly due to global trends of globalization, internationalization of markets and multinational trade agreements. One of the emerging issues in this scenario is the animal welfare. The concept of animal welfare is based on the harmonious relationship of the animal to the environment. A variety of behavioral, physiological, biochemical and immunologic parameters have been proposed to evaluate the responsiveness of the animals to stress. The aim of this study was to evaluate biochemical and physiological parameters as indicators of well-being and stress of cattle under different weaning schemes. The experimental design consists of two groups, one of conventional weaning (6months) and a group of early weaning (1month). Whole blood samples were taken at different times, -7, 0(weaning), 1, 7, 14, 21. Received samples were analyzed in a hematology analyzer, then the plasma was separated and analysis of total plasma protein was performed by the Lowry method, plasma cortisol levels by HPLC. With the results of hematologic counter observed only in the conventional group, a significant decrease in the number of lymphocytes, a significant increase in the number of granulocytes, leading to an increase in the ratio GR:L. We found a significant increase on day 1 post- weaning in both groups equally. Result matching literature refers to increases in concentrations of total proteins in response to acute stress. Levels then drop to day 7 and 14 and finally recovers baseline to day 21. As cortisol levels, we observed a response to stress with large increases on day 1, however, the characteristic peak of the response to acute stress is not seen, but a downward curve most characteristic to chronic stress is observed, being clear response in the conventional weaning group, while in the animals with early weaning seems more difficult to achieve and return to baseline levels. In conclusion we observed that in the parameters analyzed, conventional weanlings act as expected in a stress response, whereas early weaning no such response is observed.