EARLY WEANING IN CATTLE: BIOINDICATORS OF STRESS

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

Las Palmas de Gran Canaria

Congreso; XIV congreso SECAL ? 2017; 2017

INTRODUCTION The agricultural sector is changing rapidly due to global trends of globalization, 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. MATERIAL AND METHODS The experimental design consists of two groups, one of conventional weaning (6months) and a group of early weaning (1month). Calves were blood sampled via jugular venipuncture on days -7, 0, 1, 7, 14 and 21 relative to weaning (d 0). 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 and for measure the response to a bovine herpervirus vaccine we analyzed antibodies titer in an ELISA assay. RESULTS 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 of plasmatic proteins 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. 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, 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. As for the response to the vaccine, unlike conventional, early weaning animals did not show a satisfactory response. CONCLUSION In this study leukocyte subsets, plasmatic proteins and cortisol levels were altered after the weaning challenge. These results indicated that a weaning challenge as a stressor, regardless of age. The management strategies should be complemented with the screening of calves immunity to assess the efficacy of the vaccination program and the correct application of the production system. Therefore, since the conventional indicator (%GR:LY) is not very representative of the stress response, we recommend in this type of systems the use of cortisol and total proteins as indicators.