Caracterização histofisiológica das glândulas sudoríparas e das características da pelagem em vacas leiteiras face à aclimatação sazonal.

Abstract

SEASONAL ACCLIMATISATION PROCESS IN DAIRY COWS: STUDYING HISTOFISIOLOGICAL CHARACTERISTICS OF SWEAT GLANDS AND HAIR COAT

ABSTRACT: This trial aimed to study the seasonal acclimatisation process in dairy cows in a Mediterranean climate, focusing the changes in the histophysiology of sweat glands and hair coat. From 10 cows we collected data in two periods (P1 – summer; P2 – winter). Ambient temperature with a black globe thermometer (sun and shadow) was registered. From each cow, sweat rate (Ts), skin temperature (Tpl) and cutaneous tissue samples were taken to perform histomophormetical evaluation. Hair coat samples were collected for measurements and for medula expression. Conclusion: in summer, animals had higher Ts and Tpl, even though our results were not as higher as many other results in some other papers. In our trial, animals were always in shadow and ambient temperature decreased significantly at night time. Significantly differences in histomorphometric were found between periods. Hair coat was similar in summer and winter (measurements and medulation). So, the physiological mechanisms that regulate sweat rate and skin temperature changed with the acclimatisation process, confirmed by modifications in the morphometric of sweat glands and epidermis. Keywords: acclimatisation, cattle, hair, sweat glands