Respostas fisiológicas, comportamentais e produtivas de vacas holandesas em lactação sob diferentes sistemas de produção.

Abstract

Climatic variables are environmental components that have effect on animal welfare and, consequently, on the productivity of droves. Know them and verify their interaction with the animals is a way to adjust the system of production characteristics of the environment and the productive potential of the same. Therefore, the aim of this study address the aspects related physiological, behavioral and production responses of lactating dairy cows under different production systems. The study was conducted during the period from 20.01.2013 to 02.21.2013 at the Instituto Federal Farroupilha - Campus Alegrete. We used 27 lactating Holstein cows divided into three treatments, namely: animals fed primarily on pasture, animals fed on pasture and supplemented with concentrate and animals kept in confinement. Were evaluated climate, physiological, behavioral and productive. The physiological assessments consisted of monitoring the rectal temperature, respiratory rate, temperature of the surface of the hair coat, plus evaluation by hamatológica eritograma and determining the level of cortisol. The assessment of drinking behavior included recording of Daily time spent ruminating activities, entertainment and food. To evaluate production, the milk was weighed individually and daily and milk samples were collected from each animal to determine the levels of fat, protein, lactose and solids, and the determination of Somatic Cell Count (SCC). To perform the statistical analyzes, milk production was corrected to 4 % fat. The meteorological factors affected the milk composition and blood components in the three production systems studied, also there was an increase in cortisol levels in the three production systems evaluated in a stress response. Also increased rectal temperature above the normal range in the three systems evaluated and the effects of climatic factors on the physiological variables respiratory rate, rectal temperature and temperature of fur, were higher in the system pasture + concentrate. It was found that during the day the animals are subject to climatic environmental variations, with variations of temperature and moisture content and temperature and these determined different physiological parameters respiratory rate, body temperature and temperature of fur, regardless of the production system adopted. The increased supply of good quality forage decreased grazing time and bits and feedlot resulted in less time with greater power and with rumination. The grazing activity was more intense during the hours when the temperature was milder, ie, at night, for grazing systems and pasture + concentrate. In the concentrate, as long fed occurred during the day, indicating that weather conditions do not interfere in this system, when animals are housed in good facilities.