Termorregulação de bovinos leiteiros confinados em instalação compost barn em Região Semiárida

• Ano de defesa: 2017
• Autor(a) principal: Peixoto, Maria Simone Mendes
• Tipo de documento: Dissertação
• Tipo de acesso: Acesso aberto
• Idioma: por
• Palavras-chave em Português: Ambiência; Confinamento; Geoestatística; Vacas leiteiras
• Link de acesso: http://www.repositorio.ufc.br/handle/riufc/31183

The study analyzed the thermoregulatory, physiological and behavioral responses of dairy cows confined in a Compost barn installation, under the climatic conditions of the Brazilian semiarid. For this, environmental monitoring operations were carried out in a commercial farm located in the municipality of Quixadá, located in the State of Ceará - Brazil. The evaluations were carried out during five months, covering the period from October 2016 to February 2017, through collections in the morning and afternoon shifts, in a shed that housed a lot with an average of 25 lactating Holsteins cows of completely randomized design. The environmental parameters were analyzed by means of the installation of meteorological minima in the shed, in order to collect and store data regarding temperature and relative humidity. The comfort of the cows was analyzed based on the evaluation of the respiratory rate and superficial temperature of the skin, as well as the study of kriging maps obtained from the monitoring of bed temperature and evaluation of Black Globe Temperature and Humidity Index (BGHI) and the Enthalpy Comfort Index (ECI). The analysis of the behavioral parameters was performed by means of Ethograms, aiming to obtain information such as preferences for bed area, percentage of cow lying down, cow time lying down, among others. During the collection weeks in October and November, the air temperature (ºC) in both shifts, presented higher mean values, observing that all months differed statistically (p <0.05) for this variable, so that the values were high for the Holstein breed, indicating condition of thermal discomfort to the animals, throughout the experimental period. Relative air humidity (%) records, in the morning shift, indicated satisfactory values for the management of the breed, except for the month of October. On the other hand, the relative humidity of the air, in the afternoon shift, presented very low records, in each month, evaluated. By means of the kriging maps it was possible to observe that the bed surface temperature was higher in the months when the air temperature was also higher. It was observed that in the areas which did not have ventilators, the bed surface temperature presented higher values in comparison to the ventilated areas, in both shifts. These results could be understood by observing that the physiological parameters signaled thermal stress throughout the experimental period and the first two months (October and November) showed more marked discomfort values. The evaluation of the Ethogram showed that cows chose to rest in bed areas where the temperature was milder, independent of artificial ventilation. This behavior of choice probably happened due to the inefficiency and / or poor distribution of the ventilators in the shed, making the cows choose to prioritize the natural ventilation throughout the shed.