Compost Barn System and its Influence on the Environment, Comfort and Welfare of Dairy Cattle

The aim of this study was to evaluate the effect of the thermal environment on behavioral and physiological parameters of crossbred cows of different productivity levels confined in a compost barn system. For this, the Temperature and Humidity Index (THI) and Enthalpy (H). Bedding material variables (pH and humidity) were also evaluated. The animals were evaluated for physiological variables (respiratory rate RR and surface temperature ST), scores (body condition, locomotion and dirt) and behaviors. The analyses were carried out on two groups of cows (Group 1: high milk producers vs. Group 2: medium and low milk producers). Although the mean values ​​of air Tdb and enthalpy were within the range considered appropriate for thermal comfort, the THI and RH) were ​​outside the thermal comfort zone for cows. Regarding the bedding material, the bedding temperature was an average of 37.13 ºC at a depth of 20 cm, which is slightly lower than the recommended limit. A higher temperature was observed where Group 1 was housed. The average humidity of the bedding material was higher where Group 2 was housed, probably due to the lower animal density. The average pH of the bedding material was 8.5, within the recommended range. In the case of the physiological responses of the cows, the RR of Group 1 indicated better conditions of thermal comfort in the morning vs. the afternoon, with an average value of 60 mov.min-1. In the case of ST regardless of the group and time of day, average values were ​​below 35 ºC. Regarding the behavioral evaluation, Group 1 and 2 were statistically similar and had the longest rumination times, in relation to the other evaluated behaviors. Regarding active periods, medium milk producers were the most active. Regarding idle time, low milk producers spent more time idle than the other animals.