Abstract
This study aimed to assess the thermal environment, behaviour, hygiene, and lameness in dairy cows with different numbers of lactations housed in a compost-bedded pack barn system in a humid subtropical climate during autumn and winter. Between April and July 2016, behavioural and microclimatic environment assessments were conducted in a compost barn system, and hygiene and lameness assessments were performed. Crossbred cows in lactation (n = 10) were divided into two groups according to the number of lactations: primiparous and multiparous. Air temperature, relative humidity, and air ventilation speed were measured at 09:00, 12:00, and 15:00. The cows’ hygiene and lameness were evaluated using subjective scores ranging from 1 to 4 and 1 to 5, respectively. The daytime behaviour assessment was performed as sampling 0/1, using the focal method. Primiparous cows showed a greater probability of walking (P<0.05) than multiparous cows between 09:20 and 11:20, and at 15:20, and increased the water intake at 14:00. Regarding the eating behaviour and the effect of time of day within each group (P<0.05), the cows ate more in the morning’s early hours. The cows’ hygiene scores were 1 or 2, and most cows presented scores of 1 or 2 for lameness. Our research has shown that microclimatic variables may influence the walking behaviour and water intake of primiparous cows during the hottest periods of the day, even during cold weather, in a humid subtropical climate. The dairy cows showed low hygiene and lameness scores, which indicates that the compost bar positively influenced cleanliness and locomotion comfort.