Changes of the daily and hourly behavioral time of respiratory disease calves in a group rearing system for 7 days prior to the date of clinical diagnosis.

Respiratory disease in calves is one of the most prominent diseases affecting their growth. The early and accurate detection of calf disease on the farm brings proper growth of calves. The objective of this study was to compare the daily and hourly behavioral time of diseased calves with the other calves in same pen (pen-mates) for 7 days prior to the diagnosis day. The calves (from 14 to 20 heads) were reared in a group. Day 0 was defined as the day of diagnosis. The number of diseased calves was 30 in the present experiment. The lying and eating behavior of calves were observed at 10-min intervals. The diseased calves have significantly (P < 0.01) shorter eating times than the pen-mates on the diagnosis day. The longest hourly time of the eating was in the period between 08:00 and 09:00, and shortest lying time was in the period between 09:00 and 10:00. Diseased calves had significantly (P < 0.05) longer daily lying time and shorter daily eating time than the pen-mates almost for the 7 days prior to the diagnosis day. Even though the daily behavioral time was different, the difference of behavioral time in successive hour periods was limited.