Resumen
On dairy farms, calves are typically raised inside barns (either in individual or group pens), or they are raised in outdoor hutches. To evaluate the effect of all three of these commonly used rearing practices on calves, an experiment was conducted. A group of 58 Holstein dairy female healthy calves (3 days of age) was randomly divided into three subgroups (outdoor hutches, individual-housed, and group-housed in a barn). The body weight, lying bouts, lying time, and immunity parameters of each calf were monitored, and the ambient temperature and relative humidity were measured. The average temperatures outside and in the barn and hutches were -16.67 °C, -15.26 °C, and -15.59 °C, respectively, from 22 November 2020 to 27 January 2021. All calves suffered from cold stress. Group-housed calves weighed significantly less than the other calves at the ages of 1 month and 2 month (p < 0.05). The lying time of the calves housed in individual pens and group pens was longer (p < 0.05) than that of the calves housed in hutches. The morbidity attributable to bovine respiratory disease was significantly lower among the calves housed in hutches than it was among the calves housed either individually or in group pens inside the barn (p < 0.05). No significant differences in the concentrations of TNF-a, IL-1ß, and IL-6 were found between the three groups (p > 0.05). On the basis of these findings, we were able to conclude that calves housed in outdoor hutches were at a lower risk of developing a disease than were calves housed in barns without heating in winter. To optimize the management process, heating should be added to hutch systems. Moreover, more rigorous disease and environmental control management strategies should be applied when raising calves inside barns.