Behavioral and physiological changes in sows and piglets maintained in farrowing cages or open stalls during summer

Containment cages are one of the main causes of chronic stress and reduced welfare during swine production as well as in hot environments. The objective of this study was to evaluate behavioral changes and physiological parameters in the presence or absence of cages in farrowing facilities and to determine the benefits of cage removal on the welfare of pigs during summer in a tropical climate. Twenty-six sows and 290 piglets were divided into two groups: individual open stalls and cage stalls, from birth to weaning at 21 days of age. To obtain behavioral data, the animals were evaluated every 10 minutes, for 2 hours in the morning and 2 hours in the afternoon, three non-consecutive times a week, for 21 days for each sow and litter. Rectal, dorsal, and ventral surface temperatures, as well as the respiration rate, were obtained three non-consecutive times per week from all sows and a sample of piglets in the morning and afternoon. Saliva samples for cortisol determination were collected only from the sows and performed at 7-day intervals in the morning and afternoon. Sows kept in cages showed greater agonistic, stereotypical, and feeding behaviors, and less exploratory behavior. In piglets, exploratory and playful behaviors were highly expressed in open stalls. Suckling behavior was observed more frequently in cage stalls and in the afternoon. Positive behaviors were higher in open stalls for both sows and piglets. The average rectal, dorsal, and ventral surface temperatures of the sows were higher in open stalls and lower in piglets, and air temperatures were lower. Higher concentrations of cortisol were found in cage stalls and in the afternoon. In conclusion, open stalls are better than cage stalls in improving animal welfare, contributing to the presence of positive behavior even during summer.