ABSTRACT
The objective of this study was to evaluate the biochemical, behavioral, and physiological parameters in pregnant sows of native and improved crossbreeds reared within a thermally stressful outdoors system. Twenty pregnant sows of two different genetic groups (native and improved lineage) were used in this research, all animals were distributed in a completely randomized design. The behavioral evaluation was organized in subdivided plots, the sub-plots were the four periods of the day (early morning, morning, afternoon, and night), and the evaluation of physiological parameters were in three periods of the day (9:00 A.M., 12:00 A.M. and 3:00 P.M.), which was conducted for three consecutive days. Blood collection was performed by retro-orbital sinus puncture 1 day before the start of behavior analysis. Glucose levels, total protein, and creatinine showed differences between improved crossbreeds and native animals. It was observed that creatinine and total protein presented larger values for the group of improved crossbreeds, while glucose levels were higher for native animals. While behavioral variables showed behavior indicative of heat stress, as more time was spent by pregnant sows of improved genotypes getting wet, searching for water and staying in outdoors, while native animals showed much more movement behavior during morning and afternoon periods. It was observed differences were observed of time for respiratory rates, while no differences were found for rectal temperature. This indicates that in a region with hot climate, it would be more possible to raise native pregnant sows, due to their rusticity and ability to acclimate to a local condition, according to behavioral evaluation and physiological parameters. Pregnant sows of improved breeding genotypes presented higher difficulties of adaptation than native sows.
