The horses of the Brazilian army are used for expositions, and frequently subjected to intense exercise. This, together with environmental conditions of the Central west savanna result in the need for acclimatization. The objective of this study was to determine what is the effect of thermal and exercise stress on four groups of stabled horses in the savanna region. 40 Adult horses (4 to 13 years of age) from the 1st Mounted Guard Regiment (10 of each breed Thoroughbred ¾ PSC, Crossbred ¾ M and Brazilian Showjumper ¾ BH) as well as 10 Bretãs from the 32nd Campaign Artillery Group, were used. All horses were kept in the Urban Military Sector in the Federal District. The measurements made on the animals included heart and respiratory rates, rectal temperature and blood samples were taken at four opportunities during the day, in the morning and afternoon, before and after exercise. Genetic group influenced all traits except VCM, HCM e CHCM. Animals of the PSC group had higher means for leukocytes (7.83 ± 1.59), hematocytes (9.21 ± 1.27), VG (40.75 ± 4.58) and hemoglobin (14.34 ± 1.67), while crossbreds had higher total plasmatic protein levels (6,93 ± 0,66). The Breton breed had lowest levels for the majority traits examined. Exercise increased all traits except VCM, HCM and CHCM. The correlations between traits vary greatly, the highest being between hematocytes, hemoglobin and VG (>0.58), while with total plasma protein they were low (<0.26). The present work allows us to conclude that in terms of exercise of horses of the Brazilian army PSC are worst adapted and Bretã best adapted to the conditions of this study.
acclimatization; heat stress; physiological responses
