The aim of this study was to investigate possible changes in the gas composition and acid-base values of bovine venous blood samples stored at different temperatures (+4, 22 and 37 degreesC) for up to 48 h. Five healthy cattle were used in the study. A total of 15 blood samples collected from the animals were allocated into three groups, which were, respectively, then stored in a refrigerator adjusted to +4 degreesC (Group I, n = 5), at a room temperature of about 22 degreesC (Group II, n = 5) and in an incubator adjusted to 37 degreesC (Group 111; n = 5) for up to 48 It. Blood gas and acid-base values were analysed at 0 (baseline), 1, 2, 3, 4, 5, 6, 12, 24, 36 and 48 h of storage. A significant decrease (p < 0.001) was found, in the pH of the refrigerated blood after 5 h and its maximum decrease was recorded at 48 h as 0.04 unit. There were also significant alterations (p < 0.001) in the blood pH of the samples stored at room temperature and in the incubator after 2 and 3 h, respectively. The maximum mean alteration in pCO(2) value for Group I was -0.72 kPa during the assessment, while for groups II and III, maximum alterations in pCO(2) were detected as +2.68 and +4.16 kPa, respectively. Mean pO(2) values increased significantly (p < 0.001) for Group I after 24 It and for Group II after 6 h, while a significant decrease was recorded for Group III after 24 h (p < 0.001). Base excess (BE) and bicarbonate (HCO3) fractions decreased significantly for all the groups during the study, compared to their baseline values. In conclusion, acid-base values of the samples stored at 22 and +4 degreesC were found to be within normal range and could be used for clinical purposes for up to 12 and 48 h, respectively, although there were small statistically significant alterations. (C) 2003 Elsevier Ltd. All rights reserved.