ARTERIAL BLOOD-OXYGEN PARTIAL-PRESSURE, HEMATOCRIT, HEMOGLOBIN, AND CARDIAC INDEX IN BROILERS AT 2600 M ABOVE SEA-LEVEL

High incidence of cardiac failure in broilers due to hypoxic pulmonary hypertension (PH), produces huge economical losses. Adaptive response s include right ventricular hypertrophy and polycythemia. High energy level in feed could increase hypoxemia and therefore the degree of pol ycythemia, thus increasing PH. To establish normal values in arterial oxygen partial pressure (pO(2)), pH, hematocrit (Ht), haemoglobin (Hb) , and cardiac index (CI), 24 broilers (12 males and 12 females), chose n at random, from a population of 400 birds, were studied in Bogota, C olombia, 2600 m above sea level. Mean values obtained were as follows: a) pO(2): 67.21 +/- 5.21 mmHg; statistical differences between sexes and among ages were found (p<0.05); b) pH: 7.5 +/- 0.05; c) Wt: 37.13 +/- 3.27%. In males, Wt values were higher at 24 and 37 days. In femal es, there was a marked increment on day 31, but no significant differe nces were found (p<0.05). d) Hb: 11.51 +/- 1.37. e) CI (right ventricu lar weight/total ventricular weight x 100): 26.6 +/- 4.83. Highest val ues were found on day 31, being greater in the males. There were no st atistical differences (p<0.05) between sexes or among ages for pH, Hb and CI. Hypoxemia is induced by environmental hypoxia and energy inges tion. Respiratory alcalosis was found, in comparison to data by other authors. The correlation found between pO(2) and CI indicates that, in susceptible chickens hypoxemia due to airways hypoxia induces PH and therefore there is an increase in CI.