Blood gas parameters of Brahman cattle

Blood gas test evaluates hydroelectrolyte, acid-base balance, and lung function. The physiological parameters can be influenced by age and management and environmental factors, as well as the blood sample used: venous or arterial. The objective of this study was to analyze arterial and venous blood gas parameters of healthy Brahman cattle in Brazil, to determine reference values for this breed, comparing age and sex, in addition to evaluating the correlation between arterial and venous results. For the purpose of this research, 80 healthy cattle (40 males and 40 females) were grouped according to different age groups (Group I: from 5 to 30 days; Group II: from 31 days to 6 months; Group III: from 7 to 18 months; Group IV: from 19 to 36 months) and sex. The animals were examined by physical examination prior to the collection of the venous and arterial blood samples. Blood gas analyses were performed immediately after blood collections, using the I-STAT® portable device with EG7+ cartridge. There was a difference among age groups for rectal temperature (RT), respiratory rate (RR) and heart rate (HR), and age × sex interaction for RT and RR. Younger animals (Group I) had higher RT, HR and RR, regardless of sex. Females had higher RT than males, regardless of age. As for blood gas parameters, only oxygen pressure (PO₂) and arterial and venous concentrations of sodium ions (Na⁺) experienced the interaction between age × sex, while pH, carbon oxygen pressure (PCO₂), oxygen saturation (SO₂), potassium (K⁺), and calcium (iCa²⁺) concentrations of arterial and venous blood were influenced by the age of the animals. Calves in the Group I showed the main differences in blood gas parameters compared to adults (Groups III and IV). The neonates (Group I) had lower values of pH and SO₂, and higher values of PCO₂, K⁺ and iCa²⁺ of arterial and venous blood. High correlation could be observed in the values of pH, Na⁺, hematocrit and hemoglobin when measured in arterial and venous blood, therefore, one value can be obtained by the other. The other variables were very dispersed, confirming the differences pointed out in the literature between arterial and venous blood. Finally, the results of this study can be used as a reference for healthy animals of the Brahman breed.