RESUMO
In bovine medicine, blood transfusion practice represents an emergency therapy where time is critical. The aim of this study was to develop a mathematical model to calculate the required blood for transfusion, using parameters which could be easily determined on the spot. Twenty Holstein calves were assigned to two groups depending on body weight (100.1 ± 3.1 kg and 151.1 ± 3.0 kg, respectively). All animals were subjected to an anaemia induction protocol in isovolaemic conditions in order to reduce the packed cell volume (PCV) by more than one third. Twenty-four hours later, each group received an auto-transfusion therapy. In order to find a valid constant for specific weight categories with high confidence interval in cattle, we calculated the value of constant 'CC' for each individual, using a formula described for carnivores as a basis. The value of the constant for the 100.1 ± 3.1 kg and 151.1 ± 3.0 kg groups was 80.6315 ± 1.1069 and 76.5294 ± 2.5640, respectively. The comparison between the two groups demonstrated significantly different mean values (P = 0.0002, by t-test) and, furthermore, significantly different values of the constant distributions (P = 0.0001, by the Kolmogorov-Smirnov test).