The erythrocyte osmotic fragility (EOF) of bovine of Holstein, Gir/Holstein crossbreed and Gir breeds was studied, raised in the State of São Paulo/Brazil with the aim of establishing standard values of reference and determining the influence of breeding factors. In order to do this, the blood samples of 210 females, 70 of each breed were examined. The samples were collect from 18 milk producing establishments, under similar handling and feeding condictions. The results demonstrated significant differences (p<0.05) among the three studied breeds, the Holstein animals being the breed that presented the most fragile erythrocytes and those of the Gir breed the most resistent; the hybrids of the Gir/Holstein crossbreed presented intermediate values. The results were distributed in graphics and resented, numerically, in terms of 5, 50 and 95% of haemolysis.
erythrocyte osmotic fragility; bovine; breeds
