Abstract: | In 34 pure breed Arabian horses divided into four groups (Gr. I--10 pregnant mares, Gr. II--7 barren mares, Gr. III--10 foals born in 1981, Gr. IV--7 foals born in 1982) seasonal changes in total blood serum protein, its electrophoretic fractions and the activity of AspAT and AlAT were studied. Seasonal cyclicity was found in all groups in the amount of total serum proteins, and alpha 2- and beta 1-globulin fractions. Cyclicity was found in the level of albumin and activity of AspAT in three groups, not Gr. II, and in gamma-globulin, not Gr. IV. beta 2-globulin and AlAT cyclicity was found in two groups and alpha 1-globulin cyclicity was found only in Gr. II. Out of nine indices studied, cyclicity was found in eight of them in pregnant mares, Gr. I; in seven in older foals, Gr. III; in six in the young foals, Gr. IV; and in five in barren mares, Gr. II. |