EN
A population of 90 Polish ponnies, males and females in three age groups, 1st — 1.5—4.0 years old (46 animals), 2nd — 5—9 years old (23 animals), 3rd — 10 or more years old (21 animals) was examined. Haematological determinations were performed with blood from the external jugular vein in each season for 2 years. A total 720 blood samples were examined. Red blood cells content (RBC), white blood cells content (WBC), haemoglobin (Hb), haematocrit (Ht), mean concentration of haemoglobin in erythrocyte (MCHC), mean weight of haemoglobin in erythrocyte (MCH), mean volume of erythrocyte (MCV) and differential leukocyte count were examined. It was found that along with an increase of age of ponnies increase Hb, Ht, MCH, MCHC, MCV, number of neutrophils and acidophils and lower WBC and number of lymphocytes. The same trend in changes of blood parameters related to age is noted in other horse breeds.