Ten Thoroughbred foals, male and female, had the seric concentration of creatine kinase (CK), aspartate aminotransferase (AST) and lactate dehydrogenase (LDH) determined. Blood samples were collected every day from days 1 to 7 and on days 15, 30, 60, 90, 120, 150 and 180 of age. CK activity decreased significantly (p< 0.0003) in the first week and showed significant variation between day 15 and 6 months of age. AST showed a significant (p< 0.0001) increase in its values until 102 days of age, decreasing subsequently until 6 months of age. LDH values decreased significantly (p< 0.0002) between days 15 and 120, increasing subsequently until 6 months of age. At 6 months of age CK, AST and LDH activities were close to those of adult horses.
CK; AST; LDH; foal
