KETOSIS is a common disease of dairy cows resulting from a metabolic disorder that leads to hypoglycaemia and the formation of ketones (Zhang and others 2011). The evaluation of renal function has contributed to understanding of the fundamental mechanisms involved in metabolic disorders. However, there have been few studies of the renal function of dairy cows with subclinical ketosis. Impaired renal function is a common clinical diagnosis in animals and human beings (Raskin and Unger 1978, Brown and others 2007); serum creatinine and blood urea nitrogen (BUN) are markers routinely used to evaluate kidney function in animals and human beings (Keegan and Webb 2010). The objective of this study was to examine the differences in β-hydroxybutyrate (BHB), glucose, non-esterified fatty acids (NEFA), total protein (TP), BUN and creatinine concentrations in healthy dairy cows and cows affected by subclinical ketosis during the early lactation period. Venous blood was sampled from 55 healthy cows and 55 subclinically affected cows within the first two months of lactation. Animals included in the study were Holstein dairy cows, three to six years of age, all …