Energy status of dairy cows may be estimated using results for concentrations of fat, protein and urea (MUN) in milk samples obtained from bulk tank or individual cows. Using individual cow milk samples is recomended on dairy farms in our geografi cal region due to the unhomogenity of cows in the herds in respect to their genetic potential for milk production. Depression of milk fat occurs as a consequence of heat stress, underfeeding of peripartal cows, overfeeding concentrate with reduced ration fi ber levels or overfeeding with dietary fat. High milk fat content is usually combined with severe negative energy balance. Nutrition and feeding practices have great impact on milk protein level. A defi ciency of crude protein in the ration may depress protein in milk. Feeding excessive dietary protein does not signifi cantly increase milk protein. MUN analyses point out poteintial problems in feeding program on dairy farm. High MUN values may refl ect excessive dietary crude protein and/or low rumen degradable nonfi ber carbohydrates intake. Also, MUN levels is impacted by heat stress since its value is increased during the summer season. Low MUNs indicate a possible dietary protein defi ceincy. Additionally, low MUNs concentration may indicate excess in dietary nonstructural carbohydrates. On the bases on the interrelationships between protein and urea concentrations, as well as protein and fat concentrations in individual milk sample, estimation of energy balance of dairy cows may be done more accurately.