Mares have the highest nutrient requirement in the first three months of lactation. Energy is important for mares to maintain body condition and produce milk for their foal. Nutrients for milk production come from feeding and are carried by blood to mammary gland. The effect on body weight changes blood for cholesterol and triglycerides, milk for fat content and foals development were investigated through supplemental dietary fat coconut oil (CO) at four levels (0,4,8 and 16 per cent) in concentrate fed to 16 multiparous thoroughbred mares in early lactation with average body weight ñ 441,2 Kg. Mares were fed 1,5 per cent live weight with concentrate composed of corn meal wheat bran and soybean meal with 16 per cent crude protein...