In dairy the stages of pregnancy and lactation especially the period of transition which is between late pregnancy (-3 weeks) and early lactation (+3 weeks) greatly modify the metabolism in animals and induce high stress and presents huge metabolic challenges in terms of energy balance, blood metabolites and hormonal changes. The loss in the Body Condition Score (BCS) is the consequence of the negative energy balance (NEB) seen just after parturition. The levels of non-esterified fatty acids and higher β-hydroxybutyrate concentrations are indicative of lipid mobilization and fatty acid oxidation. Average to high yielding dairy animals under NEB will mobilise the body reserves to support lactogenesis and milk production resulting in metabolic disorders and sub-optimal milk yield. Various forms of fats like bypass fat and prilled fat addition to the diets is a practicable option to alleviate NEB and to improve lactating animal performance. The present review discusses the effects of various fat supplements on blood metabolites and plasma hormones in milch animals.