The objective of this study was to evaluate the productivity of dairy cows supplemented with soybean oil during the transition period. Twenty multiparous and pregnant Holstein cows were randomly allocated to two diets: control (C), 2.5% ether extract (EE) in the dry matter (DM); and fat (G), with the addition of 3% soybean oil, and 5.5% EE in the dry matter. The average values for intake were not different in the pre- and post-partum for cows on the control and fat diets except for an increase in EE intake due to great concentration of this nutrient in the soybean oil diet. Due to the higher energy density of the fat diet, cows had higher intake of total digestible nutrients and net lactation energy during the post-partum. There was no alteration in milk and fat yield, but a reduction in the milk fat content was observed for cows fed fat diet compared with the control diet. The diets used had no influence on the intake, and the fat diet resulted in an increased net energy intake and improvement in the nutrient balance during the initial phase of lactation. A non-significant increase in milk yield (+ 2.53 kg/d) was observed when using the fat diet.
dietary fat; dry matter intake; peripartum; productive performance
