Production, milk yield and composition, and feed efficiency in Jersey cows supplemented with fat

Abstract

Eight Jersey cows in early lactation, of 380 kg mean liveweight, were used to evaluate the effects of several lipid supplements on milk yield and composition and feed efficiency.  The cows were distributed in a replicated 4 x 4 Latin square design, with 21-day experimental periods, and fed isocaloric diets of corn silage and alfalfa hay and one of four concentrates: control (without lipid supplement) and three including different lipid sources: tallow, protected fact and ground whole soybeans.  Milk yield was recorded daily and on the 19th and 21st day of each experimental period samples of milk were collected for determination of chemical composition.  The data were submitted to analysis of variance and means were compared by Tukey test.  The diet with protected fat increased (P<0.05) 4% fat-corrected-milk (FCM) yield and improved feed efficiency in relation to the control.  The different lipid sources did not influence (P < 0.005) the concentration or production of fat, protein and lactose, nor the concentration of urea, total solids, calcium, ash and energy of the milk