Blood parameters of dairy cows supplemented with different fat sources/Parametros sanguineos de vacas leiteiras suplementadas com diferentes fontes de gordura

This study was carried out to evaluate the use of different fat sources in dairy cows rations and its effects on dry matter intake, milk yield and composition, and blood parameter. Twelve Holstein cows were allocated in three balanced latin square 4x4, and fed with the following rations: 1) Control, with 2.5%; 2) Refined soybean oil; 3) Whole soybean; and 4), Calcium salts of fatty acids (Megalac-E). The concentrations of total cholesterol and lipoprotein low density (LDL) were higher (P < 0.05) for cows that received rations with fat sources, which also causes increased (P < 0.05) e concentration of high density lipoprotein (HDL). The concentrations of urea and blood urea nitrogen were similar among the rations, except for the diet containing calcium salts of fatty acids, which showed lower (P < 0.05). The dry matter intake was lower (P < 0.05) in cows that received calcium salts in the rations. The animals that received a diet containing whole soybeans as a source of fat had lower (P < 0.05) yield milk when compared to other rations used. The use of fat sources in dairy cows rations influenced the blood parameters, especially for parameters related to lipidogram. Key words: lipids, lipidogram, liver enzymes, profile metabolic, proteinogram. O objetivo deste trabalho foi avaliar a utilizacao de diferentes fontes de gordura nas racoes de vacas em lactacao e seus efeitos sobre o consumo de materia seca e as concentracoes dos parametros sanguineos. Foram utilizadas 12 vacas da raca Holandes, agrupadas em tres quadrados latinos balanceados 4x4 e alimentadas com as seguintes racoes: 1) controle; 2) oleo de soja refinado; 3) grao de soja in natura; e 4) sais de calcio de acidos graxos (Megalac-E). As concentracoes de colesterol total, colesterol, lipoproteina de baixa densidade (LDL) e colesterol de alta densidade (HDL) foram maiores (P < 0,05) para as vacas alimentadas com as racoes contendo fontes de gordura em relacao a racao controle. As concentracoes de ureia e nitrogenio ureico no soro foram semelhantes entre as racoes utilizadas, com excecao da racao contendo sais de calcio de acidos graxos, que apresentou concentracoes menores (P < 0,05). O consumo de materia seca foi menor (P < 0,05) nas vacas que receberam sais de calcio nas racoes. Os animais que receberam a racao contendo grao de soja como fonte de gordura apresentaram menor (P < 0,05) producao de leite quando comparada as demais racoes utilizadas. A utilizacao de fontes de gordura em racoes de vaca