Effects of Soybeans Compared to Soybean Oil and Meal in the Ration of Dairy Cows

Abstract

Twelve lactating Holstein cows were used in a 12-week experiment to compare a conventional concentrate mixture containing: 4.2% ether extract and 13.5% crude protein with the same mixture modified by the addition of soybean oil in different combinations with protein. The rations compared were A, control plus soybean oil; B, control plus soybean oil and soybean meal; C, control plus ground soybeans. Ether extract was increased to about 8% in each experimental ration.Milk fat percentages of cows on Rations A, B, and C were 2.8, 3.1, and 3.6 compared to 3.1, 3.1, and 3.2 for the controls. There were no significant differences in milk yield or protein and solids-not-fat content. Percentages of acetic, propionic, and butyric acid in the rumen did not differ significantly. Ration B significantly increased iso-valeric and n-valeric acids and pH in the rumen compared to the control ration. Rations B and C resulted in significantly higher blood urea nitrogen than either the control or Ration A. In tail-mammary samples, mammary gland output of free fatty acids in plasma increased for Rations A and B compared to the control ration. Triglyceride uptake increased on Ration C.