Extruded Versus Raw Ground Soybeans for Dairy Cows in Early Lactation

Twenty-four Holstein cows (12 primiparous, 12 multiparous) were allotted 2 wk prior to parturition to one of two treatments.For 10 wk after parturition, cows of each age group received either 2.27 kg extruded (150°C) soybeans or 2.27 kg of raw ground soybeans in addition to corn silage and concentrate in a complete mixed ration (formulated for early lactation).Cows consumed 2.9, 2.8, 3.0, and 2.9% of body weight for the primiparous and multiparous groups fed extruded soybean and for the primiparous and multiparous groups fed raw ground soybean, respectively.Milk production in kilogram and milk fat percent for these same groups were 23.2, 2.67; 28.9, 2.68; 23.6, 3.07; and 27.2, 3.00.Milk fat percent was different between treatments.Because cows receiving extruded soybeans produced slightly more milk than cows consuming raw soybeans, there was no difference in 4% fat-corrected milk.Also, there were no differences in rumen physiology attributable to treatment.Formulating complete rations containing corn silage as the main fiber source and adequate in energy requirements for early lactation may predispose cows to a low fiber, milk fat depression syndrome.Feeding extruded soybeans to dairy cows in early lactation demonstrated no advantages over feeding raw ground soybeans.