Consumption, nutrient digestibility and lactation performance of dairy cows fed soybeans in different forms

Twelve Holstein cows were given diets containing soybean supplied in different ways in order to identify possible changes in lactation performance and evaluate the economic feasibility of the diets. The diets included: soybean meal only (SM-control); raw soybean (RaS); roasted soybean (RoS) and soybean meal plus 5% urea (SMU). The forage consisted of corn silage. We analyzed the dry matter intake, milk production and collected milk samples. To estimate digestibility, we collected six samples of feces over a period of six consecutive days. The intake of dry matter (DM), organic matter (OM), neutral detergent fiber (NDF) and non-fiber carbohydrates (NFC) did not differ among treatments. On the other hand, crude protein (CP) intake was influenced by the diets, and the highest mean values of ether extract (EE) were found with the RaS and RoS diets. The intake of total digestible nutrients (TDN) was lower in the RaS and RoS diets compared to the control diet. DM, OM, CP, EE, and NDF digestibility were not affected by the different diets, while NFCs were reduced in the RoS diet and TDN decreased with both the RaS and RoS diets. There were also no differences observed across diets for total milk production, production corrected to 3.5% fat, diet efficiency, or milk per kilogram of dry matter and/or crude protein. We conclude that raw and roasted soybeans as well as concentrate plus 5% urea in dry matter may be used instead of soybean meal as feed for high-producing cows, without affecting milk production and composition. We also observed that the SMU diet was the least costly.