Partial replacement of soybean meal with slow releasing non protein nitrogen source in dairy cows: performance and economic implications

The objective of this research was to evaluate the partial replacement of soybean meal with a slow-release source of non-protein nitrogen in the dairy cattle ration on milk production, milk composition and economic implications. Forty-four cows with an average 193±39 days in milk and the average parity number of 3.1 ± 1.4 were assigned to one of the following treatments: the control ration (containing soybean meal), and the experimental ration containing non-protein nitrogen slow-release (0.75% of diet DM as slow-release source of non-protein nitrogen). The diets were fed to cows as total mixed ration and ad libitum. Milk production, milk composition, and blood urea nitrogen were measured. Milk yield, milk fat and protein percentage, somatic cell count, and blood urea nitrogen were not influenced by treatments (P >0.05). Income over feed cost (IOFC) for the diet containing non-protein nitrogen slow-release was significantly higher compared with the control treatment (P