In saccodegradation of organic matter and crude protein of fresh grass (Lolium perenne) in the rumen of grazing dairy cows

Abstract

In three experiments, carried out in 1985 and 1986 in the Netherlands, the effects of herbage maturation and rate of nitrogen fertilization on rumen degradability of organic matter (OM) and crude protein (CP) in fresh herbage (Lolium perenne) were studied using the nylon bag technique. Experimental farms at Lelystad and Swifterbant (clay soil) and Achterberg (sandy soil) provided the herbage samples. From the results, the content of digestible CP entering the small intestine (DPI) was estimated.Crude protein content and in sacco degradability of OM and CP decreased with increasing grass maturity and with decreasing rate of N application. With every 100 g/kg DM decrease in CP content, the estimated content of DPI decreased by 19 g/kg DM, no matter how the CP content was manipulated.