In vitro gas production and dry matter digestibility of malting barley grain sown with different seeding and nitrogen fertilization rates in Canada

Two malting barley varieties, AC Metcalfe and CDC Copeland, were grown at seven sites in Canada with varying seeding rates (SR; 200 and 400 seeds/m2) and nitrogen fertilization rates (NR; 0, 30, 60, 90, and 120 kg/ha) and were assessed for variation in chemical composition, gas production (GP), and dry matter digestibility (DMD) after 24 h of batch culture. The variety affected (P<0.01) the crude protein (CP) content of malting barley grain and interacted with SR or NR on DMD. The increase in NR quadratically increased (P<0.01) CP and fiber content but linearly (P<0.01) decreased starch content of malting barley grain. Variety, SR, and NR had limited impact on in vitro GP and DMD. This study showed substantial variation in CP content and DMD among samples and that the chemical composition of malting barley grain and its potential feed value could be altered by NR.