Agronomic Assessment and Beef Cattle Nutrition Suitability of 31 Forage Type Annual Crops in the Peace Region of Alberta

Abstract Text: There is increasing use of forage type annual crops for swath grazing, bale grazing and silage for back grounding and finishing beef cattle in the Peace region of Alberta. There is therefore a need for continued effort for recent data (on agronomic adaptation, forage yield and quality, and animal performance) as new forage type annual crop varieties become available for possible inclusion into the forage based cropping systems of the region. A set of 31 annual crop varieties (16 barley, 3 oat, 5 triticale, 3 soybean, 2 field peas, 1 millet and 1 sorghum) were tested in order to identify crop varieties with superior forage yield and quality for beef cattle production. Forage dry matter (DM) yield varied (P<0.05) from 4162 kg ha^-1 (forage sorghum) to 10769 kg ha^-1 (AC Ranger barley). Only 6 of the 31 tested crops had >10.0 t ha^-1. Forage crude protein (CP) was unaffected (P>0.05) and was generally >10.0% for all crops. The 5 legumes included in the test all had significantly (P<0.05) higher forage Ca content than cereal crops. Forage total digestible nutrients (TDN) generally varied (P>0.05) from 60-67%. Crops which produced lower DM also had lower CP DM yield (DM x CP%). All crop varieties exceeded the suggested CP, Mg, K and TDN values for a dry gestating beef cow in the mid- and late-pregnancy stages. But the recommended Ca, P and Na values have not been consistently met by all crop varieties. Conducting cluster analysis procedures on the 31 crop varieties tested, using DM yield, forage chemical composition (7 parameters), energy (4 parameters), estimated digestibly (4 parameters), CP DM yield and Ca:P, hierarchical cluster analysis classified the crops into four distinct clusters of 8, 16, 6, and 1 crop varieties with, respectively, excellent, good, regular and poor degree of agronomic adaptation in the region and suitability for beef cattle.

Keywords: Annual crop; Forage; Nutritive value; Beef cattle; Cluster analysis