Increasing the Yield of Swath-Grazed Small-Grain Cereals.

Grazing whole-plant barley in windrows during winter is an effective method for reducing the cost of overwintering beef cows in Western Canada. To reach the dough stage by mid-September, when small grains are swathed prior to grazing, barley is planted in late June; delayed planting results in as much as 40% potential yield loss. Our hypothesis was that other species may be less sensitive to planting date for whole-plant yield and higher yielding swath-grazed crops would lower daily grazing costs. The objective was to compare swath-grazing potential of small-grain species planted at a range of dates from early May until late June. Spring barley, oat and triticale varieties were planted at Lacombe, AB in a randomized completed block design over three years at seven dates from May 12 until June 27, harvested at the soft dough stage, analysed for nutritive value with carrying capacities estimated based on minimum nutrient requirements for gestating beef cows in mid winter. Days from planting to harvest decreased linearly for barley, but were affected marginally for oat and triticale with delayed planting. Whole plant yield decreased linearly (30%) for barley and moderately in a quadratic fashion for oats (15%) and triticale (10%) with delayed planting. Barley and triticale had similar and higher in vitro true digestibility (IVTD) than oat; IVTD was unaffected by planting date. Potential carrying capacity for barley was reduced linearly (33%) and oats (20%) and triticale (7%) quadratically with delayed planting.  Potential carrying capacity for triticale was superior to oat due to a higher yield and nutritive value. It was possible to plant triticale as late as June 3 and maintain yield at similar levels as early May. Thus, there is potential to lower swath-grazed costs below that of barley by increasing yield through choosing triticale for swath grazing.