Swath‐Grazing Potential for Small‐Grain Species with a Delayed Planting Date

Abstract

Grazing swathed, small‐grain crops can reduce costs of overwintering beef cows (Bos taurus) by 40%. However, the late planting required to target mid‐September harvest may be associated with low yield and carrying capacity. The objective was to compare whole‐plant yield, nutritive value, and potential carrying capacity in relation to beef cow requirements for spring barley (Hordeum vulgare L.), oat (Avena sativa L.), and triticale (X Triticosecale Wittmack) when planted on seven weekly intervals (10 May–23 June) over 3 yr at Lacombe, AB; whole‐plant material was harvested at soft dough (barley and triticale) or milk stages (oat). Data were analyzed relative to planting date delay as an independent variable. Barley matured more rapidly than oat and triticale, with the latest planting date harvested on 27 August for barley, 8 September for oat and 25 September for triticale. Nutritive value for barley and triticale was unaffected by planting date, but neutral (NDF) and acid detergent fiber (ADF) concentrations increased quadratically with delay in planting for oat. In vitro true digestibility (IVTD) was lower for oat than barley and triticale. Yield declined linearly with planting delay for barley (35–39%), but increased (quadratically) as planting was delayed from late May to early June for oat (8%) and triticale (10%). Consequently, the potential carrying capacity for triticale was 1.6 and 1.8 times greater than barley and oat, respectively when planted for swathing in late August or early September.