. 2008. Annual cool season crops for grazing by beef cattle. A Canadian Review. Can. J. Anim. Sci. 88: 517Á533. With the current high feed grain costs and other economic uncertainties in the Canadian beef cattle industry, producers are trying to lower their unit costs of production. Costs can be lowered through extension of the grazing season using perennial pastures and annual crops for grazing. Oat (Avena sativa L.) and fall rye (Secale cereale L.) have traditionally been used to a nominal extent for extending the grazing season. However, there is limited information including a small number of animal grazing trials on the use of other annual cereals and annual ryegrass (Lolium multiflorum Lam.) for low cost grazing systems relative to feeding traditional harvested and stored forages. This review discusses annual cool season crops that show promise for supplementary grazing systems. Systems such as swath grazing of a cereal crop, grazing the regrowth from silage mixtures of spring and winter cereals, or fall grazing annual Italian ryegrass can be used to extend the grazing season. Economic considerations will ultimately determine if there will be an increased role in the future for grazing annual crops on cropping land as a means of extending the grazing season to reduce year-round costs for the beef cow calf operator.

. 2006. Review: The composition and availability of straw and chaff from small grain cereals for beef cattle in western Canada. Can. J. Anim. Sci. 86: 443-455. Small cereal grain residues are heterogeneous feeds consisting of several botanical fractions: chaff, grain, leaf blade, leaf sheath, internode and node. These parts vary in composition, digestibility, resistance to comminution, intake potential and energy availability. Large differences in the nutritional quality of straw and chaff may occur from year to year and between locations due to effects of environmental conditions on botanical composition and cell anatomy. Stage of maturity, harvest method and weathering will influence composition and quality of the most nutritious parts of cereal residues, the leaf and chaff. In addition, cultivars and species differ in the proportion, anatomy and digestibility of botanical fractions. As a result, the quality of crop residues is highly variable with an economic value that is difficult to accurately assess.Cereal straw and chaff are of low economic value as they are low in nutritive value, where nutritive value is the product of nutrient intake, digestibility, and efficiency of use. However, due to availability, cereal crop residues have the potential to be a substantial feed resource for beef cows. Previous reviews have not focused on straw and chaff nutrition research relevant to use by beef cattle in western Canada. This review includes discussions on yield and nutritive value with a focus on identifying information deficiencies, including the lack of detailed production statistics for determining residue yields on a regional bases and the need for more detailed nutrient composition to update regional feed data bases for western Canada.

. 2009. Potential of warm-season annual forages and Brassica crops for grazing: A Canadian Review. Can. J. Anim. Sci. 89: 431Á440. Extension of the grazing season beyond the normal perennial grazing season has been identified as a potential mechanism to reduce the cost of production on Canadian cow-calf operations. This review will provide an overview of the potential use of warm-season and Brassica crops including corn (Zea mays), Golden German foxtail millet (Setaria italica L. Beauv.), kale (Brassica oleracea L.), forage rape (B. napus ssp. biennis L.) and turnip (B. rapa L.). These crops have a high yield potential, but the cost for grazing these crops has not been adequately compared with the cost of grazing oat (Avena sativa L.), barley (Hordeum vulgare L.), and fall rye (Secale cereale L.). There are very few actual animal grazing trials evaluating the economics of using these crops in grazing systems in Canada, and this requires further research. Since the early 1900s, cow-calf producers have grazed annual crops as an alternative to deal with drought and perennial pasture shortage as a means of lowering their annual costs. Extension of the grazing season beyond the normal perennial grazing season is an alternative low-cost method. A previous review (McCartney et al. 2008) summarized the potential of annual cool season cereal crops for grazing. There has been considerable interest in evaluating the grazing potential of warmseason annual crops for their suitability in extending the grazing season in Canada because warm-season annuals tend to be seeded later and vary in days to maturity (May et al. 2007). This could be advantageous in a grazing system for extending the grazing season. This review summarizes warm-season and Brassica crops that show promise in grazing systems that are applicable to Canadian conditions. As limited published research on this grazing method can be found, historical information from other types of research summaries will be included as the information still has value.

Swath-grazed oat (Avena sativa L.) and stockpiled meadow bromegrass (Bromus riparius Rhem) were compared with (Control) a pen-fed straw-based total mixed ration (TMR) for dry, pregnant beef cows (670 ± 88 kg BW) using carrying capacity, nutritive value, cow performance, daily feeding, yardage, and total daily costs. Carrying capacity ranked (P < 0.05): oat (637 cow-d ha −1) > Control (454 cow-d ha −1) > stockpiled grass (189 cow-d ha −1). In vitro true digestibility (IVTD) ranked (P < 0.05): stockpiled forage (681 g kg −1) > oat (588 g kg −1) > Control (530 g kg −1). Average cow body condition score (BCS) off pasture was (P < 0.05): stockpiled grass (3.4) > oat (3.0), while the control was intermediate (3.3). The daily feed cost ranked: stockpiled grass ($0.38 cow-d −1) < swathed oat ($0.48 cow-d −1) < Control ($1.05 cow-d −1). Yardage (non-feed costs) ranked: oat ($0.41 cow-d −1) < stockpiled ($0.50 cow-d −1) < Control ($0.91 cow-d −1). Total daily cost was similar for oat ($1.07 cow-d −1) and stockpiled grass ($1.04 cow-d −1), both less (P < 0.05) than the control ($2.25 cow-d −1). The cost of both grazing treatments was comparable to other research, but the stockpiled treatment cost was limited by the low yield of forage regrowth.

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