Harvest Date Effect on Forage Yield, Botanical Composition, and Nutritive Value of Novel Legume-Grass Mixtures

The potential for novel forage mixtures to address reduced herbage for late season grazing was investigated. Forage legumes, sainfoin (Onobrychis viciifolia Scop.) (SF) cvs. AC Mountainview, Shoshone, and Nova (MountainSF, ShoshoneSF, and NovaSF), cicer milkvetch (Astragalus cicer L.) cv. AC Veldt (CMV), Canadian milkvetch (Astragalus canadensis L.) cv. Great Plains (CaMV), and alfalfa (Medicago sativa L.) cv. AC Yellowhead (ALF) were evaluated in binary mixtures with meadow bromegrass (Bromus riparius Rehm.) cv. Admiral (MBG), hybrid bromegrass (B. riparius × B. inermis Leyss.) cv. AC Success (HBG) and Russian wildrye [Psathyrostachys junceus (Fisch.) Nevski.] cv. Tom (RWR) for yield, botanical composition, and nutritive value on July and September harvest dates at Saskatoon and Swift Current, Saskatchewan, Canada from 2016 to 2018. Hybrid bromegrass-legume mixture produced 16–38% greater forage compared to RWR-legume (7.5 vs. 5.6 Mg ha−1 in July and 6.1 vs. 5.1 Mg ha−1 in September at Saskatoon, and 3.2 vs. 2.0 Mg ha−1 in July at Swift Current). MountainSF and ALF had the greatest legume contribution to total yield at July harvest at Swift Current (67.7 ± 3.2%) and Saskatoon (62.1 ± 2.1%), respectively, while CaMV had lowest composition at Swift Current (20.2 ± 2.5%) and Saskatoon (12.6 ± 3.5%). The CMV and ALF-grass mixtures at Saskatoon and legume-RWR mixtures at both sites in July had greatest CP content. The July harvest had greatest yield, legume content and nutritive value compared to the September harvest at both sites. Study results suggest if yield is the objective, then either ALF or CMV with HBG may be considered. If nutritive value is the goal, any legume with RWR is an option. Finally, ALF or CMV in mixture with either HBG or RWR could be summer or fall stockpile forage in the Northern Great Plains of western Canada.

PSI-19 Preference grazing evaluation of new forage varieties, and the effect of animal temperament on grazing behaviour

In Canada, new forage varieties need not undergo grazing trials before registration and sale. As such, little is known about forage performance under grazing, or how animal preference and temperament affect grazing behaviour. To determine these effects, 6 cool-season forage species including meadow bromegrass (Bromus bieberseinii), orchardgrass (Dactylis glomerate L.), sainfoin (Onobrychis viciifoila ssp. Viciifolia) and three alfalfa varieties (Medicago sativa L.) were established in monoculture and grass-legume binary mixtures (14 treatments) at the Livestock and Forage Centre of Excellence (Saskatchewan, Canada). Forages were seeded in randomized adjacent 0.3 ha (21 × 125 m) strips within each of three, 5 ha paddocks. Sixty-nine Bos taurus crossbred steers (396 ± 34 kg BW) were homogenously allocated to the 3 paddocks for grazing observations. Individual steer temperament was characterized via novel object and corridor tests prior to grazing. The 9 steers showing the most bold or shy temperaments were labelled for identification while grazing. The grazing period length was 19 d, from July 27 to August 15, 2019, with observations made during the first six days. Observers determined forage preference based upon the number of animals grazing each forage type every 30 min for 2 h in the morning and 2 h in the evening. Animal preference did not differ (P > 0.05) between the forage treatments. Yield of grass and legume components did not differ (P > 0.05) between monocultures or binary mixtures (1255 kg ha-1 ± 277 kg ha-1). Steer temperament affected (P < 0.0001) animal distribution, with bold steers traveling further from the center of the paddock than shy steers or average herd animals (P < 0.05). These preliminary results indicate that differences in grazing behaviour were due to individual animal temperament rather than forage preference or performance.

Yield and nutritive value of grazed complex legume–grass mixtures under increasing nitrogen application rates

Complex pasture mixtures are advantageous, but little information exists on the best forage species and nitrogen (N) management in eastern Canada. We compared under mob stocking four complex mixtures of one of two legume species [alfalfa (Medicago sativa L.) and birdsfoot trefoil (Lotus corniculatus L.)] plus one of two grass mixes [No. 1 — timothy (Phleum pratense L.), meadow fescue (Schedonorus pratensis (Huds.) P. Beauv.), reed canarygrass (Phalaris arundinacea L.), and Kentucky bluegrass (Poa pratensis L.); No. 2 — tall fescue (Schedonorus arundinaceus (Schreb.) Dumort., nom. cons.), meadow bromegrass (Bromus biebersteinii Roem. and Schult.), reed canarygrass, and Kentucky bluegrass] under three N application rates at three sites over the first three post-seeding years. Legume species had little effect on most forage attributes mainly because of their low contribution to forage dry matter (DM) yield (<30%) in second and third years. The grass mix with tall fescue and meadow bromegrass (No. 2) yielded similar or slightly better than the one with timothy and meadow fescue (No. 1) but tended to have a greater neutral detergent fibre concentration, and lower N and total digestible nutrient concentrations. Nitrogen fertilization increased forage DM yield only in second and third years when the legume contribution to forage DM yield was <30%, and it increased N concentration and decreased nonstructural carbohydrate concentration. These results highlight the challenge of maintaining legume species in rotationally grazed pastures of eastern Canada and confirm recommendations of applying no or little N fertilizer on grazed legume–grass mixtures when the legume contribution to forage DM yield is >30%.

Diversified Forage Cropping Systems and Their Implications on Resilience and Productivity

Plant diversity is associated with resilient ecosystems. Loss of plant biodiversity triggered by anthropogenic and climatic factors jeopardizes environmental stability and sustainable forage production. The understanding of biodiversity mechanisms and functional traits of species can help to design forage production systems to buffer against perturbations. Resilience and productivity are linked to plant species characteristics and interactions that enable them to recover from adverse conditions and compensate for the loss of susceptible species. Benefits of diversified crops including enhanced carbon assimilation, nitrogen fixation, and turnover are transferred to soil microbes which in return contribute to resilience against drought and poor soil fertility. In the absence of disturbances, these mechanisms are credited for stability and climax ecosystems. Cultivated systems are more fragile because management interferes with many functions while maintaining few. Strategies that sustain an entire range of functions can increase production regardless of climatic and management factors. This has been demonstrated in binary mixtures of cool season grasses including meadow bromegrass (Bromus biebersteinii Roem. & Schult.), orchardgrass (Dactylis glomerata L.), smooth bromegrass (Bromus inermis Leyss.), and intermediate wheatgrass (Thinopyrum intermedium (Host) Barkworth & D.R. Dewey) with alfalfa (Medicago sativa L.). Suitable combinations of perennial species and cultivars bred for compatible traits can enhance resilience and productivity in a wide range of ecosystems.

Impact of calving seasons and feeding systems in western Canada. I. Postweaning growth performance and carcass characteristics of crossbred steers

Durunna, O. N., Block, H. C., Iwaasa, A. D., Thompson, L. C., Scott, S. L., Robins, C., Khakbazan, M. and Lardner, H. A. 2014. Impact of calving seasons and feeding systems in western Canada. I. Postweaning growth performance and carcass characteristics of crossbred steers. Can. J. Anim. Sci. 94: 571–582. Crossbred steers (n=272) weaned from early (EC) and late (LC) calving systems (CS) were used to evaluate the impact of two feeding systems (FS) on postweaning performance and carcass characteristics. The steers were randomly assigned to either a rapid-gain feeding (RF) or a slow-gain feeding (SF) system. The RF steers were managed to have body weight (BW) gain of 1 kg d−1 on a silage-hay diet during the backgrounding period prior to finishing, while the SF steers were first backgrounded on a hay diet (gain of 0.7 kg d−1), then grazed alfalfa–meadow bromegrass pasture and annual cereal swaths prior to finishing. All treatment groups received a conventional diet during finishing until the steers attained a target backfat thickness or BW or both. There was no difference (P=0.48) between the two FS for the average age of the steers at the beginning of the experiment. There was a CS×FS effect (P<0.01) on the age at slaughter, where the steers in the EC-RF, EC-SF, LC-RF and LC-SF were 426, 659, 504 and 606 d, respectively. The longer time on feed for LC-RF steers compared with EC-RF suggests the potential effect of summer ambient temperatures at finishing. The EC-RF group had the least carcass fat thickness (P<0.01), but there was no main or interaction effect (P>0.08) on dressing percentage or lean meat yield. There was a FS effect (P<0.05) on meat colour and marbling texture where SF steers had more desirable meat colour and marbling texture. Beef producers adopting EC-RF would finish their calves earlier but at a lighter weight.

Late summer forage yield, nutritive value, compatibility of warm- and cool-season grasses seeded with legumes in western Canada

Biligetu, B., Jefferson, P. G., Muri, R. and Schellenberg, M. P. 2014. Late summer forage yield, nutritive value, compatibility of warm-and cool-season grasses seeded with legumes in western Canada. Can. J. Plant Sci. 94: 1139–1148. In late summer and fall, quality and quantity of forage are important for weight gain by grazing animals in western Canada. The objective of this study was to evaluate forage nutritive value, dry matter (DM) yield, and compatibility of crested wheatgrass [Agropyron cristatum (L.) Gaertn.], meadow bromegrass (Bromus riparius Rehm.), green needle grass [Nasella viridula (Trin.) Barkworth], northern wheatgrass [Elymus lanceolatus (Scribn. & J. G. Sm.) Gould], western wheatgrass [Pascopyrum smithii (Rydb.) Barkworth & D.R. Dewey], Russian wildrye [Psathyrostachys juncea (Fisch.) Nevski], big bluestem (Andropogon gerardii Vitman), or switchgrass (Panicum virgatum L.) in eight grass monocultures, and their binary mixtures with alfalfa (Medicago sativa L.), sainfoin (Onobrychis viciifolia Scop.), or cicer-milkvetch (Astragalus cicer L.) harvested once in August or September. A field study was conducted over a 7-yr period from 1998 to 2004 near Swift Current (lat. 50°25'N, long. 107°44'W, 824 m elev.), SK, Canada, using a randomized complete block design. Forage DM yield was similar between August and September harvests (P>0.05). Binary mixtures of alfalfa–grass produced highest (P<0.05) DM yield ranging from 2449 to 2758 kg ha−1. The monoculture of crested wheatgrass (2143 kg ha−1), sainfoin with crested wheatgrass (2061 kg ha−1), and cicer-milkvetch with green needle grass (1838 kg ha−1) or cicer-milkvetch with western wheatgrass (1861 kg ha−1) produced the second highest (P<0.05) DM yields in the ranking. The two warm-season grasses produced the lowest (P>0.05) DM yields over the 7-yr period. Monocultures of green needle grass or northern wheatgrass had the highest acid detergent fiber (ADF) and neutral detergent fiber (NDF), while warm-season grasses with legumes had the lowest. Alfalfa with western wheatgrass and alfalfa with Russian wildrye had the highest crude protein (CP) concentrations. Monocultures of meadow bromegrass, crested wheatgrass, green needle grass, or cicer-milkvetch with meadow bromegrass, and sainfoin with crested wheatgrass had the lowest CP concentrations. In vitro organic matter digestibility (IVOMD) was greater for mixtures than for the grass monocultures. Concentration of Ca and P was greater for warm-season grasses than cool-season grasses. Alfalfa with western wheatgrass was the best combination considering yield, quality, and compatibility for deferred grazing in late summer and fall in the semiarid prairies. Tested warm-season grasses are not recommended for seeding as binary mixtures with legumes for southwestern Saskatchewan.

Adapting the CATIMO grass model to meadow bromegrass grown in western Canada

Bonesmo, H., Baron, V. S., Young, D., Bélanger, G. and Jing, Q. 2014. Adapting the CATIMO grass model to meadow bromegrass grown in western Canada. Can. J. Plant Sci. 94: 61–71. The Canadian Timothy Model (CATIMO) simulates the growth and nutritive value of timothy grown in eastern and western Canada, Norway, and Finland, but has not been parameterized for meadow bromegrass (Bromus riparius Rehm.) grown under Canadian prairie conditions. We parameterized and evaluated the CATIMO model to simulate the dry matter (DM) yield and N concentration of meadow bromegrass grown in western Canada with data from sequential sampling in primary growth and regrowth from two field experiments for a total of 5 yr of observation. Primary growth DM yield was simulated well [R2=0.95; normalized root mean square error (NRMSE) =16%; model simulation efficiency (EF)=0.93]. Simulations of the regrowth DM yield (R2=0.49, NRMSE=39%, EF=0.47) were not as successful as that of the primary growth, but they were within expected ranges for regrowth DM yields in western Canada. Forage N concentration was poorly simulated in primary growth (R2=0.32, NRMSE=38%, EF=−0.95) and regrowth (R2=0.27, NRMSE=30%, EF=−2.43). Plant-available soil moisture down to 30 cm was simulated well (R2=0.74, NRMSE=19%, EF=0.50). The parameterized model for meadow bromegrass expands the use of the CATIMO model to drier geographical areas where timothy may not be common, and it represents a first attempt to provide DM yield assessment of meadow bromegrass under Canadian Prairie conditions for whole-farm modeling.