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Lardner H.A.,University of Saskatchewan | Lardner H.A.,Western Beef Development Center | Lardner H.A.,University of Nebraska - Lincoln
Journal of animal science | Year: 2014

Reproductive performance was evaluated in beef heifers born over a 2-yr period to determine the effects of target breeding weight (TBW) and development system (SYS) on growth and subsequent reproductive efficiency. Spring-born Angus heifers (253 ± 0.7 kg) were randomly allocated over 2 consecutive yr (yr 1, n = 80; yr 2, n = 96) to be developed to either 55% (350 kg) of mature BW (moderate gain, MG) or 62% (395 kg) of mature BW (high gain, HG). Each MG and HG group was further assigned to 1 of 2 replicated systems: (1) bale graze bromegrass-alfalfa round bales in field paddocks (BG) or (2) fed bromegrass-alfalfa round bales in drylot pens (DL). Heifers were fed a diet of bromegrass-alfalfa hay (56.9% TDN; 9.8% CP) and barley grain supplement (85.1% TDN; 12.3% CP). After the 202-d development period, heifers were exposed to bulls for a 63-d breeding season. Target BW × SYS interactions were not detected for any measured parameters. During the winter development period, MG heifers had lower (P = 0.01) ADG than HG heifers and MG heifers had lighter (P = 0.01) BW at breeding. The proportion of heifers attaining puberty by 14.5 mo of age was less (P = 0.05) in MG (20 ± 4%) than HG heifers (52 ± 3%). From the end of the 202-d development period to pregnancy diagnosis, ADG was greater (P = 0.04) in MG heifers than HG heifers (0.83 vs. 0.71 kg/d). First-calf pregnancy rates were 86 and 88% for MG and HG heifers, respectively (P = 0.41). Second- and third-calf pregnancy rates of cows, developed in either a MG or HG system as heifers, were not different (P = 0.74; 94.7 vs. 95.9% and 93.8 vs. 93.9%, respectively). Economic analysis revealed a $58 reduced development cost for heifers developed to 55% compared with 62% of mature BW without a loss in reproductive performance.

Biligetu B.,University of Saskatchewan | Jefferson P.G.,Western Beef Development Center | Muri R.,Agriculture and Agri Food Canada | Schellenberg M.P.,Agriculture and Agri Food Canada
Canadian Journal of Plant Science | Year: 2014

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.

Durunna O.N.,Agriculture and Agri Food Canada | Girardin L.C.,103 610 Stensrud Road | Scott S.L.,Alberta Livestock and Meat Agency | Robins C.,Box 83 Rivers | And 4 more authors.
Canadian Journal of Animal Science | Year: 2014

The majority of beef producers in western Canada have adopted a spring calving system. Evaluating alternative calving systems such as summer calving may lead to better use of forage resources to optimize cow-calf productivity. In order to evaluate the impact of calving system on cow-calf productivity, 346 Hereford or Angus crossbred cows were used in a 3-yr research study (2007 to 2009) at Brandon, Manitoba; Swift Current, Saskatchewan and Lanigan, Saskatchewan. Cows were bred to calve from February to May (early-calving system, EC) or from May to August (latecalving system, LC). Each system was evaluated for effect on performance and reproductive efficiency. Forage yield, utilization and nutritive value were assessed. Cow body weights (BW), ultrasound measures of backfat and calf BW were evaluated at precalving, breeding and weaning. There was no difference between calving systems for pregnancy rate (P=0.13) EC (93.0%) vs. LC (95.8%); calving rate (P=0.89) EC (92.0%) vs. LC (91.7%) or proportion of calves born alive (P=0.85) EC (99.5%) vs. LC (99.6%). The average length of calving season was not different (P=0.26) between the two systems. The EC cows had greater (P=0.002) BW losses from calving to breeding but greater (P=0.001) BW gain from breeding to weaning than LC cows. Although calves born in LC had greater birth BW (P=0.003) than EC calves, calf weaning rate (P=0.01) and calf weaning BW (P<0.0001) were greater in EC. The higher weaning rate and higher weaning BW with EC has the potential to increase cow-calf productivity and may be more attractive to beef producers in western Canada.

Iwaasa A.D.,Agriculture and Agri Food Canada | Jefferson P.G.,Western Beef Development Center | Birkedal E.J.,Agriculture and Agri Food Canada
Canadian Journal of Plant Science | Year: 2014

A study was conducted over 4 yr (1999, 2000, 2002 and 2003) at Swift Current to evaluate the forage preferences of steers grazing five different crested wheatgrass (CWG) cultivars: Kirk (2n=28), Fairway (2n=14) and Parkway (2n=14) [Agropyron cristatum (L.) Gaertn.], Hycrest (2n=28) (A. cristatum×A. desertorum) and Nordan (2n=28) [(A. desertorum (Fisch. Ex Link) Schult.)]. Animal grazing frequencies for each CWG cultivar patch were converted to percentages (Grazing%) for each grazing time period. Grazing% for Kirk and Hycrest CWGs were similar with Nordan having higher (P < 0.05) Grazing% compared with the hybrid and diploid CWGs. Contrasts revealed no differences (P=0.48) in Grazing% between diploid versus hybrid cultivars, while higher (P < 0.01) Grazing% were observed for tetraploid compared with diploid and hybrid CWG cultivars. For forage nutritive values, significant Cultivar (P < 0.01) and Year (P < 0.0001) main effects were observed. Overall mean values for percent crude protein (%CP) and percent acid detergent fibre (%ADF) for Nordan, Kirk, Hycrest, Fairway and Parkway were 10.6±0.3 and 29.2±0.4, 11.0±0.3 and 28.7±0.4, 10.4±0.3 and 29.7±0.4, 9.9±0.3 and 28.5±0.4, and 10.0±0.3 and 28.7±0.4, respectively (±SE). Correlation coefficients between Grazing% and all nutritive value constituents were low and not significant. This study observed grazing preference differences among different CWG cultivars that may lead to grazing management strategies to improve pasture utilization potential and animal production.

Cutforth H.W.,Agriculture and Agri Food Canada | Jefferson P.G.,Western Beef Development Center | Campbell C.A.,Agriculture and Agri Food Canada | Ljunggren R.H.,Agriculture and Agri Food Canada
Canadian Journal of Plant Science | Year: 2010

In the semiarid prairie of western Canada, there is renewed interest for including short durations (53 yr) of perennial forage in rotations with annual crops. However, there are producers who want to grow longer durations (]4 yr) of perennial forages in rotational systems. Therefore, we assessed spring wheat (Triticum aestivum L.) yield, grain protein, and water use efficiency following 6 yr of either crested wheatgrass [Agropyron cristatum (L.) Gaertn.], or alfalfa (Medicago sativa L.), or wheat, and then 1 yr of fallow. Yield, water use, and water use efficiency were significantly lower in the first year of spring wheat production (2000) when the prior crop was crested wheatgrass or alfalfa than when it was wheat. In the second year (2001), which was a near record drought year, wheat yield and water use were significantly lower when the prior crop was alfalfa than when it was grass or wheat. From 2002 to 2005, there were no consistent differences in water use, water use efficiency, or yield of wheat due to the prior perennial crop. Wheat grain protein concentration was significantly higher following alfalfa compared with following crested wheatgrass or continuous spring wheat from 2000 to 2005. This effect was attributed to the higher N-supplying power of the soil following alfalfa. Soil water content below the rooting depth of most annual crops (]120 cm depth) was reduced by the prior alfalfa crop, and there was no evidence from 2000 to 2005 that soil water recharge was occurring below the 150 cm depth.

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