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Durunna O.N.,Agriculture and Agri Food Canada | Robins C.,Box 83 RiversMB | Scott S.L.,Alberta Livestock and Meat Agency | Block H.C.,Agriculture and Agri Food Canada
Professional Animal Scientist | Year: 2014

The productivity and disease tolerance of annual forages may have large effects on the performance of beef cattle in a swath-grazing system. This study was conducted to evaluate the effects of crown rust (Puccinia coronata Corda f. sp. avenae Eriks.) on the forage yield performance of 2 oat (Avena sativa L.) cultivars (HiFi and CDC Baler) with or without fungicide application in a swathgrazing system. The cultivar HiFi has good resistance to crown rust, whereas CDC Baler is susceptible to crown rust. Unfortunately, barley yellow dwarf virus (BYDV) infected both cultivars and may have influenced the results of the current study. Forage DM yield, regrowth, and forage residue yield samples were collected from each treatment. The nutritional quality of the samples was also analyzed. Mixed-model ANOVA was used in the statistical analysis of forage yield and nutritional performance. The cultivar effect was significant (P < 0.01) for DM yield, regrowth, residue yield, and nutrient quality. The application of fungicide had no influence (P > 0.61) on the DM yield, regrowth, and residue yield of the cultivars. There was no interaction effect (P > 0.16) between cultivar and fungicide application for all yield performances. The results from this study suggest that using a resistant cultivar (HiFi) resulted in greater (P < 0.01) forage DM yield and gross margins. The application of fungicide on HiFi was not economical because of the cultivar's resistance to crown rust. The HiFi cultivar also showed moderate resistance to BYDV. Although agronomic traits need to be considered in selecting cultivars for swath grazing, it is also important for producers to select cultivars with good disease packages that are environmentally suited to the production area. Because of its susceptibility to BYDV, CDC Baler may not be suitable for swath grazing in areas with severe BYDV infestation. © 2014 American Registry of Professional Animal Scientists.

Khakbazan M.,Agriculture and Agri Food Canada | Durunna O.N.,Saskatchewan Ministry of Agriculture | Sirski T.K.,University of Manitoba | Brewin D.G.,University of Manitoba | And 7 more authors.
Canadian Journal of Animal Science | Year: 2015

The choice of calving date influences the net revenue of a calving operation as it affects the number of days that calves spend in each feeding phase and when they are subsequently marketed. These two factors determine the costs, revenue, and risk (variance) of each calving system for the calving phase of a beef system. The majority of cow-calf producers in western Canada have adopted early calving (EC) in spring due to management factors. However, late calving (LC) in the summer is an alternative beef calving system associated with higher returns due to lower system costs and higher beef prices. It may offer a better match between cow nutritional requirements and pasture availability. The objective of this study was to compare the revenues and risks for a traditional EC system and an alternative LC system at three sites in western Canada. Biological and economic data from three field experimental sites in western Canada (Brandon Research Centre in Manitoba, Western Beef Development Centre in Lanigan, Saskatchewan and Semi-Arid Prairie Agriculture Research Centre in Swift Current, Saskatchewan) were used to determine the costs and benefits of the alternative beef calving system. The results showed that even though the EC has higher cost than the LC, the EC is slightly better than LC in terms of higher net revenue potential, but it comes at a greater risk due to higher revenue variances. TheECsystem is usually more preferable for risk-neutral producers, whereas the LC system is more preferable for risk-averse producers. © 2015, Agricultural Institute of Canada. All rights reserved.

Durunna O.N.,Saskatchewan Ministry of Agriculture | Baron V.,Agriculture and Agri Food Canada | Scott S.L.,Alberta Livestock and Meat Agency | Robins C.,Box 83 RiversMB | And 2 more authors.
Canadian Journal of Animal Science | Year: 2015

The objective of this experiment was to determine whether avoiding grazing during the sensitive pre-dormancy period (ca. 6 wk prior to a dormancy-inducing frost) would improve forage production, stand quality, alfalfa persistence and animal productivity in perennial pastures. There were two pasture species (PS), alfalfa-grass (AG) or grass (G), and three grazing phases. Phase I was conventional rotational grazing of all AG and G sections. In Phase II, one half of AG and G was rotationally grazed (conventional treatment, CT) while the other half was not (rested treatment, RT). Resting AG and G in Phase II required transferring RT animals to swath-graze early-seeded cereals. In Phase III, RT animals that swath-grazed in Phase II were moved to graze the rested sections of the pastures while those that grazed the unrested sections (CT animals) were transferred to swath-graze late-seeded cereals. There was no PS (P>0.05) or rest period (P>0.13) effect on total forage yield, carrying capacity, forage disappearance and forage residues. There was no effect (P>0.13) of resting on botanical composition or yield in AG. The current study did not observe significant benefits of resting on pasture yield, botanical composition or animal performance.

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.

Durunna O.N.,Saskatchewan Ministry of Agriculture | Block H.C.,Agriculture and Agri Food Canada | Iwaasa A.D.,Agriculture and Agri Food Canada | Scott S.L.,Alberta Livestock and Meat Agency | And 6 more authors.
Canadian Journal of Animal Science | Year: 2014

Fatty acid profiling, meat and organoleptic quality assessments were conducted on 160 carcasses of crossbred steers born into one of two calving systems and later assigned to one of two postweaning feeding systems. The steers were weaned from either an early calving or late calving system and later assigned to either a rapid-gain feeding (RF) or a slow-gain feeding (SF) system. The RF steers received a silage–hay diet during the backgrounding period prior to finishing, while the SF steers received a hay diet at backgrounding and 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 body weight. Fatty acid analyses were conducted on longissimus dorsi muscle (LDM) and subcutaneous fat samples. Other analyses included LDM composition, tenderness and taste panel evaluations. Total saturated fatty acid was greater (P<0.02) in samples from RF steers, while total monounsaturated fatty acid was greater (P<0.01) in SF steers. The SF steers had greater (P<0.01) conjugated linoleic acid concentration. There was no main or interaction effect (P>0.05) on beef aroma, flavour and tenderness but the SF steaks had lower (P = 0.02) cooking losses than RF steaks. The SF strategy has the potential to create a value chain that would lead to finished steers with higher backfat omega-3, conjugated linoleic acid and trans vaccenic acid and less cooking moisture losses. © 2014, Agricultural Institute of Canada. All rights reserved.

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