It’s Looking Like a Long, Cold Winter 🎙️
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This article written by Dr. Reynold Bergen, BCRC Science Director, originally appeared in the June 2026 issue of Canadian Cattlemen magazine and is reprinted on BeefResearch.ca with permission of the publisher.
This is an update on the August 2022 column Alfalfa for Canada’s Climate.
Legumes are the most economical way grazers can increase pasture and cattle productivity (provided bloat risk is managed by using low-bloat species or varieties, anti-bloat agents, adjusting grazing timing, or the use of mixed legume-grass stands). Alfalfa has received the most breeding focus and is the most common and productive legume available. Canadian cattle producers need winter-hardy alfalfa that yields well and withstands grazing pressure. It’s difficult to put these three traits together in the same variety.
Everything starts getting ready for winter as fall approaches and days get shorter. Squirrels cache nuts. Bears gorge on berries. Calves are weaned, feed supplies and quality are evaluated, and pregnant cows and heifers are split into winter feeding groups based on age and body condition score. My father-in-law recruits us to help split and haul firewood up to the woodshed. These activities are all about making sure there’s enough energy to get through the winter and early spring.
Alfalfa does this too. Alfalfa begins to go dormant as fall approaches. It switches from using photosynthesis to power above-ground forage growth to storing sugar in the roots. Dormancy ratings range from 1 to 11 and refer to how much fall regrowth can be expected. Varieties with a lower fall dormancy rating number (more dormant) regrow less than varieties with a higher rating (more regrowth). Fall dormancy supports winter survival but reduces forage yield.
Winter survival ratings range from 1 (extremely winter-hardy) to 6 (non-winter-hardy). Grazing tolerance also plays a role in this. Grazing alfalfa during the critical fall adaptation period removes the leaves that drive photosynthesis and replenish the root system’s winter energy stores.
Agriculture and Agri-Food Canada (AAFC) has been breeding alfalfa for improved winter survival for over 30 years. A team led by Vern Baron (Lacombe) and Annie Claessens (Quebec City) summarized their recent progress at a scientific conference last year (Winter Hardiness, Dormancy and Grazing Tolerance in Alfalfa Populations Suitable for Northern Climates).
What They Did
They studied 25 different yellow- and purple-flowered Canadian alfalfas with fall dormancy ratings below 3 (very dormant). These were established varieties, cultivars under development, and specific strains that had been collected from pastures that had been seeded decades ago. They evaluated genetic relationships among the alfalfas. They established plots in Normandin, Quebec and Lacombe, Alberta, in 2016 and evaluated fall dormancy and winter survival in 2017 through 2019. Eighteen alfalfas were seeded in 2019 and 2020 for grazing trials at Lacombe. They were grazed in 2021 through 2023, and forage yield and survival were assessed in 2024.
What They Learned
Genetic relationships. The yellow-flowered, creeping rooted alfalfa varieties and the tap-rooted purple varieties fell into two genetically distinct clusters. The yellow alfalfas fell into two genetic clusters based on whether they were diploid (two sets of chromosomes) or tetraploid (four sets of chromosomes). The purple varieties were all tetraploid but grouped into three genetic clusters that corresponded to slight differences in fall dormancy (regrowth) ratings.
Winter survival across all genetic types was higher in Lacombe (75 to 95% survival after three years) than in Normandin (66 to 81%). In Lacombe, survival tended to be lower in the least dormant (92% survival in 2017, 78% in 2018, 75% in 2019) than in the most dormant group of purple alfalfas (95, 93, and 91%). Diploid yellow alfalfa tended to have higher survival (96, 96, and 95%) than tetraploid yellow alfalfa (98, 88, and 83%). In Normandin, winter survival did not differ among the purple alfalfas in 2017 (96 to 99%) or 2018 (88 to 96%), but the least dormant group tended to have lower survival in 2019 (66% vs. 73 to 77%). Diploid and tetraploid yellow alfalfa had identical survival rates (98% in 2017, 93% in 2018, 81% in 2019).
Fall dormancy. Even though all 25 varieties were rated as very dormant, the different genetic groups tended to differ in their fall regrowth. This was related to winter survival—yields decline when fewer plants survive. Among the purple-flowered alfalfas, regrowth yield tended to be lower among the groups with lower fall dormancy ratings, as expected. Among the yellow-flowered alfalfas, the diploid group were more dormant (less regrowth) than the tetraploid group. Trends were similar between Lacombe and Normandin. Overall, the range in fall dormancies overlapped among the purple (1.0 to 2.3) and yellow (0.9 to 2.4) alfalfas.
Yield and grazing tolerance were reported for 11 individual cultivars/populations. Two alfalfas were both the highest yielding and the most grazing tolerant. But they were very different plants. Yellowhead is a creeping rooted, tetraploid, yellow-flowered alfalfa. The other was a tap-rooted, purple-flowered strain that was growing in a field in northwest Alberta. Yellow-flowered alfalfas are often thought to be better suited for northern climates, but that’s not always the case.
More research is needed to continue to test the up-and-coming varieties for fall dormancy, grazing tolerance and winter survival, compare these alfalfas to commercially available varieties, assess whether they can compete in mixed grass stands and how they perform in different regions, etc.
What Does This Mean To You?
This project isn’t completed, but it is over. AAFC eliminated the Quebec City and Lacombe research stations, their forage programs and these research teams in January.
Bottom Line
The Canadian Food Inspection Agency (CFIA) has registered 31 new alfalfa varieties in Canada since 2022, but they were all developed in the U.S., at locations 312 to 1,200 km south of Normandin and 715 to 1,611 km south of Lacombe. Those varieties weren’t tested in this study but may not have performed too well this far north. Large multinational breeding companies focus their breeding efforts on their largest markets, not on developing high yielding, winter-hardy varieties for small regional markets like Canada. If these AAFC researchers aren’t relocated, the University of Saskatchewan will be Canada’s only perennial forage variety development program. It’s beginning to look like Canada’s cattle and forage producers will be in for some long, cold winters.
The Beef Cattle Research Council is a not-for-profit industry organization funded by the Canadian Beef Cattle Check-Off. The BCRC partners with Agriculture and Agri-Food Canada, provincial beef industry groups and governments to advance research and technology transfer supporting the Canadian beef industry’s vision to be recognized as a preferred supplier of healthy, high-quality beef, cattle, and genetics. Learn more about the BCRC at www.BeefResearch.ca.
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