Cathie Erichsen Arychuk, P.Ag.
Bison Production Specialist
Proper management of pastures through the year allows you to have a spring calving pasture with enough quality forage to support the bison cow herd. A calving pasture spreads new calves out on clean, disease free ground and allows the cows to meet their nutritional needs while searching out the first shoots of green grass.
Spring Grazing on Stockpiled Dormant Pastures
Finally, after a long winter, the snow is starting to melt. Underneath the snow this year, last year’s grass is still green. Wouldn’t it be interesting to know what the nutritional value of that old grass is? Would it be possible to turn bison onto pastures now and have them use some of that old grass? Sure would be cheaper and easier than feeding baled hay, if it would work. It would also be nice to have new calves out on a clean pasture rather than in the wet, muddy pen where the cows wintered.
Lately there’s been a lot of interest in reducing the cost of winter feeding with practises like swath grazing. Another option is to look at stockpiling forage on pastures for grazing in the dormant season, mainly early winter and early spring.
The Grey Wooded Forage Association and some Forage Specialists have been looking at what feed quality remains in grass stands on pastures in the winter and early spring. They have several years of data collected for forage stands in west central Alberta. Their results are quite interesting. They found that forage quality in the winter can be much higher than expected. Depending on management, crude protein levels in stockpiled forage in April can be as high as 15 to 17%. Some of the pastures they are testing provide good enough forage to support lactating cows, before pasture growth starts in the spring.
The research done so far shows that the pastures have to be managed properly to get high quality stockpiled forage in the early spring. The best quality was found on pastures that were grazed or hayed by early to mid July, and then allowed to regrow undisturbed until freeze-up. This resulted in high quality, immature forage that kept its nutrient level over winter. High forage quality also depended on plant species. Low growing grasses, with finer leaves, were more protected by the snow and maintained higher quality through the winter. Also, pastures used for dormant season grazing had to have adequate forage present by freeze-up to support the cows. Producers had saved pastures specifically for grazing in the dormant season.
Eastern Alberta has quite different growing conditions than the west central area. Information on dormant season forage quality is quite limited for eastern Alberta. The information available suggests that animals grazing stockpiled forages in the dormant season will likely need supplemental protein and phosphorus. Growing conditions are different from where the Grey Wooded Forage Association did its work. Here, regrowth on pastures in late summer is limited and unpredictable. You may have to allow forage to accumulate most or all of the growing season to have enough for grazing in the winter and early spring. That would mean that stockpiled forage here would be more mature, and less nutritious than the grasses tested in the west. However, by providing a protein and mineral supplement, you may still be able to graze pastures for more of the year.
Good pasture management through the growing season will allow you to stockpile forages for early spring grazing that will meet all or most of the nutritional requirements of your cow herd.