Grazing grass and legume mixtures in late summer and fall has the potential for promising gains, research conducted in south and central Saskatchewan shows.
There are proven benefits to including a legume in a mixture to improve grass pastures. But researchers at the University of Saskatchewan’s Livestock and Forage Centre of Excellence (LFCE) saw an opportunity to study binary mixtures at different soil zones to better understand the yield, nutritional quality and animal performance offered by new varieties.
“Anytime we can increase the use of forages, there’s an opportunity to be had,” says Bart Lardner, animal science professor at the University of Saskatchewan, speaking during the 2021 Saskatchewan Beef Industry Conference in January.
Graduate student Sam Peprah conducted this three-year study with Lardner and fellow U of S researchers Daal Damiran, Bill Biligetu and Kathy Larson, along with Alan Iwaasa of the Agriculture and Agri-Food Canada Research and Development Centre at Swift Current, Sask.
The study evaluated the yield, quality and animal performance of four forage mixtures at two locations: the AAFC Research Centre at Swift Current, which is in the brown soil zone, and the LFCE at Lanigan, in the dark brown-thin black soil zone. The four treatments established in 2015 were AC Yellowhead alfalfa with Tom Russian wildrye grass; AC Yellowhead alfalfa with Success hybrid bromegrass; AC Mountainview sainfoin with Tom Russian wildrye grass; and AC Mountainview sainfoin with Success hybrid bromegrass. Yearling steers grazed each site for about 30 to 40 days in August and September for three years.
The study focused on late summer to fall grazing. Lardner refers to this as the “summer slump” — those late July, August and September time periods when things get a little bit dry under grazing conditions.”
As alfalfa can cause bloat when grazed, mixing it with a grass species is recommended to reduce that likelihood. Sainfoin, on the other hand, doesn’t cause bloat when grazed. While earlier varieties had low persistence, Lardner explains, AC Mountainview has been much more promising, with greater biomass and successful rates of gain in grazing trials.
“But there’s limited information evaluating sainfoin in the Aspen Parkland area of Saskatchewan,” he adds.
Russian wildrye grass also had limited data on quality, yield and animal performance in the Aspen Parkland area. Though difficult to establish, this species is drought- and saline-resistant and is recommended as a late-season pasture species.
“Tom Russian wildrye is one of these newer varieties, and it yielded 19 and 22 per cent greater compared to those earlier varieties… at Swift Current and Saskatoon.”
Hybrid bromegrass is a cross between meadow bromegrass and smooth bromegrass, providing the best of both species. “It is known as a dual-purpose forage where you can grow it for hay or you can turn around and graze the regrowth. Hybrid does have a greater hay yield compared to meadow brome and a better regrowth compared to smooth brome for grazing,” says Lardner.
At the Swift Current site, the total herbage yield for the three-year period ranged from almost 3,300 lbs. per acre (AC Mountainview sainfoin and Tom Russian wildrye) to about 3,900 lbs. per acre (AC Yellowhead alfalfa and Tom Russian wildrye). On average, the ratio of legume to grass content was approximately 34 per cent legume to 66 per cent grass.
The total herbage yield at the Lanigan site ranged from about 2,900 lbs. per acre (AC Mountainview sainfoin and Tom Russian wildrye) to almost 5,000 lbs. per acre (AC Yellowhead alfalfa and AC Success hybrid bromegrass). Here, the legume to grass content ratio was about 15 per cent legume to 85 per cent grass on average.
“Soil zone and species adaptation influenced the yield or the biomass growth. It influenced the germination and establishment of either the legume or grass species,” Lardner says. While AC Yellowhead alfalfa with a grass had higher yields at Swift Current, Success hybrid bromegrass with a legume had higher yields at Lanigan.
Proteins ranged from about 6.7 to 7.3 per cent at Swift Current, compared to about 7.5 to almost 10 per cent at Lanigan. At Swift Current, acid detergent fibre ranged from 35 to 37 per cent, and neutral detergent fibre ranged from around 54 to 59 per cent. Acid detergent fibre at Lanigan ranged from 38 to 41 per cent, while neutral detergent fibre ranged from 61 to 66 per cent. Energy was around 57 to 59 per cent at Swift Current and around 54 to 59 per cent at Lanigan.
Lardner explains that with both species, adaptation and soil zone played a role in the energy content and protein content of the stands, which is reflected in performance differences. During the 30- to 40-day grazing period, steers gained 45 to 62 lbs. at the Swift Current site, with an average daily gain of 1.6 to 1.9 lbs. Steers at Lanigan gained 33 to almost 50 lbs. in that period, with an average daily gain of 1.3 to just less than two lbs.
“Despite the late summer-fall grazing in that summer slump time period, we found that the gains were reasonable at both locations.”