Swath grazing is an economic management strategy that helps ranchers extend their grazing practices into the spring and winter months. Unlike the drylot system, this approach cuts costs through reduced use of machinery or fuel and eliminates the need to haul manure. It has been shown that swath grazing can reduce the cost of beef production by over 40%.
Traditionally, producers grow one crop (monocrop) for swath grazing because seeding activities, controlling weeds and predicting yield are more straightforward to manage. The swath quality usually makes the practice more appropriate for older cows than for young calves. Rather than growing only one crop type, the polycrop system grows several species of crops together. Polycrops are gaining popularity among beef producers as a strategy for reducing production risks and perceived better land stewardship. From a feed perspective, it can be described as growing a total mixed ration (TMR) where different species with complementary nutrient profiles can help meet the nutritional requirements of young growing cattle (backgrounders) while reducing the production and feed availability risk due to unpredictable weather conditions. This leads us to ask whether this polycrop system can facilitate better land stewardship and animal welfare than the conventional monocrop system.
What we did and why
From 2021 to 2024, Lakeland College researchers evaluated two forage systems (monocrop and polycrop) for economics, forage characteristics, animal performance, soil quality and virtual management tools. Three paddocks were seeded to SO-1 oat, while another three paddocks were seeded to a polycrop consisting of oat, forage peas, rapeseed and turnips. The oats in the monocrop were seeded at 157 kilograms per hectare (140 pounds per acre), while the polycrops were oat (45 kilograms per hectare / 40 pounds per acre), forage peas (11 kilograms per hectare / 10 pounds per acre), brassicas (turnips plus rapeseed) at 2 kilograms per hectare (1.8 pounds per acre). Seeding was done in the first week of June, swathing in August/September, while the steers grazed from November to January/February.
The forage samples for quality analysis were collected at the soft dough and hard dough stages, but swathing was done at the hard dough stage. Polycrops are usually associated with improved soil health and biology; therefore, we took baseline soil samples before the paddocks were seeded in the first year. We also took another set of samples in the fourth year. We wanted to assess the difference between the two forage systems (monocrops versus polycrops) over three years of continuous use for swath grazing. About seven to 10 steers grazed each paddock yearly. We also took the opportunity to survey beef producers to identify their motivators or deterrents for swath grazing. This part of the study was important because if swath grazing was associated with all these benefits, it begs the question, why was the system’s adoption so low?
We also embarked on this research to provide valuable information about emerging strategies that can provide economic options to enhance producers’ bottom lines. We evaluated the NoFence virtual fencing system for its battery performance and solar recharging ability during frigid Alberta winters. Testing the system with different steers, swath grazing during winter will help us determine its robustness during Alberta’s winters, given the shorter day lengths and intense cold conditions. The outcomes from this study can guide producers in making informed investment decisions on which system better fits their operation.
Both an oat monoculture and a polycrop mixture can be viable alternatives for winter swath grazing while backgrounding steers. Image courtesy of Lakeland College.
The results
The three-year study showed that the cost of growing the polycrops (4 cents per kilogram DM) was slightly higher than oat monoculture (3 cents per kilogram DM). The forage yield was greater in the oat monocrop (8,903 kilograms per hectare / 7,943 pounds per acre) than in the polycrops (6,163 kilograms per hectare / 5,499 pounds per acre). On the other hand, the forage utilization efficiency was greater in the polycrop (72%) than in the monocrop (58%). However, the greater oat yield resulted in greater residues because all animals were allotted new swaths whenever a paddock ran short of feed resources. The extra residues may have supported additional animals in the oat monocrop paddocks.
Most of the forage nutritive values (e.g., crude protein and total digestible nutrients [TDN]) from both systems were similar, but the soluble sugar content was greater in the polycrop. Even though the sulphur contents in the brassicas were high (0.63% to 0.68%), they were diluted to safer levels (0.28%) in the forage mix, thereby assuaging any safety concerns in feeding the polycrops.
There was virtually no difference in the average daily gains of the steers assigned to either the oat (1.54 pounds per day) or polycrops (1.48 pounds per day). At the end of the grazing period, there was no difference in average dry matter intake or backfat thickness measured in animals in both groups.
As the steers swath grazed during the winter, the virtual fence collars had a slower average charging rate but maintained over 95% average battery charge. The soil results suggest that improvements are achieved over little increments. Even though the results did not show any significant change for the majority of the physico-chemical characteristics of the soil, the polycrops had a more favourable water infiltration duration. The soil biology analysis showed that the polycrop system maintained more uniform microbial communities over the three years than the oat monoculture system.
We understood from prior studies that swath grazing was not the preferred extensive grazing method among western Canadian cow-calf producers, given that only 20% of producers adopted swath grazing. When asked about the factors that motivate or discourage them, the top two reasons current practitioners engaged in swath grazing were associated with savings on labour and fuel use. On the other hand, the top two deterrents were potential biomass wastes or losses and frigid weather.
Why it matters to producers
The information gathered in this study provided objective information that should help producers make informed production and investment decisions. The study showed that oat monoculture produced more biomass but had similar nutritive values as the polycrops. The cost of swath was slightly lower for the oats monoculture, but both systems had similar effects on the steers’ body performance and soil health, which suggests that a polycrop mixture can be a viable alternative to oat monoculture for winter swath grazing with young beef steers.
