Swath Grazing Tips
Written By: Owen Taylor
Hello, friends.
In lieu of "Warm Season Week," I wanted to share my experiences using the Warm Season Cover blend for swath grazing over the past couple of years.
Warm Season Cover
Seeding
When it comes to seeding the Swath Grazing Cover, it is crucial to wait until the soil temperature reaches at least 6-8 degrees Celsius. The blend consists mostly of warm-season species, which require a minimum soil temperature for germination. Generally, for swath grazing purposes, I don't sow until the first week of June at the earliest, and often I wait until the middle of June for a couple of reasons:
Warm season plants have very little frost tolerance, so delaying seeding until later in June reduces the risk of a late frost that could kill most of the species in the blend.
Additionally, by seeding later, the swaths won't be exposed to the elements for an extended period as you won't be swathing until later in the summer.
Image: Scouting a Swath Grazing Cover field in Rathwell, Manitoba in 2022.
Swath Grazing Cover
Swathing
The swath grazing cover reaches maximum biomass at approximately 50 days, which serves as a good indicator for swathing timing. This year, I learned (through a mistake) that timing is crucial. I had an excellent stand on 35 acres, with sorghum sudan reaching well over 7 feet in many areas and already heading out before I swathed it. I found that this reduced the palatability of the sorghum sudan, and the cattle wasted more of the stalks. It wasn't a disaster by any means, but going forward, I will swath as soon as the sorghum starts to head out.
For comparison, I cut another field earlier, and the cattle noticeably cleaned up the swaths better.
Another lesson I learned (another mistake) was letting the sorghum grow so tall. Due to its height, I couldn't use a swather and had to resort to a discbine for cutting. Using a discbine instead of a swather has a couple of significant disadvantages:
To learn more about C4 plants & their waxy leaf characteristics, click here.
When swath grazing, you don't want to crimp the plants. Typically, we crimp plants to increase dry-down time in silage or haymaking situations. However, in a swath grazing scenario, we aren't concerned about dry-down time, and crimping the swath allows rain or snow moisture to enter the stem, reducing feed quality and potentially causing mold issues.
Warm season plants naturally have a waxy coat on their leaves, which sheds rain and snow effectively, helping the plant maintain its maximum feed value. So, if possible, always use a swather. If a swather isn't an option, I would recommend loosening the crimper rollers as much as possible on your discbine or haybine and leaving the swath as narrow as possible to minimize the exposure of plants to the elements.
When using a swather, the bigger, the better. This will help cattle find it easier to locate the swaths, especially in heavy snow conditions. We had a customer this year who put two 35ft swaths together, and his cows easily grazed/found the swaths through several feet of snow.
Swath Grazing Cover
The Grazing
Image: Post swath grazing residue.
I often get asked, "How many acres do I give them at once?"
I believe it's beneficial to limit the amount of acreage they have access to at one time, but the number of acres depends greatly on the number of cattle. A good rule of thumb is to give them 5-7 days' worth of grazing at once. In my experience, this duration prevents them from being too picky and reduces "spoiling" by minimizing laying, defecating, and urinating on uneaten swaths.
For example, if you have 100 cows weighing 1400 lbs and they consume 3% of their body weight per day, they'll consume 4200 lbs of dry matter per day. Estimate how much dry matter you have per acre. This estimation can be challenging, but I usually estimate how many bales per acre I would have had if I had baled it. For instance, a good warm-season blend can easily yield 4 large round bales per acre. This would mean 6000 lbs of dry matter per acre. Based on these numbers, if you wanted to give these cows 7 days of grazing, you would need to provide them with 5 acres (4200lbs per day X 7 days = 29400lbs / 6000lbs per acre = 4.9 acres).
Just a side note, if my high school math teachers knew I was solving math equations for the entire internet to read, they would all be shocked. So, please feel free to double-check my math! Hopefully, this calculation helps you.
As with mob grazing during the summer, there will be some trial and error involved. Don't give them 7 days' worth of feed and leave for Mexico without conducting some experimentation first!
To gain more Farmer Perspective
swath grazing farmer panel
Thank you for reading, and as always, feel free to reach out with any questions you may have (pertaining to cover crops, not math equations, please).