4Diamond makes a good point, it depends alot on your environment. That said, in various ecosystems you simply have to adjust your rest period between grazings. On some of our native grass, we graze it once per year, and it gets to rest for at least 100-120 days, some of it won't be touched for a year or more. This is because in our region on an average rainfall year, that native prairie wool will not fully recover in less than 100 days. By fully recover I mean it's mature and heading out again. It's completing another life cycle.
The basis of mob grazing is to build topsoil. By grazing large, mature plants comprising thick dense swards, you are depositing an amazing amount of material into your top 6inches, as well as several feet down into your subsoil. Remember that whatever you see for top growth, is mirrored by root growth under the surface. When you look at my pictures I posted of all that alfalfa, milkvetch, sainfoin, clover, wheatgrass, bromegrass, creeping red fescue, etc, etc, imagine just how much root growth there is under the surface in the soil. Every time an animal takes a bite, there is some sluffing off of root mass. That root mass builds carbon and hundreds of other nutrients in the soil, which through the interaction of microorganisms, animal hoof action, manure, urine, rainfall and air pressure systems pushing and pulling oxygen and nitrogen-rich air through the topsoil, creates organic matter. The more organic matter on your soil that larger your sponge for holding moisture. It's that simple.
Anyway, to the other question, is it worthwhile? I spend an average over the season of 2 hours per day with these cattle. 400 head billed out at 80 cents/head/day = $320/day. So you can look at it as my gross pay is $160/hour.
OR
You can look at it per acre. THis year with lots of moisture we are going to graze these girls for 100 days on roughly 450 acres. $32,000 divided by 450 acres = $71.11 per acre gross. We had planned on drilling a well and setting up a pipeline watering system. It hasn't happened so I am hauling water. Next year with the water system in place, I will have less labour and the ability to graze 800-1000 head. The profit margin greatly improves in that scenario.
I have a couple of friends who are grazing much larger mobs than this, and making a profit at it. Some do it as their sole income, others as an enterprise within the farm. Neil Dennis, Steve Kenyon, Bruce Downey are all guys I have read about, talked to or spent time on their farms seeing the results and learning how to adapt it to my place. When I was at Bruce Downey's place some years ago, it was bone dry throughout the country, but his place was still green and he had regrowth taller than his neighbor's first growth. He was running 2,000 yearlings in one mob, charging 75 cents per day. I like that math. $150,000 gross pay in 100 days of grazing. That size of a mob gets to be much more work of course.
As for moving every 4-6 weeks being as good as mob grazing, I can't see that at all. There are alot of variables to know before we could discuss that. If you put 100 pairs in a section of pasture for 5 weeks, they are going to graze the best meadows down low, other stuff a bit, and some acres not at all. Lots of litter would be left standing instead of trampled over. If it's standing it's oxidizing into the atmosphere, instead of decomposing into the soil where we want it. Nutrients are going to take many, many more years to recycle in that system, especially in arid environments like ours where decomposition is slow at the best of times.
In a mob grazing scenario, the animals are grazing the top third of the plant, and being moved on. This has many benefits:
-The top third of the plant is the highest energy, better animal performance
-Leaving lots of the plant behind means it has plenty of leaves acting as solar panels to absorb sunlight and get regrowth happening quicker
-Getting the litter trampled so it makes contact with the soil is crucial to kick start the decomposition process. Grazing something with low stocking rates over a large area for 4-6 weeks would not do that other than in a few select areas around mineral licks or water holes.
-So no, I guess I don't agree with that study, but like I said, lots of variables and unknowns.
In all, I think it's like anything else. If you think it will work for you, try it on a small scale and see how you do. If it doesn't work, don't go telling everyone it's a failure, it simply didn't work for you. It's no different than feedlots, cake, ivomec, implants, swath grazing or any other thing we've discussed at length on here over the years. Good for some, not for others. For us, it is easy cash flow and lower risk than any other enterprise we do. It gives us financial breathing room so we don't have to work so hard at marketing meat or working off-farm to make ends meet. I don't mind work, but if I can make my living off my own land, and be greatly improving my topsoil along the way, I'm a happy man. :wink: