James Freyr wrote:there is no mention if the pastures in these tests have dung beetles.
Seriously? Anywhere from 1 to 20 days? After 3 days on the same paddock, the cattle will be grazing the tender shoots of the species they first grazed. At 20 days on the same paddock is there any meaningful difference between that kind of rotation and just constant stocking? If you want a meaningful experiment, you would need to break the 1-20 days into subsets of 1, 3, 5, 10 and 20 days, or something like that and compare each of those to the MOB grazing.
an RG system refers to stocking densities less than 100,000 pounds of bodyweight per acre and one- to 20-day stays in a paddock before rotating to the next one.
For example, a cattleman may have 200 heifers that each weigh 1,000 pounds on a 1-acre tall fescue-based paddock for eight hours (0.33 days), and those animals may not rotate back to this area for 60 days.
To present the subject, a shorthand notation that Dr. Woody Lane and I have developed (see Dr. Lane’s article in the June issue of Progressive Forage) will be used. For instance, the example of mob-grazed heifers mentioned above could be summarized with the shorthand MOB,0.33,200K (note the lack of spaces).
Similarly, a rotational grazing (RG) system where those same 200 heifers grazed a 10-acre, tall fescue-based paddock for three days before being rotated to the next 10-acre paddock could be described with the shorthand of RG,3,20K.
which means 100 heifers on 1 acre, 3 times a day for 3 acres a day compared to 100 heifers on 3.3 acres for a day (100/3.3=30) so, again, 10% more pasture. That means that the MOB is eating more of the grasses as they have less available and, as the top part of the plant has more energy and protein available, they're probably eating roughly 20% more of the plant with the diminishing returns, stressing the plant that much more, resulting in poorer regrowth on the MOB pasture. The lower down on the plant they eat, the lower the protein content and the lower the digestibility, so we're just seeing what we'd expect to see. Wait, it gets better.
In Michigan, perennial cool-season grass pastures had forage up to 30 percent lower in protein and 15 percent lower in digestibility when managed under a MOB,0.33,100K system compared to an RG,1,30K system.
Under the previous nomenclature, the RG,1,50k could be 50 heifers on 1 acre for a day, or 50 heifers on 6 acres in 6 days and RG,6,5K would be 50 heifers on 10 acres for 6 days, or 1.67 acres per day. With 60% fewer acres a day for the same number of heifers, is it a surprise that there would be a loss in BC for the RG,1,50k group?
Arkansas, an RG,1,50K system – meant to represent a MOB-like system common in their region – resulted in a significant loss of body condition in cows compared to an RG,6,5K system.
So, 200 heifers on 1 acre twice a day, so 2 acres a day compared to 200 heifers on 40 acres (200/5=40) for 10 days. 200 heifers on 20 acres in 10 days vs 200 heifers on 40 acres for 10 days; twice the acreage for the latter group should produce better gains per head. With twice as much pasture available I don't think a 300% increase in gains per head is surprising.
In contrast, researchers in Nebraska found that yearling steer gains averaged 0.4 pounds per head per day on a MOB,0.5,200K while an RG,10,5K system produced 1.5 pounds per head per day (Figure 1).
Those numbers really jump out at you, right? 5,551 steps per day versus only 1,592 steps per da... wait a minute, that's 1,592 FEWER steps per day, so actually 3959 steps per day, but that doesn't jump off the page like printing 5,551 and 1,592. If Mr. Dennis Hancock hadn't already lost your respect for fucking with the numbers, he should right here. The reason the MOB group has more steps also isn't due to having
They found that cattle grazing in a MOB,0.5,200K system took 5,551 steps per day, while cattle in an RG,15,7.5K took an average of 1,592 fewer steps each day. Their observation was that this was likely the result of having long (300 feet) and narrow (12 feet) rectangular paddocks where animals were stocked so densely they had to regularly move around other cattle to find enough forage.
it's because the paddock set-up will have travel lanes back to the water supply that fence the heifers out of the recently grazed paddocks so they don't re-graze the new shoots, thereby weakening the grazed plants. If you watch any video of MOB grazing, they're not jockeying for position, they're just standing and eating. If they're grazing a large paddock for 15 days, they're wandering all around to find the new shoots on the best plants. At this point I'm pretty pissed at this Hancock guy.
to regularly move around other cattle to find enough forage
is the over-riding conclusion, but it's not mentioned until after the Cock says
Each of the researchers stated the variability in species diversity they observed seemed to have more to do with weather events than grazing management
and no grazer wants to lose legume species. This guy's not biased, is he?
they tended to lose shorter-growing grass and legume species in the MOB,0.33,100K relative to the RG,1,30K systems
Again, we're comparing 200 heifers on 20 acres for 10 days vs. 200 heifers on 40 acres for 10 days. Of course you're going to get more trampling with twice the stocking rate. Add to that, the top 33% of the plant has the majority of the energy in the grasses, so consuming 33%, trampling 56% and leaving 11% standing is pretty much the picture of perfect MOB grazing management.
The efficiency of forage use is often the most hotly debated aspect between advocates for rotational and mob grazing. In Nebraska, the MOB,0.5,200K resulted in 56 percent of the forage being trampled while 33 percent disappeared (likely consumed; Figure 2). In contrast, the RG,10,5K system resulted in only 19 percent being trampled and 44 percent being consumed.
How's that for a non sequitur? It has nothing to do with anything, but it implies that increasing stocking density doesn't result in any benefit.
Additional research in Nebraska examined incremental increases in MOB stocking densities of up to 750,000 pounds of bodyweight per acre and found the rate of trampling did not increase at stocking densities greater than 100,000 pounds of bodyweight per acre.
First of all, we're talking Michigan, not Texas, so it's entirely possible that a) warmer soil temps can have a positive effect as soil microbes can benefit from the 'free' energy provided by warmer soil, which anyone who gardens in the north can appreciate when it comes to getting plants to grow and b) there's absolutely no quantification of the temperature and moisture levels, so there's no indication of whether or not they are anywhere near the point of being harmful and, c)
Proponents of mob grazing have observed that the trampling of forage keeps the soil from heating up in the sun and helps to keep the soil from losing moisture. Research in Michigan, however, found that soil temperatures were lower and soil moisture was higher in the RG,1,30K relative to the MOB,0.33,100K systems.
the guy pretty much admits that it's a crock of shit.
Conclusions from their research must be drawn cautiously until more replications of these treatments can examine these effects over more soil types and landscape positions
Actually, if one has an understanding of microbial activity in the soil and the benefit of litter mass with regards to that microbial activity, one would assume that, when the use of MOB grazing results in 56% of the pasture being trampled compared to the 32% and 19% as seen in Figure 2, yet the resulting litter mass experiences a 2% loss in litter mass, the law of conservation of mass would imply that the high amount of trampled litter is being very efficiently incorporated into the soil as organic matter by the microbes. It doesn't just disappear.
Mulch on the soil surface – With all that trampling of forage, one would assume that a mob system would result in more residue on the soil surface. However, work in Nebraska indicated that the MOB,0.5,200K resulted in an average of 2 percent loss in litter mass, which was similar to the non-grazed control.
Meanwhile, the RG,15,7.5K and RG,10,5K systems resulted in a 7 to 12 percent increase in residue on the soil surface (Figure 3).
It's late and I'm ready to punch this guy, so let's just go with "does not provide clear answers", even though he then goes on to point out that MOB results in more compaction in MI because, let's face it, we all know he's got an axe to grind at this point.
Soil compaction – With those ultra-high stocking densities, some worry that excessive soil compaction may occur as a result of the hoof traffic. Here again, the research does not provide clear answers.
So, not only does he preface and postface his statement, he still wants to say that the OM was lower in the MOB grazing, though he won't tell us by how much (so, not much), nor if it's significant (it's not; you don't preface and postface if it is). I think his mother ran off with a MOB grazer and he's still emotionally scarred by it.
Very limited research data are available on this aspect, but the research in Michigan found that soil OM was higher in the RG,1,30K relative to the MOB,0.33,100K system at each increment in a 12-inch soil profile. Again, one should be cautious with conclusions until this research can be replicated across other soil types and landscape positions.
This whole section is a jumbled mess. There's no explanation of the testing parameters or timeline. Are we talking about short-term emissions, because the high impact of MOB will expose more volatile elements in the short term compared to lower stock densities but, as I've pointed out, the long-term carbon sequestration of MOB grazing should be accounted for, as should the sequestration of methane and nitrous oxide from microbial and insect activity.
The greenhouse gas emissions from the soil of the RG,1,30K pastures were 50 to 70 percent less than the MOB,0.33,100K system per animal unit. This is largely because the RG,1,30K and MOB,0.33,100K systems in their experiment were different in the stocking rate.
There's not enough info given to analyse this. I suspect profit is listed on a per head basis, but it's not clear. MOB grazing will almost certainly result in a lower profit per head, but it maximizes profit (meat production) per acre, especially over a longer time period. The way to maximize your per head profitability is to drop your stocking rate down, letting a few cows selectively graze your entire acreage. Without knowing what the chart is actually supposed to represent, it's impossible to critique it.
I like this. Can we just say that encompasses the whole 'article' (I use the term loosely)?
Weaknesses and Data Gaps
Every beef producer that uses MOB grazing seems to carry far more cattle per acre (stocking rate) as well as stocking density. The consensus seems to be that you will see poorer performance per animal but the greater number of head per acre more than makes up for it, resulting in a higher profit per acre. Additionally, many experienced practitioners of MOB grazing carry 3-5 times the stocking rate of their non-MOB neighbours and are unable to get enough cattle to utilize the forage they have available.
More importantly, most of the studies to date set the stocking rate equal across treatments. Research has not yet determined if rotational and mob grazing management systems differ in their optimal stocking rates or in carrying capacity over the long run.
and it's quite apropos. There is a significant number of people who aren't comfortable with numbers, regardless of their intelligence. Some people like to hurl 'statistics' at them in order to baffle them. Ancel Keys published the "Seven Countries Study" that linked dietary fat to heart disease. This study became a significant pillar of the nutritional guidelines, though it seems that Keys completely omitted 15 countries where the diet and heart disease didn't fit his hypothesis. Recently, there's been this graph floating around, purporting to prove that the US is actually experiencing a cooling trend:
There are three kinds of lies: lies, damned lies, and statistics.
Carson Albright wrote:.... that people do tend to exaggerate or over emphasize the benefits of things online, and was wondering if Mob grazing is one of those cases.
Travis Johnson wrote:but I get the same results from spending a few hours on a tractor and bushogging my field.
Tj Jefferson wrote:Only question I have with the more selective grazing is do you see an increase in noxious weeds and unpalatable stuff? Thats my biggest concern.