Mob Grazing Sheep

Acres U.S.A. reader query: I am looking for information on mob grazing sheep. I am most interested in how it is done; what kind of fences or techniques will hold sheep in; and what kind of animal impact results.

When mob grazing is written about it is almost exclusively about cattle. Cattle are great, but sheep seem more profitable in our situation. We have been trying to direct market our cattle for increased profits, but in the rural West too many backyards contain livestock. Plus, trying to deal with butchers that don’t care enough is highly frustrating. Can you point me in the right direction for any information on mob grazing sheep?

Brett Williams
Northwest College, facilities assistant

Response by Nathan Griffith, editor Sheep! magazine: By “mob grazing,” most operators mean very high stocking densities per acre for very brief durations and very long recovery times. Notice there are three “veries” in there. I’ll add one more: Historically, it’s very labor- and capital- intensive.

A sheep looks directly aheadLast I checked on mob grazing with sheep (admittedly several years ago) No-Risk Ranching guru Greg Judy was starting to dabble with sheep, so he’d probably have some good tips for the practice. That said, it’s important to remember that — especially with sheep — highest productivity doesn’t always translate into highest returns on investment.

Productivity Vs. Profit

The highest returns per acre of which I’m aware came from the now-forgotten process of “soiling.” This means growing and harvesting crops on a schedule designed to use each feed at its best ratio of nutrient concentration and volume yield: Each successive removal of forage from the land is transported to the livestock, which are kept in small enclosures designed to maximize comfort and conserve both liquid and solid manures.

Those valuable outputs are immediately spread on portions of the farm that need it most.

The practice of soiling livestock was introduced in the early 1800s into New England by the legendary Josiah Quincy of Massachusetts. In New England, soiling was found to average about four to six times the livestock output per acre of well-managed production by more consuetudinary methods.

Soiling of livestock was the subject of numerous investigations and big enthusiasts for about 100 years, after which it completely disappeared. Under some conditions, it could be made to pay with dairy cattle, but in all, the semi-skilled labor requirement was exceedingly high, as was the management requirement.

These two inputs, together with the vagaries of weather and occasional absences of workmen familiar with a given farm’s characteristics, upset the whole apple cart repeatedly, causing major disturbances in flow of operations.

The theory with mob grazing is that yields — in pounds of livestock harvested per acre per year — should go up, sometimes up to double or more the yield of low intensity set stocking. There is some question whether the labor and capital inputs for mob grazing will be repaid at the final reckoning.

Most mob grazing sheep experiments and reports were carried out in Britain in the 1960s and ’70s. The big authors for these data have been Malcolm McGregor Cooper (1910-1989), Robert John Thomas (d. 2013), C. R. W. Spedding (1925-2012) and Henry Fell (1929-present). Others too, factor here, but the list would be too long to hold your attention.

Sheep Vs. Cattle

Neat cattle (i.e., bovines, or kine) are very different from small cattle (sheep, goats and most farmed deer species) in grazing behavior, nutrient requirements, fencing requirements, parasite and predator susceptibility and their average yields on grass. So cattle data don’t really apply directly to these forms of livestock.

Sheep for example, require considerably more protein in their diets than cattle, which isn’t surprising, considering the greater output per ton of livestock and per acre. So, waiting until grass is tall and then grazing it — as is done with mob-stocking of cattle — is apt to be a real loser in terms of financial and animal welfare successes, because at that height it’s usually gone below the 11 percent absolute minimum protein content (dry basis) for sheep health.

Short grasses, richly and tightly grown, are the goal for sheep, even considering their greater parasite proneness. If you drop a quarter in a rich sheep pasture, you should be able to easily find it by simply retracing your steps. Of course, on the unfenced range it’s all different, but it doesn’t change the application of principle.

Even at high stocking densities, sheep tend to be more selective than cattle, having “the lips for it.” Sheep have very agile, prehensile lip operation, able to successfully sort their foods with great effectiveness. Not so cattle: The big square mouths of kine and their raspy tongues shovel in big boluses of a variety of grass mixtures gulped down in a practically indistinguishable blob. And yet, alas, cattle don’t like weeds in those mouthfuls unless “trained” to it. They just stand around mooing and defiling their weed patch, unless forced to “eat it or starve.”

Then too, bovines’ gelatinous manure limits any grazing within a foot of their plops, unless cruelly forced to do so. Furthermore, confining sheep to certain swards that would’ve been great for cattle will sometimes have other deleterious physiological effects.

For example, confinement to a paddock with diseased, droughted or bug-distressed clovers, particularly red clovers, causes conversion of the clover’s formononetin and biochanin A into estrogenic equol. Cattle convert that too, but can rid the equol from their bodies within about 8 hours. It takes 30 days for a ewe to get rid of equol, and during that period, she will normally remain sterile, or possibly lose her current conceptions. If grazed continuously on such swards for longer than 30 days, ewes have been known to go permanently, irreversibly sterile.

Certain nasty parasites, notably of the Nematodirus and Bunostomum groups, have potentially very long pre-patent periods in soils, often overwintering and appearing with a vengeance on heavy spring growths. Both these groups can be very deadly to lambs in particular, despite long resting periods. They’re especially bad when grass is tall and eaten down to the moisture zone. Lowered protein content of long-recovery swards after mob grazing can be deadly in view of the rise of 50 percent or more in protein needs by heavily parasitized sheep.

Often a single strand of hot wire will contain cattle. If tightly confined, sheep need either netting, or at least four hot wires. Sheep also are more strongly affected by predators. When bunched tightly behind electric fences, they are very easily spooked en masse by a sudden aggressive predator appearance. Spooked sheep will commonly stampede an electric fence and be off. This may even happen if sheep are surprised by the unexpected appearance of their own attendant, with whom they’re trusting and familiar.

Ineffective Trampling

One of the principles of mob stocking (in the 1970s known as HILF stocking, for High Intensity, Low Frequency) is the intentional encouragement of trampling of around a third to half the vegetation by the cattle.

The trampling of vegetation helps knit together the surface soil to prevent erosion in wet seasons and offers better germination success for new seedling emergence. Sheep aren’t really good tramplers: A 50- to 75-pound weaned feeder lamb is about a tenth the weight of its corresponding weaned calf. But a sheep’s hoof area may be a sixth to a fourth that of the calf, often resulting in only half the pounds per square inch trampling energy. In other words, ineffective trampling of the ground occurs with sheep. This is an advantage in steep wet pastures, as there is little pugging (deflocculation) of the ground with sheep. The ratio of a 120- to 160-pound ewe is again about a tenth that of a 1,200- to 1,600-pound cow, with hoofs only one-sixth to one-quarter their size (a lot fewer pounds per square inch).

Because the average live carcass tonnage yields of sheep per acre of grass are so much higher than cattle to begin with, mob stocking has in the past offered little further advantage.

Capital and Labor

A large number of paddocks are needed for three or four-day rotations, 19 paddocks to 26 paddocks are commonly recommended for intensive rotational sheep grazing, which demands a lot of capital per head of grazing capacity, plus a lot of labor to keep up.

Nineteen paddocks wouldn’t be nearly enough for the several-times-a- day monitoring and/or moving required in true mob stocking. Doing the math, a 45-day minimum rest period (some rest theirs 120 days), and rotated only twice a day, would demand 90 paddocks. That’s a lot of fences and gates (or netting moves)!

Not to mention watering facilities, shade, salt licks, etc. Some “less intensive” mob stocking sheep experiments have been conducted in Australia and the British Isles.

Alas, most sheep HILF grazing research was done in pre-internet days. Great sheep ag libraries such as Massey University in New Zealand have little interest or resources for digitizing their mass of literature.

Just scratching the surface here has resulted in more text than the average sheep enthusiast would want to read, I suppose. And we haven’t even looked at the fact that all grazing systems put back into the soil (in the form of urine and dung) significantly less fertility than they’ve removed in the form of meat, milk, hides and fiber.

Encouraging vegetation to do its best isn’t a substitute for feeding the soil, unless something substantial replaces the extra nutrients removed by all that extra growth stimulated by “pulse grazing.”

Then too, researchers at the University of Virginia years ago began recommending sheep rotations not be shorter than eight to 10 days, due to higher coccidiosis levels when forage gets eaten down quicker than that in a paddock. Personally, I haven’t seen problems with this one, but it’s a factor when considering mob stocking.

And of course, any high-labor management should always consider operator labor (and family labor) as an expense, and never regard it as a “free” resource. Why? Because unrequited effort brings resentment and a hatred of the activity. And eventually outside help will be needed due to factors beyond the operator’s control. United States Department of Labor stats indicate an average payment schedule of about $9.66/hour for uneducated farmworkers and $30.85 for trained or credentialed farm or ranch managers.

Personally, I’ve seen very few novel sheep husbandry methods that paid well, but maybe that’s just my limited exposure to these systems due to the parts of the country I’ve lived in.

Sheep operators should honestly consider and project whether their investments in a mob sheep outfit will at least cover its labor, land, management and livestock inputs — at reasonable prices consumers and/or processors will not hesitate to patronize — before making a bold, hard-to-reverse move in the direction of such a high labor production system. If so, then by all means go for it. And make sure to hit it hard, or not at all.

By Nathan Griffith, editor of Sheep! magazine.

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This article appeared in the October 2017 issue of Acres U.S.A. magazine. Download the entire issue here:

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