Rotational stocking – commonly called rotational grazing – has been an instrumental improvement in grazing systems across the U.S. By moving the herd around the farm, we have increased the amount of forage produced in pastures, reduced weed pressure and better utilized the standing crop. However, enthusiasm around rotational grazing seems to feed into some unrealistic expectations of how a stocking method can push a grazing system.

Jonathan Kubesch

Extension Forage Specialist / University of Arkansas

Email Jonathan Kubesch

Enthusiastic rotational graziers, especially newer farmers and ranchers, seem convinced that rotational stocking will fix most ills in their grazing systems. The popular press materials also push this perspective. An electric fence supplier had a guest article suggesting that daily moves on a single acre could support a cow for a full year. This year, my farm visits in Arkansas seem to suggest that we must address other aspects of our grazing system beyond developing a pasture rotation.

For that small cow (let’s pivot to a growing Angus heifer) on that single acre, we can assume she will need 3% of her bodyweight in dry matter (DM) intake. Every day, that Angus cow will need about 26 pounds of forage DM in the tank. With daily moves and most rotational systems where the cattle move at least weekly, we can expect 65% to 70% utilization of the pasture. We actually need to provide about 39 pounds of forage DM out there daily for about two-thirds of that forage to make it into the rumen.

In Arkansas and much of the southern U.S., our pasture expectations can range from 2 to 4 tons per acre, with extremes on both ends of that range. At that 2-ton production figure, we are short about 10,000 pounds of forage DM each year. At a 4-ton production figure, we are still short about 6,300 pounds of forage DM. Rotational stocking alone will not correct our forage deficit. To fully support this Angus heifer on forage, we would need to provide her with about 2 acres of highly productive pasture.

This math exercise also doesn’t address the fact that grass grows at different rates over the calendar year, and that forage might not always meet nutritional requirements. We often handle time in grazing systems by setting a stocking rate that accounts for the number of head over the total amount of grazing acreage for a defined period of time, typically a growing season or calendar year. Depending on how we adjust our herd, forage base and stored feed resources, we can deal with one of the fundamental challenges in grazing: The animal demand is constant on a variable forage supply.

We can push the productivity of our pastures and hayfields with fertilizer, weed control and rotational grazing toward some carrying capacity. Unfortunately, carrying capacity is something we can only get so close with our actual stocking rate. If we could know the grazing system’s carrying capacity ahead of time, we could always match forage supply with animal demand. Setting and adjusting a stocking rate will be crucial to trying to chase that carrying capacity. Looking at the example above, we probably want to give each cow-calf pair a few acres. Well-fertilized, clean pastures, with regular rotation will provide more livestock feed than casually managed pastures. The good news is that pasture production has increased somewhere between 25% and 50% since the 1940s across the southern U.S.

Once we adjust animal demand to what we currently can grow, we need to consider ways to increase the forage supply overall but also develop a forage distribution that keeps that supply steady across the year. A 300-day grazing framework is a great starting point for making these adjustments to pastures and hayfields. Strategic fertilization – like giving a stockpiled bermudagrass or fescue field a shot of nitrogen (N) in early fall – can help push our total forage production and help us spread the forage supply into our gaps or slumps in the calendar. Additionally, developing realistic expectations for what can be done on the farm should reflect the personal and managerial abilities of the farmer.

I'm a part-time, four-wheeler farmer in East End, Arkansas, on crawfishy ground. I make most pasture management decisions from my four-wheeler or a small gas tractor. My pastureland can be extremely productive but suffers from poor drainage in the late winter and early spring. I graze and finish steers on some neglected pasture that has been divided into five paddocks. In order to improve pasture productivity, I will need to improve the soil fertility, renovate the stand to a more productive species composition and control my input costs, given some limitations in operational size. As a statewide forage specialist and a father of two young kids under 2, my farming has to fit a busy schedule. Daily cattle moves will not work at my farm, but weekly moves can. More importantly, the poor pasture species and my home life will not benefit from complex rotational grazing.

This article isn’t meant to dissuade from rotational grazing. A 2012 Natural Resources Conservation Service (NRCS) synthesis of the research on rotational grazing confirmed a roughly 30% bump in forage growth from effectively rationing the pasture out to livestock. Strategic use of mob grazing or manipulations of paddock size can be used for targeted weed control from grazing, as has been shown in Virginia. Missouri work purports a bump in utilization from 35% to 65% when moving from continuous to  rotational grazing systems. Most of these benefits are captured when the animals move through a few different fields and where the rest period of each field is greater than the grazing period in each field.

Rotational stocking really does work to better use the grass we can grow, to a point. However, the botanical composition, soil fertility and weed pressure in our pastures will set a carrying capacity to which we must stock the appropriate number and classes of livestock. And ultimately, the amount of management that we are willing to apply to our grazing systems will determine how much rotation is within reason.