Feature

 

 

Reducing methane means money to beef producers
Dec. 12, 2004
Even a simple rotation that moves cattle through pastures once over a grazing season is well worth the effort.
Just about any rotational grazing system will benefit the health and productivity of the grass, improve livestock feed efficiency and reduce the amount of methane lost to the atmosphere, say Canadian forage and beef researchers.

The rotation can be as simple or as complex as weather or management will allow, but in most cases avoiding a season-long, continuous grazing plan has both environmental and economic advantages, they say.

“A rotational grazing system can produce two main benefits,” says Duane McCartney, a forage and pasture management specialist with Agriculture and Agri-Food Canada’s (AAFC) Lacombe Research Centre. “It helps the grass stay healthy and productive and in turn can improve feed efficiency and lead to improved beef weight gains.”

Get in and get out

A rotational grazing system should be designed to get cattle in and get out - use the grass and then remove cattle so plants can regrow with time to put down essential root reserves.

As well pastures shouldn’t be used at the same time every year. Under better growing conditions plants may be able to support more than one grazing pass during a growing season without compromising growth. Under drier conditions pastures may only be used once each season. In either case it’s important to develop a rotation that schedules grazing so pastures are used at different times each grazing season.

“If you use Pasture One in early spring this year, it should be scheduled for either summer or fall grazing next year, says McCartney. “A rotation should allow plants in each pasture to set seed and fully store root reserves at least once every two or three years.”

A properly managed rotational grazing system often can increase both the quantity and quality of forage available to cattle. That should translate into increased feed efficiency, reduced production of methane gas and ultimately improved weight gain. That all points toward improved profitability.

One recent Manitoba study, for example, evaluating rotational grazing at five sites over two years showed a 2.5 times increase in forage production under rotational grazing versus a continuous grazing system.

Research over the years by specialists such as McCartney, Dr. Paul McCaughey with AAFC’s Brandon Research Centre, and Dr. Karin Wittenberg a professor in animal science with the University of Manitoba, reinforces the message now being delivered to Canadian beef producers through the federal Greenhouse Gas Mitigation Program (GHGMP) for Canadian Agriculture.

The GHGMP is funding a wide range of communication and demonstration projects across the country all designed to show how improved management practices can benefit beef production and reduce greenhouse gas production, or enhance carbon sequestration in agricultural soils. Reducing greenhouse gas emissions not only benefits the environment, but has a clear economic return as well.

Methane economics

The more methane an animal releases the more energy it is losing. Here’s how it works:

Ruminant livestock, such as beef and dairy cattle, produce methane as part of the normal digestive process. Methane gas is produced as a byproduct of the fermentation of feedstuffs in the rumen. Most of this methane is emitted from the mouth and nose through eructation and respiration.

“The methane is not just a greenhouse gas,” explains Wittenberg. “It’s lost feed energy that could have been used to produce meat or milk. On average about two to 12 percent of total feed energy consumed by cattle can be lost as methane gas. In other terms that is like losing one out of every 10 to 20 round hay bales.”

“Identifying feeding practices that reduce this methane production by cattle will improve feed utilization and address environmental concerns,” says Wittenberg. “In general, when animal production efficiencies are improved (through proper nutrition, management, reproduction or genetic selection of animals), the amount of feed required to maintain an animal is reduced as more feed energy is diverted to production. This means a drop in the methane per unit of meat or milk produced. If fewer animals can be maintained in the herd with improved productivity, then the total amount of methane produced from the overall herd can also be lowered.”

Back to grass

Supplying cattle with high quality forage can increase feed efficiencies and reduce methane production by about 20 percent in forage based feeding systems. Similar results can be achieved with proper management whether straight grass or mixed legume/grass pastures are grazed.

Manitoba research showed beef cows grazing an alfalfa-grass stand produced 25 percent less methane than a group on a straight grass pasture. In related studies, steers grazing a grass pasture early in the season, when grass was in its most vegetative state, had 29 to 45 percent reduced methane production compared to grazing steers at mid and late seasons. From a production standpoint, weight gains by animals grazing higher quality forage were significantly higher.
That’s where a rotational grazing system can produce dividends, says McCartney. His research shows the value of creating a simple three or four pasture system, that includes an early-spring, turnout pasture, which is sometimes referred to as a sacrifice pasture.

“That sacrifice pasture makes it possible to get cattle grazing earlier and takes the pressure off native grasses, or other domestic species that may not be ready until later in the season,” he says.

Crested wheatgrass works well for a turnout pasture. It’s an early, hardy grass that grows well under moist or dry conditions. Fertilizing the pasture in the fall will produce even better results, he says.

“The fertilizer allows you to get cattle out 10 days to two weeks earlier than if you didn’t fertilize” says McCartney. “The strategy with early spring grazing with crested wheatgrass is to graze it down to the ground. This wouldn’t be recommended with most other grasses, but it works with crested wheat, especially if there’s added fertility to help it bounce back.”

He recommends hitting the crested wheat hard, in early May for example. Grazing it to the ground will delay seed set, and that two to three weeks will give bluegrass and brome pastures time to produce enough growth for grazing in late May or early June. The crested wheatgrass often recovers enough over the spring and summer so it can be grazed again in late fall, at the end of the growing season.

Pasture scientist Paul McCaughey’s research has looked at more intensive rotational grazing systems, which involve moving cattle through pastures weekly or even daily.

He notes that single pasture or season-long grazing can work, but properly done it requires more management. A number of management techniques including herding, salting and watering practices need to be used to ensure proper distribution of cattle over the whole pasture to prevent cattle from “camping” on favored spots near water.

“Properly managed it can be very labor intensive,” he says. “With the portable fencing available today, it may be easier to manage a rotational system.”

The objective of rotation grazing is to improve harvest efficiency, and get more efficient use of the forage by livestock while managing plant energy reserves in a way that won’t deplete plant energy, says McCaughey. “This keeps pasture regrowth strong and vigorous, pastures in production longer, and prevents weeds from moving in.

“The key is to keep the grass vigorous and growing and in a vegetative state,” he adds. “The grazing plan needs to ensure the forages have time to put down root reserves before the end of the growing season. Plants that are continuously grazed and don’t have time to store reserves before freeze up, will be less vigorous, less productive and may eventually die out, especially if they are grazed in the same manner year after year.”

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© Canadian Cattlemen's Association, 2004,

 

© Canadian Cattlemen's Association, 2003,
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