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Managing forage in a dry year

Planning for drought needs to occur before drought arrives

Drought is normal in Western Canada and it is not going to go away. We just don’t know when the next drought will be, or how long it will last.

“Drought affects two basic parts of the rancher’s business,” says Dr. Art Bailey, range science professor emeritus at the University of Alberta. “On the demand side, livestock need forage and water. On the supply side, every ranch provides both forage and water. When drought hits, the supply of forage declines, and water supply may also be reduced.”

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Bison on pasture near Pigeon Lake, Alberta.

The very best animal genetics are of little help during a drought because of inadequate forage supply, Bailey adds.

Have a plan

“Ideally, planning for drought needs to occur before the drought arrives,” says Dr. Mike Schellenberg, forage and range ecologist at Agriculture and Agri-Food Canada (AAFC) in Swift Current. For forage stands, that means seeding drought-tolerant species along with less drought-tolerant species. Schellenberg and his colleagues found that combining bunch grass species such as Stipa ssp., with rhizomatous species such as wheatgrasses, takes advantage of both dry and moist conditions.

Producers who haven’t drought-proofed perennial stands can use annual species mixtures for emergency feed or as part of their regular rotations.

“The key is early seeding so the seeds can take advantage of early spring moisture,” says Schellenberg. “Planting a combination of species which includes cool-season grasses such as triticale, barley, and legumes including hairy vetch, and field pea and brassicas such as forage turnip, forage radish can provide a good nutritional package.”

Schellenberg cautions that some species in annual mixtures can accumulate high nitrate or sulphur levels, especially if grazed in the fall. He adds that producers can add warm-season grasses of corn and millet, but during a drought they don’t provide much biomass.

Dr. Paul Jefferson, former head of the Western Beef Development Centre and former forage research scientist at Swift Current, says that combining drought-tolerating species like crested wheatgrass with drought-avoiding species like alfalfa in tame pastures will give livestock producers in the brown soil zone a resource to manage grazing during drought.

After a dry spring, perennial forages will not regrow enough if summer rains occur, Jefferson adds. Producers can use late-seeded annual crops for grazing or hay if they get rain after July 1. Straw or straw/chaff can replace a portion of winter hay requirements for beef cows, if properly managed, he adds.

“You can also use some hay fields for grazing during drought,” says Jefferson.

“There is no cookie cutter strategy for managing drought,” says Dr. Walter Willms, retired range ecologist at AAFC Lethbridge. But planning to leave carryover is effective. Litter conserves moisture and provides future emergency feed, at least in the first year of drought, he says.

Dr. Jim Romo, retired range professor at the University of Saskatchewan, found that for every kilogram of litter carryover per acre there was a 20 per cent yield increase the next year in the brown soil zone. The litter increased water infiltration.

“The best strategy is to manage your grazing to have enough reserves in the rangeland plants that for one season you can take a little more than the recommended half,” says Dr. Paul Nyren, retired director of Central Grasslands Research Extension Centre in North Dakota.

Research results tend to show that if pastures are in good condition they can weather a one-year drought with little harm, says Nyren. But more than a year will damage the perennial forage species.

Producers can also bank some forage as protected bales or silage, he says. Several years ago, researchers at Dickinson, North Dakota, put corn silage in a trench and covered it with plastic and dirt. It was still good 10 years later, says Nyren. That should work with other grass or cereal silages, he adds.

Jack Kyle, retired Ontario pasture extension specialist, recommends creating a feed and forage budget, plus a budget to cover livestock needs. The budget should cover how much forage is available, what other feedstuffs are available and how much is required to meet the needs of your livestock on a class-by-class basis. Kyle suggests reviewing it monthly or bi-weekly. During a drought, he recommends reviewing it every week.

Grazing is still the cheapest option for winter feed. But whatever the means, try to line up winter feed supply by mid- to late July. Drought in central and southern Alberta pushed hay prices up to $17 for small squares and $180 or more for large rounds at local auction markets last winter.

My colleagues and I evaluated every conceivable storage method for big round bales, and the only method that worked for long-term storage was under a roof. When big round bales were stored outside, we found that unless there was an air space all around the bale, moisture would be trapped at the point of contact, causing rot. I understand from some farmers that pushing the butt ends of round bales tightly together with a bale spear will prevent moisture infiltration.

Protect the plants

Barry Adams, retired range ecologist and former director of Alberta Public Lands, emphasizes that the range manager’s goal is to minimize range damage and stay in business. Heavy to moderate use of rangeland during drought greatly reduces future production and profit potential.

“Grasses don’t store carbohydrates in their roots but in crowns of the stubble,” says Dr. Shabtai Bittman, sustainable cropping systems research scientist at Agriculture and Agri-Food Canada in Agassiz, B.C. “Protect the crowns by not cutting and grazing too low. If you graze too low you may also remove the axillary buds before they have had a chance to elongate and this can be very destructive, especially to some grasses like timothy and brome.”

Bittman says that old leaves, even if they’re green, contribute little to photosynthesis and may burn more sugar than they synthesize. “Grazing and clipping is very much about protecting energy and nutrient reserves in newly formed buds. If we graze close to ground, regrowth is poorer as you would expect,” he says.

When plant stems are elongating, they consume stored nutrients, which is why they accumulate so much herbage. Grass plants are weak and vulnerable to drought or cold during elongating, especially if there is competition, Bittman says.

For most pasture species, the golden rule is to leave a photosynthetic panel behind, says Dr. Scott Wright, former AAFC crested wheat plant breeder in Saskatchewan. That means taking half, leaving half and letting it regrow. With hay, that means planning a single cut before it seeds out.

The exception, says Wright, is crested wheatgrass, especially AC Parkland.

“You need hard spring utilization,” says Wright, adding that from what he’s seen, fall grazing crested wheatgrass doesn’t seem to work well. “AC Parkland still seems to have better utilization and fewer wolf plant formations than other varieties,” he adds.

Alfalfa is more drought-hardy than drought-tolerant. It’s a water-spender, and its deep roots, which can grow up to 15 metres to reach groundwater, dry the soil over repeated drought years. More typically the root system reaches two to three metres, depending on the subsoil. Alfalfa’s deep root system and ability to store carbohydrates in the crown make it resilient to drought.

Alfalfa’s persistence also depends on the stand management. Dr. Ed Bork, a range professor at the University of Alberta, recommends adjusting grazing to conserve deep-rooted forage plants such as rough fescue, orchard grass, meadow brome and alfalfa. This will extend the active growth period.

“This maintains forage availability and quality during late summer, fall and even into the dormant season,” says Bork. “Maintaining a diverse sward of forage is also likely to help in this regard, as a more diverse sward will ensure that at least some drought and heat-tolerant plant species are present to withstand dry conditions, thereby stabilizing forage yield during climatic variability.”

For those who graze conservatively and leave adequate leafage behind to regrow and replenish energy in the roots, there will be more forage available even under drought conditions. Cool-season grasses and forbs need soil moisture in May, June and July when about 80 per cent of growth occurs. Plan ahead if there is an extremely dry spring. Modify normal management to match the livestock demand to the lower forage supply. Find other pasture or hay, or start reducing the herd by culling dry cows and surplus bulls. Severe drought will require more severe culling.

On the supply side, most conservatively grazed ranches have undergrazed pastures far from water. Bring in portable water to enable grazing. Graze any available bush pastures. Cattle will browse aspen, rose and raspberry suckers. As a last resort, start using up surplus silage or available hay before more of the herd is to be culled and pray for rain.

Bittman says producers shouldn’t always write off drought-stressed grass. While it might look terrible and have less crude protein, the herbage may have retained its total digestible nutrients. Bittman adds this doesn’t hold as well for drought-stressed legumes, as they often shed leaves, leaving only stems.

Dr. Bart Lardner, professor at the University of Saskatchewan, Jack Kyle, and Grant Lastiwka, forage specialist with Alberta Agriculture, all agree that rotational grazing is key to managing grazing pressure. Short grazing periods for any one area, and long rest times, are especially important during a drought.

Lastiwka is concerned that only lowering stocking rates on larger pieces of land over a long grazing period will support over- and undergrazing patterns. He suggests running fewer cattle, but also grouping herds in a way that uses more of the landscape through higher stock density/unit time, keeping grazing intervals short and rest periods long.

Avoid overgrazing any area of the pasture if possible. But in an extreme drought, some paddocks can be grazed heavily as a sacrifice pasture, while allowing more rest time for the other paddocks. Rotate animals once grazing conditions no longer meet their needs.

A drought might also shift the economics around fertilizer use, making the benefits more affordable.

“Maybe it is an investment that will not pay full dividends this year but will compensate for past regressions by giving plants greater root growth for following year productivity,” says Lastiwka.


How one family dealt with drought in 2018

Doug and Linda Wray and family have a cow-calf operation at Irricana, east of Calgary. The Wrays try to be proactive in their analysis, planning and execution in dealing with drought.

One strategy is to run part of the calf crop as yearlings. If it gets dry, the yearlings can go, leaving grass for the cow herd. But in 2018, the Wrays only saw 50 per cent of average rainfall, and the ratio of yearlings to cows was not high enough to compensate.

In 2017, they built a hay shed to store feed longer for insurance. Unfortunately, they didn’t get a chance to fill it before winter 2018.

The Wrays monitor rainfall and soil moisture in the spring, with the next month or two of growth in mind. By August 2018, they knew that their normal winter feed would likely come up 2.5 months short. Expensive hay limited their purchases so they booked straw to bale to help fill the gap.

As dry conditions stretched into fall they weaned early to keep condition on the cows. They protected the grass and kept the cattle moving forward by moving them every two or three days all summer.

About the author

Contributor

Duane McCartney is a retired forage-beef systems research scientist at Lacombe, Alta.

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