Spring Grazing Management Imperative

Green Grass Doesn't Always Mean the Nutrients are Complete

Russ Quinn
By  Russ Quinn , DTN Staff Reporter
Connect with Russ:
Grazing needs more thought than just letting the cattle loose. (DTN\PF file photo)

OMAHA (DTN) -- Among the days cow-calf producers perhaps most look forward to is the day they can turn their pairs out to grass, whether that be Midwestern pasture or High Plains rangeland. However, before that day even arrives, many days of planning and work need to be accomplished first.

Spring grazing management begins long before the gates are opened and trucks and trailers enter the grasslands. From maintaining structures to making sure cattle nutrition and herd health are optimum, there are several factors producers need to contemplate before grazing occurs.


There is not a shortage of things to be completed before cattle are turned out on grass, according to Casey Schuhmacher, a cow-calf and stocker producer from Chadron, Nebraska. There is a list of things he covers every year before cattle head to grass on his northwest Nebraska operation.

Among his basic items is the maintenance of facilities such as fence and water supply structures, such as stock dams, pipelines, solar or windmills. Obviously these facilities need to be examined fully and repaired if necessary to assure cattle are contained and water is available.

"These are the usual things to go over to get to grazing," Schuhmacher told DTN.

Other considerations at this time often are decisions about rebreeding cows without calves. Depending on forage availability, some producers will keep the cows while others will decide to sell these cows, he said.

Erica Lundy, Iowa State University Extension beef specialist, said producers need to make sure the grass is ready for grazing. In southwest Iowa where Lundy is located, forage growth has been good this spring with only a few areas missing the rains and needing moisture.

Lundy said growth of around 4 to 6 inches of grass is usually the point when many cattle producers in the region will begin to graze in the area.

"I think many people use the saying 'take half and leave half' in terms of grazing not to overgraze pastures," Lundy said.

Schuhmacher said his grass might be a little behind this spring due to cooler conditions slowing the growth but he estimated the grass would still be in the normal range. The moisture in the region has been adequate but he also said it wouldn't take much of a hot and dry spell to get him concerned about drought.

One tool Schuhmacher is using to evaluate grass productivity is Grass-Cast (https://grasscast.unl.edu/…), a grassland productivity forecast. This forecast is a result of a collaboration between Colorado State University, USDA, National Drought Mitigation Center and the University of Arizona.

Grass-Cast uses almost 40 years of historical data on weather and vegetation growth and seasonal precipitation forecasts to predict if rangelands are likely to produce above-normal, near-normal or below-normal amounts of vegetation.

Schuhmacher finds the Grass-Cast forecast useful, he said. It has been doing a good job with the fairly limited amount of data the forecasters have to work with, he said.


Lundy said another part of spring grazing management would be to feed cattle supplementation before they head to grass.

Cows should be in good body condition before heading to grass to assure they are in optimal condition for breeding season. Those cattle who are too skinny or even too heavy will be more difficult to breed back, she said.

Cattle producers in Lundy's area of southwest Iowa have several options available to supplement cattle before they go to grass. At the top of the list would be corn and co-products available from ethanol plants.

With the COVID-19 pandemic, products such as DDG have increased some in price and availability might be in question with some ethanol plants closing. This may have some cattle producers rethinking their rations, she said.

"The markets are unstable right now but we still do have some options," Lundy said.

Once cattle are grazing this does not mean the automatic end of feeding supplements. In a news release from Kansas State University Extension from April 21 (https://www.ksre.k-state.edu/…, K-State beef cattle Extension specialist Bob Weaber said just because the pasture is green doesn't mean it has enough nutrient value.

Green grass often has a high water content, which limits the nutrient availability, he said.

"Most pastures this time of year are in fair condition, which means they will provide 50 to 100 pounds of dry matter per acre," Weaber said. "Producers can supplement with hay or 20% range cubes to give the cows energy with the appropriate amount of protein."

K-State Extension veterinarian Bob Larson said it is also important to provide salt and other minerals for cows moving to grass. He recommends a high-magnesium mineral early in the spring grazing season.

"If the cow is not ingesting enough magnesium from the grass or through a supplement, she might experience grass tetany, which impacts her nervous system causing her to be weak or even become aggressive," Larson said.

He added that grass tetany is more common in the spring because the lower soil temperatures keep the magnesium from rising to normal levels, which it does in the warmer, summer months.

Lundy said cattle producers would want to feed high-magnesium mineral for two to four weeks before the cattle go to grass. This mineral should also be fed for two weeks after the cattle start grazing, she said.


Cattle producers should also consider herd health before cows are moved to pastures.

Larson said he encourages producers to work with their veterinarians to make sure the cows have been given updated vaccinations.

"With mature cows there is some flexibility in the time of year vaccines are given, so it is important for producers to work with their veterinarians to build a program that makes the most sense for their operations," Larson said.

Lundy said fly control is another part of herd health producers should deliberate before the cows go to grass.

There are different options available to combat flies, she said.

Among the more popular methods to control flies would be feeding mineral with insect growth regulators (IGR). Mineral with IGR is feed with compounds that typically interfere with fly development.

Topical sprays and pour-on insecticide can also control flies as can insecticide cattle ear tags, she said.

Russ Quinn can be reached at russ.quinn@dtn.com

Follow him on Twitter @RussQuinnDTN

Russ Quinn