Grazing early spring pasture growth won’t give cows the nutrients they need – and can harm later forage growth, says Justin Sexten, a University of Missouri (MU) beef nutritionist. He says there’s little quality or quantity to be had at that time.

“Early pasture growth contains mostly water – only 25% dry matter,” Sexten says. “Producers see this when they describe their cows as being ‘washy,’ ” meaning the grass digests at a fast rate.

After a hard winter, a cow nursing a calf would have to eat 150 lbs of that early grass to meet her needs, he says. But that’s hard to do because the quantity of the grass is minimal. “A cow can’t get a full mouthful of grass with each bite.”

Sexten recommends delaying grazing and continued feeding of hay and possibly some grain supplementation.

Early grazing isn’t a good idea, agrees Rob Kallenbach, MU Extension forage specialist.

“Grass that is nipped too short too early removes plant reserves needed for spring growth. Cool-season grasses stored sugar reserves in the lower stems last growing season. The reserves jump-start growth.”

Removing those reserves slows growth all season, Kallenbach adds.

The specialists advise producers to manage pastures carefully this year as they recover from last summer’s record-breaking drought.

So don’t turn herds onto pasture until there’s at least 5” of growth. “Allow 2,000 lbs of dry matter per acre to accumulate,” Sexten says. A lactating cow’s daily nutrient demand equals 2.5% of her body weight. A dry cow requires 2% of body weight. Many producers underestimate cow size when calculating feed needs, so try to accurately estimate cow weights, he says.

To meet nutrient demands, producers may have to buy more feed or cull herds, Sexten warns. Animals most in need include cows nursing calves and preparing for rebreeding later in spring. Cows with poor body-condition scores are less likely to rebreed on time.

Spring-calving cow herds need nutrients the most in April and May. Late snows have so far delayed grass growth, but brought moisture needed for that growth.

Sexten and Kallenbach advocate measuring pasture dry-matter growth weekly or biweekly, then plotting forage accumulation to figure when to move cattle through grazing paddocks.

To use forage measurements to create a grazing wedge, visit www.grazingbeef.missouri.edu.

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