by Elizabeth Cronin, North Dakota State University

Monitoring grazing use in the fall has the potential to significantly affect 2024 forage production. North Dakota State University (NDSU) Extension has found that heavy grazing use in the fall can reduce forage production the following growing season by more than 50%.

“As we transition into fall, it can be tempting to keep cattle on pasture longer to stretch feed resources,” says Miranda Meehan, NDSU Extension livestock environmental stewardship specialist. “However, this decision can have long-term impacts on forage production and pasture health if overgrazed. Currently, nearly half (48%) of pastures in [North Dakota] are reported as being in fair or lower condition.”

Cool-season grasses dominate pastures in our region, which can make up 85% or more of the species composition. These cool-season grasses develop tillers in the fall, and the development of these tillers has a direct effect on plant growth the next year.

“If tillers do not establish or survive the fall, a delay in growth and development will occur the following growing season, as new tillers will need to develop in the spring.” — Bob Larson

“If livestock graze tillers below the growing point in the fall (in between the bottom two leaves), they usually will not survive the winter,” says Meehan. “If they do survive the winter, plant vigor (health) is low, and forage production is reduced. Drought stress also affects the survival of fall tillers. Fall droughts either don’t allow buds to come out of dormancy, thus no new tiller growth, or cause death to those tillers that did grow. If tillers do not establish or survive the fall, a delay in growth and development will occur the following growing season, as new tillers will need to develop in the spring.”

Monitoring degree of use is one way to prevent negative effects to tiller development. The recommended utilization level for grasslands is 40%-60%. At this level, rangeland utilization is fairly uniform, with 65%-80% of the height of desirable forage species being grazed. Ranchers should remove livestock when utilization exceeds this level.

An NDSU Extension study found that pasture with greater than 80% forage utilization had delayed forage growth and reduced forage production by as much as 57%. Read more about this study at ndsu.ag/grazinguse.

The North Dakota Grazing Monitoring Stick can aid in monitoring forage utilization on range and pasture. The tool does require an ungrazed area with similar forage species for comparison.

Here are the steps for using the grazing monitoring stick:

1.  Calculate the percent of the plant height removed by dividing the grazed height of the plant by the ungrazed height. Subtract this amount from 1.
2.  Multiply this amount by 100 to determine the percent of height removed.
3.  Correlate this number with those in the chart in the NDSU Extension publication “The North Dakota Grazing Monitoring Stick: A Way to Measure Range and Pasture Utilization” to estimate the percent of entire plant weight removed.

“A general rule of thumb is to target 50% utilization by weight during a grazing period, as well as at the end of the grazing season,” says Kevin Sedivec, NDSU Extension rangeland management specialist. “If greater than 50% utilization occurs during a grazing period, plant recovery will be slower, which means plants require a longer recovery period between grazing events to maintain their health.”

High use of grasslands, especially in the fall, can result in tiller mortality by either removal of the growing point or physiological stress to cool-season grasses. If pastures receive high grazing use, they must be given adequate time to recover, and turnout should be delayed on these pastures in 2024. If pastures are not given time to recover, forage production and pasture condition will decline.

“Monitoring pastures will be especially critical for those currently experiencing drought, as drought stress may increase tiller mortality,” says Sedivec.

Editor’s note: Elizabeth Cronin is an editor for North Dakota State University Agriculture Communications.