The cost ranchers pay for their animals to graze on federal land will drop by nearly 25 percent in 2018, the Bureau of Land Management announced Tuesday.

Beginning on March 1, the federal grazing fee for 2018 will be $1.41 per animal unit month, a unit of measurement that refers to the use of public land by one cow and her calf, one horse, or five sheep or goats for a month, according to a news release from the BLM. In 2017, the fee was $1.87 per animal unit month, a 24.6 percent decline year-over-year.

The fee applies to around 18,000 grazing permits and leases administered by the BLM, and nearly 6,500 permits administered by the U.S. Forest Service across 16 western states, including Oregon, according to the release.

The index on which the fee is based, which was created when Congress passed the Public Rangelands Improvement Act in 1978, is calculated each year based on grazing rates on private land, beef cattle prices and the cost of livestock production. It cannot rise or fall by more than 25 percent each year, according to the release.