Wild horses in Nevada enjoy their freedom. The BLM is looking to remove 2500 horse from the Calico area.
The Bureau of Land Management has indicated it intends beginning the muster in the area known as the Calico Complex on December 28.
Wild horse advocates expressed dismay at the decision.
The Equine Welfare Alliance accused the bureau of turning a "tin ear" to public submissions after the department indicated it would sign a "No Impact" decision.
A no impact decision means that the public comments sent to the bureau had not affected their decision to proceed with the round-up.
"This egregious decision further perpetuates the perception that the bureau is managing the wild herds to extinction," the alliance said in a statement.
Alliance president John Holland accused the bureau of operating "in direct opposition" to the 1971 Wild Free Roaming Horse and Burro Act which they are supposed to be implementing.
"This outrageous decision makes a mockery of the whole public comment process," he said.
Wednesday marked the deadline for the public to submit comments for the bureau's National Wild Horse and Burro Advisory Board meeting to be held on December 7.
The alliance accused the bureau of turning a deaf ear to public comment during its last meeting in Washington DC, cutting short many prominent wild horse advocates as they tried to address the board.
It said many of those trying to comment online on Wednesday reported they were unable to do so because the bureau mailbox was full and not accepting new email.
The fate that awaits 2500 wild horses in Nevada. Mustangs at the Palomino Valley National Wild Horse and Burro Center, an adoption and holding facility north of Sparks, Nevada. © BLM
A legal challenge against the Calico muster, which involves five formal herd management areas, has yet to be heard.
It is being mounted by the organisation, In Defense of Animals, and ecologist Craig Downer. The case is scheduled to be heard on December 16.
The cost of the Calico muster has been put at $US900,000.
The Humane Society of the United States has also called for a halt to the Calico muster.
President and chief executive Wayne Pacelle, in a letter he wrote to US Interior Secretary Ken Salazar on November 24, said it appeared the bureau intended to continue with "the same short-sighted management policies and predecures that have led to the current broken programme and fiscal crisis".
He continued: "No single example illustrates the bureau's contradictory impulses more clearly than the gathers the agency has planned for the Calico Complex."
Pacelle urged Salazar to halt the Calico muster to provide time for the humane society to present its new economic model for future wild horse management, which he promised would be cost-effective and humane.