The Bureau of Land Management wants to remove up to 2700 wild horses from the five formal herd management areas that make up the complex.
The scale of the muster has angered wild horse advocates, who argue it is cruel and unnecessary. The bureau counters that the horses need to be removed to maintain a healthy ecological balance in the area.
The latest information from the bureau shows that 1878 horses have so far been removed, with 1744 of them shipped to short-term holding facilities at Fallon.
To date, 28 horses have died or been euthanized during the muster.
Veterinarian Richard Sanford said in a report that 18 of those horses had died or were euthanized as acts of mercy because they were not adapting to being fed grass hay in a domestic setting.
These horses ranged in age from 12 to 20 years and were losing condition, he said.
"These horses came off the range in poor condition and were most likely eating brush (woody shrubs) because of the lack of preferred grass forage on overgrazed rangelands.
"Upon arrival horses are fed a mixture of grass hays - some orchard grass, some rye grass.
"Most horses adapt well to this ration." he said. "It is as close to a diet of range grass as any hay that we can find.
"A small percentage of horses do not make the transition from range forage, especially if they have been eating brush, to a domestic diet of hay, but most make the transition without serious complications.
"The few horses that have not adapted to this domestic ration are primarily older, poor body condition pregnant females."
He said the horses that have trouble adapting to feed typically show a lack of appetite, loose manure, weight loss and pregnancy loss.