The society urged Congressional leaders to support the proposals for wild-horse management proposed by Interior Secretary Ken Salazar. It labelled the plans as more humane and fiscally responsible.
Salazar proposes the release of non-reproducing herds into new preservation areas, using better pastureland further east of the current western rangelands.
Salazar hoped the new herd areas would reduce costs and even provide tourism opportunities for nearby communities.
He proposes balancing population growth rates with adoption demand through greater use of fertility control, strategic manipulation of sex ratios, and the release of non-reproducing herds on to existing herd management areas.
The humane society said its reaction to the plan was one of cautious optimism, and acknowledged its aim was to transform the Bureau of Land Management's current wild horse and burro programme from one that is often inefficient, costly and inhumane to one which is technologically advanced, fiscally sound and more humane.
The society said the immunocontraception vaccine Porcine Zona Pellucida (PZP) had tremendous potential for managing wild horses in an effective, humane and cost-effective manner.
"Peer-reviewed studies have shown that by treating more mares with this drug and returning them to the range, rather than detaining them indefinitely in holding centres, the cost of managing wild horses could be reduced by as much as 14 per cent per year, saving taxpayers more than $6 million annually.
"This promising strategy will enable the agency to finally get off the treadmill of rounding up and warehousing horses, and manage these majestic creatures more efficiently where they belong - on the range - saving millions of tax dollars annually," said Wayne Pacelle, the society's president and chief executive.
"A more humane and fiscally sound programme will be of great benefit not only to our treasured wild horse and burro populations, but also to the American taxpayer."
The bureau's efforts to explore and develop new, innovative ways to manage its wild horse programme come in the wake of controversy after the agency's announcement in June 2008 that it would consider euthanizing or selling for slaughter more than 10,000 wild horses currently housed in federal holding facilities.
The announcement generated public and congressional opposition, and a call for a more progressive, humane one.