EQUINE | Equine Disease Quarterly
37,000 animals in 33 off-range pastures. The pastures,
located in the Midwest and Western US, each house
between 200 and 3,000 horses under federal contracts
between the private landowners and the BLM. While
no reproduction occurs on these pastures, the BLM still
pays for the animal’s care and feeding in these semi-
free-roaming environments.
When the Wild Free Roaming Horses and Burros Act
(the Act) was passed in 1971 and amended in 2005,
it instructed BLM to maintain equid populations in
balance with other uses of the range such as wildlife
management, recreational use, livestock grazing, and
mineral, oil, and gas extraction. Toward this end, the
Bureau determined that the appropriate population
size on the range should be about 27,000 animals.
The animals that exceed this target number (currently
about 55,000) can be considered excess along with the
49,000 animals already in BLM corrals and pastures. The
Act as originally written directs the BLM to offer the
excess animals for adoption and sale without limitation
followed by the humane destruction for the remaining
excess animals. However, in the annual budget provided
to BLM since the 1980s, Congress has prohibited the
BLM from euthanizing healthy animals or selling animals
in a manner that may lead them to being processed
for commercial use (i.e. slaughter). This leaves the BLM
in the position of having to feed and care for about
50,000 excess animals off-range, which literally “eats
up” almost two-thirds of the program’s $80M budget.
Another 55,000 excess animals struggle to survive on
public rangelands that exceed population targets and
are often overgrazed.
To address population growth rates and excess numbers
on the range, the BLM has supported the development
of contraceptives for wild horses and burros since the
1980s. A couple of contraceptive products (porcine
zona pellucida and GnRH vaccines) work well to prevent
mares from conceiving if given annually or boostered
24
following the initial vaccination. This approach can work
well on smaller herds where animals can be individually
identified and approached for darting. Unfortunately,
repeatedly catching the animals for treatment just
isn’t practical. Most wild horses and burros on BLM
rangelands can’t be approached within half a mile, let
alone the 20-60 yards needed for darting. Longer lasting
contraceptives have not proven reliable in larger field
trials. Recent efforts to spay mares in the context of a
field research/ feasibility project have been stopped by
litigation from wild horse advocacy groups.
The dilemma is clear: excess wild horses and burros on
western rangelands and in BLM corrals and holding
pastures. The numbers exceed those that can be placed
into long-term homes, albeit with restrictions on what
new owners can do with the animals, through adoptions
and sales. The solutions are anything but straight-
forward. BLM continues to explore better, longer lasting,
and permanent methods of contraception to control
population growth rates. They also continue to try to
find new ways to encourage adoption and placement of
excess animals into private long-term homes. Ultimately,
the direction forward depends on the program’s budget
and the policy provided by Congress as they work to
address the realities of the situation and wishes of the
public.
CONTACT
Albert J Kane, DVM, MPVM, PhD
[email protected]
(970) 494-7234
Advisor, APHIS/BLM WH&B Partnership
USDA APHIS Veterinary Services
Fort Collins, CO
The information, ideas, and opinions expressed are those of
the author and do not necessarily represent those of the Unit-
ed States Departments of Agriculture or Interior.
• Equine Health Update •