Courtesy of Canadian Journal

IN THE SHADOW OF

Wild One shot at a time... BY MARGARET EVANS

Earlier this year, the Governor of New Mexico In recognizing a growing conundrum with increas- announced that he would use stimulus funds to ing herd sizes, overgrazed ranges, and a no-kill purchase 12,142 acres of land known as the policy, he has taken a multi-pronged approach in Ortiz Mountain Ranch adjacent to Cerrillos Hills encouraging the creation of sanctuaries State Park and create a state-owned wild horse in the mid-west and eastern states, the use of fer- The vaccine is sanctuary. tility control, and a more educational approach to While there are a number of environmental, showcasing free-ranging herds to a curious public. administered with a economic, and public input hoops to jump through Wild across North America, from Sable before horses are acquired, likely from the Bureau and Assateague islands on the east coast, to the dart gun and, of Land Management (BLM), now should be a per- western plains of Canada and the USA, are an fect time to look at how these horses are going to iconic feature of the landscape, representing not given in spring, be managed in the longterm to keep their num- just their heritage but an evolutionary ancestry does not interfere bers in check with the available range. It’s an issue that began on this continent 50 million years ago. that has as much relevance to the management of Managing them today, though, requires some with a current wild horse herds in Canada as in the USA. form of population control to keep numbers relative The idea of individual sanctuaries has already to resources and other wildlife communities. pregnancy. been floated by US Interior Secretary Ken Salazar. According to the BLM website, the free-roaming herd

12 www.horsejournals.com • November 2010 Courtesy of Canadian Horse Journal

FACING PAGE: Immunocontraception has just begun being applied to other groups of wild horses. This black and his are from the Pryor Mountain National Wild Horse Range, located on the Montana-Wyoming border.

PHOTO COURTESY OF THE SCIENCE AND CONSERVATION CENTER, ZOOMONTANA

population of 38,400 animals exceeds by 12,000 the Center, ZooMontana, Billings, Montana. ABOVE: PZP, an immunocontracep- number that can be sustained on public lands in ten Along with research colleagues, Kirkpatrick tive administered by a dart gun, western states. Historically round ups, auction sales, developed the fertility program in the late 1980s. has been used to manage the wild and, in more recent years, adoptions have been the When the National Parks Service (NPS) decided to horse population of Assateague standard modus operandi of BLM. But with the manage wild horses on Assateaugue Island (ASIS) Island since 1994. recession there has been a sharp drop in adoptions off the coastline of Maryland, they opted for a or sales of eligible horses, leaving some 34,000 ani- mechanism that was “humane, effective, and pub- mals held off the range in corrals or controlled pas- licly acceptable” to the two million visitors who tures at great expense to the taxpayer. enjoy the horses every year. A better strategy for population control is “They chose the fertility control route and we needed. did the preliminary research from 1988 to 1993 to In the past two decades, fertility control establish safety and effectiveness,” explained (immunocontraception) has proven to be arguably Kirkpatrick. “Then in 1994 the NPS began actual the most effective, the most humane, and the management of the herd with PZP. Their first goal brightest long-term hope for wild horse herds. was to stop growth in the herd which, at that time, “PZP (pig zona pellucida) fertility control in was 175 animals. We did that almost immediately. wild horses has been used successfully for 21 The second goal was to bring the herd to 150 using CLAUDIA NOTZKE, ASSOCIATE PROFESSOR, FACULTY OF MANAGEMENT, UNIVERSITY OF LETHBRIDGE OF MANAGEMENT, PROFESSOR, FACULTY CLAUDIA NOTZKE, ASSOCIATE PHOTO: years,” said Dr. Jay Kirkpatrick, reproductive biolo- only contraception and we did that by somewhere gist and director of The Science and Conservation CONTINUED ON PAGE 14

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November 2010 • Pacific & Prairie Edition 13 Courtesy of Canadian Horse Journal ANA TION CENTER, ZOOMONT A COURTESY OF THE SCIENCE AND PHOTOS CONSERV

ABOVE, LEFT: PZP works by causing a CONTINUED FROM PAGE 13 gather and the process goes on ad infinitum. In mare’s immune system to stop a around 2005. The third goal was to bring the herd contrast, the NPS attacked the problem (at the stallion’s sperm from fertilizing to approximately 100 and we are currently at 116, source). The ASIS herd was stabilized and is head- her egg. It is effective, humane, all without the removal of a single animal.” ing for the goal of 100 animals without the has no side-effects, does not PZP is a vaccine made from a protein in pig removal of animals or the disruption of social impact the herd’s social structure, oocytes (eggs). It stimulates a mare’s immune sys- groups and behaviours. The secondary effects of and is reversible. tem to produce antibodies that prevent a stallion’s the ASIS fertility control management have been sperm fertilizing her egg. The vaccine is adminis- a three times increase in longevity for , decreased mortality, and increased body condition ABOVE, RIGHT: The goal of using tered with a dart gun and, given in spring, does scores. None of that has happened with (horses PZP on the Assateague horses not interfere with a current pregnancy. It has subjected to) gathers and removals.” is to maintain a genetically sound been shown to have no side effects, does not In 2009, BLM conducted not only a gather and population of horses within a safe impact a band’s complex social behaviour, and can be maintained each year with a booster. It is also removal of Pryor horses but also introduced a long- margin. So far, the program has reversible, to bring the mare back into fertility. acting form of the fertility vaccine to 39 mares. The brought the herd from 175 to 116 The ongoing work has been published in peer- round up, though, proved to be extremely unpopu- animals using only contraception. reviewed scientific journals and over the years lar given stress factors, potential for injuries, the every aspect of the herd — population changes, break-up of family bands, and the dispersal of young safety, genetics, behaviour, and reversibility — stock which removed future genes from the herd. has become the most extensive and innovative Currently the BLM is working on an environ- process Kirkpatrick has seen in nearly 40 years in mental assessment which might, in the future, wildlife management and reproduction work. The follow the ASIS plan. Some 17 Pryor mares were core science was aimed at maintaining a genetical- treated in spring 2010. Once the new assessment ly sound population at a level well within the safe has been completed, Kirkpatrick is hopeful that margin of a minimum viable population (MVP) many more mares will be treated with the PZP which, for Assateague, is 48 animals. vaccine in the coming years. The success of immunocontraception as a man- In an economic time when budgets are tight, agement tool in both captive and free-ranging cost and time effective management strategies are wildlife species is widespread. Fertility control is absolutely essential. The success of the PZP pro- used on African elephants, urban deer, Catalina gram has gained worldwide attention and Island bison, Asian macaques, and in a host of zoo enquiries continue to be received from diverse populations around the world. While the management groups looking to start similar fertil- Assateague Island horses became the flagship ity projects to control such populations as New herd back in the early 1990s, the management Forest and Dartmoor in the UK and technique is in play in a wide number of herds Przewalski’s horses in Hungary. across the western states. It is now being applied In the BC Interior, the non-profit organization to the acclaimed Pryor Mountain herd which Critteraid has taken the initiative with their ranges in 31,000 protected acres along the “Project Equus” to offer some unique options to the MontanaWyoming border where they have a simi- Penticton Indian Band to help in the management lar history and structure to the Assateague horses. and population control of their free-ranging horses, According to Kirkpatrick, both herds are his- where animals in poor condition continue to breed toric. The Assateague horses arrived on the island on overgrazed land. In addition to offering a pro- 350 years ago and the Pryor horses have been gram that addresses public safety, sound equine The success of established for at least 200 years. Both have a legal health, sustainable range management, and com- mandate for their existence. They have similar passionate training, they are proposing fertility immunocontraception population variables ranging from 100 to 200 ani- control for approximately 200 horses. Critteraid mals and both pose a threat to their environment, has already underwritten the cost for one individ- as a management tool one being a fragile barrier island and the other ual to receive training from Kirkpatrick in the use being a drought-ravaged upper Sonoran desert. of the dart gun and administration of the vaccine. in both captive and “Gathers and removals of Pryor horses have One shot at a time, wild horses are benefitting been going on since the range’s establishment in from a non-invasive, humane, and controllable free-ranging wildlife 1968,” explained Kirkpatrick. “Because it (a gath- way of keeping their populations in check while er) does not attack the fundamental problem, i.e. their ancestral ranges are managed in sensitive species is widespread. reproduction, the herd simply increases after each and sustainable ways. b

14 www.horsejournals.com • November 2010