Free Standard AU & NZ Shipping For All Book Orders Over $80!
Register      Login
Wildlife Research Wildlife Research Society
Ecology, management and conservation in natural and modified habitats
Shopping Cart: ( empty )
You are here: Home > Journals > WR > WR07106 > Fulltext
RESEARCH ARTICLE
Contents Vol 35(6)

Achieving population goals in a long-lived wildlife species (Equus caballus) with contraception

Jay F. Kirkpatrick A C and Allison Turner B
+ Author Affiliations
- Author Affiliations

A The Science and Conservation Center, 2100 South Shiloh Road, Billings, MT 59106, USA.

B Assateague Island National Seashore, Berlin, MD 21811, USA.

C Corresponding author. Email: zoolab@wtp.net

Wildlife Research 35(6) 513-519 https://doi.org/10.1071/WR07106
Submitted: 28 July 2007  Accepted: 2 May 2008   Published: 22 October 2008

Abstract

The ultimate goal of any wildlife contraceptive effort is some alteration of the target population, either through a slowing of growth, or stabilisation or reduction of the population. Early population models suggested that short-term contraceptive agents applied to long-lived species would not achieve significant population changes. Native porcine zona pellucida antigen (PZP), a short-term contraceptive vaccine, was applied to a herd of wild horses inhabiting Assateague Island National Seashore, MD, USA, over a 13-year period, with an immediate goal of achieving zero population growth, a secondary goal of reducing the population from 175 to 150 and a tertiary goal of reaching 120 individuals, all without the physical removal of animals. Contraceptive efficacy ranged from 92 to 100% on an annual basis (96.28 ± 2.49%), and the percentage of adult females that was treated on any given year ranged from 42 to 76% (67.78 ± 18.21%). The goal of zero population growth was achieved in 2 years, an initial decline in the population became apparent in 8 years and by Year 11, the population declined to 135, a decrease of 22.8%. The lengthy period required for achieving a population decline was caused by increasing body condition scores, reduced mortality and significantly increased longevity among treated females.

Additional keywords: equids, fertility control, horses, immunocontraception, population, zona pellucida.


Acknowledgements

This study was funded by Assateague Island National Seashore, The Science and Conservation Center, National Park Service Grant CA-1600–30005, and National Institute of Health Grant 1 R15 HDZ6898–01A1. Special thanks is extended to J. Karish, J. Kumar, B. Rodgers, G. Olson, L. Points and C. Zimmerman of the National Park Service.


References

Asa C. A. (2005). Assessing efficacy and reversibility. In ‘Wildlife Contraception: Issues, Methods and Applications’. (Eds C. A. Asa and I. Porton.) pp. 53–65. (Johns Hopkins University Press; Baltimore, MD.)

Cameron E. Z. , Linklater W. L. , Minot E. O. , and Stafford K. J. (2001). Population dynamics 1994–1998 and management of Kaimaniwa wild horses. (Ed. J. Jasperse.) Science and Research Unit, Science, Technology and Information Services, Department of Conservation, Wellington, New Zealand.

Conservation Breeding Specialist Group (2006). Horses of Assateague Island population and habitat viability assessment. Final report. IUCN/SCC CBSG, Apple Valley, MN.

Cooper, D. W. , and Larsen, E. (2006). Immunocontraception of mammalian wildlife: ecological and immunogenetic issues. Reproduction 132, 821–828.
| Crossref | GoogleScholarGoogle Scholar | CAS | PubMed | Eggert L. S. , Maldonado J. E. , Fleischer R. C. , Powell D. M. , and Ballou J. (2005). An assessmenr of the genetic status of the feral horse population of Assateague Island National Seashore. Final report to the National Park Service. (Assateague Island National Seashore, Berlin, MD.)

Feist, J. D. , and McCullough, D. R. (1975). Reproduction in feral horses. Journal of Reproduction and Fertility 238(Suppl.), 13–18.
Garrott R. A. (1997). A preliminary investigation of the potential effects of reproductive inhibition as a means of controlling feral horse populations. In ‘Contraception in Wildlife’. (Eds P. N. Cohn, E. D. Plotka and U. S. Seal.) pp. 243–254. (Edward Mellon Press: Lewiston, NY.)

Garrott, R. A. , and Siniff, D. B. (1992). Limitations of male-oriented contraception for controlling feral horse populations. Journal of Wildlife Management 56, 456–464.
| Crossref | GoogleScholarGoogle Scholar | Goodloe R. B. , Warren R. J. , and Sharp D. C. (1997). Immunosterilisation of feral and captive horses: a preliminary report. In ‘Contraception in Wildlife’. (Eds P. N. Cohn, E. D. Plotka and U. S. Seal.) pp. 243–254. (Edward Mellon Press: Lewiston, NY.)

Greger, P. D. , and Romney, E. M. (1999). High foal mortality limits growth of a desert feral horse population in Nevada. The Great Basin Naturalist 59, 374–379.
Killian G. , Miller L. A. , Diehl N. K. , Rhyan J. , and Thain D. (2004). Evaluation of three contraceptive approaches for population control of wild horses. In ‘Proceedings of the 21st Vertebrate Pest Conference’. pp. 263–268. (University of California, Davis: Davis, CA.)

Kirkpatrick J. F. (1995). Management of wild horses by fertility control: the Assateague Experience. Scientific Monograph 95/26. (National Park Service, U.S. Department of the Interior: Washington, DC.)

Kirkpatrick, J. F. , and Turner, A. (2007). Immunocontraception and increased longevity in equids. Zoo Biology 25, 1–8.
Kirkpatrick J. F. , Naugle R. , Liu I. K. M. , Bernoco M. , and Turner J. W. (1995). Effects of seven consecutive years of porcine zona pellucida contraception on ovarian function in feral horses. Biology of Reproduction Monograph I, Equine Reproduction VI, pp. 411–418.

Linklater, W. L. , Cameron, E. Z. , Minot, E. O. , and Stafford, K. J. (2004). Feral horse demography and population growth in the Kaimanawa Ranges, New Zealand. Wildlife Research 31, 119–128.
| Crossref | GoogleScholarGoogle Scholar | McCullough D. R. (1997). Demography and management of wild populations by reproductive intervention. In ‘Contraception in Wildlife’. (Eds P. N. Cohn, E. D. Plotka and U. S. Seal.) pp. 119–132. (Edward Mellon Press: Lewiston, NY.)

National Research Council/National Academy of Sciences (NAS) (1982). Wild and free-roaming horses and burros: current knowledge and recommended research. (Bureau of Land Management, US Department of Interior: Washington, DC.)

Nettles, V. F. (1997). Potential consequences and problems with wildlife contraceptives. Reproduction, Fertility and Development 9, 137–144.
| Crossref | GoogleScholarGoogle Scholar | CAS | Perkins A. , Gevers E. , Turner J. W. , and Kirkpatrick J. F. (1979). Age characteristics of feral horses in Montana. In ‘Symposium on the Ecology and Behavior of Wild and Feral Equids’. (Ed. R. Denniston.) pp. 51–58. (University of Wyoming: Laramie, WY.)

Plotka, E. D. , Eagle, T. C. , Vevea, D. N. , Koller, A. L. , Siniff, D. , Tester, J. R. , and Seal, U. S. (1988). Effects of hormones implants on estrus and ovulation in feral mares. Journal of Wildlife Diseases 24, 507–514.
|  CAS | PubMed | Stafford K. J. , Minot E. O. , Linklater W. L. , Cameron E. Z. , and Todd S. E. (2001). Use of an immunocontraceptive vaccine in feral Kaimaniwa mares. Conservation Advisory Science Notes 330. (Department of Conservation: Wellington.)

Turner, J. W. , and Kirkpatrick, J. F. (1983). Steroids, behavior and fertility control in feral stallions in the field. Journal of Reproduction and Fertility. Supplement 32, 79–87.


Turner, J. W. , Liu, I. K. M. , Rutberg, A. T. , and Kirkpatrick, J. F. (1997). Immunocontraception limits foal production in free-roaming feral horses in Nevada. The Journal of Wildlife Management 61, 873–880.
| Crossref | GoogleScholarGoogle Scholar |

Turner, J. W. , Liu, I. K. M. , Flanagan, D. R. , Rutberg, A. T. , and Kirkpatrick, J. F. (2001). Immunocontraception of feral horses: a single-inoculation vaccine provides one year of infertility. The Journal of Wildlife Management 65, 235–241.
| Crossref | GoogleScholarGoogle Scholar |

Turner, J. W. , Liu, I. K. M. , Flanagan, D. R. , Bynum, K. S. , and Rutberg, A. T. (2002). Porcine zona pellucida (PZP) immunocontraception of wild horses (Equus caballus) in Nevada: a 10 year study. Reproduction 60(Suppl.), 177–186.
|  CAS | PubMed |

Willis, P. , Heusner, G. L. , Warren, R. J. , Kessler, D. , and Fayrer-Hosken, R. A. (1994). Equine immunocontraception using porcine zona pellucida: a new method for remote delivery and characterisation of the immune response. Journal of Equine Veterinary Science 14, 364–370.
| Crossref | GoogleScholarGoogle Scholar |