PZP in the Pryors

We recommend that the BLM stop their failed PZP program that has promoted out-of-season births, abscessing, permanent lumps and bleeding on mares. The majority of young mares receiving the drug have never foaled or foaled out-of-season (September-December). The majority of older mares have foaled regardless of field darting, experiencing long term and short-term trauma. Ironically, the initial stated reason for the administration of PZP by BLM was “purely from the standpoint of compassionate use” and “to prolong the life of the older mares”. But it has not proven to be a humane management tool and BLM now complains of “too many older horses”.

Some facts:

• Nearly 50% of the young mares receiving the drug in the years 2001-2004 have never foaled. Of the 34 young mares to receive the drug between 2001-2004, 11 have died, 13 have foaled and 12 have not foaled.

• Of the 13 young mares that have foaled, five foals have been born out of season. One foal born in September 2005 never grew to full-size and was subsequently bait trapped and adopted out in September 2006. Another foal, born to a mare darted as a yearling and two-year-old in 2003 and 2004, was born in December of 2006. Two seven year-old mares given PZP as one and two year-olds, foaled for the first time in September of 2007. (The majority of Pryor Mountain mares foal from May 15-June 15).

• Administration of PZP was stopped on younger mares in 2005 due to a natural decrease in population because of mountain lion predation, and the unexpected absence of foal production by the young mares.

• Of 21 older mares (11 years of age and older) given PZP beginning in 2003, 12 mares have foaled in spite of the field darting with PZP. Only nine mares have not foaled (drug worked as designed). One mare produced a foal at the age of 21 in 2007.

• Aside from the cruelty of raising a newborn foal going into a Montana winter, the drug has had other negative side effects in the form of abscesses, bleeding, and swelling on the hips of field darted mares. Of the 54 mares listed on the PMWHR Injection and Reaction Observations –updated June 2007 (BLM-03262), 41 mares are listed with swelling, nodules, bleeding or a combination of all these. 20 mares still have visible signs of nodules even years after they were injected.

• To our knowledge this is the only herd in the West to receive PZP via field darts (Assateague Island off the coast of Virginia uses field darts with few reported problems).

• The stated goal of the scientific community regarding an ideal wild horse fertility control agent was that it should be “at least 90% effective” (Wild Horse Contraceptive Research document, 1991 USGS website, posted 2-21-06). The PZP program in the Pryors has fallen far short of this goal.

phoenix • Cloud’s mother had an abscess appear on a dart injection site in June of 2007. This wound grew to encompass an area over most of her left hip all the way to her tail setting. BLM removed she and her foal and put them in the Britton Springs Corrals at the base of the mountain for several weeks for treatment. The mare lost significant weight while away from her family band and was thin upon her release. The wound healed but Cloud’s mother did not pick up weight going into winter and is very thin. Her situation now is life threatening in our opinion. We hope her strong will and her family will help her survive.