Problem

There are some 15,000 feral donkeys on Federal Bureau of Land Management (BLM) and tribal lands in the arid west. Generally referred to as ‘wild burros’, they are exquisitely adapted to harsh arid environments where they out-perform other native species, and cattle that graze on range pasture leases. Stakeholders such as environmentalists, the livestock industry, and wild horse and burro advocates are demanding a sustainable solution to the problem. So far, round-ups and adoptions, plus measures such as castration or vasectomy of males, and immunocontraception of females have not kept up with the number of burros that are born and survive.

In “polygamous species”, such as the wild burro, sterilization of males has not been an effective strategy because even with alpha male sterilization, lower status males will breed receptive females. So, nearly 100 % of males have to be castrated or vasectomized to halt population growth. On the other hand, a surgical solution allowing female sterilization would have some major advantages. Further, much of wild equid social interactions are driven by male competition for mates and leaving males intact maintains natural herd structure. Unlike immunocontraception, surgical procedures, such as tubal ligation, are permanent and do not require repeated gathering of wild herds, with the resultant stress, expense, and danger.

A surgical solution to female sterilization would have some major advantages. The difficulty in doing tubal ligations in wild burros is providing restraint, for anesthesia and positioning. The BLM and others use hydraulic chutes to restrain both mustangs and wild burros and these units have proven to be safe and effective. However, they only hold animals upright or tilt them to lateral recumbency (for hoof trimming). To use a tested, minimally invasive surgery technique (requiring only 3 small incisions of 1 cm each) the patient would have to be tilted into dorsal (on its back). We are searching for an engineering group to design a hydraulic chute that would provide safe, clean, and rapid restraint and positioning for minimally invasive surgery.

The ideal chute would:

• Be well padded with smooth hydraulic controls, because these animals are wild and will struggle violently if given a chance
• Be able to quickly restrain an animal, allowing jugular vein access for anesthesia
• Tilt a 1000 lb. patient onto its back without dropping soil or manure on to the ventral abdomen
• Tilt the patient into the Trendelenburg position (hindquarters and caudal abdomen elevated approximately 45 degrees above horizontal) and hold them there for the procedure
• Gently slide the patient onto a skid for removal to the recovery area
• Do the above quickly with a minimal amount of manual intervention
• Be portable and self contained, as the procedures would be done in remote desert areas

Following design and prototype construction(this could be a scale model), this chute would then be fabricated in full size, tested on cadavers, and then field tested on the Navajo Reservation.