MEDICINE I: DRUGS, DISEASE SURVEILLANCE, AND DISASTERS


Fig. 1. Mud entrapment presents significant challenges to responding equine veterinarians including egress/access, personal safety, interactions with other emergency responders, and field conditions for handling and treatment of the horse(s). Left photo—Initial efforts using the saddle as a pulling point was a good strategy for a pilot line, but the leather failed, and that position on the dia- phragm causes panic in the horse. Right photo—As more responders arrived with ground pads of plywood, a simple forward assist was employed to pull the exhausted horse to solid ground. Note that the head should be lifted to protect the eye; both the head and the tail should not be used as pulling points. Photo courtesy FAFC, Southard, NJ, January 2022.


entrapment requires knowledge of behavior and anat- omy to prevent injury when placing webbing or slings,2 as well as proper personnel positioning (Table 1). Successful responses to mud rescue scenarios are


intimately tied to a practitioner’sexpertise and advice. Every entrapment is different, and thus there is no standard operating procedure that can be applied to ev- ery situation.However, best practices in equine techni- cal rescue do exist for safer, more efficient approaches to these scenarios. (Note: “Best practices” refers to pro- cedures that produce superior results in particular typesofsituationsand constantlyevolve based on knowledge and technology available at the time.) Slides,drags,vertical lifts,and assists are basic to tech- nical large animal emergency rescue—a specialty type of heavy rescue for some fire and rescue emergency response services. Callouts of emergency responders for equine mud entrapment frequently result in a request for a local veterinarian through dispatch at the local 911 center. In this article, it is assumed the veteri- narian is responding (Fig. 2) and wants to proceed with an effective plan for extrication. Example 1: Dr. Erica Koch gets an evening call


from 911 dispatch and the horse owner requesting as- sistance for amud rescue of a horse trapped for several hours about a half mile (1km) from the trailhead (December 2020). She deployed to the parking lot and was assisted by fire/rescue personnel to hike to the actual location of the animal (off trail, laterally recum- bent in thick, wet mud and chunks of ice, getting dark and below freezing temperatures). After providing treatment in situ, the animal was manually manipu- lated with webbing out of themud onto a tarp, and the tarp was dragged to flat ground where the animal stood and walked to the trailhead, where it was loaded into a trailer and delivered to Dr. Koch’s clinic for fol- low-up care (hypothermic and dehydrated). Example 2: The owner was riding along the


Columbia Riverbank, Washington when the horse slipped into the mud (Fig. 3). She called 911 for assis- tance, and they reached out to a local technical large animal emergency rescue (TLAER) team to resp- ond to the location. Meanwhile, the owner discussed


options with the TLAER team leader, who suggested they give the animal room to move and stop pulling on the head. The owner let the horse relax, and it self- extricated a few minutes later before the arrival of deploying first responders.


2. Understanding the Problem


Mud entrapment is fundamentally a small surface area problem. Equines have amuch greater weight on a tiny surface area of their hooves and long legs—like


a large drum walking on toothpicks. Thus, they easily flounder into unstable ground where a human can stand (Fig. 4). Based on the fluid physics, the less an animalmoves,


actually “float” on the surface of most mud environ- ments due to their large lungs and gaseous intestinal production. Upon arrival to the scene, they will tend to have their head and neck and 6 to 12 inches of topline


and hindquarters out of the mud, with their nostrils flaring due to desperate efforts to escape (Fig. 5). Pressure applied to the chest and abdomen of a


horse (especially by mud, also by webbing or slings) causes a physiological response (squeeze or sulk) that minimizes effort to struggle, resulting in diminished efforts by the animal to get up, especially if excite- ment is managed well by the animal handler. This physical “sedative effect” has been utilized by farriers, veterinarians, and horsemen throughout history to cause horses to become quiescent for various proce- dures. However, it is dangerous to personnel when the pressure is relieved; the horse may give an explo- sive effort or reactions—be ready to step back.


AAEP PROCEEDINGS / Vol. 68 / 2022 69


the easier it is to extricate as struggling causes a dewa- tering “vacuum effect,” creating suction around the extremities as the particles of sand and soil pack around them. Since horses do not understand “Stop struggling!” like humans would be ordered to do, dis- traction with hay or grass may be attempted. As they become more exhausted and depressed, horses stop struggling, and their medical condition deteriorates as hypothermia and crush syndrome becomemore likely. Equines do not sink like shown in movies—they


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