TECHNIQUE

Medical Management of Cranes in Slings (Disease Investigation & Management - Treatment and Care)

Crane in a sling. Click here for full-page view with caption. Chick in sling. Click here for full-page view with caption. Chick with hobbles in sling. Click here for full-page view with caption. Chcik with hobbles and snowshoes in sling. Click here for full-page view with caption.

Summary Information
Type of technique Health & Management / Disease Investigation & Management / Techniques:
Synonyms and Keywords --
Description Cranes and other long-legged birds may be maintained in a sling in the event of injury or disease which prevents them from standing unaided.
Make the sling
  • The sling is made from an appropriate material such as soft cotton canvas (see below: Equipment). (P138.18.w1)
  • The size will vary depending on the size of the crane. For an adult crane, 4 - 7 kg, the starting material should be about 55 cm from front to back and 75 cm long from side to side.
  • Preferably measure the material against the crane before cutting any holes. (P138.18.w1)
  • Cut leg holes about 7 cm wide, 10 cm long, about 4-5 cm apart in the middle of the material. (P138.18.w1)
    • Make sure these are sufficiently large that they do not cause constriction around the legs. (P138.18.w1)
    • Make sure the distance between holes is not so small as to reduce the strength of the material but not so large that it will bunch up underneath the crane, between its legs. (P138.18.w1)
  • Cut a hole for the vent, about the same size as the leg holes. (P138.18.w1)
    • This should be large enough that it will be effective allowing for shifts in body position by the crane. (P138.18.w1)
    • Ensure that there is at least 8-9 cm of material between the back edge of the vent hole and the edge of the material, so that it retains good strength. (P138.18.w1)
  • Wing holes have sometimes been used; these are a bit larger than the leg holes and are in front of and slightly lateral to the leg holes.  If used, make sure these are sufficiently large that they do not cause constriction around the wings. (P138.18.w1)
  • Consider incorporating padding material to reduce the risk of development of pressure sores. (P138.18.w1)
  • Make sure the whole of the crane's keel will sit in the sling to provide security and ensure the crane will not fall out, forwards. (P138.18.w1)
  • Attach a band of cloth, 20-25 cm wide (for adult cranes) across the back of the crane, fitting snugly over the back and wings, but not tight enough to constrict breathing. (P138.18.w1)
    • Attach this to the sides of the sling using either tape-covered safety pins or by using two shorter strips, each attached firmly to one side of the sling and attaching to each other using several wide strips of Velcro (Velco makes it easier to remove this strip and lift the crane out when necessary, and is safer (no hazard associated with pins). (P138.18.w1)
  • Preferably make TWO slings, allowing one to be used while the other is washed when soiled with faeces or blood. (P138.18.w1)

Make a frame and suspend the sling
  • Make a frame, 1 x 1.5 m, preferably movable (on wheels). (P138.18.w1)
    • PVC water pipes are appropriate for constructing the frame. (B703.10.w10)
    • With a moveable frame the crane can be moved outside into more natural surroundings when practical, providing exposure to stimuli such as the weather and (if appropriate) conspecifics. (P138.18.w1)
  • Attach the four corners of the sling to the corners of the frame. (P138.18.w1)
  • Small link chain allows for easy adjustment of the height of the sling; the number of links can be counted and marked for replication. (P138.18.w1)
  • Pad edges and hard surfaces with towel/ layers of duct tape to reduce the risk of injury if the crane kicks its legs. (P138.18.w1)
  • An alternative option is to attach the four corners of the sling to a hook above the crane;  (P138.18.w1)
    • this enables rotational movement, but continuous rotation one direction may occur with resultant "winding up" of the sling (increasing tightness and height). (P138.18.w1)
    • It is more difficult to take the crane out of the sling. (P138.18.w1)
Position the crane in the sling
  • Position the crane so that the thoracic inlet is slightly higher than the tail: this is the case normally when the cane is standin; it also helps prevent the crane from falling forwards out of the sling. (P138.18.w1)
  • Use a back strap to help prevent the crane from falling out of the sling backwards. (P138.18.w1)
  • If weight bearing is desirable, position the sling in the frame such that when the crane's full weight is in the sling the toes touch the ground with the legs slightly flexed. (P138.18.w1)
  • Monitor the leg (and if appropriate, wing) holes closely to make sure they are not placing pressure on the limb vessels or nerves. (P138.18.w1)
  • Monitor all areas of the crane touching the sling for pressure sores, particularly around the keel, and where the limbs pass through the material. (P138.18.w1)
    • Padding can be added if necessary. (P138.18.w1)
  • Monitor the crane to ensure that does not injure itself (e.g. banging limbs against objects, friction with the edges of the sling material round the limbs resulting in wounds) (P138.18.w1)
  • If necessary, initially give small doses of a tranquilliser, e.g. 0.5 mg/kg diazepam. (B703.10.w10)
General maintenance
  • Remove/cover or pad all long or sharp objects (loose strings, safety pins etc.) or holes/gaps which the crane could swallow, impale itself on or or tangle itself in. (P138.18.w1)
  • Place food and water containers on a low bench in front of the crane, at a height such that the crane can reach them. (P138.18.w1)
    • Secure the containers so they cannot be tipped over. (P138.18.w1)
    • Make sure there is no part of the containers which the bird could injure itself on/with. (P138.18.w1)
  • Entice the crane to eat, e.g. using mealworms on the feed, earthworms in a container of soil or sand. (P138.18.w1)
  • Tube (gavage)  feed as necessary: many cranes refuse to eat or drink while in a sling.
  • Consider providing "toys" with which the crane can interact - ensure these are safe. (P138.18.w1)
  • Provide other cranes or non-threatening animals for company, as appropriate. (P138.18.w1)
Physical therapy
  • Physical therapy is important. (P138.18.w1)
  • In a Mississippi sandhill crane, the following regimen was applied:
    • Post fixation (intramedullary pin and cerclage wire to stabilise an oblique fracture of the right femur, mid-diaphysis), the crane was placed in a sling. Five days later it escaped from the sling during the night and fractured the left distal radius and ulna; these fractures were reduced and an intramedullary pin and cerclage wire used to stabilise the ulna, followed by application of a figure-of eight bandage.
    • By a week after the second surgery, the crane showed severe bilateral paresis of the legs, uncoordinated leg muscle movements and moderate bilateral contraction of the digital flexor muscles; there was evident disuse atrophy of the pelvic limb muscles, with hyperextension of the hocks and hyperflexion of the digits. The crane was unable to support its body weight or to ambulate
    • Passive range of motion exercises were started 3 - 4 times a day on all leg joints from hips to toes to stretch the contacted muscles.
    • Twice daily, the sling plus crane was lifted from the support frame and the crane was "hand-walked" for 30 minutes at a time.
    • After seven days, improved coordination was apparent, although not of muscle strength.
    • Sling-walking was continued and hydrotherapy added in the second week, in a solar-heated 1 metre deep pool: the crane was "walked" to the pool in the sling, then suspended with its legs submerged in the water for 15-20 minutes two to three times a day, with the crane kicking against the resistance of the water during this period. Additionally, the crane was repeatedly lowered further into the water to standing in the pool and supported to walk through the pool.
    • In the third week, brief hand-assisted walks were introduced with the crane not in the sling.
    • In week four, a nylon dog harness was fitted for support during assisted walking sessions (rather than using the sling), enabling increased freedom of movement such as hock sitting. The harness was also used for the hydrotherapy sessions. Each day the duration of exercise sessions was increased by 15 minutes.
    • At four weeks from initial surgery, with radiographic evidence of excellent callus formation on the femur, the intramedullary pin was removed from the femur. At four weeks from the wing surgery date, radiographic evidence of satisfactory healing of the radius and ulna enabled removal of the intramedullary pin from the ulna.
    • When the figure-of-eight bandage was removed, considerable muscle contracture was present in the wing; passive range of motion exercises, both flexion and extension, were initiated at each wing joint.
    • By the fifth week, the crane had regained enough musculoskeletal strength and endurance to be engaging in 12 hours a day of walking and pool exercises with only partial support via the harness; the crane was returned to the sling support at night. "Tail tugs" were used to improve muscular strength: for 1-2 minutes, repeated five times within a 515-miute period, the tail feathers were grasped gently, near the base of the feathers, as the bird tried to walk away against this resistance; this made the bird press its feet firmly against the ground while contracting the leg muscles, stimulating muscle development.
    • In the sixth week the use of the sling was discontinued and the crane was allowed unrestricted pen exercise. At this stage the crane still could not rise from sternal recumbency without assistance, therefore 24-hour monitoring and the harness were used to assist rising as needed.
    • In the seventh week the crane became able to stand up from sternal recumbency without assistance; 24-hour monitoring was continued, but use of the harness stopped and the crane was allowed unrestricted pen exercise
    • In the eighth week the crane became fully independent and was able to return to its usual pen.
    • It was noted that more frequent wing bandage changes and physical therapy starting earlier might have prevented the permanent contracture of wing muscles which led to inability to completely extend the affected wing.
    • By one year after the injury, the crane was showing normal physical and behavioural characteristics.
Appropriate Use (?)
  • For the management of cranes (and other long-legged birds) with leg injuries or debilitating disease which is preventing them from standing. Maintaining cranes in a standing position if possible is preferable because: (P138.18.w1)
    • Cranes in sternal recumbency are unlikely to eat. (P138.18.w1)
    • Individuals in sternal recumbency due to an injury may flail around and further injure themselves. (P138.18.w1)
    • Being in a more normal physical posture (i.e. in a sling rather than recumbent) may assist the crane's mental outlook and improve the cranes desire to recover. (P138.18.w1)
    • Treatments such as injections and gavage (tube) feeding can be carried out by a single person. (P138.18.w1)
    • Circulation can be improved without time-consuming repeated lifting and exercise every few hours (cranes left in sternal recumbency can develop circulatory compromise without such treatment). (P138.18.w1)
    • Cranes properly positioned in a sling may be able to carry out some of their own physical therapy by kicking their legs or pushing away from the ground with their legs. (P138.18.w1)
Notes --
Complications/ Limitations / Risk
  • Complications can include anorexia and the development of pressure sores in addition to disuse atrophy of the muscles. (P138.18.w1)
  • Being in a sling is an additional potential stressor for the crane: this is an unfamiliar structure and limits the crane's movement, both of which the crane may find stressful. (P138.18.w1)
    • The psychological response of a crane to slinging varies depending on the crane's individual personality, rearing method and degree of illness. (P138.18.w1)
    • Use of sedative drugs such as diazepam can reduce stress on a crane in a sling. (P138.18.w1)
    • There is a risk of hyperthermia if e.g. a heat lamp is being used. (P138.18.w1)
Equipment / Chemicals required and Suppliers
  • Appropriate sling material. A soft cotton canvas is preferred. This maintains its shape well, will not contribute to development of hyperthermia, and is less likely to cause constriction around the legs than many other fabrics. (P138.18.w1)

    • For chicks and small adults terry cloth towels can be used. However this material may stretch and therefore lose shape. (P138.18.w1)

    • Synthetic sheepskin has been used, but the edges of this can be rough around the leg and wing holes, requiring cushioning. (P138.18.w1)

Expertise level / Ease of Use This procedure should be carried out by an individual with appropriate training and practical experience.
Cost/ Availability
  • Costs of the materials to construct a sling and frame; this should not be particularly expensive.
  • Costs, particularly staff time, to manage the crane while it is in the sling.
Legal and Ethical Considerations Inappropriate use or poor application of this technique may cause further suffering to the bird and have implications under animal welfare legislation.
Author Debra Bourne MA VetMB PhD MRCVS (V.w5)
Referee  
References P138.18.w1, B703.10.w10

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