External injury caused by a hook is usually minimal, local abcessation which heals with little or no intervention once the hook has been removed.
Caution should be taken when removing what appears to be a simple hook in skin – they can bleed profusely. Fishing line cause far more extensive injuries by being wound round a limb causing deep wounds which become heavily infected and may even amputated the distal part of the limb.
Hooks caught in the mouth also bleed profusely and cause a fair a mount of bruising but recovery is generally quick after removal. Fishing line is often found caught under the lower beak and can be found by running your finger nail under the birds chin. This should be cut off and gently removed. The line may have embedded itself deeply and the wound may need debrided and cleaned. Unless very severe these problems clear up well.
Line may also get caught round the tongue with the trailing ends being swallowed these can some times be gently pulled up with the bird conscious but generally it is easier if they are anaesthetised. This is also the case for hooks caught at the very back of the mouth adjacent to the top of the oesophagus,(an area we call `the bastard’). It is incredibly difficult to reach from either end and has to be treated on a very individual basis. Hooks caught in the oesophagus show a variety of symptoms ranging from, a small mobile lump, soft tissue swelling and huge bulging necks. A hook which can be felt externally and seen on x-ray may well have been walled off and already disintegrating. Large oesophageal tears may not show a hook on x-ray, the kind fisherman may have already retrieved that hence the large tear.
Beware endoscopy as the oesophagus is voluminous and tears can be missed in the folds.
Once the hook reaches the ventriculous it is ground down and is not a problem. The only time to perform a proventriculotomy is to remove large foreign bodies which will not grind down or will cause a poisoning problem.
Anaesthesia and Oedematomy Swans do not need to be starved before anaesthesia, but in the case of oesophageal problems it is best to supply only water.
- Intravenous drip of Hartmanns solutions with a 22g catheter (24g forcygnets) in the medial tarsal vein. This provides fluids through the operation and makes induction with propofal (Rapinovet; Mallinckrodt Veterinary) at about O.8m1/kg
- Entubate the trachea with an un-cuffed tube held in place on the beak witt tape. Maintain on Isoflurane (usually 2.5 – 4%)
- Place the swan in left lateral incumbency with the keel supported with a wedge to assist respiration.
- Pluck or clip the swelling sparingly.
- Prep as usually.
- Clamp over the incision site with haemostas and then make longitudinal incision. Avian skin bleeds profusely.
- Exercise great care as the normal anatomy may be completely disarrayed, and covered with food.
- Gently remove any food/debris/hook/line and flush area thoroughly.
- It is tempting to strip all solid pus of the area but haemorrhaging is very likely as it becomes entwined with the underlying tissue.
- Identify the oesophageal tear, debride edges and suture using 3/0 silk – continuous simple in the mucosa and continuous inverting in the muscularis.
- Suture the skin with 3/0 chromic gut leaving a gap at each end and fill the subcutaneous area with honey to act as antibacterial and debriding agent.
- Cover with Amoxycillin injection (Clamoxyl LA; Pfizer) continue to apply honey daily.
- Withhold food for 1 hour after anaesthesia and only give soft food such as bread for 2-3 days.
- Allow water access as soon as possible to encourage normal behaviour.
The more severe wounds may break down and need re-suturing.
Swans need to ingest grit and small stones which provide their gizzard with grinding stones to break up their food. To do this they sift mud and silt through their beaks, swallowing the grit. A swan’s long neck allows it to reach further down under water and this is why more swans become lead poisoned than ducks or geese. Geese tend to graze more and so are more at risk of picking up gun shot lead rather than fishermen weights.
If not treated promptly lead poisoning will kill. Legislation was passed banning the smaller sizes of lead fishing weight but there is a huge amount left in riverbanks and floors.
Lead poisoning causes anorexia, which leads to emaciation, anaemia, muscle weakness, bright green droppings and general malaise. The gizzard, a muscle, ceases to function and even if the bird can eat its foodstuffs are not proceed and congeal in the proventriculus and oesophagus.
Clinical symptoms include emaciation, lethargy, bright green droppings and limber neck where the lower part of the neck lays across the birds back.
Blood analysis can be used but some swans have a naturally high lead reading and are not ill. Radiographs of the gizzard and clinical symptoms are a better guide.
Lead shot will appear as radio opaque.
Once x-rayed the swan should be put onto a intravenous drip using a 24g catheter (22g for cygnets) in the medial tarsal vein secured with lots of Elastoplast. This means that if the bird wishes to stand or change position it can and eliminates the need for constant supervision or sedation. 5mls of Edta (sodium calcuim edetate Strong – Animal care) should be added to a litre bag of Hartmanns Solution with 10mls of Duphalyte and 2m1 subcutaneous injections of B 12. The thigh is the best injection site, as it does not bruise as much as the breast.
The intravenous drip should be maintained for 48 hours, with a second bag of fluids and medication running consecutively. A 48 hour break should be taken and then daily subcutaneous injection of Edta and water for injection should be given on a one day on, one day off basis. B12 may be given daily until the appetite has returned.
Post lead poisoned swans very often suffer with absorption and digestive problems and may need to remain in care for a considerable time or possibly be re homed in a safe environment where a good diet can be maintained.It must be remembered that in spells of extreme cold weather swans may appear lead poisoned as the lead laid down in their bones is released, the same may be true of females at breeding time. This is not usually severe enough to require treatment, if it is a one off injection is enough.It used to be common practice to remove the lead from the gizzard surgically. It is now considered too traumatic and surgery on an already debilitated swan is rarely a good idea. The only exception to this is when a large plum weight or sinker has been ingested, in which case it should be removed through the proventriculos not the gizzard and is not something to be under taken lightly.It is better to encourage an extra intake of grit through the bird’s food and drinking to speedily evacuate any metals.
Lead shot or pellets elsewhere in the bird’s body are not considered a lead poisoning hazard.