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For tortoise, terrapin and turtle care and conservation

CARAPACE AND OTHER BONE INJURIES IN CHELONIANS

OLIPHANT F. JACKSON, Ph.D., M.R.C.V.S.

Over the last ten years I have seen a number of carapace injuries and can divide them into those due to trauma and those caused by a nutritionally defective diet. The latter far outnumber the former.

It seems that people do not appear to recognise the dangers that exist for their tortoises and terrapins. There are tortoises that fall off balconies onto paving slabs many feet below, tortoises (and I think here of several box tortoises) that are chewed like bones by the owner's dog, those chelonians that bury themselves under piles of brushwood that the owner sets alight in early summer when they decide to have a bonfire, those damaged by the blades of modern mowing machines with horizontally rotating blades, the hover mowers, when these are used to clear thick overgrown grass, the struggling terrapin that locks itself free from the hands that are carrying it, let alone those chelonians that are allowed to be near parked cars and are run over.

All the above, with the exception of the bonfire case, which will be a burn, cause part of the skeleton of the 'bony box' to be fractured. This may involved limb bones, the plastron, the 'bridges' along the sides or the carapace; or sometimes several of them together.

Many years ago when I lived in Northern Rhodesia I was in charge of the Ndola snake park and looked after the other animals. One of these was a very large Leopard Tortoise (Geochelone pardalis) that was allowed to roam freely round the small zoological collection. One day in the heat of midday it was sheltering from the heat of the sun under a staff car in the zoo. When the owner drove off the back wheel fractured the carapace making a wide crack This was one of the worst fractures that I have ever had to deal with in a chelonian. In order to hold the crack together I had to insert six long stainless steel orthopaedic screws across from one side of the fracture to the other.

The tortoise that fell off the balcony onto paving slabs fractured its plastron transversely across both humeral shields. This was a bad site for a fracture as the very strong pectoral muscles, that are such an integral part of the muscles of the fore legs, are inserted into the whole of this area of the shell. This made the fracture move at each inspiration and the wound would not stop bleeding because of this movement. In order to immobilise it four stainless steel orthopaedic screws were inserted vertically upwards into the plastron, two in front of the fracture and two behind, these were then bridged across with fibreglass and epoxy resin in order to immobilise the break. Other smaller fractures can now be easily bridged with these modern epoxy resins. One of the additional problems in terrapins is how to make sure that the whole area will remain totally waterproof. In Utrecht they advocate sealing it with silicone sealant as used in aquaria. I find this makes a very sticky surface and instead I use UHU all purpose clear adhesive.

All of these procedures have to be carried out under a general anaesthetic and the comminuted fractures of the carapace caused by hover mowers can take hours of work to clean up, lifting the small fragments of bone out of the lung, which lies immediately under the dome of the carapace, mending the lung and then creating a new dome before, once again, covering it with an epoxy resin.

When the carapace is burnt, either in a bonfire or, as happens in the Mediterranean countries, in a grass fire, the keratin shield and some of the bone underneath the shields is killed. It takes several weeks before the shields begin to curl up, and when they are removed the dead grey bone is exposed. At the edges of the burn the live bone bleeds if the keratin is removed so this is one way of knowing the extent of the burn. The separation of the dead bone from the live bone beneath it takes many months depending on the depth of the burn, the temperature of our summer and the metabolic rate of the tortoise. If a tortoise is allowed to hibernate all healing processes stop and full healing of such a burn will take about two years in the U.K. If you want to help the healing then the tortoise must not be hibernated but be kept warm and fed throughout the winter. Then healing will occur in only eleven months!

Another terrapin with a fractured humerus on one foreleg posed a problem. How was I to immobilise the bone? Plaster of Paris was out of the question and in any case the humerus of a chelonian is a very curved bone and almost impossible to encompass in anything. I hit on the answer of how to put the foreleg into a form of sling. I folded the foreleg into the bodv under the marginal shields and, by putting firm strapping round plastron and carapace on a diagonal, found that I was able to hold the leg immobile. The terrapin. being a male, soon learnt how to swim and feed with only three functional legs. Now I will be accused of having a sex prejudice I suppose!

Now for the horror of the nutritionally induced defects of bone in chelonians known as Nutritional Osteodystrophy. As in so many species of reptile there is a tremendous demand for calcium, vitamins A and D during the early growth period. Most of the diets offered to hatchling tortoises and baby terrapins are rich in phosphorus and low in calcium, and deficient in vitamins. With hatchling tortoises the feeding of lush young greenstuff, rich in vegetable protein, is an added problem as it produces excessive growth of keratin in the shields.

The signs of nutritional osteodystrophy differ between tortoises and terrapins so I will deal with them separately.

The disease in hatchling tortoises is seen as:-

  1. raised shields (scutes) on the carapace which start as merely slightly raised lumps and then may increase to make each one conical.
  2. the shell as a whole appears undersized for the tortoise.
  3. the hatchling is unable to take its own weight on its legs, the hind legs are bent upwards at the knee joint and held out backwards at an angle.
  4. the nails are very long because of the lack of wear since they are not in contact with the ground.
  5. the beak is overgrown.
  6. the plastron is often still soft and pliable.
  7. when X-rays are taken the abnormal thickness and texture of the bone of both carapace and plastron is diagnostic.

In terrapins the most common finding is that of' soft shell with both plastron and carapace being easily depressed under finger pressure. In long standing cases there is often considerable distortion to the contour of the shell. The bone in some cases is so decalcified that it proves impossible to see any bone shadow on an X-ray. The lung areas are very small, which makes it very difficult for the terrapin to swim. This condition takes about two years of incorrect feeding to manifest itself and one of the complaints is that the terrapin no longer swims but spends almost all of the time out of water. It always amazes me that the owners are completely ignorant of the fact that they have caused this damage as, almost without fail, they say that they have been feeding it correctly on mince, or turtle food every since they bought it.

This condition should never be allowed to occur and all efforts must be made to teach people how to feed their reptiles property from the start The treatment of both depends on correcting the diet In the case of tortoises the addition of a suitable vitamin/mineral supplement such as Vionate (CibaGeigy)* to each and every meal is essential. This not only brings the calcium to phosphorus ratio to 1.2:1 or 1.5:1 but also adds the extra essential trace minerals and all the vitamins. (At this point I must make it clear that SA 37 is not an efficient supplement for chelonia). It is also advisable to feed a much wider variety of foods and I cannot do more than tell people to read and follow the good advice in Henny Fenwick's book on taking care of your tortoise. Terrapins should all be fed on whole fresh fish, such as spratts, sardines, herring, whitebait; varied with earthworms, small crustaceans, prawns or shrimps, and shellfish like water snails, whelks or mussels. It is difficult to get Vionate into terrapins as it floats off the food when this is placed in water, one technique that I have found helps is to cut open the belly of the fish, put a fine sprinkling of Vionate into the cut and then close it together.

REFERENCE

Fenwick, H. (no date). Taking Care of Your Pet Tortoise, Cambridge. Published by the author.

* Vionate has a safe shelf life from the date of manufacture of 2 years if stored correctly.
Two things reduce this drastically:

  1. if the lid is left off then some of the vitamins will be rapidly oxidised
  2. if it is stored beside the heat then the whole process of decay is speeded up.

 

So think carefully about how you store it and use it.

Testudo Volume Two Number Five 1987

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