ABSTRACT. The causes of death in registered Antarctic sledge dogs have been classified under 13 headings. for the most part, these categories are what one might expect from the knowledge of the life and environment of these dogs. The exception is the condition now called “cervical lymphadenitis” since its aetiology is unknown.

From this review it can now be seen that accidents and fights ("extrinsic" causes), and osteoarthritis, are the most frequent reasons for fatalities. together, they account for 67.9 per cent of male deaths and 47.5 per cent of female deaths. However, accidents and fighting have most effect on the juvenile husky, whereas osteoarthritis  almost invariably affects huskies older than 5 years.

Culling is the only category showing more female than male deaths. There is a continual tendency to reduce the number of females to that required for breeding purposes And to replace females with males in sledge teams. Considering that this dog population is closed,  one could reasonably expect the figures for culling to be  higher than they are. Against this, there is the obvious need for continual replacement of fatalities and an inadequate knowledge of the technique of culling.

Despite the presence of a permanent breeding population of huskies at the British Antarctic Survey stations  since 1945, when the original dogs were brought from Labrador, no veterinary information became available until M.F. Godsal visited these stations in the austral summer of 1963-64. Apart form a few occasional additions from Greenland in 1954 and 1961, and from Canada in 1954, the present dogs are all directly descended from the original imports. The breeding and maintenance of sledge dogs has been well described by Bingham, James, Adie, Reece and Taylor.

Nowadays, mechanical transport has to a large extent superseded the dog team but for field work from Stonington Island in the Antarctic Peninsula and Halley Bay on the Brunt Ice Shelf dog teams are still used extensively, and they have long since proved themselves to be a safe and reliable means of transport in mountainous terrain. In this manner, journeys of 600 miles are still undertaken regularly. Although there is no doubt that, in difficult conditions, a well-fed and well-driven team is a most efficient means of travel, modern demands are such that air support has now become essential if the dog team is to operate to its maximum efficiency.

Previous work
Before 1963-64, all research and medical work on the dogs had been done by medical officers or zoologists, producing very good results particularly on the nutrition and work output of sledge dogs. From their work it was shown that seal meat, with its high fat and protein content, was the ideal dog food. Furthermore, seal blubber is essential to the dog's well-being in conditions of poor weather or hard work. However, away from the coastal areas the dogs are fed on the sledging diet, Nutrican (manufactured by Bob Martin Ltd.). Comparisons of this diet with the previously used dog Pemmican (Manufactured by Bovril Ltd.), and with Pemmican and seal meat,  were carried out and the present diet has only been varied on composition when the manufacturers have had to turn to other sources for the basic constituents.

It is now customary to feed at least 1.5 lbs.  Nutrican daily when conditions and supplies permit. Feeding at this rate will not stop the members of a hard-working team from loosing weight progressively but fortunately the dogs recuperate very rapidly when Nutrican or seal meat is once again unlimited.  In 1967 vitamins and minerals were added to Nutrican to supplement the vitamins included after Taylor's work.

Sledge loads
For practical purposes, 120 lb/dog is still considered as a fair maximum sledge load, although air-support facilities often lower this figure. Taylor measured the pull exerted by a dog team; he was able to show daily fluctuations of up to 50 per cent and stressed that many factors including gait, changes in temperature, diet, snow surface and the psychological effect of long and monotonous journeys affected the dogs’ performance.

Teams
The standard survey team consists of nine dogs, the leader often being a bitch. The lighter, more responsive dogs are usually in the lead and the heavier workers in the rear. Pups are trained to harness from 6 months onward and they are usually in full work shortly after reaching the age of 9 months. A normal health husky dotes on human company and gives every appearance of thoroughly enjoying its work. The present dogs average between 70 and 95 lb. in weight when well fed and exercised, with bitches weighing 10-20 lb. less than the dogs. As a general rule, the Labrador type, with its long strong back and powerful relatively shorter legs, is found to be ideal for the work.

At all of the stations except Halley Bay the dogs are "spanned out" in the traditional manner at all times, the only exception being whelping bitches. At Halley Bay the dogs are put into ice tunnels when the winter temperature drops below -30C.

Harnesses
Each dog has its own tailor-made harness from 1.5 inch wide lampwick,  which is soft and strong, and spreads the load across the shoulders and chest. There are several methods of attaching the harnessed team to the sledge but the commonest method is the centre trace. Occasionally the fan method has found favour.

Distances
There is considerable variation in distances travelled on field journeys but a round haul of 900 miles is not unusual. A good dog might cover at least 8,000 miles during its working life; one litter of pups covered 1,000 miles before they were 1 year old, having started full work at 6 months of age. Much time is wasted because of bad weather, with the resultant boredom in both men and dogs during these lie-up periods. Under good conditions in the Antarctic peninsula a sledging party may average 16 miles/day.

Retirement
The older dogs are usually incapable of further useful work by the time they are 8 years old. They are then destroyed or retained for breeding, or for pup training. Many dogs become too slow before they are 8 years old. It was mainly because this had been observed that M.F. Godsal toured the stations and determined that the reason for this slowing was osteoarthritis.

Present work
Osteoarthritis was found to be a major problem in Antarctic sledge dogs and it was investigated during two summer tours of the Survey's stations. One season was devoted to a pathological survey and another to a clinical approach involving x-radiography. In addition, entropion of the eyelids was found to exist in the dogs and surgical correction was carried out where necessary. In 1967-68, true haemophilia was encountered in two related litters at one station. As both of these conditions are thought to be hereditary in origin, the complete genealogy of the British Antarctic Survey sledge dogs was traced with the aid of G.K. McLeod.

Where a condition had been reported in the past, advice was given as to its possible cause, treatment and further investigation. Among these were a disease known as "Signy Neck" (but referred here to as cervical lymphadenitis), a condition erroneously called "ringworm", pyometra and endometritis, and corneal opacity.

By far the largest part of the work involved the examination of every dog at each station, the instruction of medical officers and stations members on aspects of the veterinary treatment of dogs (particularly the treatment of wounds), distribution of appropriate drugs to each station, surgical treatment of individual dogs, and finally, advice on many of the subjects involved with the maintenance of a large colony of dogs.  It was a privilege, as novices to the Antarctic,  to learn a very large amount from dog drivers and their dogs.

As a result of these visits, great emphasis was placed on the many advantages of carrying out complete post-mortem examinations, and the advisability of continued veterinary investigation at regular intervals. Following recommendations, it is hoped that more dogs will be introduced from the Arctic in the near future.

In the next issue of the Fan Hitch we will present Part II of this research paper entitled "Occupational Osteoarthritis"