It must not be thought, however, that we are completely helpless and that the present condition of affairs must be allowed to continue indefinitely. Nocard and Leclainche have minutely laid down the lines to be followed as regards prophylaxis, though unfortunately the measures recommended cannot always be carried out.
Tuberculin having been proved an exact means of detecting tuberculous lesions in animals even where none were suspected, it is desirable, firstly, to test all the animals in a given establishment with tuberculin; and, secondly, to separate into classes (1) all animals which have reacted, and (2) those which have resisted.
The stables, etc., should then be completely disinfected by sweeping, washing first with hot water, then with strong antiseptic solutions, brushing over the walls with quick-lime solution and fumigating with sulphurous acid or formic aldehyde. The healthy animals should then be placed in one shed and the diseased animals in another. In order to render this system of isolation really efficacious the isolated animals and the healthy animals should have nothing in common, and the persons tending the two classes of animals, the buckets and other utensils, the watering places, etc., should be kept rigorously apart.
The animals known to be tuberculous should as rapidly as possible be prepared for slaughter, and if pregnant cows are included in the number the calves should be removed to the healthy stable immediately after birth and brought up either on boiled milk or by a healthy mother, experience having shown that congenital tuberculosis is of rare occurrence.
After the tuberculous animals have left the shed, this should again be thoroughly disinfected, in order to make it fit for the reception of healthy subjects.
Unfortunately such precautions can only be observed in model establishments. They necessitate expenses and immediate sacrifices of a very serious character, and breeders too often view only the sacrifice without regard to the after benefits. For this reason the above system has only been practised in certain of the best known and best managed farms.
To ensure the full benefit of these precautions, and to prevent a fresh introduction of tuberculosis into the herd, every new animal introduced should be subjected to the tuberculin test. Unless this precaution is taken, there is always a risk of introducing a tuberculous subject, thus nullifying all the precautions previously taken.
The problem is therefore still very complex, and the system can only give good results when rigorously observed and followed out.
As, however, in spite of all precautions, animals regarded as healthy are always, under normal conditions of existence, more or less exposed to accidental infection, it is desirable to subject the entire herd to the tuberculin test annually. This would cause the immediate detection of any animals with latent infection, so that they could be removed from the herd.
These wise precautions might, if understood and observed, eliminate the disease from the country, but they depend on individual initiative, and have not as yet been grasped by the mass of small breeders, farmers, etc. This class only see the difficulties in the way of realising the idea, without appreciating the constant benefit which they would derive from it.