TUBERCULOSIS AMONG CATTLE HERDS.

Otago Witness, Issue 2362, 1 June 1899, Page 4

TUBERCULOSIS AMONG CATTLE HERDS.

Tl^ Lancashire (Eng.) County Council have recently published the report, of which the following is a, summary, of the Agricultural Sub-committee upon the tuberculin experiments carried out at the County Council farm from September 1895 to March 1899.

In August, 1595, Mr H. S. Uaine, the lecturer on agriculture to the Lancashire County Council, called the attention of the Farm Sub-committee to the great prevalence of tuberculosis amongst the dairy cattle of Lancashire, and, after the question as to the best means to be adopted for dealing with the disease had been fully discussed, it was decided as a first step to ascertain the number of cattle affected amongst the dairy herd at the (Jounty Council farm, by the application of the tuberculin test. As the reliability of the test was then legarded as an open question, a small subcommittee was appointed in August 1895 to conduct a preliminary experiment for the purpose of testing the value of '" tuberculin." The carrying out of the test was placed in the hands of the council's veterinary surgeon, the farm bailiff acting tinder his instructions.

Thirteen cows, including some of the best milkers, and the pare shorthorn bull were selected as fair types of the herds and it may be as well to say here that the herd was made tip of well-bred dairy cattle, mostly milking shorthorns, together with some Jerseys. Most of the cows had calved their second or third ci-lves, and nearly all, except the Jerseys, had been purchased as heifers. To all outward appearance the animals selected were in good health and condition at the time of the first operation. Before operating, the animals were carefully examined, and the thermometer wis used night and morning for three days in order to establish the mean temperature of each animal. The .tuberculin used was supplied by Messrs Francis Willows and Butler, of London, and 60 minims were injected into the loose tissues about the dewlap, the parts having been first thoroughly disinfected with a 10 per cent solution of pure carbolic acid.

The operation took place on the 13th September 1895,' and resulted in no fewer than 9 out of the 14 animals giving a decided reaction. This was so unexpected that the committee resolved to re-test the same animals, and about five weeks later, on the 17th of October of the same year, the test was applied under the same conditions, and, with the exception of one animal, the same result was arrived afc. This cow, one of the heaviest milkers of the herd, and which did not react at the second test, but which had visibly deteriorated in the interval, died during the following

month front tubercle of the .membranes covering the brain and spinal cord '(tubercular meningitis), thus confirming the opinion of most experts that in very advanced cases of tuberculosis no reaction will be produced by the injection of tuberculin. After a. still further trial of the tuberculin test, the sub-committee authorised Mr ,Hutchinson, v the veterinary surgeon, to apply the test to all the remainder of the diary herd over nine months of age. This was done during February and April 1896, and of 33 cows tested, no fewer than 25 reacted ; but of the young stock tested, 27 .in number, between nine months and two years old, which had been bred on the farm, only one reacted. Having arrived at this stage of tha -experiment, the committee considered the best means of preventing the spread of tuberculosis in the dairy herd, and also of dealing with the animals proved- to be tainted with the disease. After careful consideration, and after taking the advice of Mr Hutchinson and of the manager of the farm, the following regulations were laid down: —

1. That all the healthy cows be isolated from those tainted, both in the cowhouse and in the pastures.

2. That separate vessels be provided for food and drink."

3. That the cowhouses be cleansed; that is, the walls scraped, the woodwork scalded and scoured, and the whole thoroughly disinfected.

4. That all the fat cattle sold to the butcher be followed to the block, and inspected after slaughter. 5. That all the calves be reared on milk produced by non-reacting cows only. 6. That only young bulls that have been tested and do not react be sold for breeding purposes

7. That no fresh animal be brought on to the farm that has not been previously tested.

8. That the stock be tested periodically,

It may be stated here that all these regulations have been strictly adhered to up to the present time. In December 1896, and in January 1897, 35 cows \vere tested, of which 11 reacted ; and 12 young bulls, bred on the farm, were tested, of which none reacted. In January and February of 1898, the test was carried out on 37 cows, and of these only 4 reacted ; and during that year, of 51 young animals tested only 2 reacted.

At the date of the report 72 animals above six months old, none reacting, were upon the farm, of which 4 had been tested three times. There are in addition 6 animals which have reacted, but are to all appearances in good health. These are, however, isolated from the resb in a specially built cattle house. Mr Hutchinson had, in almost every case; followed the career and disposal of each animal sold from the farm for slaughter — whether they reacter or not — with the result that, i in 94-. 4 per cent, of the cases examined tubercular deposits, to a greater or less extent, were easily found in those animals which had reacted ; but in no case where the animals did not react was there any trace of the disease. It may be noted that only in two cases on the farm had the disease affected the udder.

The committee draws the following conclusions from the experiment as far as it has gone:

(a) That by means of the test the sounch] cows can be distinguished from the un- j sound ; and by separation, the farmer to a very great extent can check the spread of the disease, and can deal with the unsound' animals in such a manner as to minimise j the consequent loss. The fact of animals j remaining on the farm, as they did at Hutton, 18 months or more after reaction, shows that the disease may be retarded in its progress by favourable sanitary conditions as to food, light, and air.

(b) The experiments .seem to prove that it is very advisable not to breed from unsound animals ; for, though it is now generally accepted that the disease itself ia not hereditary, it is admitted that the predis-* position "to disease may be inherited, and fchnfc the offspring of sound parents are much more likely to keep healthy than those of unsound parents. As a matter of fact, it may be noted that two cases did occur at the farm where calves from unsound cows died tuberculous at seven or eight weeks old, although they had been excluded as far as possible from other ' sources of in-< fection.

((}) The committee is also convinced that periodical applications of the test are necessary, as instances occurred where cows which not react at one test reacted when tested six months or .so later, although apparently every source of infection had in the meantime been eliminated. It may be that in these cases some factors such as infection through rabbits or game have been overlooked, or that the infection was already present in the animal at the first test, but the disease was at too early a stage to cause reaction.