THE TUBERCULIN TEST.

Dominion, Volume 1, Issue 71, 17 December 1907, Page 2

THE TUBERCULIN TEST.

FARMERS CAN USE IT. HO W IT IS APPLIED'. In America tlio dairy farmers are cncouragod to perform their Own tuberculin tests upon cows to ascertain the prevalence or absenco of tuberculosis. ' Tho United States Department of Agriculture, recognising that " tlio eradication of this cattlo scourgo is largely dependent upon tho wholesale use of tlio tuberculin test," makes tuberculin for freo distribution. In New Zealand the farmers are not encouraged to perform tho operation themselves, but tlio inoculation will bo done for them by the Department's veterinary surgeons for a very, small feo. If tho "home uso" of the system in America is calculated to eradicate tuberculosis, it may bo worth New Zealand's while to copy it. A farmer who would not for* worlds liavo a veterinary surgeon coiyo performing uncanny, mysterious operations with his cows might, after instruction, liavo .no scruplo about pricking tlio cows hinisolf with tho mystic lieedlo. Farmers aro naturally norvous of Goyernmont .officials, and it soems feasiblo that tho Americans, in stripping the tuberculin test of all its mysteries and its official setting, may have taken a valuable step toward a more general use of tho test. We cull tho following from a Wisconsin bulletin on tho subject:— ■ What Is Tuberculin? Tuberculin is a product oftho growth of tho tuberclo organism in artificial cultures. In its preparation it is so treated as to destroy the vitality of all organisms, and is a perfectly harmless product when used as directed/ It does not injure a healthy animal, nor will-it cause the disease to spread in a tuberculous animal. Tho value, of this agent' in determining the presonce of tuberculosis is now undisputed. When useil with ordinary judgment, the errors aro only a fow per cent., and in skilled hands it is almost infalliSlo. In Pennsylvania, 4000 animals that had given characteristic reactions wore slaughtered and oxamined, and the presence of tho disease was demonstrated in all but eight animals.' Easy to Apply. Tho test is very simplo in its application and requires no especial technical skill. The introduction of the tuberculin caiuses a tcm-' porary fevor in affected animals. Tho test consists in making a simple hypodermic injection and in taking a series of t-empora-tures. Anyone who, is familiar with the handling of cattle can make a successful test, if tho details which aro mentioned in describing tlio method of procedure aro carefully observed. ' , r . Time to Apply the Test. Tho most advantageous time to apply tho i test is during thoso seasons in which tho animals aro stabled, thiring tho summer, tlio auimals becomo restive if kept in the stablo during tho. day, and in very hot, weather, tho normal temperatures may bo so high as to lead to erroneous results. .. What Animals not to Test. As a ruloi animals should not bo testedwithin four or fivo .days before or after calving, nor while in " heat." Those normal functions usually do not cause any marked changes in temperature,-but, in i,ome pases, they may; but in order to lie certain,' it iswell to exclude sue!) animals from the test. Animals suffering fi'om any disease (fever, garget, eta.) should bo excluded- Animals' which show a temperature of 103.5 degrees to 104.degrees F. should not.be injected. As ■ a rule calves -less than tlireo months .old should hot, bo tested. -.'■■■ Ordinary Temperatures. In cattlo-the normal daily temperature, varies considerably, often I—2 degrees F. in tho courso of a few hours. A number of factors may produce such changes. Cold water, when drank in considerable quantities, may reduce the temperature soveral degrees. A temporary, excitement may' cause 'a rise; ex- - cessivo summer heat .also increases tho nor-" nial temperature. This is especially.-'truo where animals aro kept in:tho stablo in iho summer. Tho average -normal temperature, of milch cows generally runs from 101 degrees to 102.5 degrees i>\ On account of tho easo with which these, variations'in temperature aro it is important to keep the animals that are being' tested, in as nearly a normal condition as possible. They should be fed as usual." The animals should not bo allowed free access to cold water during the period in which temperatures aro boing taken. Water can bo given in moderate amounts, preferably in tlio. stable, and at such timos as will least.influence the temperature of the animals. The Testing Outfit. A syringo of at-least Sec capncity is needed. Tho samo should bo provided with a number of stout needles,' which' should bo kept in good condition by sharpening on an oil stone. At least two clinical or fever , thermometers will : bo ■ needed, and whoro more than fivo animals.are to be tested, a larger number should be provided. In order to prevent breakage of thermometers, some device should be used to fasten the same to tho animal. A string may bo tied around tho thermometer at tlio constriction just above tho bulb, and again near tlio top. This is attached to a small " bulldog " clamp, procurable at almost any' stationery 'store. After inserting tho * thermometer, tho clamp is fastened to tho long hairs at tho base of tho tail.' If tho thermometer is then thrown out of the rectum, it will not bo broken by dropping on to tbo floor. Mailing tlic Test. Tho test is divided into threo parts:—(l) Taking tho normal temperatures before injection j (2) tho injection of tho tuberculin ; (3; takinc of temperatures after injection! During tlio day preceding the injection, at interval? of two or three hours, tako a series of four or fivo temperature readings oil each j animal. The injection should be made in' the' evening of the day on which the normal temperatures have been taken (8 to 10 p.m.). Temperatures after Injection.. • ' Eight to ten hours after the injection of the tuborculm, temperature readings should bo begun. These readings should be taken every two hours until at least livo have been made. Where auimals show a marked rise, it is 'well to tako readings more frequently, ar.d temperature observations should be continued on these until a permanent decline toward tho normal is noted. 1 he thermometers used aro self-registering, i.e., tho mercury remains at the highest point reached ' until shaken down by* tho operator. Shake - the column of mercurv down until it is beloiv 99 degrees F.. : Always read the thermometer before inserting to sc-o that it is properly shaken down. Smear tho end of the bulb with a littlo vaseline, and insert thermometer full length. Do not push with much force, ami liso caro in insorting tho instrument. After threo minutes, remove, road, record, shako down the mercury below 99 degrees 1 1 , and insert in tho next animal. Familiarise yourself especially in tho matter of reading, tlio thermometer, and if any troublo is experienced, ask your druggist or doctor to show you how. Doso of Tuberculin.. The tuberculin furnished by the Experiment Station is supplied by tho* United States Department of Agriculture, and is in such a concentration that a proper dose consists of 2cc. per 1000 pounds estimated live weight. Proportionate doses are used for lamer or smaller animals. Moderate variations m the doso will liavo no injurious effect. One cubic centimeter (cc.) equals J dram, or 15 drops. Ordinary hypodermic syringes are generally graduated in drams or cubic centimeters. Making the injection. The injection is usually mado in front of tho shoulder whoro tho skin is thin and loose, but can be made elsowhore, Tho syringo

should bo sterilised by placing 'in cold watc# a uasm and gradually.bringing.the water ~J,¥ J' 1 ", the. Isyringb. through.' the. need 0 from the bottlo of tuberculin, ' The lioodlo can bo inserted through' tte skin uulo on the syringe. Beginners will have loss tronble however, if tlio 'needle-is inserted and the syrmgo attached later. A told of the skin is made -with-the,left-hand, fm- Jrl '!> < \! nscrtc '}; in the pocket, thus lmt-1? M i° nn t -0 tllr 9Ugh the, skin, h i r< * not to forco t-bo samo inio tho nesli. Iho secret of success in injecting: is to havo stout, sharp needles. . . „ - Interpretation of the Tedi. , -; * ' -Animals which aro 'affected" withi/fobeill culqsis, even m tho incipient stagesplvill { on \ a 'i' so ii ' tcmperaturo'froln" ,ei D ht to fourteen hours after injection# If ■ tlie: maximum temperature' after injeotio'n' -- ia approximately 2 degrees to 2.5' degrees, F. ; .or inoro. above the average normal'toinpferature, and tho fever persists" for 'some hours, ■ the animal is tuberculous. Some Consider a riso of 1.0 degrees F; above the normal'maximum as sufficient- to indicate a positive *'reaction. Usually the reaction fovfer is'-much' nioro marked, the temperature rising- from' 3 degrees to 5 degrees. : 'When the temperaturo reaches 104 degrees F., or above; I 'and ismaintained for 3ome hours, the animal 'is' ? usually"regarded as tubercular,'if?no fever"'was shown before injection • Sudden t-lons of temperature that are -not. continued ' tor some hours should not be looked' upon 'as inactions. AMien tho temperature rises only ' ■ degrees or a little less above. the average ' normal temparature tho case should bo regarded as "suspicious." Such animals, should do retested in the course, of six to eight weeks, but not before, as there, must •- be time for tho elimination of tho.''first *? tubcrculm from tho system. Experience and a knowledge of' all conditions that may haye an influence on the temperatures aro necessary in . making a correct ' interpretation! Ay hero tuberculin ,i SI sent out by the Station, ' the temperature record sheets are to bo rs-'. - turned to tho writers as soon as tho tost is - completed; and an interpretation of the re-, suits, with recommendations as to disposal. .- jrill bo. made. -- - -- , Disposal of Tuberculous Animals. As soon as any animal is found to be tubeirculous, it should be removed; from • tho ro- • mainder of tho herd, so as to prevent further spread of the disease. The subsequent disposal will depend upon varying conditions. -;' Tuberculous animals cannot: bo disposed'of • by law, ; except under conditions that are' •provided for,by tho State. -, -■ ; . Tho owner has threo options as to tlio method of disposal:— , 1. The ■ cattle, _ if in good physical condition, may bo shipped under the auspices of tho State Livp Stock Sanitary Board to some packing centre, where they can. be oxamined by federal inspectors. The owner receives tho full net value; of tho cattle. , This amount- >'■ will depond upon whether tho meat is con-M demned or not on account of the extent -,of ••} the disease. When tho disease is in the early, stages in the glands, ; it is entirely safe for \ 2. The cattle may bo appraised by three •• appraisers. The owner receives two-thirds 1 of tho ■ appraised valuation, tho maximum appraisal valuo being fifty dollars. • Tho • cattle are then slaughtered on the place by tho St-ato authorities; or are shipped by them to be slaughtered under federal'inspection. ' Tho roturns from thoirsale go to the State: ' .3. If the affected cattle aro valuable, pure- , bred animals, the owner may hold them in - quarantine,. under the rules of tho Ststo Live Stock Sanitary Board. Which of these op- ' tions ought to bo adopted by theiowner will depend upon the cirnumstancos-of each in- . dividual case'; 'and -the Department of Bacteriology holds'itsolf ready to take up a consideration of tlicso cases individually. " ' r Disinfection of-tho Stable... ..- !' -'v ' .It is exceedingly'-impprtant'' after' t-he dis- ; ' posal of the affected'animals that the stable- ; should lie disinfected. ' All dust, dirt, and manure should be removed from the ceilings, walls, and floors. Loose and brokon feed boxes and mangers should, be removed before applying disinfectant. '"A thin whitewash prepared from fresh unslaked. limo is to bo applied by means of a.... spray puiAp, if possible, to' tho walls, ceilings, and floors. Tho whitewash should bo thin, if a pump is used, nnd-if applied hot will be more It is'well to add one pound of .chloride of' limo (bleaching, powder) to each three gallons of whitewash. Do not ' use air-slaked lime as this has no disinfecting 'value. Tho mangers and feed boxes can be scrubbed with a hot saturated solution of sulphate of iron ' (copperas). ' Tho stables should bo. whitewashed two to three tinies yoarly. < ~