A MOST SERIOUS MENACE.

Dominion, Volume 4, Issue 991, 5 December 1910, Page 10

A MOST SERIOUS MENACE.

CONTAGIOUS MAMMTIS. . :■■■ :■•■ .. ■■■■ I »•'•••••' :t 'A fowwoefes ago tlioro appeared in.l ; Thk Dominion'.'an article in which it. l was stated that a certain farmer had' (;>. . - 1 , had ; very good results from his treat-. ■ Mont of cows 1 stricken with contagious \ ■ • mammitis, and-the treatment was ex-'*. • ; plained. , . • !■...■■ •..■■■ In the annual report of tho Live [[?;[Stock and Meat Division of tho Depart-. ; . -mont of Agricultura there is an csten-' i. give; report by Mr.' H. A. Eeid, i F.R.C.V.S., D.V.H., on the esperi\meats respecting the dis'caso'which have ; ■ been made at tho Wallaceville Labora-' ?. . fcory: Tho following are extracts from . : Mr. Reid's report . "Reports as to tho prevalence of,oon£y: tagioa& inastitii (also called mammitis) ■ continue to be/received from all parts ■ 'of the Dominion. Tho wide distribution |V. ' .of, the disease constitutes a most serious r " • . menace to. tho dairy industry. It is . difficult, _wii;h any degree of 'accuracy, | ■ to appraise the monetary loss incurred f .by tho presence of contagious mastitis, [ but thoso who havo had tho misfortune to encounter its ravages are in a posi-, fcion to appreciate'what the'lpss must t. r;; . ' .'.apiount to in the • aggregate. Con- / tagious mastitis may unquestionably bo i'l held to be one of the most insidious |; ~ and persistent , pathological conditions inet.with .in. cattle of .this country, .only. ' rivalled in this respect by that other ■' bovino glagae, ."tuberculosis. During ; • tho year a very large.number of milksamples obtained from suspected cases have been , submitted for eSamanation. : 'V These wero generally found to contain. [ . : . i 'the pathogenic.organism. Contagious i: . "mastitis" represents only one of the .. . several catarrhal conditions affecting ;■ V tho udder of the cow. A cursory micro- . Bcopical examination of a sample of milk : ; V. .."is of ten not sufficient to deddo whether not it has been yielded from, an afC " footed smirco. Even tho proseuco of streptococci in milk cannot be taken iv' .to, indicate that' the cow from which . tho ' samplo has been obtained is --'effected. Such-organisms belong fre-: quently to the., benign group of lactic-scid-forming germs, and may'lk; found in milk from' udders which are in every rc&pect healthy. ■ ■ Difficulty Experienced. ' ' • '.'Slice' no absolutely' reliable method l'f : is'known for readily distinguishing b0... ... - tween the Streptococcus lacticus and the Drganism of contagious, mastitis (Streptococcus pyogenes), much difficulty is . experienced in d«3idirig' from "a 'micro- • . scopic examination of tho milk whether ' the animal is, afFcctfd with'the disease' ■ . ■ '" .or, not. In all cases, where possible, clinical, evideneo should accompany the - bacfcerioscopic nnalysis. Slight... .variations in.'the morphology of; Streptococcus.: . • :'• pyogenes', hay# /frequently; been ; noted.. Such changes do not/'howeyer, influence ...its virility,;'and, upoii; inoculation into . ■ a susceptible animal the organism can ;. -V" ..usually -bo •'recovered in its more fre- : quently encountered form., ."It has ; been found as a result of observation that one of tho more certain .'' indications,, that .; contagious , mastitis : exists in- a profuso Catarrh in the milk-/ ■'''■secretion,' together with .an unusual' / . .-.i' proportion of pus-cells or dead and degenerate, leucocytes. 'Whenever tho " white colls are estimated' to exceed . 100,000:pbr culii.^.centimeter, associated with the presence of streptococci, _con"tagious mastitis may . be correctly'diag- : 'nosed in fully' '90. per cent, of ■cases. . \ . "The condition of.'the udder- and ■ .. milk, although as a rule/abnormal, canv ■ not. definitely decid<\ whether the animal ? iai.tide .'from diseaii:.' Milk to all appearanco perfectly.' normal , has .'. been, found-'.on : several;.occasions to contain--tho virulent.germ: whilo udders from ■.*. which all palpable traco of inflammation . has vanished jnay, still yield "an infcctiyo : . - supply. Such conditions; constitute .one ■,:.;■ •. of;the most seridus "fei'tures of the , diseasej both as regards its recognition and eradicatioh.'i Kxiieri'mce.leads* me :*■. • to" believe that,shoidd' any cow 1 in. a ■ ■' herd prove to be:affected, bacterioscopic '' " examination' of. tho.'niilk -from- each of '.'^the". ifemiiiriing. aaid appaieartly healthy cows can alone determine ilieir freedom . : from disease. . . . ■ : "It has been Repeatedly stated by : ; many, independent observers that cows, iv ' iparticularly heifers, 'turned; out .after [f; - tlio dai.rj'ing season' mth healthy udders, i . : , como dn after calving showing symptoms : ■ of acute, streptococcic .mastitis. .1 havo .had personally' verify ; such statements, and have been unable i':in' certain "cases to trace the source of infection.. ,Should the cown bo in'poor , . condition prior to calving, this, in itself p/-. may . serve to lower, the vntality of tho r cellular : ;defences, and jfavour tho. de- !):•: ..velopment of the diseiie. Tho funcUV ; - "tional activity of tho .gfcnd at this I/, ' ..', . p'enod may also, facilitate- access of -tho j , infective agent. . . j:■.-■•. • • -'.Two- Mothods-of Treatment.f : V "The usipl._method of treatment by |v'• v . means- of. antiseptic injections having proved, useless, or, at. least, unsatisr S', factory, in onr hands'; it was ..decided .-v ' : tip try the application of a . ..vaccine |v/ itreatment.: for tho cure of tlie' diseaso. r. . . -Thij method is based upon the result } ./ attending tho. treatment of certain in- ( :! fectiye.processes in.tho human.subject, V/ . notably; tubsrculosis and ■ staphylococcic ! ■ : infections. . - .. ' • j" . : - "In the, majority.;of cases" xccehtly j;. ' treated by this' method distinct'amelioj/. ; nation of.:clinical symptoms has taken ?'■ ■ ' " .pla'co, . and .tho; milk-secretion;'has, beji. ' obmo normal -in I ,appearance to tho naked cye.v . Microscopic examination of the i"-\_ .milk after twenty-four hours' incuba- ; ' . -t|on,.bas, however, determined the pref Benofi_ of Streptococcus pyogenes, which [. '/.' /.proved virulent lipon inoculation,into a I. - / susceptiblo subject. This result has ..followed- ~treatment extending . ovei (>';• ; periods ,up to . fifty-two days, so that, j v besides .the disadvantage of protracted Tccoyery, during Which the animal re- !'. mains a centre of infection, thero it i'. : : V'-also , the more serious. defect of .onlj K- '• to-, apparent euro having been estab- ; lished. Tho treatment, although proj . ; bably beneficial, seems likely to mislead f l ';. and render efforts to control the diseasi l.; :;. less_ effective. Moreover, should tin i subject, undor treatment bo exposed i< any depressing influence, such as cold r',\ or the presence of another focus o i.:. .; : . disease, the success attending its ap r ';: . • plication is rendered still moro-doubt f, ful. 111-one experimental case, in wliicl 1 tho cow under treatment was affcctei • with latent tuberculosis, increase in t-h j. : , - dose of .vaccine employed appeared t j,j;/: activate the-, tubercular, 'disease ///:■ / Symptoms of acute pulmonary tubei jV''.- culosis supervened, and the animal La to be destroyed;" I Mr. Eeid then deals with treatmen !: ■ by means of the hyiwdermic inoculatao F:. ; of the' living specific organism, wliie ' method is based-on tho same principl ! : .V ; ':. as that last described, tho diffcrenc L'."- being that .in this case cultures of t-h I -living streptococcus, unaitenuated b Iheat. Were . employed. ■;■ ■ '' .-"The: pracfo'ce/' he sava, "has muc j;. tho Same'objections as tho method < I ':.-■ 'n'iih cleVitl cultures, and, i [ / addition, the serious risk involved < I - diss'Siwinatiug".tho disease ■ accidental] . -" :, by means, of tho virulent organism! ! /■': . ' .' iii ccrtaiii .'-individual'cases very sati: C-, . factory results.-hare been attained, if: • J; G. Clayton, Ciovernment' Veterii i arian, 1 employed this method in tl: i . . treatment of a badly-infected ■ hen !;. ■ with tleoidedlv bnr.eficial results. Owin r to tlio l'euatli of timo occuuied, -has

. ever, it is difficult to know whether to aEcribo' tho recovery ,of tho animals to their own recuperative.powers or to tlio effect of/the viccine. Moreover, the cultures prepared at the laboratory wero • forwarded to Mr. Clayton, aud most .' probably had undergono some attenua■'wion during transit. Mr. Lyons, Gov- • eammeut Veterinarian, has also undertaken treatment of contagious mastitis by this method, with very successful ■ results in certain, cases. Further cx-p-jriments aro being conducted in vaccinal treatment, and moro encouraging results may bo hoped for. ' Best Thing to Do. "On account of its great economic importance, I would strongly urge all fa.-murs to:report ; the appearauco of any ' cases' 1 of : suspected contagious mastitis ill their herds, and to deal in a radical mangier with a view to its elimination, Further experience has shown tho. futiliv-y of treatment by means of anti•soptic. injections into,the udder. Isolation or . segregation of;. affected cows— which may bo turned out with a calf with a view to fattening them off— strict attention to personal cleanliness, ■ aind fao maintenance' of the'byre in a sanitatry condition,, are the only means yet available to effectively control the spread of the disease. Finally, the wide ■ distribution of the diseaso behoves dairy-farmers to, as far as possible, breed from their own stock, and avoid buying in outside animals, unless they are 'in a position to bo confidently assured that - the newly-purchased ' animal is not, or has not, been a subject of contagious mastitis."