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Effects of Heredity in Bovine Tuberculosis*
16
The Veterinary
7 ournat.
of age rarely show evidence of the di sease, yet on autopsy may presen t lesions . (3) Turkeys [as outlined in (2) ] may pass throu g h an attack of this affection , after which they are chronic carriers of the infective agent for an indeterminate period. (4) Treatment of affected birds may or may not be effective. M uriat ic a,cid has g iven goo d re sults, but is not infallible . It can be used without fea r of untoward re sults. Emetine hydrochloride ha s been effective in a few in stance s, but is too dan ge rous for g eneral adoption and can only be used under skilled direction. (S) The hatchin g and rearin g of turkeys by artificial mean s on uninfected g round and away from other fowl giv es promise o f a means for overcoming the ravages of thi s malady . (6) All weak or inferior pou lts should be destroyed at once an d none but the mo st vigorous individual birds retained for breedi ng purposes.-Ft·om R eport of Ve t erinary Director-G eneral, Departmen t of Agriculture, Canada.
EFFECTS
OF HEREDITY I N TUBERCULOSIS.*
BOVI N E
Bv HARLO\
Professor of Ciinical 111edicim, Univer sity a11d Bellevue Hospital .M edical Co//tg<: Visiti11g Plzysician to flu ll1ontejiore Hospital and to the City H ospital, New York .
THAT a ve ry hi g h percentag e of dairy cattle are tub e r culo u ~, that is, are " reacto r s," is a uni ver sall y admitt ed fa ct . State and munic ipal laws a re more and more in sistin g that the milk of tubercul ous anim als shall n ot b e so ld , and th e que sti on of b ov ine tuberculo sis has become a serio us econom ic as well as hygi enic problem. W hen one reali zes that for general use milk mu st be fu rn ishe d at a rate which can be paid by th e average citizen and at the same tim e appreciate s the fact that th e dairyman must expect fr om IS t o so per ce nt . o f hi s stock to be ruled out if the tub erculin te st s are ri g idly en forced, the ·problem of milk supply becomes a factor of very g reat difficulty as well a s importance . A further fact o f g reat bearing is th e stron g probability that the more hi g hly bl oo ded cattl e are mo st likely to be • Read before the Association of American Physician&, May 13.
E(jects of Heredity z"n Bovine Tubercu!oszs.
17
found to be reactors. Thi s makes the problem of the honest and ambitio u s dairyman even more difficult, f.or if he attempt to increa se the quality of milk or the butter production of his herd , he a lm ost invariably breeds in tuberculous stock, and unless extraordinary and expen sive methods of iso lation are practised di ssem ination o,f the infection is almost certain to follow. On the other hand, if he fails to thus improve his stock he is very likely to get into trouble because the quality of his milk may be found deficient and he thus also lays him self liable to prosecution. The difficulty of improving breed is a very serious matter, particularly f.or the farmer of small capital, since the pri·ce o! blooded stock is always hi g h and he is v·e ry likely to purchase as non-reactors cattle which have been "plugged" against the tuberculin reaction by dishonest dealers. This trick of " plugg ing," though familiar to most stock men, I find is not widely known by physic ians. There is no doubt but that when tuberculin test s are kn own to be about to be made, this method is practised so that negative results are obtained ev·en in cattle which may be extensive ly so disea sed . " P lu gging" is performed by injecting a dose of tuberculin a few days before the public or lega l test. For some time after the reaction which follows this injection, sub sequent tuberculin te sts are ne gative so that ·e ven widely diseased an imal s may be tested and so ld apparently as free from tuberculo.sis . As can be seen, detection of this fraud may be practica lly impossible. Another point often unrecognized by the hygieni st is that the tubercul in te st in cattle as in man is positive in animals whi ch while they may harbour foci of the disease are not active ly tuberculous, that is, the reaction may be g iven by cured cases. If we were to apply to man routine tubercu lin te sts it is certain that we shou ld find many supposed and actually healthy individual s who would respond to the r eacti o n. The term " reactor" is therefore indi scriminately app lied by stock men to animals perhaps not actively or obviously tuberculou s and yet which simp ly g ive the reaction. It is found, however, that when such stock, apparently o ther wise soun d, be hou se d and fed with perfectly healthy non-reactors the non-infected herd sooner or later become widely diseased for the sensitiveness of uninfected animals to tuberculosis is remarkable and apparently much g reater than in man. The common practice of dairy men is to largely igno re
18
The 1/:elerinary
7 ournal.
this fact, to take the chance as part of the risks of the business. and to eliminate only such animals as are ·obviously sick. These usually form but a small percentage of the real reactor group and under such methods the dis ease can never be eliminated from the herd. The problem then becomes very complex, particularly from an economic standpoint. It is true that thorough pasteurization of milk will eliminate the possibility of transmittin g tuberculous infection to man. I do not propose to enter into the discus sion of this problem at this time but to especially point out that reactors in any herd eventually cause the more or less complete infection of that g roup. The experiments conducted at Woodcrest, previously reported,* hav e apparently furni shed a so lution for thi s problem though it must be admitted a very expensive one indeed for the breeder of moderate capital, si nce it practically nece ssitate s se parate and distinct e stabli shment s and perso nnel, and enough capital to permit a mo.re or less idle and larg ely non-productive g roup of animals. To me personally the fact of greatest interest ha s been that the inbreeding of tuberculous animals has in no way impaired the type or desirability of the offspring. It ha s been conclusively shown th at the calves are very rarely, if ever, infected before or at birth. That the slightest carelessness in expo sure ·of the newborn calves to infection leads to certain di saster is illustrated by ten recent infections at Woodcrest through the neg li gence of one workman in not minutely followin g out the instructions laid down. Tuberculous animals of de sirable types may therefore be freely used for breeding purposes provided that the calves are not allowed to come in c·o.n tact with the infected parents . The economic as well as the biolo g ical importance of this apparent fact is obvious. To establish the fact that reactors may furni sh and perpetuate most desirable traits as to type, fertility, milk , and cream producti on, and to therefore controvert the suggestion that such infected animals should be utterly destroyed , notes of the following g roup of anima ls are presented, taken by permiss ion of Mr. Dimick from the records of Woodcrest Farm. • Trans. Soc. Exp. Mtd. n11d Bioi., 1914, val. xi, No.
2,
p. 50.
Effects of He1·edz"ty in Bovine Tube1•culosis.
19
Pietje 22d, No. 70884.-The foundahon dam of this strain was imported from Holland by the Woodcrest Farm. She was supp osed ly of the highe st type representin g the Holstein-Fresian breed and her pedigree show s descent from the finest animals of thi s stock. It ha s not been possible to a sce rtain whether or not she was derived from tuberculous parentage, but early tests at the Woodcrest Farm showed her to be a " reactor," although apparent ly in perfect health . She died of generalized tuberculosis at the a ge of fourteen years, four months. She is credited with four calves born in Holland and seven in thi s country. She made the following remarkable record:Butter, 5even days' tes t Milk, seven days' test Butter, thirty days' lest 1\lilk, thirty days' test Butter, six months' test
31 "62 673 ·go 128"3 7 2,786 "40 566·6o
lb .
" " " ,
Thi s last item is stated to be the world's record for butter production for this time . During thi s same period she pr.oduced 13,673"90 lb. of milk. While at the Woodcrest Farm she gave birth to an annual car£ with records as follows:(1 ) W oodcrest Pietje .-A bull calf; a perfect and effectively fert ile specimen , so ld a s a herd bull. This animal is not known to be tuberc ul ou s, althou g h it is strong ly probable that he is . (2) Pie tje 22d's Woodcrest Lad.-Thi s animal is a perfect spe cime n in every re spect and has been retained at the head of the Bo utekou Farm as a stud animal. He i~ known to be tubercu lous and is isolated \Vith the tuberculou s herd . A daughter o f th is animal bras produced at the age of four years 35 lb. of butter in seven days. This is stated to be a world's record for this age. (3) Pietje 22d's daughter.-This animal at birth was a perfect sp ecimen in every apparent re spect, although she was found to be tuberc ul ous in the seco nd year of her age. Her record is as foll ows: Butter, seven days 1\lllk, 5eve n days Butte r, thirty days 111 ilk, thirty days
25"19 lb . 553 "40 " 104"29 " 2,202 . 22
,
She was fertile each year and her offspri ng have all been perfect sp ecimens of their kind. She died in January last from a genera liz ed tuberculosis one week after the delivery of her last and perfect ca lf. Thi s animal ha s no.t yet been submitted to the
20
The Veterinary Jourual.
tuberculin te st but inasmuch as it was removed from the mother immediately after birth, from previous experience, it is assumed to be non-tubercul ou s. S he was the dam of Woodcrest Jamaica Pietje; a bull calf, perfect in every re spect and now the head of a valuable herd. This a nima l has proved to be normally fertile. A dau g hter in her second year ha s given a butter rec·O·r d for s·e ven days of 16·o7 lb., and of milk for the same time of 350·30 lb . \tVoodcrest Jamaica P ietje was removed from the dam at birth, iso lated from the tuberculous herd , and is free from any disease. Also dam of \tVoodcrest Johanna Pietje: a perfect and fertile bull. He is free from tube rculo sis as he was remove d from the dam immediately after birth. Dam also of Woodcrest Pietje Pontiac: a perfect male sp ecimen removed from the dam immediately after birth and consequently fr ee from disease. This animal was sold while a calf for $2,ooo, and is the anticipated head of a valuable herd. (4) Pietje 22d's second daught er .-This animal has always been tuberculou s, having received the infection apparently from her dam shortly after birth, none the le ss she was in every way a perfect spec imen and gave a record of butter production for seven days of 29·63 lb .; of milk in the s ame period 584·70 lb. Butter thirty days, 117·24 lb.; butter for one yea r, 829·53 lb . Milk fo,r the same time, 19,722·90 lb . This animal
Veterina1y College Passes .
21
o f an infantile diarrha:a in its very early youth, before it had been re g istered. The male parentag e in many if not most of these instances ha s been also tuberculous in all probability. The qu-e st io n of ,,·hethe r o·r not the offspring became tuberculous depends entirely upon exposure after birth. The point of g reate st importance illu strated by this remarkable family is that no defects of a biological nature ha:ve been found in any of the offspring of thi s definitely tuberculou s stem. A ll are perfect speci mens. There ha s been no reduction in fertility, and judg ing from the milk and butter records no diminution in butter or milk production, and, as stated, several world's records have been attained by these animals. This family is apparently fa irly illu strativ·e of others of lik e nature , and in so far as the obse rvatio ns go it S·e ems definitely demons trated that parental tuberculosis in the cow causes n o defects t o be apparent in the offspring even thou g h the calf be bo rn in the almo>St terminal stages of the di seases in the dam . This report is al so intended to po int out that the term " reac tor " as u sed by stock men often means what in human medicine wo uld be class ed as healed tuberculo sis. It seems to show that definitely tuberculou s animals may be sa fely utilized for breedin g purposes and that they may be crossed and inbred with entire di srega rd ·of the factor of tuberculosis and purely for the purpose of improving or mai ntainin g type . Mo st imp ortant of all, the fact stand s out that althou g h it may not be wi se to utili ze the unpas teuriz·e d milk of reactors for human consumption nor yet for the feeding ·O·f calves or other anima ls, yet reactors may be suc cess fully and safely used a s brood stock and thu s cease to be an econo mic waste.-Americau Jour11al of th e Medica l Sciences.
VETERINARY ·CO LLE GE PASSES. The foll o win g students passed their re spective examinations, VIZ.: -
"A, " or First P.rofessioual .-William U. Ma in, Glasgow. " B ," or Second Professional.-I saac McCauley, Kilrea, Ireland . "C, " or Third Professional.-David E. Orr, Glasgo \v. " D," or Final Examination (obtained the Diploma of the R oyal Co llege of Ve t erinar:y Surgeo11s).-Archibald W. Campbell , Wishaw (Second-class honours) ; Thomas M. T·imoney, Glasgo w; Neil A. M. Macewan, Ardrishaig; Henry J. Hughes , Po ntypridd, \i\Tales.
The Veterinary
7 ournat.
of age rarely show evidence of the di sease, yet on autopsy may presen t lesions . (3) Turkeys [as outlined in (2) ] may pass throu g h an attack of this affection , after which they are chronic carriers of the infective agent for an indeterminate period. (4) Treatment of affected birds may or may not be effective. M uriat ic a,cid has g iven goo d re sults, but is not infallible . It can be used without fea r of untoward re sults. Emetine hydrochloride ha s been effective in a few in stance s, but is too dan ge rous for g eneral adoption and can only be used under skilled direction. (S) The hatchin g and rearin g of turkeys by artificial mean s on uninfected g round and away from other fowl giv es promise o f a means for overcoming the ravages of thi s malady . (6) All weak or inferior pou lts should be destroyed at once an d none but the mo st vigorous individual birds retained for breedi ng purposes.-Ft·om R eport of Ve t erinary Director-G eneral, Departmen t of Agriculture, Canada.
EFFECTS
OF HEREDITY I N TUBERCULOSIS.*
BOVI N E
Bv HARLO\
Professor of Ciinical 111edicim, Univer sity a11d Bellevue Hospital .M edical Co//tg<: Visiti11g Plzysician to flu ll1ontejiore Hospital and to the City H ospital, New York .
THAT a ve ry hi g h percentag e of dairy cattle are tub e r culo u ~, that is, are " reacto r s," is a uni ver sall y admitt ed fa ct . State and munic ipal laws a re more and more in sistin g that the milk of tubercul ous anim als shall n ot b e so ld , and th e que sti on of b ov ine tuberculo sis has become a serio us econom ic as well as hygi enic problem. W hen one reali zes that for general use milk mu st be fu rn ishe d at a rate which can be paid by th e average citizen and at the same tim e appreciate s the fact that th e dairyman must expect fr om IS t o so per ce nt . o f hi s stock to be ruled out if the tub erculin te st s are ri g idly en forced, the ·problem of milk supply becomes a factor of very g reat difficulty as well a s importance . A further fact o f g reat bearing is th e stron g probability that the more hi g hly bl oo ded cattl e are mo st likely to be • Read before the Association of American Physician&, May 13.
E(jects of Heredity z"n Bovine Tubercu!oszs.
17
found to be reactors. Thi s makes the problem of the honest and ambitio u s dairyman even more difficult, f.or if he attempt to increa se the quality of milk or the butter production of his herd , he a lm ost invariably breeds in tuberculous stock, and unless extraordinary and expen sive methods of iso lation are practised di ssem ination o,f the infection is almost certain to follow. On the other hand, if he fails to thus improve his stock he is very likely to get into trouble because the quality of his milk may be found deficient and he thus also lays him self liable to prosecution. The difficulty of improving breed is a very serious matter, particularly f.or the farmer of small capital, since the pri·ce o! blooded stock is always hi g h and he is v·e ry likely to purchase as non-reactors cattle which have been "plugged" against the tuberculin reaction by dishonest dealers. This trick of " plugg ing," though familiar to most stock men, I find is not widely known by physic ians. There is no doubt but that when tuberculin test s are kn own to be about to be made, this method is practised so that negative results are obtained ev·en in cattle which may be extensive ly so disea sed . " P lu gging" is performed by injecting a dose of tuberculin a few days before the public or lega l test. For some time after the reaction which follows this injection, sub sequent tuberculin te sts are ne gative so that ·e ven widely diseased an imal s may be tested and so ld apparently as free from tuberculo.sis . As can be seen, detection of this fraud may be practica lly impossible. Another point often unrecognized by the hygieni st is that the tubercul in te st in cattle as in man is positive in animals whi ch while they may harbour foci of the disease are not active ly tuberculous, that is, the reaction may be g iven by cured cases. If we were to apply to man routine tubercu lin te sts it is certain that we shou ld find many supposed and actually healthy individual s who would respond to the r eacti o n. The term " reactor" is therefore indi scriminately app lied by stock men to animals perhaps not actively or obviously tuberculou s and yet which simp ly g ive the reaction. It is found, however, that when such stock, apparently o ther wise soun d, be hou se d and fed with perfectly healthy non-reactors the non-infected herd sooner or later become widely diseased for the sensitiveness of uninfected animals to tuberculosis is remarkable and apparently much g reater than in man. The common practice of dairy men is to largely igno re
18
The 1/:elerinary
7 ournal.
this fact, to take the chance as part of the risks of the business. and to eliminate only such animals as are ·obviously sick. These usually form but a small percentage of the real reactor group and under such methods the dis ease can never be eliminated from the herd. The problem then becomes very complex, particularly from an economic standpoint. It is true that thorough pasteurization of milk will eliminate the possibility of transmittin g tuberculous infection to man. I do not propose to enter into the discus sion of this problem at this time but to especially point out that reactors in any herd eventually cause the more or less complete infection of that g roup. The experiments conducted at Woodcrest, previously reported,* hav e apparently furni shed a so lution for thi s problem though it must be admitted a very expensive one indeed for the breeder of moderate capital, si nce it practically nece ssitate s se parate and distinct e stabli shment s and perso nnel, and enough capital to permit a mo.re or less idle and larg ely non-productive g roup of animals. To me personally the fact of greatest interest ha s been that the inbreeding of tuberculous animals has in no way impaired the type or desirability of the offspring. It ha s been conclusively shown th at the calves are very rarely, if ever, infected before or at birth. That the slightest carelessness in expo sure ·of the newborn calves to infection leads to certain di saster is illustrated by ten recent infections at Woodcrest through the neg li gence of one workman in not minutely followin g out the instructions laid down. Tuberculous animals of de sirable types may therefore be freely used for breeding purposes provided that the calves are not allowed to come in c·o.n tact with the infected parents . The economic as well as the biolo g ical importance of this apparent fact is obvious. To establish the fact that reactors may furni sh and perpetuate most desirable traits as to type, fertility, milk , and cream producti on, and to therefore controvert the suggestion that such infected animals should be utterly destroyed , notes of the following g roup of anima ls are presented, taken by permiss ion of Mr. Dimick from the records of Woodcrest Farm. • Trans. Soc. Exp. Mtd. n11d Bioi., 1914, val. xi, No.
2,
p. 50.
Effects of He1·edz"ty in Bovine Tube1•culosis.
19
Pietje 22d, No. 70884.-The foundahon dam of this strain was imported from Holland by the Woodcrest Farm. She was supp osed ly of the highe st type representin g the Holstein-Fresian breed and her pedigree show s descent from the finest animals of thi s stock. It ha s not been possible to a sce rtain whether or not she was derived from tuberculous parentage, but early tests at the Woodcrest Farm showed her to be a " reactor," although apparent ly in perfect health . She died of generalized tuberculosis at the a ge of fourteen years, four months. She is credited with four calves born in Holland and seven in thi s country. She made the following remarkable record:Butter, 5even days' tes t Milk, seven days' test Butter, thirty days' lest 1\lilk, thirty days' test Butter, six months' test
31 "62 673 ·go 128"3 7 2,786 "40 566·6o
lb .
" " " ,
Thi s last item is stated to be the world's record for butter production for this time . During thi s same period she pr.oduced 13,673"90 lb. of milk. While at the Woodcrest Farm she gave birth to an annual car£ with records as follows:(1 ) W oodcrest Pietje .-A bull calf; a perfect and effectively fert ile specimen , so ld a s a herd bull. This animal is not known to be tuberc ul ou s, althou g h it is strong ly probable that he is . (2) Pie tje 22d's Woodcrest Lad.-Thi s animal is a perfect spe cime n in every re spect and has been retained at the head of the Bo utekou Farm as a stud animal. He i~ known to be tubercu lous and is isolated \Vith the tuberculou s herd . A daughter o f th is animal bras produced at the age of four years 35 lb. of butter in seven days. This is stated to be a world's record for this age. (3) Pietje 22d's daughter.-This animal at birth was a perfect sp ecimen in every apparent re spect, although she was found to be tuberc ul ous in the seco nd year of her age. Her record is as foll ows: Butter, seven days 1\lllk, 5eve n days Butte r, thirty days 111 ilk, thirty days
25"19 lb . 553 "40 " 104"29 " 2,202 . 22
,
She was fertile each year and her offspri ng have all been perfect sp ecimens of their kind. She died in January last from a genera liz ed tuberculosis one week after the delivery of her last and perfect ca lf. Thi s animal ha s no.t yet been submitted to the
20
The Veterinary Jourual.
tuberculin te st but inasmuch as it was removed from the mother immediately after birth, from previous experience, it is assumed to be non-tubercul ou s. S he was the dam of Woodcrest Jamaica Pietje; a bull calf, perfect in every re spect and now the head of a valuable herd. This a nima l has proved to be normally fertile. A dau g hter in her second year ha s given a butter rec·O·r d for s·e ven days of 16·o7 lb., and of milk for the same time of 350·30 lb . \tVoodcrest Jamaica P ietje was removed from the dam at birth, iso lated from the tuberculous herd , and is free from any disease. Also dam of \tVoodcrest Johanna Pietje: a perfect and fertile bull. He is free from tube rculo sis as he was remove d from the dam immediately after birth. Dam also of Woodcrest Pietje Pontiac: a perfect male sp ecimen removed from the dam immediately after birth and consequently fr ee from disease. This animal was sold while a calf for $2,ooo, and is the anticipated head of a valuable herd. (4) Pietje 22d's second daught er .-This animal has always been tuberculou s, having received the infection apparently from her dam shortly after birth, none the le ss she was in every way a perfect spec imen and gave a record of butter production for seven days of 29·63 lb .; of milk in the s ame period 584·70 lb. Butter thirty days, 117·24 lb.; butter for one yea r, 829·53 lb . Milk fo,r the same time, 19,722·90 lb . This animal
Veterina1y College Passes .
21
o f an infantile diarrha:a in its very early youth, before it had been re g istered. The male parentag e in many if not most of these instances ha s been also tuberculous in all probability. The qu-e st io n of ,,·hethe r o·r not the offspring became tuberculous depends entirely upon exposure after birth. The point of g reate st importance illu strated by this remarkable family is that no defects of a biological nature ha:ve been found in any of the offspring of thi s definitely tuberculou s stem. A ll are perfect speci mens. There ha s been no reduction in fertility, and judg ing from the milk and butter records no diminution in butter or milk production, and, as stated, several world's records have been attained by these animals. This family is apparently fa irly illu strativ·e of others of lik e nature , and in so far as the obse rvatio ns go it S·e ems definitely demons trated that parental tuberculosis in the cow causes n o defects t o be apparent in the offspring even thou g h the calf be bo rn in the almo>St terminal stages of the di seases in the dam . This report is al so intended to po int out that the term " reac tor " as u sed by stock men often means what in human medicine wo uld be class ed as healed tuberculo sis. It seems to show that definitely tuberculou s animals may be sa fely utilized for breedin g purposes and that they may be crossed and inbred with entire di srega rd ·of the factor of tuberculosis and purely for the purpose of improving or mai ntainin g type . Mo st imp ortant of all, the fact stand s out that althou g h it may not be wi se to utili ze the unpas teuriz·e d milk of reactors for human consumption nor yet for the feeding ·O·f calves or other anima ls, yet reactors may be suc cess fully and safely used a s brood stock and thu s cease to be an econo mic waste.-Americau Jour11al of th e Medica l Sciences.
VETERINARY ·CO LLE GE PASSES. The foll o win g students passed their re spective examinations, VIZ.: -
"A, " or First P.rofessioual .-William U. Ma in, Glasgow. " B ," or Second Professional.-I saac McCauley, Kilrea, Ireland . "C, " or Third Professional.-David E. Orr, Glasgo \v. " D," or Final Examination (obtained the Diploma of the R oyal Co llege of Ve t erinar:y Surgeo11s).-Archibald W. Campbell , Wishaw (Second-class honours) ; Thomas M. T·imoney, Glasgo w; Neil A. M. Macewan, Ardrishaig; Henry J. Hughes , Po ntypridd, \i\Tales.