Cattle Plaque in Belgium

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CONCLUSIONS. Lamb dysentery is already a serious menace to sheep-raising. The disease is annually spreading further north in Scotland and further south in England, and only shows signs of abating where it has been in existence upon a farm for seven or eight years. The disease takes a heavy toll of life (30 per cent.) amongst lambs, mainly during the first two weeks of life. Lambs over fifteen or eighteen days old are immune. The disease only appears each year with the lambs of susceptible age and disappears when these are all dead or have grown beyond the susceptible age. The disease is caused by a bacillus of the coli type which invades the body from the inflamed bowel. The lesions are inflammation and necrotic ulceration of the intestines. All the evidence goes to show that the ewe acts as a carrier of the bacillus and is responsible for carrying infection from season to season on the same land and also to other farms. A preventive serum was made and used on the lambs on the day of birth, but, while it undoubtedly immunised them, it did not give in all cases long enough protection to tide lambs over the susceptible age. Further tests with preventatives will be made with the object of immunising the lambs to carry them over the susceptible period of life. These will include the inoculation of pregnant ewes and of the new-born lambs. Much might be done to minimise losses by the precautions recommended for infected farms and by altering some of the present customs followed during lambing time.

RESEARCHES REGARDING EPIZOOTIC ABORTION OF CATTLE.

By Sir JOHN M'FADYEAN, M.B., B.Sc., LL.D. (From the Research Institute in Animal Pathology, Royal Veterinary College, London.) (Continued from p. 64.)

HERD NO.2. THE first sample of blood from this herd was forwarded on the r Sth September 1917 and the test had a positive result, the agglutination being complete in I in 200. The owner was informed that the result showed that the cow in question (afterwards known as NO.9) had been infected with contagious abortion, and it was then learned that she had been purchased the previous March and on the 24th August had calved six weeks before the proper time. The calf was born alive but died almost immediately. The last previous owner, when informed of the abortion, affirmed

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that the cow could not have been infected while in his possession, but her present owner held the contrary opinion, as he had had no reason to suspect the previous existence of the disease in his herd at any time during the past five years. Immediately after the abortion the cow had been placed in a shed by herself, and the cows which had been in the same field were put into a fresh field and strictly isolated from the rest of the herd, which at this time numbered about 130 head, divided into two lots kept on different premises-South Farm and North Farm. The animals that had been in the same field with the infected cow at this time were the following:NO.2. Due to calve 30th January 1918. NO.3. Due to calve 7th January 1918. NO.4. Due to calve r zth February 1918. Nos. 5 and 6. These were twin heifers not supposed to be in calf NO.7. Due to calve rath January 1918. Her previous calf had been born three and a half weeks prematurely, but it survived and did well. No.8. Due to calve 6th December 1917. No. 13. This was a bull calf sucking the cow NO.9. Blood from these eight animals and also from the cow No. 9 (second test) was taken on the z jrd October 1917, and when tested the result was positive in two of them, viz., in NO.9 and NO.4. In the former case agglutination was again complete in all tubes up to I in 200, and in No. 4 agglutination was advanced in I in 50 and negative in the higher dilutions. On the same date blood was tested from a cow, No. 12, which had been purchased at the same time and from the same owner as NO.9, and two cows, Nos. 10 and I I, which had been kept with No. 12. Also from a cow, No. I, which had never been near NO.9, but in February 1917 had calved a dead calf at eight months. The result of the test was negative in all these cases. In December the owner intimated that NO.4, which was not due to calve till r zth February, aborted on the 5th December, a fact which he considered strong evidence of the accuracy of the test. On the r zth December 1917 blood was again forwarded from the above Nos. 2, 3, 5, 6, 7, and 8, and when tested the result was negative in all of them except NO.2. In that case agglutination was advanced in the i tube (I in 25) but negative in the others, and the owner was advised to have this animal strictly isolated for a month and then to send another sample of blood from her. On receipt of this advice the owner removed Nos. 3, 5, 6, 7, and 8 to a fresh field and left No. 2 where she had been since the first case of abortion on the 24th August. On the 16th January the owner intimated that No.2, which was not due till the 30th of that month, had a dead calf on the 5th, and that NO.7, which was due on the 14th January, had calved on the zznd December The calf was weakly and did not survive. In the meantime NO.3 and No.8 had calved live calves at full time. On the 23rd January 1918 blood was again sent from Nos. 2, 3,5, 6,7, and 8, and also from another cow, No. 14, which had calved a little too early. This cow formed part of the herd that had never

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been in contact with the infected lot. The result of the test was as follows : NO.2. Agglutination complete in all tubes (up to I in 200). NO.3. All negative. NO.5. All negative. No.6. i adv., ! dist., I and 2 neg. NO.7. Complete in i, ~, and I, nearly complete in 2. No.8. All negative. No. 14. All negative. The interesting facts in connection with these tests are (I) the increase in the agglutination titre of NO.2 since the first test on the r zth December, and (2) the failure of Nos. 6 and 7, which had both passed the previous test. NO.7, as previously noted, had calved prematurely in the interval between the two tests. No further communication was received regarding the herd until the 27th March 1918, when the owner intimated that No.6 had aborted on the 3 r st Jan uary previous. At this time NO.9, the cow that first aborted, viz., on the 24th August, together with the bull calf (No. 13) sucking her, and Nos. 2, 4, 5, 6, and 7 were kept together but isolated from the remainder of the herd. NO.3, which had passed all the tests and which had been kept separate with her live full-term calf since the 24th December, and No.8, which had also passed all the tests and now had a live calf, had been separated from the infected lot on the 30th November. The owner was informed that no good purpose would be served by having another test of the reacting animals at this time; but, as he was anxious to return Nos. 3 and 8 to the healthy herd if that was considered safe, blood was forwarded from these two animals on the 15th May, and also from two new animals numbered IS and 16, No. IS was a cow which the owner thought was either carrying a dead calf or was going to calve prematurely, and No. 16 had had a dead calf taken from her on the 4th May. She was not due to calve till the 29th May. The result of the test was as follows : NO.3. i adv., others neg. No.8. All negative. No. IS. All complete (up to I in 200). No. 16. All negative. A further test was made of the serum of No. IS in order to see what was the height of the agglutination titre, and it was found that agglutination was nearly complete in I in 500, and distinct in I in 1000. When these results were intimated to the owner it was learned from him that Nos. IS and 16 had not been in contact with any of the animals previously suspected or found to be infected. They belonged to that part of the herd which was kept at South Farm, into which no animal had been brought from outside for less than about two years. Moreover, as previously mentioned, no cases of abortion, except those previously noted, had occurred in either part of the herd during the previous five years. The animals isolated in consequence of the case of abortion on the 24th August 1917 had been attended to by a man who never came near the rest of the farm, and the place where these

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isolated animals were kept was a mile distant from the rest of the herd. On the 28th May blood was again forwarded from the cows Nos. 15 and 16, and from another cow, No. 17, which also belonged to the herd at South Farm. The test had an entirely negative result in Nos. 16 and 17, and in the case of No. 15 agglutination was again complete in I in 200 (the highest dilution used). The owner was advised to have blood tested from all the animals of South Farm, and the first lot, from thirty-six animals, were taken on the t zth June. The test had a negative result in all the cases except the following:No. 28. Complete in all tubes (up to I in 200). No. 29. Distinct in i tube only. No. 31. Complete in all tubes. The owner was informed that Nos. 28 and 31 were certainly infected, and that No. 29 should be considered doubtful. It was recommended that that animal should be isolated from both diseased and healthy animals and that another sample of blood should be sent from her in a fortnight. A letter subsequently received from the owner conveyed the information that Nos. 28, 29, and 3 I were non-pedigree dairy cows which had been purchased as heifers three years previously, along with another, No. 30, blood from which had been included in the recent test. No. 28 had had three calves since purchase, her last being born on the z and May 1918, nine days before the expected time. The calf was alive when born but survived only five hours. The other reacting animal, No. 31, was pregnant and due to calve on the zznd August next, and it may here be stated that she calved on that very day. Her previous calf had been carried to full term. The doubtful animal, No. 29, had a healthy calf at full term on the roth March previous. With the exception of the above-mentioned four dairy cows all the animals included in the test of the r ath June were pedigree animals kept at South Farm, and since purchase the dairy cows had not been in any way isolated from the other animals kept there. The owner now reported that he had three dairy cows which had also been purchased as heifers in 1915 at the same time and place as the above-mentioned four dairy cows, and that they were in the part of the herd at North Farm. On the 17th September 1918 blood was forwarded from thirtynine animals at South Farm, these including all those that had not reacted to the previous test and also No. 29, in which the result of the previous test was doubtful. On this occasion the test of No. 29 was quite negative, but there were two new reactors, Nos. 19 and 30. No. 19. i compo t nearly compo It was afterwards ascertained that this animal was a pedigree bull, and that blood from him had passed the previous test on r zth June. (For the history of this bull see p. I 12.)

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No. 30. i and t tubes both compo This, it should be noticed, was one of the non-pedigree dairy cows which had been purchased three years previously, and had passed the test on the r zth June. Her last calf had been born at full term on the zznd April, and she had been served again on the 3 r st July by a yearling bull which was afterwards sent to the butcher. At the same date, 17th September, blood was sent from the following six animals belonging to the North Farm portion of the herd:Nos. 52, 53, and 54. These were the cross-bred dairy cows previously referred to, which had been purchased three years ago. Nos. 55, 56, and 57. These were three pedigree cows which had not been breeding and which the owner thought ought therefore to be tested. He had, however, no other reason to suppose that abortion existed in this part of the herd. The only reactor in this lot of six animals was the cross-bred No. 53, in which agglutination was complete in both the i and ~ tubes. She had calved a full time healthy calf on the 22nd June and had not since been served. She was immediately isolated. As the owner at this time was not quite satisfied with the results of the recent test, a general test of all the other animals at North Farm was not immediately carried out, but on the 20th November blood was again sent from the above cross-bred cows at that farm and tested with the same negative result in Nos. 52 and 54, and with a positive result in No. 53: i compo t nearly cornp. In view of this confirmation of the previous test of No. 53, the owner now decided to have all the remaining animals at North Farm tested, and blood was forwarded from them (numbered 60 to 94 inclusive) on the 30th November 1918. The result was negative in all of them. On the z Sth May 1919 blood was forwarded from twenty-five of the animals at South Farm (Nos. 22 to 46), all of which had been tested with a negative result on r gth June and zoth September 1918. On this occasion the result was again quite negative except in the following two : No. 22. i and t cornp. This cow had given birth to a healthy calf at full term on the r r th Jannary 1919, and on the 27th April following had been served by a bull (No. 20) which passed the present test. She had not settled to this service. No. 46. i and t tubes both dist. This was a heifer which had been served for the first time on z yth January 1919 by the same bull as No. 22. These were the only animals served by this bull that ever reacted. As the owner was not quite satisfied with regard to the result of the above test, blood was again forwarded from Nos. 22 and 46 on the 4th June and the test had the same result as before. These two animals were then removed from the healthy herd and isolated, and it was suggested that another test of the non-reacting animals at South Farm should be carried out after a month or six weeks. Blood was accordingly sent from them (thirty-five in number) on the 23rd July 1919, and the result of the test was quite negative in every case.

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Up to the time of writing (May 1921) no case of abortion has since occurred in the herd at either of the two farms.

Subsequent History

0.1 the

Infected Animals.

A number of the infected animals were put out of the herd soon after their infection was detected, but the following, on account of their value, were retained for a time in isolation, in the hope that it might eventually be possible to return them with safety to the herd, or at least to put their progeny into the herd. Cow NO.2. zoth October 1917. Tested for the first time, with negative result. r zth December 1917. Tested: i adv.,?r neg. 5th January 1918. Had a dead calf, three weeks premature. z jrd January 1918. Tested: Compo up to I in 200. z Sth May 1919. Tested: Compo in I in 50 (highest dilution used). 15th January 1920. Tested: i and t compo The above dead calf was to a service by bull No. 19 on the 25th April 1917, but a test of the bull's blood on the l2th June had a negative result. Cow NO.4. z jrd October 1917. Tested for the first time. Result: i nearly comp, t adv., I neg. Due to calve r zth February. 5th December 1917. Aborted. 4th September 1919. Gave birth at full term to a bull calf, No. 107.

r yth January 1920. Tested: i nearly comp., t adv. 26th November 1920. Tested: i nearly comp., t adv.

Calf No. r oth September 1919. Tested comp., ?r very adv. 26th November 1920. Tested: The owner was advised that he from infection. Helle?

107.

when fifteen days old:

i

nearly

Result negative. might regard the animal as free

No.5.

z jrd October 1917. Tested for the first time. Result negative. r ath December 1917 and 23rd January 1918. Tested with a negative result on both occasions. z Sth May 1919. Tested : i adv., t dist. 27th June 1919. Gave birth at full time to a dead calf (breech presentation). This was her first calf. 15th January 1920. Tested: i dist., t neg.

Heifer No.6. z jrd October and r zth December 1917. Tested with negative result. 23rd January 1918. Tested: i adv., ! dist., I neg.

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j r st January 1918. Aborted. Date of last service r jth August 19 17. z Sth May 1919. Tested: t and i camp. zoth August 1919. Gave birth to a full-term calf, No. 106. r yth January 1920. Tested: t and ~ camp. 26th November 1920. Tested: t camp., 1 nearly camp.

r yth January 1920. old. Result negative.

Calf No. 106. Tested for the first time when five months Cow NO.7.

z jrd October 1917. Tested for the first time, with negative result. r zth December 1917. Again tested with the same result. z zrid December 1917. Aborted. Date of last service 9th April 19 1 7. z jrd January 1918. Tested: t, ~, and I comp., 2 nearly camp. z Sth May 1918. Tested: t camp., ~ nearly camp. r yth January 1920. Tested: i cornp., ~ dist. 2 I st March 1920. Gave birth to a full term calf, No. IIO. zoth November 1920. Tested: t apprec., ! neg. Calf No. 110. zoth November 1920. Tested for the first time, with negative result, when eight months old.

Cow NO.9. A cow which had been purchased by the present owner in March 1917 with the following history. She had a live calf on the 14th January 1916, and was not served again until the zoth September following. She was again served on the zoth November and 6th January following, and she calved about six weeks prematurely on 24th August 1917. The calf was born alive but died almost immediately. r Sth September 1917. Tested for the first time. Result positive up to I in 200. zoth October 1917. Again tested with the same result. r Sth February 1919. Gave birth to a full-term calf. zoth May 1919. Tested: t and ~ camp. t oth January 1920. Tested: t camp., ~ dist. 3rd July 1920. Gave birth to a full-term calf, No. 112. 26th November 1920. Tested: t nearly cornp., i adv.

26th November 1920. negative result.

Calf No. I 12. Tested when nearly five months old, with

Cow No. IS. r jth May 1918. Tested for the first time: t and! camp., and nearly camp. in I in 500. The cow was pregnant, and due to calve on the 27th July. H

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z and November 1918. Tested: camp. in I in 50 (highest dilution used). 7th February 1919. Gave birth to a decayed fcetus. zSth May 1919. Tested: i and! camp. r yth January 1920. Tested: i and t camp. r st June 1920. Produced a full-term calf. 26th November 1920. Tested: 1 nearly camp., ~ dist. Cow No. 30. 22nd April 1918. Calved at full term. r zth June 1918 Tested for the first time, with negative result. 31st July 1918. Served by a yearling bull out of a cow that afterwards passed the test. r zth September 1918. Tested: i and ~ both camp. zznd November 1918. Tested: i and! nearly camp. oth May 1919. Gave birth to a full-term calf. z Sth May 1919. Tested: i and! nearly camp. zoth November 1920. Tested: i camp., ~ nearly camp. Cow No.

22.

This cow was tested with a negative result on the r yth June and zoth September 1918. She had a full-term calf on the I r th January 1919, and when tested on the 26th May 1919 the result was positive: i and ~ camp, 26th November 1920. Tested: i nearly camp., l adv. This cow fostered the following calf. Calf No. 108. This was a bull calf born on the r yth February 1919 out of a tested cow (No. 34), and it was fostered by the above cow (No. 22). The calf was tested on three occasions, viz., roth September 1919, roth January 1920, and zoth July 1920, with a negative result on each occasion, Bull No. 19. This animal was born in another herd on the r jth March 1<)15, and purchased by the present owner in March 1916. t z th June 1918. Tested for the first time, with negative result. 17th September 1918. Tested: i and ~ camp. z and November 1918. Tested: i and ~ nearly camp. zSth May 1919. Tested: i and! camp. r yth January 1920. Tested: i and! camp. In 1917 this bull served the cows Nos. 2, 4, and 6, the last on the r jth August. These three cows afterwards became infected, presumably through contact with the cow that aborted in August 1917, as the bull's blood was negative to a test on the r ath June 1918. All the cows served by the bull between r jth August 1917 and September 1918 either passed the test before or after service. He was not used for service after his infection was detected in September 1918, and he was sold for slaughter in 1920.

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Bull No. 95. This was a young bull which was being used exclusively for the service of the infected cows during their isolation. He had been put with these animals before he was tested for the first time on the zSth May 1919, and agglutination was then advanced in the I in 25 tube and distinct in I in 50. Blood from the bull was again tested on the 23rd September 1919 and agglutination was then only appreciable in I in 25 and negative in I in 50. SUMMARY.

The owner of this herd was strongly of opinion that his cattle had been free from contagious abortion for several years, and that the disease was introduced by a cow which was purchased in March and aborted in August 1917, but the subsequent blood tests revealed the existence of infection in cows that had been in the herd for some years and had never been in association with the suspected cow. Having regard to all the facts, it appears to be probable that the disease has been slumbering in the herd for an indefinite time, but that the cow purchased in March 1917 brought a fresh source of infection. However that may be, it can hardly be doubted that the system of testing and isolation saved the owner from what might have been a serious outbreak and eventually eradicated the disease. How much saving this meant can be inferred when it is stated that every live calf born in this herd may be valued at £100. As in the case of the herd previously dealt with, the repeated tests indicated that the bulls had nothing to do with the spread of the disease, since the first positive result had no apparent relationship to the date of service. They also showed the long persistence of the disease in some of the animals, including one of the bulls, and the rapid decline of the agglutination in calves out of infected cows. HERD NO.3.

This was a large and valuable pedigree herd including over sixty cows. In May 1913, at which time the owner believed it to be free from abortion, a cow aborted about three months before her proper time, and a month later a heifer carrying her first calf aborted, also about three months before the proper time. Blood was forwarded from both these animals and tested with negative results. On the r st March 1914 blood was again forwarded from the above cow because she had aborted twins. The result of the test was negative. The next sample of blood was forwarded on the 31st March 1914 with the information that it was from a heifer which had aborted at the seventh month. She had been bought a year ago and the calf was her first one. The result of the test showed that the case was one of contagious abortion, agglutination being complete up to I in 200. It was understood that this heifer had been served about three weeks before she was purchased in 1913 but she was served twice afterwards.

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On receipt of intimation that the case was one of contagious abortion the owner thought it well, on the 5th April 1914, to forward blood from another heifer which it had been found impossible to get in calf. Twice in succession there had been an interval of three or four months between her services, and on one occasion a discharge was noticed to be coming from her. The result of the test in this case was quite negative. As the owner reported that for the three years previous to 1913 the herd had been free from abortion, he was strongly advised to have a general blood test carried out, and on the 7th May blood was forwarded for the first time from forty-eight of the animals. The result was entirely negative in all except the three following : 5--n W. Camp. in all three tubes. B--s. Camp. in 1 and nearly camp. in I and 2. Mina. Camp. in all three tubes. It was advised that these three animals should be isolated, and that thorough cleansing and disinfection of the premises should be carried out. On the t Sth May blood from eight more animals (first test) was tested and the result was negative in every case. On the 8th June 1914 blood from a further three animals (first test) was tested with negative results. On the roth June blood was forwarded from one animal that had not been tested and from twenty-one animals that had passed the previous test. The result was negative in all the cases. One of the cows (Pearl) included in this test had given birth prematurely to twins. She was one of those that had passed the previous test. On the 25th June blood was forwarded from four animals which had previously been tested with negative result. The result was again negative in all the cases. A week later blood from one animal not previously tested was forwarded and the result of the test was negative. At the same time the blood of a heifer was tested with a view to purchase and the result was negative. On the 14th August blood was forwarded from a heifer (N o. 36) with the information that she had aborted about four and a half months after service, and that the appearance of the fcetus indicated that it had been dead for some time before expulsion. The result of the test was quite negative. The previous test of this heifer on the 7th May was also negative. On the 8th October 1914 blood was tested from the following animal:S--n W, Agglutination camp. in all three tubes. This cow had been tested with a similar result on the 7th May, and it was now reported that she had recently slipped her calf at five and a half months. On the 15th December 1914 a sample of blood was again sent from the cow Mina, which was found to be infected on the occasion of the test in May. In the present test agglutination was nearly complete in 1 and I and negative in 2. This cow was now carrying her third calf and was due to calf in about six weeks. Her two previous calves had been carried to full term.

On the r zth February 1915, blood was forwarded from a heifer, C--s. This was an animal of great value which had just aborted her calf between the sixth and seventh months of pregnancy. She had passed the test in May 1914 and the result of the present test was also negative. On the 8th March 1915 blood was again forwarded from the cow Mina, and agglutination was nearly complete in k and negative in I and 2. The cow had calved normally in the previous January. On the zSth March 1916 blood was forwarded from two cows and a bull recently purchased with a view to their introduction into the herd. The result of the test was negative in each case. Although it was now believed that the disease had been eradicated from the herd the owner was strongly advised that he must for some time regard any case of abortion occurring in it as contagious until the contrary has been proved, and that he should also continue to send blood from every animal that it was intended to introduce into the herd. On the z Sth March 1916 blood was accordingly forwarded from two cows and a bull recently purchased, and the result of the test was negative in each case. Nothing more was heard about the herd until the 30th March 1917, when blood was sent from three cows that were said to have calved prematurely, and the result of the test was quite negative in each case. These three cows formed part of one lot of animals which had been alone together during the winter and the premature calvings were all about the same time. Again there was an interval of over a year without any case of abortion, but in May 1918 a cow gave birth to a dead calf a month before the proper time. This cow had been caught in some barbed wire on the previous day and had torn off about half her tail. In the same month another cow aborted twins at six months. (She had also aborted twins in her previous pregnancy.) Blood was forwarded from both of these animals on the zoth May 1918 and tested with negative result. On the 3rd June 1918 blood was tested with negative result from a newly purchased cow. On the 5th July 1918 blood was tested with negative result from a cow that had given birth to a mortified calf about three months before full term. On the 9th July blood was tested from a cow which the owner intended to purchase, and the result was positive, agglutination being complete in I in 25 and I in 50 (only tubes used). On the roth July, 8th October, 6th December, and 19th December samples of blood were forwarded from other cows that the owner wished to purchase, and the test had a negative result in each case. The next sample of blood was forwarded on the 14th February 1919 from a cow (Blossom) which had aborted four months and one week after service, and the result of the test was positive: 1: and l cornp. The owner, on being informed that the case was undoubtedly one of contagious abortion, furnished the following history of the animal : -

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She had been bought in 1915 and had had three calves while in the present owner's possession. Her blood had never been included in any of the tests for contagious abortion because she was one of five cows which had been separated from the main herd and strictly isolated on account of reactions to the tuberculin test. It was not intended to return any of these animals to the main herd. On the 27th February blood was sent from the five animals that had been kept with the cow Blossom, and the result of the test was negative in each case. The owner was advised, however, that in order to clear these animals of the suspicion attaching to them it would be necessary to have another test of their blood in about two months. Blood was accordingly forwarded from them again on the 28th May, and on this occasion the result was again negative in three but positive in one of them (No.3), in which agglutination was complete in I in 50. The owner was informed that in consequence of this reaction on the part of one of the group the other three animals must continue under suspicion, and that after their separation from the reacting animal it would be necessary to have another test in two months. Blood for a third test of the three animals was forwarded on the j rst July, and the result was negative in each of the cases. The owner was then informed that he might regard these three animals as not infected. The occurrence of the case of abortion in the cow Blossom in the circumstances described must be regarded as rather remarkable. The owner thought that the cow must have been infected at the time of purchase, as he could see no opportunity for her infection afterwards and the four animals which had been intimately associated with her for a year before she aborted were exonerated by the first test to which they were subjected after separation. The circumstances indicate that the companion cow, NO.3, must have been infected through association with Blossom, and probably at the time that cow aborted, since she failed to react to the first test. The case affords convincing evidence of the danger of trusting to the result of a single test to prove that an animal recently exposed to infection is actually healthy. Subsequent to the abortion of Blossom blood has on various occasions been forwarded for testing from animals that had been recently purchased, or from cows that were for some reason under suspicion, but in all these cases the result of the test was quite negative. HERD NO.4.

The following can hardly be regarded as a case in which the disease was with certainty eradicated by the method of testing and separation, but it is described here because it serves as an illustration of what may be expected when an attempt is made to deal with a badly infected herd and accommodation for the reacting animals cannot be provided at a separate farm. Although the herd contained animals of high value is was not entirely composed of pedigree stock, and as the cows were mainly

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used for supplying milk the owner was under the necessity of purchasing a good many new animals at intervals. For more than a year after the first general test was carried out many of the reacting animals were kept on in the herd, but separate housing accommodation was provided for them, and the owner also undertook to keep the non-reacting and the reacting cows separate at grass. Assistance in dealing with contagious abortion in the herd was first sought in 1914. The disease had been in existence in the herd for at least three years, but exact particulars regarding the cases of abortion during that period could not be supplied, as the facts were only known to a bailiff who had left in August 1913. Afer his departure a number of cows that aborted were isolated, and sold after fattening. On the r Sth April 1914 blood from seventy-four animals in the herd was tested with a result that indicated infection in thirty-four of them. In all of these except nine agglutination was complete in 1 in 200. The exceptional cases were the following:No. 156. i nearly comp., 1 neg. " 153. i comp., 1 nearly comp., 2 dist. 168. i dist., 1 apprec., 2 neg. " 158. ~ comp., 1 nearly cornp., 2 dist. 170. i and I comp., 2 nearly compo 13. i comp.; 1 dist., 2 apprec. " 174. i nearly comp., 1 dist., 2 neg. " 19. i and I comp., 2 nearly compo 0' 177. i comp., 1 and 2 nearly compo In the remaining forty samples there was no agglutination in I in 50 (which was the strongest dilution used on this occasion). Among animals from which blood was sent there were three which had been isolated after abortion. These were as follows : No. 27. Aborted zoth March 1914. Agglutination complete up to I in 200 (highest dilution used). " 163. Aborted February 1914. Agglutination complete up to I in 200 (highest dilution used). " 154. Aborted February 1914. Agglutination complete up to I in 200 (highest dilution used). One of the reacting animals was a bull (Bull NO.1), and in that case also agglutination was complete up to 1 in 200. As he was a valuable animal the owner was advised not to sell him, but to retain him for the service of the valuable pedigree cows that had reacted to the test. On the 14th May 1914 blood was sent from thirty-nine of the animals, and among these there were three new reactors : August Roan. Agglutination complete in all tubes up to I in 200. This cow had come into the herd on 9th August 1913, and it was understood at the time that she had only recently calved. She had not been served while in the present owner's possession. No. 162. Result complete up to 1 in 200. Particulars were not supplied regarding this animal. " 183. Result i adv., I dist.,2 apprec. This was a calf born 16th August 1913.

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Agglutination also occurred in other three samples, and when the result was reported to the owner he admitted that, owing to some misunderstanding, these three animals had not been separated after the first test, but had been left with the non-reacting animals. Special interest attaches to the new reactor August Roan, as she must have been infected since she came into the present owner's possession although she had never been served and was barren at the time when she developed the power of reaction. The reaction of calf No. 183 is also interesting, because it cannot be interpreted as the result of congenital infection, in view of the fact that the test of its blood had a negative result in the previous test on the rSth April. After the result of the second test was reported to the owner it was ascertained that this calf had been sucking one of the infected cows, but that a few days after the first test in April the calf was removed from the cow. It therefore appears to be probable that the calf was actually infected from the cow in question, although infection of calves in that way appears to be uncommon. I n a letter received from the owner on the 24th June it was intimated that no cases of abortion' had occurred in the herd recently, and that the infected bull was being used only for the infected cows. A number of these were reported to be not holding to service. On the 8th July 1914 blood was forwarded from thirty-two animals that had previously been tested with negative result. On the present occasion there were three new reactors, viz., White and Red C. T., Red and White G. N., and heifer calf 184. In each of these cases agglutination was complete up to 1 in 200. It was learned that White and Red C. T. had aborted on the 5th July, about ten weeks before the proper time. The test of her blood had been negative on the two previous occasions. Red and White G. N. afterwards aborted, viz., on the 25th July, her date of service having been 4th December 1913. No 154 had been born on 31st March 1913; unfortunately it it is not known whether the dam was infected or not. On the z rst July 1914 blood was forwarded from six animals and tested with the following results : Bull NO.1, which was found to be infected Oll the occasion of the first test. Result: Complete agglutination up to 1 in 200. No. 173. This cow had passed two previous tests but had aborted on the roth July, her date of service having been r zth February. Result: Complete. agglutination up to I in 200. White and Red C. T. Result again positive, agglutination being complete in all three tubes. Light Red S. Y. This was a cow newly purchased with a view to her introduction into the herd. Result positive: Complete in all three tubes. Red and White S. Y. This cow had also been newly purchased. Result negative. On the 7th August 1914 blood was forwarded from three newly purchased cows, and the result of the test was negative in each case.

GENERAL ARTICLES.

1I9

On the 14th September 1914 thirty-three samples of blood were forwarded and when tested the result was positive in one only:No. 155. Agglutination compo in t and 1, and adv. in 2. The above thirty-three samples of blood included two from bulls, one of which (Bull NO.2), was being used for the healthy cows only. The other was a young animal (Bull NO.3) that six weeks previously had served a number of the infected cows. On the 14th November 1914 blood was forwarded from thirty-six animals, two of these being newly purchased cows and the remainder animals previously tested with negative results. The result of the test was quite negative in all the cases. On the z t st December 1914 blood was forwarded from ten newlypurchased cows, and the result was negative in all of them. On the 14th January 1915 blood was forwarded from ten animals, four of these being newly-purchased cows, while five were young animals that had not been previously tested, and the tenth, No. 169, was the dam of one of the calves (192). The result of the test was negative in all the cases except one, viz., No. 169. In this animal agglutination was adv. in ~, dist. in I, and neg. in 2. This cow aborted on the 7th January following. The date of her last service was the 1 t th August 1914. On the 22nd February blood was forwarded from forty-nine animals and the result was negative except in the following three:Red and White Y. D. Result: Compo in t and I, and nearly camp. in 2. Black Hood. Result: Compo in all three tubes. No. 151. Compo in all three tubes. On the 16th June 1915 forty samples of blood were forwarded from the herd, and the test had a positive result in the following two cases : Red 18: t comp., 1 dist., 2 apprec. Jersey: t and I comp., 2 nearly compo The first of these animals had passed all the previous tests, but the second had been purchased at the end of April and had apparently been put into the herd without having her tested. Blood from the two bulls used for the clean herd were included in the above test, but one of them had been used to serve the Jersey cow. This cow was supposed to be in calf at the date of sale, but she came into service soon afterwards. The owner was warned that he must expect disappointments if he introduced into the herd any animal that had not previously been tested. On the 25th June 1915 blood was forwarded from eight animals in the herd, and the result was positive in the following two animals : No. T8 1. Agglutination compo in all three tubes. This was one of the cows found to be infected on the occasion of the first test. Her last two calves had been carried to full term. Red Cow with Grey Tail. Result: t comp., 1 nearly comp., 2 neg. The six animals in which the above test was negative included

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No. 170 and No. 177. Both of these reacted on the r Sth April (see p. 117), and on that account the owner sent blood from them for a further test on the 8th July, when the result was again completely negative in both cases. It should be noted that on the occasion of the first test of these two cows agglutination was not complete in the I in 200 tube in either case, and it is probable that even at that date the animals were on the way to recovery. No. 170 calved at full term on roth June 1914, and the cow had not since been served. No. 177 had also carried her last calf to full term and had not since been served. The owner was advised that he might regard these two cows as fit to return to the herd. On the r yth July blood was forwarded from two cows and tested with a negative result in the case of one of them, No. 159. In the other, No. 160, agglutination was complete in all three tubes. She had been tested with negative result on the 25th February 1915. On the roth August 1915 blood was forwarded from eight animals, and the result of the test was positive in one, viz., No.2 Red and White, in which agglutination was compo in ~, adv. in I, and dist. in 2. Four samples of blood were forwarded on the 17th September 1915 and tested with negative results. In September 1915 there still remained on the farm twelve infected animals, but these were sold before the end of the month. On the 28th September blood was forwarded from eleven animals which had recently been bought, and in the case of two of these the result was positive, agglutination being complete in all three tubes in one of them and complete in I in 50 in the other. The last test of the herd was carried out at the end of December 1915 when blood was forwarded from thirty-five animals. The result of the test was negative in all of them except the following two:No. 170. Result: t adv., I apprec., 2 neg. No. 12. Result: ~. and I comp., 2 adv. Particulars were not furnished by the owner as to the history of No. 12. The reaction on the present occasion of No. 170 is interesting in view of the fact that her blood was tested with completely negative results on two occasions in July 1915. The facts might be interpreted in two different ways. In the first place it might be supposed that at the date of the tests in July the cow had actually recovered, and that in the interval she had become re-infected. The second and more probable explanation of the facts is that in a recovering animal the agglutination titre shows considerable fluctuations. In this connection it ought to be noted that at the period when this herd was dealt with I in 50 was the strongest dilution employed in the tests. Subsequently it was discovered that this frequently failed to reveal either very recent or very old infection, and consequently a I in 25 dilution Ci tube) was introduced into the test. It is very probably that if such a dilution had been employed in testing the blood of No. 170 in July 1915 the result would not have been entirely negative. In a letter dated 7th January 1918 the owner intimated that he had had no cases of abortion in the herd since May 1916.

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HERD NO.5.

The first test of blood from this herd was made in October 1914. The animal in question was a heifer that had aborted on the roth October, and agglutination was complete in i, !Z, and 1. It was ascertained that in a lot of eight heifers on the same farm three cases of abortion had occurred in the spring of 1913. These three animals were afterwards isolated and sold to a butcher. In April, June, and September 1914 three other cases of abortion, all in cows, had occurred. On the 3rd November 1914 blood from eighteen animals in the herd was tested with the following result:Q. A. Complete in all three tubes. T. Y. Complete in all three tubes. L. L. ! and 1 comp., 2 nearly compo Belle. !z comp., 1 and 2 nearly cornp. Rain. ~- and 1 comp., 2 nearly camp. Shamrock. All compo Betty. All.cornp. Cowslip. ! comp., 1 nearly cornp., 2 adv. Rosebud. ~ and 1 comp., 2 dist. All the reacting animals were cows. The nine non - reacting animals included four cows, one valuable bull, and four young calves. On the roth November 1914 blood was forwarded from fourteen other animals in the herd, and the result was negative in all the cases except one, No. 35, in which agglutination was comp, in ~, nearly cornp. in 1, and adv. in 2. It was subsequently ascertained that this was a heifer belonging to the same lot as the one that aborted on 16th October. The reacting animals were promptly removed to separate premises,. and on the znd February 1915 blood was forwarded from thirty-one animals in the herd, and tested with a positive result in the following fourteen : Doris. Agglutination compo in all three tubes. Heifer 33. ! and 1 cornp., 2 nearly comp. Shamrock. All camp. Rosebud. All com p. Betty. All cornp. L. L. ! and 1 comp., 2 nearly compo No. 36. All compo Cowslip 22. All comp. Patience. ! and 1 comp., 2 nearly compo Belle. All compo Heifer 31. All camp. Heifer calf out of Belle. !z and 1 comp., 2 nearly camp. Duchess. All cornp. No name. ~ comp., 1 and 2 neg. It will be observed that several of these had previously reacted, but blood was sent from them for a second test in the hope that it might show evidence of recovery. On the 7th May 1915 twenty-one samples of blood from the herd were tested, and reactions occurred in the following : Daisy. t apprec., 1 neg.

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Calf ex Doris. ! adv., I apprec., 2 neg. Calf ex Duchess. All compo Belle. All compo Calf ex Belle. ! nearly comp., I apprec., 2 neg. Daisy had passed the two previous tests, and had calved at the proper time about three weeks before the present sample of blood was sent. Another sample of blood from Daisy was forwarded on the zoth May and tested with exactly the same result: ~ apprec., I and 2 neg. The owner was informed that the cow might be regarded as non-infected. On the 22nd July blood was tested from a cow with a view to her purchase, but the result indicated that she was infected: t nearly comp., I and 2 neg. On the 27th September IgI5 blood was tested from twenty animals in the herd and the result was negative in all of them except Belle, which was an old reactor. In that case agglutination was complete in all tubes. Amongst those in which the result was negative were the calves out of Daisy, Doris, and Belle. On the 24th January IgI6 blood was forwarded from nineteen animals, and the result was negative in all of them except one, in which agglutination was very advanced in ~, dist. in I, and neg. in 2. When the result of the test was reported it was ascertained that this animal was a bull, and that he had been on the premises since September IgI5. Before he was brought to this herd he had been tested with negative result in another herd in which he was bred. He had never been used for the service of any infected cow. He had been born in July IgI4 and his dam had been tested afterwards with negative result. Another sample of blood was forwarded from this bull on the 7th February and agglutination was adv. in t, and neg. in I and 2. A third sample of blood from the bull was forwarded on the 6th March IgI6 and the result of the test was exactly the same as on the first occasion, viz., t adv., I dist., and 2 neg. Blood was again tested from the bull on 2gth April IgI6 and on this occasion agglutination was compo in k, adv. in I, and dist. in 2. On the zznd May IgI8 blood was forwarded from the healthy section of the herd now numbering twenty-two animals including calves, and the result was quite negative in every case. Another general test was carried out on the zoth February I 9 I 8 and the result, as on the previous occasion, was negative in every case. On the roth December IgIg blood was forwarded from all the animals in the herd, viz., twenty-eight, and the result was quite negative except in one, in which agglutination was dist. in i, and neg. in l It was afterwards learned that this was a bull calved in May IgI8. He was included in the previous test in July IgIg, and the result of the test was then negative. Blood was again forwarded from the bull on the I7th January and on this occasion the result of the test was quite negative. It was therefore advised that the bull might be considered not infected.

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12 3

A general test of the herd was again carried out on the r r th June 1920 and it had a negative result in every case. The herd then numbered one bull, ten cows, thirteen heifers, and one calf. HERD NO.6.

This was a small but select herd of valuable pedigree animals which was believed to be quite free from contagious abortion. I t was stated that no case of abortion had occurred in it for three years previous to May 1915. On the roth May in that year a sample of blood was forwarded from a cow Dewdrop which had recently calved at full term. but to which a slight suspicion attached because the calf was small and there was a discharge for about ten days after parturition. The result of the test was negative. The next sample of blood was forwarded on the t oth November 1915 from a cow J--n T. that had aborted at the seventh month of pregnancy, and when tested agglutination was compo in ! and 1, and nearly compo in 2. It was reported to the owner that the case was undoubtedly one of contagious abortion, and an offer was made to test all the other animals in the herd. A list subsequently received showed that the herd at this time comprised twenty-three cows, ten young heifers and calves varying in age from fifteen to seven and a half months, and five heifer calves under six months old. There were also three bulls in the herd at this time, but only one of them was being used for the cows. His age was one year and nine months. The other two were younger animals. None of the younger heifers had yet been served. Fifteen of the cows were in calf at the time, seven had not yet been served since the previous calving, and one was barren and being' fattened off. It was suggested that, at least in the meantime, the testing of the young animals might be allowed to stand over, but that the older animals should be tested as soon as possible. Blood was accordingly forwarded on the 9th December 1915 from eighteen of the cows, and the result was negative in all of them except the following two;G--n. Result i j, and 1 camp., 2 nearly compo This cow had had her last calf on the 22nd January 1915 and the date of her last service was 25th June 1915. J--n. Result: Agglutination cornp, up to I in 200 (the highest dilution used). On the r yth December the reacting cows were sent off to separate buildings at a considerable distance from the place where the herd was kept, and arrangements were made to have them looked after by a man who would have nothing to do with the nonreacting animals. After these infected animals had been removed the whole of the buildings and yards were cleansed as thoroughly as possible and disinfected. On the 31st December blood was forwarded from two other C;OWS for the first time and tested with negative result. On the r zth January 1916 blood was forwarded from twelve animals that had passed the previous test and the results were

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again negative in all of them except in a cow F --e, in which case agglutination was cornp. in t, adv. in I, and dist. in 2. This cow had her last calf on the 8th November 1914, and, as she had not been served since, her infection was of special interest. The cow was promptly removed from the non-reacting portion of the herd and placed with the other reactors. 28th February 1916. On this date blood was forwarded from twelve animals and tested with negative results. rst April 1916. On this date blood was forwarded for the first time from two cows and tested with negative result. On the 6th April 1916 blood was forwarded from a heifer calf to which the reacting cow G--n had given birth on the 31st March, and the result of the test was positive: ! and I comp., 2 nearly comp. On the 6th July 1916 blood was forwarded from one of the bulls and tested with negative result. The owner wished the test to be carried out because this was the bull that served J--n T., the cow that aborted on the r zth November 1914. On the 24th July 1916 blood was forwarded from all the healthy cows and heifers in the herd, nineteen in number, and the result was negative in all of them. On the 3rd August 1916 blood was tested for the first time with negative results from two young heifers, now in calf. r Sth May 1917. Blood was forwarded for the first time and tested with a negative result from another young heifer now in calf. z Sth July 1917. Blood was forwarded from the bull D. F--m, which had served the three isolated infected cows, and the result of the test was negative. 28th August 1917. Blood was forwarded on this date from a cow (D--) that had calved twenty-five days before the proper time. The calf was small but appeared healthy, and the result of the test was negative. It was advised that a second sample of blood should be sent from the cow in a few weeks, and that she should in the interval be kept isolated. A further test was therefore carried out on the zoth September, and the result was again negative. zoth November 1917. On this date blood was forwarded for the first time from two pregnant heifers. In one of them (M--l) the result was quite negative. In the other (D--;-s) agglutination was compo in 1, ~, and I, and nearly compo in 2, and it was intimated that this animal must be regarded as certainly infected. No further communication with regard to the herd was made until May 1918. On the 7th of that month blood was forwarded from all the twenty-nine cows and heifers which now formed the healthy portion of the herd and when tested the result was completely negative in all except two : Fame, agglutination adv. in I in 25, and neg. in I in 50. Dora, agglutination dist, in I in 25, and neg. in I in 50. Nothing further was reported from the herd until zoth February 1919, when blood was forwarded from the above heifer Fame. which had calved a live calf seven days over time on the z r st January, and had since had a discharge.

GENERAL ARTICLES.

The test of the blood was quite negative. No case of abortion has occurred in the herd since the date of the last test, but in February of the present year a sample of blood was tested from a heifer that had calved eleven days before her time and afterwards showed some discharge from the vagina. Both cow and calf were reported to be otherwise all right, and the result of the test was quite negative. As already stated, the cows found to be infected were removed to separate premises and kept there under strict isolation until they were eventually disposed of. While under separation they were subjected to a number of tests at intervals, in the hope that a marked decline in the agglutination titre would indicate that they had recovered, and that they might eventually be returned to the healthy herd. That hope, however, was not realised and none of them was returned to the herd. While under isolation three of the cows had calves, and in one of these the first blood test, made when it was about four months old, had a negative result. In the other two calves the first test was positive and the second negative. The details of the various tests to which these six animals were subjected are shown below:-

Cow J--n T. roth November 1915. Aborted at seventh month of pregnancy. roth November 1915. Tested i j, and 1 comp., 2 nearly compo r zth January 19[6. Tested: ~ and I comp., 2 nearly comp. jrd August 1916. Tested: compo up to 1 in 200. zoth February 1917. Tested: ~ comp., I nearly comp., 2 apprec. 8th April 1917. Gave birth to a heifer calf. roth June 1917. Tested: comp up to I in 200. zoth September 1917. Tested: i nearly camp., ! and 1 camp., 2 nearly compo 26th November 1917. Tested: nearly compo in 1 in 200. 7th May 1918. Tested: i and ~ nearly cornp.

Calf out

0./ the above Cow.

This animal was born on the 8th April 1917, and tested, for the first time, with a negative result on z Sth July 1917.

CowJ--n. 9th December 1915. Tested for the first time. Agglutination camp. up to I in 200. 17th January 1916. Tested: all cornp. 31st July 1916. Gave birth to a heifer calf. 3rd August 1916. Tested: compo up to 1 in 200. 26th February 1917. Tested r j- comp., I nearly camp., 2 adv. roth June 1917. Tested: camp. up to I in 200. zoth September 1917. Tested: camp. up to 1 in 200. 26th November 1917. Tested: cornp. up to 1 in 200. 7th May 1918. Tested: comp, i and !.

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Calf out of tlte above Cow. Born 31st July 1916. 3rd August 1916 Tested: Positive up to r oth June 1917. Tested: Negative.

I

in 200.

Cow G--n. 9th December 1915. Tested for the first time. i and I cornp. 2 nearly compo 17th January 1916. Tested: i comp., I nearly comp., 2 adv. 31st March 1916. Gave birth to a heifer calf. 3rd. August 1916. Tested: i comp., I nearly comp.. 2 neg. 26th February 1917. Tested: i nearly comp., I dist., 2 neg. roth June 1917. Tested: t and I comp., 2 nearly comp. zoth September 1917. Tested: i and i comp., I dist., 2 neg. 26th November 1917. Tested: i, i, and I comp., 2 nearly compo 7th May 1918. Tested: i and t compo

Calf out of tlte above Cow. Born 31st March 1916. 6th April 1916. Tested: i and I comp., 2 nearly compo 14th November 1916. Tested: negative.

HORSE POX AND COITAL EXANTHEMA.

By J. F. CRAIG. M.A., F.R.C.V.S., and D. KEHOE, M.R.C.V.S., Royal Veterinary College of Ireland, Dublin. DR. D. A. De j ong ' in 1914 and 1915 definitely proved the identity of contagious pustular stomatitis with equine variola, and there can no longer be any doubt as to the etiology of the former disease, which had previously been the subject of considerable controversy among continental writers. The exact position of so-called vesicular or coital exanthema in relation to horse pox has not been definitely settled, although it has been surmised from time to time that the two conditions are identical. The following outbreak, which came under our notice in April 1920, has some bearing on the question. The animals affected were thoroughbreds and included one stallion and six mares. The stallion up to the time at which the outbreak occurred had shown no evidence of any disease of the genital organs, and the facts rather suggest that the disease was brought in by one of the mares. I The Relationship between Contagious Pustular Stomatitis of the Horse. Equine Variola (Horse Pox of Jenner) and Vaccinia (Cow Pox of Jenner). Dr D. A. De Jong. "Folia Microbiologica" Vol. IV, 1916. pp. 239-266. Translated in "Journal of Comparative Pathology and Therapeutics," Vol. XXX., Part 3, September 1917, pp. 242-262.