Prophylaxis of lamb dysentery / by T. Dalling, J.H. Mason, and W.S. Gordon.

  • Dalling, Thomas.
Date:
[1927?]
Catalogue details

Licence: In copyright

Credit: Prophylaxis of lamb dysentery / by T. Dalling, J.H. Mason, and W.S. Gordon. Source: Wellcome Collection.

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    B.—Farms on which no controls were kept. Such farms were mostly in Northumberland and serum was used usually from the beginning of lambing. Post-mortem work was not carried out, no controls were kept, and the figures were supplied by the farmers at the end of the lambing season. On all farms the death rate had been heavy for the past two or more years. The results are tabulated in Table VI, and show that of 1,877 lambs so treated, two died of lamb dysentery. The serum used on these farms was 50 per cent, lamb dysentery B. welchii antitoxin and 50 per cent. B. coli anti¬ serum. TABLE VI. Serum. Uncontrolled. All lambs on infected farms were injected with serum soon after birth. Farm. Lambs injected. Lambs died. A. 820 2 B. 650 0 C. 210 0 D. 70 0 E. 52 0 F. 75 0 I 1877 2 Hare and Glynn (2) suggest that our serum results in 1926 may be due in part to the non-specific action of horse serum. In 1927 we attempted to carry out an experiment in which lambs on an infected farm were to be injected with normal horse serum. Unfortunately, owing to the low incidence of the disease on this selected farm, we are unable to draw any conclusions. We know, however, from work some years ago that a low titre serum (made from organisms isolated from lamb dysentery subjects) proved useless in preventing the disease. Experiments with L.D. B. welchii T.A.M. alone. We carried out a number of experiments in which toxin-antitoxin made from the lamb dysentery type of B. welchii alone constituted the vaccine. The results of injecting serum made from the L.D. type of B. welchii into young lambs suggests that B. coli has little pathogenic significance on lamb dysentery, and the results recorded in Table VII would seem to strengthen this view. Two types of experiment were undertaken : (a) inoculation of ewes once in autumn and once in spring, and (b) inoculation of pregnant ewes twice in the spring. Of 466 lambs born of ewes inoculated once in autumn and once in spring, five or 1*08 per cent, died of lamb dysentery, while of 105 lambs born from control ewes on the same hirsels, 14 or 13‘33 per cent. died. Of 1,934 lambs born of ewes inoculated twice in the spring, 42 or 2T7 per cent, died of lamb dysentery, while of 187 lambs born of inoculated ewes on the same farms, ten or 5*34 per cent. died. Summary and Conclusions. (1) Vaccines made from a type of B. welchii and from strains of B. Coli isolated from lambs affected with lamb dysentery have been
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