Vaccination of Sheep against Scabby Mouth

New Zealand Journal of Agriculture, Volume 81, Issue 1, 15 July 1950, Page 19

Vaccination of Sheep against Scabby Mouth

By

J. J. G. PEDDIE,

Bacteriologist,

Department of Agriculture Animal Research Station, Wallaceville.

CONTAGIOUS ecthyma vaccine issued by the Department of Agriculture Animal Research Station, Wallaceville, is, if properly used, 100 per cent, efficient in preventing scabby mouth in inoculated sheep. DURING the past season several flock owners have written stating that lambs vaccinated against contagious ecthyma have subsequently developed the disease. If such breakdowns were the result of a faulty vaccine or due to the presence of a new disease, the position would be serious. In almost every instance of possible breakdowns the vaccine issued and affected sheep or material from affected sheep were tested at Wallaceville. In all tests the vaccine proved active and thoroughly effective in preventing subsequent development of the disease. Contagious ecthyma proved to be the trouble with all affected sheep or material from affected sheep, so that a new disease of similar type cannot be stated to exist. Further, some flocks in which breakdowns had occurred showed positive “takes” to revaccination. Failure on Part of Vaccinator From the facts it is clear that the failure has been on the part of the vaccinator. Two main factors seem to be involved in such cases: First, the wax-like material normally found on

the skin of the sheep clogs the eye of the needle so that little or no vaccine is removed from the bottle when the needle is dipped. Care must therefore be taken to keep the eye of the needle cleaned. To do this it is essential not only to wipe the needle but also to dab it either in the wool of the sheep or in cottonwool. Secondly, the pressure used in scarifying should be sufficient to break the skin surface. This does not necessarily mean that blood should be drawn, but it is better to err on the safe side and scratch firmly. The vaccine is supplied as a powder contained in a small phial. Each phial contains sufficient material to vaccinate 500 animals. It is not economic to make this vaccine up in smaller amounts, so that if smaller numbers of animals are to be treated one phial is made up and unused vaccine is thrown out. The strength at which the vaccine is used is four times greater than necessary, so that there is a large margin of safety. Method of Vaccination The method of vaccination is as follows: , - 1. The powder in the small phial is added to the bottle of diluting fluid supplied and this is shaken vigorously to ensure thorough mixing. ■ 2. Lambs are vaccinated on the bare skin on the inner side of the thigh. 3. The needle with the sawn-off. eye is dipped in the vaccine mixture and used to scratch the skin. A single firm scratch about 2in. long is sufficient. The eye of the needle should be kept clean and sufficient pressure used to ensure a “take”.

The vaccine must be used within a month from the date of issue and once mixed must be used within 24 hours. If possible, vaccinated animals should be examined 10 days after vaccination, when all vaccinated animals should show typical scab formation at the scarified area. In all cases of suspected breakdown the following material should be sent to the Chief Diagnostic Officer, Animal Research Station, Wallaceville: — 1. Any unused vaccine. 2. An affected sheep or material from affected sheep.