Abstract
A total of 2,698 dairy herds were surveyed in 1981–1982 in New South Wales and north eastern Victoria in a review of the methods used to monitor them for the presence of Brucella abortus., The methods used to monitor dairy herds were testing of all breeding cows over 1 year of age using the rose bengal test (RBT) and complement fixation test (CFT), the bulk milk ring test (BMRT), and testing of blood samples collected at abattoirs using the RBT and CFT. The surveyed herds had at least one whole herd test, and BMRT was done at regular intervals in the period of the survey.
Of the 99 (3.7%) herds that reacted to the BMRT, 91 (3.4%) herds had false positive reactions and 8 (0.3%) herds were declared infected on follow‐up herd testing. False‐positive reactions were obtained in 22 herds on more than one occasion. Common causes of false positive reactions to the BMRT were thought to be previous vaccination with Strain 19 and sampling in very early or late lactation.
Of the 98 (3.63%) herds that reacted to the whole herd serological tests, 80 (2.96%) herds had false‐positive reactions and 18 (0.67%) herds were declared infected. Strain 19 vaccination was thought to be an important cause of false‐positive reactions. Fifty‐three (2.0%) herds showed suspicious reactions on abattoir monitoring but none was declared infected on follow‐up testing.
Of the 18 herds with infected or equivocal status, the BMRT identified 8. In a further 6 herds, the infected cattle were not in the milking herd. Four other herds had milkers with high CFT titres which could not be confirmed as infected on culture. In no herds were culture positive RBT or CFT reactors from the milking herd detected without the BMRT being positive. The proportion of false‐positive reactions to the BMRT was high but the BMRT proved very useful in identifying dairy herds infected with B. abortus, when the prevalence of brucellosis was very low. Aust Vet J, 64: 97–100
Reference
- Anon (1979a) – Bovine Brucellosis and Tuberculosis. National Brucellosis and Tuberculosis Eradication Campaign. Standard Definitions and Rules, Vol 1, Australian Bureau of Animal Health, Canberra . [Google Scholar]
- Anon (1979b) – Bovine Brucellosis and Tuberculosis. National Brucellosis and Tuberculosis Eradication Campaign. Standard Definitions and Rules, Vol 2, Australian Bureau of Animal Health, Canberra . [Google Scholar]
- Alton G G, Maw J., Rogerson B A and McPherson G G (1975a) – Aust Vet J, 56: 57. [DOI] [PubMed] [Google Scholar]
- Alton G G, Jones L M and Pietz D E (1975b) – Laboratory Techniques In Brucellosis, 2nd edition, Monograph Series No. 55, WHO, Geneva . [PubMed] [Google Scholar]
- Beck C C, Ellis D J, Fitchness G J, Laiho E R and Whitehead G C (1964) J Am Vet Med Ass, 144: 620. [PubMed] [Google Scholar]
- Cannon R M and Roe R T (1982) – Livestock Disease Surveys: A Field Manual for Veterinarians., Aust Govt Publ Serv, Canberra , p 15. [Google Scholar]
- Cargill C., Lee K. and Clarke I. (1985) – Aust Vet J, 62: 49. [DOI] [PubMed] [Google Scholar]
- Corner L A, Alton G G and Iyer H. (1985) – Aust Vet J, 62: 187. [DOI] [PubMed] [Google Scholar]
- Cullen G A and Corbel M J (1970) – Vet Rec, 87: 101. [DOI] [PubMed] [Google Scholar]
- Farrell I D (1974) – Res Vet Sci, 16: 280. [PubMed] [Google Scholar]
- Hoare R J T (1985) – The Implementation of Control Programs for Bovine Masitis, M V Sc Thesis, University of Sydney. [Google Scholar]
- Hornitzky M. and Searson J. (1986) – Aust Vet J, 63: 172. [DOI] [PubMed] [Google Scholar]
- Nicoletti P. (1969) – Am J Vet Res, 30: 1811. [PubMed] [Google Scholar]
- Nicoletti P. (1979) – Proc 83rd Ann Meet, US Anim Hlth Ass, 83: 91. [Google Scholar]
- Pietz D., (1977) – In Crawford R P. and Hidalgo R J. (Eds), Bovine Brucellosis: An International Symposium, College Station , Texas , Texas A & M University Press. [Google Scholar]
- Plackett P., Cottew G S and Best S J (1976) – Aust Vet J, 52: 136. [DOI] [PubMed] [Google Scholar]
- Roepke M H, Paterson K G, Driver F C, Clausen L B, Olson L. and Wentworth J E (1950) – J Am Vet Med Ass, 11: 199. [PubMed] [Google Scholar]
- Roepke M H and Stiles F C (1970) – Am J Vet Res, 31: 2145. [PubMed] [Google Scholar]
- Rolfe D C (1984) – Bovine Brucellosis Breakdown: Papers Presented at a Workshop., Victorian Department of Agriculture, p 93. [Google Scholar]