Epidemiology of salmonella infection of calves (2) : detailed study in a large beef rearing unit
Osborne, A.D.; Linton, A.H.; Pethiyagoda, S.
Veterinary Record 94(26): 604-610
1974
ISSN/ISBN: 0042-4900 PMID: 4439620 Document Number: 70358
A three year study on the incidence of salmonella excretion by calves introduced to a large calf rearing unit for a beef progeny testing programme is described. The incidence of excretors in animals picked up from farms of birth was 3.16% of 1708 animals. Over the six weeks which followed introduction to the unit the level of infection, as judged by excretion of the organism, rose to a peak usually by the second week after arrival and then fell gradually so that at the end of the period very few animals were identified as excretors. On only one occasion was excretion detected in an animal of 12 weeks of age, and no evidence of continued carriage of the organism could be detected in animals slaughtered after one year. With the aid of biotyping of isolates of S. dublin it was possible to trace spread of infection within a pen following the introduction of infected animals and after movement of animals from one pen to another. No serious outbreak of disease was encountered during the period of study. Although this could be attributed in part to the use of attenuated S. dublin vaccines, it was influenced, almost certainly, by the quality of the buildings and the high standard of management.