[Experimental infection with Salmonella abortus ovis in rams]

The susceptibility of rams to experimental challenge with Salmonella abortus ovis was investigated by subcutaneous, conjunctival or preputial administration of 1 X 10(10) viable salmonella to 3 groups of 6 adult Préalpes rams. Slaughter and autopsy of 15 rams were made 83 days after challenge. Each of the 3 remaining rams was introduced in 3 groups of 6 salmonellosis-free ewes. The subcutaneous injection caused a significant hyperthermia, a rapid increase in antibody titers without detectable genital excretion of salmonella. The conjunctival or preputial challenge caused a significant serological response without fever; S. abortus ovis was isolated from samples taken 1 to 13 days after challenge only in rams challenged by the preputial route. No salmonella was isolated from organs of the 15 slaughtered rams. Ewes made pregnant by the 3 remaining rams showed no signs of infection. In our experimental conditions, a genital colonization was not observed; a passive genital carriage of S. abortus ovis was shown to be possible; its hypothetical epidemiological role was discussed.