How early can heifer calves be vaccinated for Lepto and be protected?
That was one of the questions asked by the research team that reported their finding in Cortese, V.S. and Others, "Efficacy of a flexible schedule for administration of a Leptospira borgpetersenii serovar Hardjo bacterin to beef calves." American Journal of Veterinary Research 75:507-512, May 2014.
Very condense protocol: 55 calves in 3 treatments
1. Control - no vaccine
2. One dose of L. Hardjo vaccine (about 20-29 days of age)
3. Two doses of L. Hardjo vaccine (1st on between 20-29 days old, 2nd dose average 136 days after first)
22 days after the second vaccination all three groups were challenged with L. Hardjo pathogen.
Findings: Was it possible to isolate in either urine or kidneys the pathogen to which they were exposed in the challenge?