Evaluation of periparturient dairy cows and contact surfaces as a reservoir of Cryptosporidium parvum for calfhood infection.

OBJECTIVE

To determine whether periparturient cows or contact surfaces to which newborn calves are exposed are reservoirs of Cryptosporidium parvum oocysts.

ANIMALS: Periparturient cows and their calves.

PROCEDURE: Using direct fluorescent antibody (DFA) and acid-fast (AF) assays, fecal samples taken before and after calving from periparturient cows were tested for C parvum oocysts. Fecal samples from calves were collected every other day from age 7 to 21 days and were tested by use of the AF assay. Topsoil from close-up and maternity pens and scrapings from wooden walls and floors of calf hutches were tested for C parvum oocysts by use of DFA assay.

RESULTS

None of the 384 fecal samples obtained 1 to 21 days before or after calving or on the day of calving from 154 periparturient cows contained detectable C parvum oocysts. Despite this lack of detectable periparturient shedding, the period prevalence of calfhood infection was 92% (123/134) from age 7 to 21 days. Soil samples from the close-up and maternity pens where newborn calves spend the first 12 hours of life also were negative for C parvum oocysts. Wood scrap ings from the outer 2 mm of the walls and floors of empty and cleaned calf hutches that were ready to receive calves were C parvum oocyst-positive.

CONCLUSIONS

Conditional on sensitivity of DFA, periparturient cows did not appear to shed detectable C parvum oocysts. In contrast, the floors and walls of wooden calf hutches contained detectable C parvum oocysts on the surface.