Field testing of prophylactic measures against Cryptosporidium parvum infection in calves in a California dairy herd.
OBJECTIVE
To test the ability of oral vaccination or probiotic treatment with lactic acid-producing bacteria to protect calves from Cryptosporidium parvum infection under field conditions.


METHODS
134 Holstein calves born on a dairy farm where cryptosporidiosis was endemic.


METHODS
Calves were randomly assigned to 1 of 3 treatment groups at birth. Calves in the vaccine group received an oral dose of C parvum vaccine within several hours of birth. Calves in the bacteria group received an oral dose of lactic acid-producing bacteria daily for the first 10 days after birth. Control calves were not treated. All calves were monitored for diarrhea and fecal shedding of C parvum oocysts for 3 weeks.


RESULTS
There were no significant differences in the incidence of diarrhea and oocyst shedding among the 3 groups.


CONCLUSIONS
Neither vaccination nor probiotic treatment was effective in preventing C parvum infection in calves under field conditions. High numbers of C parvum in the environment may have overwhelmed any potential benefits of these regimens. Further work is necessary to develop effective prophylaxis against C parvum under field conditions.
USDA, Agricultural Research Service, National Animal Disease Center, Ames, IA 50010-0070, USA.
J A
JA
Harp
P
P
Jardon
E R
ER
Atwill
M
M
Zylstra
S
S
Checel
J P
JP
Goff
C
C
De Simone
D000818:Animals; D002140:California; D002417:Cattle; D002418:Cattle Diseases / Q000469:parasitology / Q000517:prevention & control*; D003457:Cryptosporidiosis / Q000517:prevention & control / Q000662:veterinary*; D016785:Cryptosporidium parvum; D003967:Diarrhea / Q000469:parasitology / Q000517:prevention & control / Q000662:veterinary; D016052:Protozoan Vaccines / Q000627:therapeutic use*; D011897:Random Allocation
D016052:Protozoan Vaccines