Susceptibility to Tropical Theileriosis of Calves Born to Dams Immunized with Theileria annulata (Hisar) Cell Culture Vaccine

Author： Beniwal R.K. Sharma R.D. Nichani A.K.

Publisher： Springer Publishing Company

ISSN： 0049-4747

Source： Tropical Animal Health and Production, Vol.30, Iss.6, 1998-12, pp. : 341-349

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Abstract

The susceptibility/immune status to tropical theileriosis of calves born of immunized dams was evaluated. Six cows were vaccinated with the Theileria annulata cell culture vaccine in the eighth month of pregnancy. Sera from the immunized dams exhibited very high post-vaccination antibody titres as determined by the indirect fluorescent antibody (IFA) test. The calves born to these dams did not show antibodies against T. annulata at the time of birth (IFA titres of <1:20). the="" new-born="" calves="" were="" fed="" colostrum="" from="" their="" mothers="" and="" were="" challenged="" with="" t.="" annulata-infected="" ground="" tick="" supernate="" at="" 5–7="" days="" of="" age.="" all="" the="" calves="" developed="" fever="" (from="" day="" 5–6="" onwards)="" and="" parasitological="" reactions="" (from="" day="" 8–9="" onwards)="" after="" challenge.="" there="" was="" a="" significant="" decrease="" in="" the="" haemoglobin="" and="" packed="" cell="" volume="" of="" the="" calves="" after="" challenge.="" all="" the="" calves="" showed="" signs="" of="" acute="" theileriosis="" by="" day="" 9–10="" after="" challenge="" and="" had="" to="" be="" treated="" with="" buparvaquone="" in="" order="" to="" save="" their="" lives.="" the="" study="" indicated="" that="" detectable="" levels="" of="" anti-theilerial="" antibodies="" were="" not="" transferred="" from="" immune="" dams="" to="" their="" offspring.="" all="" the="" calves="" born="" to="" immunized="" dams="" were="" fully="" susceptible="" to="" theileriosis="" and="" thus="" themselves="" needed="" vaccination.="">