Effect of Vaccination in the Field with the Theileria annulata (Hisar) Cell Culture Vaccine on Young Calves Born during the Winter Season

Author： Khatri N.

Publisher： Springer Publishing Company

ISSN： 0165-7380

Source： Veterinary Research Communications, Vol.25, Iss.3, 2001-04, pp. : 179-188

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Abstract

The responses were monitored of young crossbred calves vaccinated against tropical theileriosis during the winter against a field tick challenge in the disease season. Thirty-eight calves below 2 months of age, born after the end of the disease season, were selected at an organized farm. Twenty-five animals were vaccinated with Theileria annulata (Hisar) cell culture vaccine (developed at CCS HAU Hisar laboratory) after the end of the disease season and 13 calves were kept as non-vaccinated controls. These calves were observed for their susceptibility to theileriosis in the new disease season. There was an increase in antibody titre in 18 of the 25 vaccinated animals one month after vaccination. The antibody titre then declined gradually, but remained higher than those of the non-vaccinated animals at month 0. No fever or other clinical signs of tropical theileriosis were observed in any of the vaccinated animals. Nine out of 25 (36%) vaccinated calves showed occasional piroplasms (<0.5%) in="" blood="" smears.="" all="" the="" vaccinated="" animals="" withstood="" the="" field="" tick="" challenge.="" on="" the="" other="" hand,="" 9="" of="" the="" 13="" (69%)="" unvaccinated="" calves="" exhibited="" occasional="" piroplasms,="" and="" included="" three="" clinical="" cases="" of="" tropical="" theileriosis.="" these="" observations="" suggest="" that="" young="" crossbred="" calves="" vaccinated="" with="" the="" t.="" annulata="" (hisar)="" cell="" culture="" vaccine="" at="" the="" end="" of="" the="" disease="" season="" were="" relatively="" resistant="" during="" the="" next="" disease="" season.="">