Efficacy of an inactivated oil emulsion vaccine against hydropericardium syndrome in broilers

Two inactivated vaccines were prepared against hydropericardium syndrome. T he vaccine prepared from liver homogenate extracted with chloroform, inacti vated with formalin and adjuvanted with liquid paraffin was highly effectiv e against challenge in chickens aged three, five and seven weeks. Seroconve rsion following vaccination and challenge was assessed by the agar gel immu nodiffusion test The inactivated oil emulsion vaccine was highly effective against the syndrome in both experimental trials and field trials.