A survey of infectious bovine keratoconjunctivitis in the Gisborne and Hunterville regions of New Zealand

A postal survey of 400 beef farmers in the Hunterville and Gisborne districts sought to identify features of farms or management procedures that might influence the occurrence, transmission or severity of infectious bovine keratoconjunctivitis (IBK). The overall response rate was 72%. The annual incidence of IBK outbreaks rose from 10% to 28% between the years 1977 to 1981 and was similar for both districts. Prevalence was highest during mid-summer and lowest in mid-winter. Larger properties were more prone to outbreaks. In both districts, farmers of IBK-free properties purchased fewer cattle than those who had experienced IBK and this distinction was more evident in the Hunterville area. Only in the Gisborne district did a Hereford breed predisposition to infection become apparent. All age groups were affected with IBK but the attack rate was highest in the younger cattle. Eleven percent of farmers routinely treated their cattle for IBK and that produced an earlier resolution of lesions and fewer cattle in which healing extended longer than four weeks. Most farmers considered IBK to be an inconvenience which limited livestock production through reducing growth rates and lowering monetary returns when stock had to be sold at unsuitable times. Eye disfigurement caused loss of value in stud and export stock.