Abstract
This study was carried out to investigate the epidemiological prevalence of diseases from birth to weaning in 268 Koeran native calves which was delivered from three stock farm in Chonbuk area. We examined body weight gain, incidence rate of diseases and mortality rate in relation to age, season, environmental temperature and rearing management conditions for one year. The results of this experiment were as follows: Birth weight and body weight gain of Korean native calves born of primiparae were lower than those of multiparae. Body weight gain of diseased calves was lower than normal calves. Of 268 delivered calves, 242 calves(90.3%) were affected with gastronistestinal and/or respiratory diseases. The prevalence of the diseases were gastronitestinal disease(54.1%), gastronitestinal and respiratory disease(21.6%), and respiratory disease(14.5%). Of 242 diseased calves, 33 calves(13.6%) were occurred gastronitestinal disease and respiratory disease at different time respectively. Of 268 delivered calves, 126 calves were died(47%). The prevalence of the death were gastronitestinal disease(31.4%), gastronitestinal and respiratory disease(14.5%), and respiratory disease(1.1%). 81% of the diseases and 76.2% of the death were occurred in winter and a change of season(December to May). 59.1% of the diseases and 52.4% of the death were occurred at atmospheric temperatures below 1$0^{\circ}C$. 91.7% of the diseased calves and 96.8% of the dead calves were born of primiparae. 77.2% of the gastronitestinal disease were occurred within 2 weeks old, and the incidence was decreased with increasing age. Whereas the incidence of respiratory disease was incidence with ageing, and 69.2% of the respiratory disease were occurred between 2 weeks and 5 weeks old. And 62% of the gastronitestinal and respiratory disease wre occurred between 1 week and 3 weeks old. 65.1% of the dead calves were died within 2 weeks old. The morbidity and population mortality rate in each farm stock were 56.5%-104.9%, and 14.5%-64.2%, respectively.