EPIDEMIOLOGICAL EVIDENCE OF CALF NEONATAL COLIBACTERIOSIS IN LARGE INTESIVE DAIRY FARMS

Abstract

During the period 2009-2010 twenty two large intensive dairy farms in 12 regions of Bulgaria were investigated for neonatal calf diarrhea. Epidemiological studies were purposely for determination of prevalence of enterotoxigenic E. coli as a primary causative agent and to determine the parameters of the disease in newborn calves population. A total of 188 samples were studied which 155 of suckler's faeces and 33 samples of bowel contents of dead calves after illness from diarrhea. In the period of study in 49.5% of samples were positive for bacterial findings. One hundred and fourteen strains were isolated belonging to seven taxonomic varieties. This species is designated as a primary agent in the etiopathogenesis of intestinal diseases of calves during the first week of the live. A higher prevalence of neonatal colibacteriosis were find out in the farms were do not use immunization as active prophylactic of pregnant cows against neonatal diarrhea. In the same farms a higher morbidity, case fatality and cumulative mortality were deterninated among the heifers compared to those borned from older cows. No significant seasonal fluctuations have established in these indicators.