Incidence and Associated Risk Actors of Heifer Mastitis in Dairy Farms at Mekelle Town, Northern Ethiopia

A longitudinal study was conducted from November 2013 to May 2014 in Mekelle town, Northern Ethiopia, to assess the incidence of heifer mastitis, to isolate and identify the causative pathogens and their susceptibility to different antimicrobials and also identify risk factors associated with occurrence of heifer mastitis. Twenty-five heifers were included from 4 dairy farms and 11 cooperative small holder's dairy farms during the study period. Total of 100 quarters were examined to detect clinical and subclinical mastitis by physical examinations of udder and milk and California mastitis Test (CMT), respectively. The incidence of mastitis per gland at risk was 64 % and the spontaneous cure rate of infected quarters was 33 %. Incidence of heifers' intra-mammary infections (IMI) in the study area was highest at calving (28%). Infection per quarter revealed that 49% were mastitis positive of which 8.2% of their quarters were clinical and 45/49 (91.8%) quarters were sub clinical type of mastitis. The incidence rate per quarters were statistically significant (p <0.05) and higher in rear quarters than front quarters. The univariate logistic regression showed that among potential risk factors considered from the farm attributes, breed, age, practice of milking mastitic cow last, housing nature, hand wash before and in between milking and udder hygiene had significant effect on the prevalence of subclinical mastitis. Coagulase negative Staphylococci (CNS) (54.5%) and Staphylococcus aureus (21.8%), were the predominant bacteria. Relatively most of the isolates are susceptible to Chloramphenicol, Gentamycin, Ciprofloxacin and Vancomycin but resistant to Penicillin. The study also revealed that S.aureus, E.coli and S.agalactiae were highly incident at calving. It is concluded that prevalence of CNS, lack of hygienic practice and infestation of ticks should give serious attention.