Incidence of Heifer Mastitis and Identification of Major Associated Pathogens in Dairy Farms at Wolaita Soddo Town, Southern Ethiopia

Abstract

The replacement stock is one of the vital parts of dairying no dairy farmer can afford to overlook. Although heifers, as calves and as primiparae, have been thought of as a group as free of mastitis, many studies indicated that clinical mastitis (CM) was even higher in heifers during calving than multifarious cows. The present longitudinal study was conducted to assess the incidence of heifer mastitis, to isolate and identify the causative pathogens and their susceptibility profile against some antimicrobials. By using convenience sampling method a total of 28 heifers from two sampling point (large scale dairy farms1 and small holders’ cooperative dairy farms2 were followed and sampled throughout study period. Physical examinations of udder and milk and California mastitis Test (CMT) was applied detect clinical and subclinical mastitis, respectively. Accordingly, a total of 112 quarters were examined. The incidence of mastitis per gland at risk was 60.7% and the spontaneous cure rate of infected quarters was 24.18%. Incidence of heifers intramammary infections (IMI) in the study area was highest at calving (35.7%). Infection per quarter revealed that 43/112 (38.3%) of which 9/43 (20.9%) quarters were clinical and 34/43 (79.0%) quarters were sub clinical type of mastitis. However, 5(4.5%) of the total quarters examined were blind. Incidence of mastitis in rear quarters was significantly higher than front quarters (p<0.05). The result revealed that high milk producing heifers (HF and jersey) were significantly susceptible to mastitis (p<0.05). The univariate logistic regression showed that 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. Staphylococcus aureus (30.3%), Coagulase negative Staphylococci (CNS) [15.2%] and Streptococcus agalactiae (15.2%) were the predominant bacteria. Relatively most of the isolates are susceptible to chloramphenicol, gentamycin, ciprofloxacin and kanamycin but resistant to penicillin. High incidence of heifer mastitis especially occurs as a subclinical type and in high milk producing breeds and older age groups in this area. Serious attention should be given to heifers prepartum udder health because it is most essential for control and prevention of heifer mastitis.