Prevalence of Subclinical Mastitis among Small Ruminants and Isolation of Some Etiological Bacterial Pathogens in Jimma Town, Ethiopia

Abstract

Subclinical mastitis in small ruminants is of concern due to the animal welfare, economic, public health, productivity, and livelihood impacts that it may pose. A cross-sectional study was conducted from October 2017 to April 2018 in and around Jimma town, Southwest, Ethiopia; to estimate the prevalence of subclinical mastitis, to isolate bacterial pathogens responsible for the occurrence of subclinical mastitis, and to identify risk factors associated with the development of subclinical mastitis in small ruminants. Milk samples were collected from 186 apparently healthy lactating small ruminants, tested on the field with the California Mastitis Test, and samples tested positive were subjected to bacteriological examinations. Out of 372 milk samples collected, 92(24.8%) samples from 70 animals were positive by the California Mastitis Test and these were cultured on different media. Through bacteriological examinations, six isolates of bacteria were identified which include; S. aureus (8.1%), S. epidermidis (10.2%), S. intermidus (2.2%), S. hyicus (1.6%), S. agalactiae (3.2%), and E. coli (12.4%). The highest prevalence of subclinical mastitis recorded was due to Staphylococcus species (22%) followed by E. coli (12.4%) and the least prevalence was due to S. agalactiae (3.2%). The overall prevalence of subclinical mastitis among small ruminants was 37.6%. Age and parity number variations among small ruminants were found important in influencing the prevalence in statistically significant (P = 0.00) extents. The highest prevalence of subclinical mastitis was recorded in old (24.7%) and in small ruminants having >5 parity numbers (24.7%). The high prevalence of small ruminant subclinical mastitis in the study area suggests that intervention strategies their-goal-being prevention and control of subclinical mastitis should be designed; so as to improve the welfare of animals, to save people consuming the milk of small ruminants from zoonotic risks, and to harvest the diverse benefits that may be generated from small ruminant production.