Prevalence of Bovine Mastitis and Assessment of RiskFactors in and Around Wolayta Sodo, Ethiopia

Abstract

The purpose of this cross-sectional study was to estimate the prevalence of mastitis and to assess the associated
risk factors in dairy breeds (jersey, indigenous zebu, and high grade Holstein) in the Woliata Soddo area and surrounding areas
from November 2013 to May 2014 at the Soddo regional veterinary laboratory. A clinical examination and Californian Mastitis
Test (CMT) were conducted on 386 nursing cows, including 216 indigenous zebu, 88 jersey, and 82 high grade Holsteins. The
patients who tested positive for both clinical and subclinical mastitis were then tested for bacteria. Among the 134 animals
tested, 34.7% tested positive for clinical mastitis and 61.19 percent tested positive for subclinical mastitis. A total of 21.94
percent of the 966 quarters tested positive for mastitis. Mastitis was much more common in high grade Holstein cows (54.8%),
jersey cows (44.3%), and indigenous zebus (23.1%) compared to other breeds (P< 0.000). Regarding quarters, however, no
discernible variation existed between breeds. Mastitis was most common between 1 and 120 days into early lactation (43.8%),
between 120 and 240 days into mid-lactation (32.8%), and beyond 240 days into end-lactation (23.8%). Additionally, the
difference between lactation was statistically significant (P<0.000). There was a positive correlation between parity and
mastitis prevalence (r=0.8), with the greatest incidence occurring at lactation stage 6 and thereafter. Microbiologic analysis was
performed on 134 udder quarter samples; 111 (82.8%) were found to be culturally positive, whereas 23 (17.2%) were found to
be negative. Out of the 124 bacteria that were recovered in positive samples, 43.54% were Staphylococcus, 28.89% were
Streptococcus, and 19.35% were Coliform. Findings informed calls for further education of dairy cow owners and calls for
additional research into financial losses.