Prevalence of subclinical mastitis, associated risk factors and antimicrobial susceptibility of the pathogens isolated from milk samples of dairy cows in Northwest Ethiopia.

Subclinical mastitis (SCM) is a problem of dairy cattle worldwide that affects the income of dairy farmers and besides a health risk to humans. A cross-sectional study was carried out to estimate prevalence, identify risk factors of SCM and antimicrobial susceptibility test of bacteria isolated from SCM quarters. California Mastitis Test (CMT) positive milk samples were cultured and bacteria isolated. The isolated bacteria were checked for their antimicrobial susceptibility using Kirby-Bauer disk diffusion method. The study findings showed that 32.7% of the quarters and 60.1% of the cows were CMT positive. The isolated bacteria were 29.5% Staphylococcus aureus (S. aureus) and 9.3% Streptococcus agalactiae (Str. agalactae). In the risk factors study, cows from farms of poor hygiene, increased age and stage of lactation had higher odds of SCM. Of the isolated bacterial species, 75.7% and 71.4% of S. aureus isolates were resistant to the effects of penicillin and ampicillin, respectively. Streptococcus agalactiae were resistant to the effects of oxytetracycline (76.9%), streptomycin (61.5%) and cloxacillin (53.8%). Whereas the majority of S. aureus (98.6%) and Str. agalactiae (88.5%) were susceptible to the effects of gentamycin and Clindamycin respectively. In conclusion, SCM had high level of prevalence and associated risk factors with pathogens that were resistant to commonly used antimicrobials. Implementing strict preventive measures and limiting spread of pathogens is a preferred approach rather than treatment with antibiotics to control mastitis in the study area.

Prevalence of bovine viral diarrhea virus antibodies and risk factors in dairy cattle in Gondar city, Northwest Ethiopia.

Bovine viral diarrhea (BVD) is a disease that affects cattle and other ruminants worldwide and causes considerable economic losses. A cross-sectional study was carried out between December 2017 and July 2018 with the aim to estimate the prevalence of Bovine Viral Diarrhea virus (BVDV) antibodies and to identify potential risk factors associated with the occurrence of the disease in dairy cattle in peri-urban areas of Gondar city, Northwest Ethiopia. A total of 339 serum samples obtained from randomly selected dairy cattle aged 6 months and older were assayed using a BVDV antibody competitive-Enzyme Linked Immunosorbent Assay (c-ELISA) kit. Descriptive statistics were used to estimate antibody prevalence of BVDV at animal and herd-level and logistic regression was used to identify potential risk factors. The study findings showed that the animal-level antibody prevalence of BVDV in the study area was 26.84 % (95 % CI: 22.1 %-31.6 %) and the herd-level seroprevalence was 68.3 % (95 % CI: 56.2 %-80.4 %). Logistic regression model demonstrated that age >2 years (OR = 4.75, 95 % CI: 2.20-10.26), herd size >11 (OR = 7.28, 95 % CI: 2.50-21.22), and poor farm hygiene (OR = 3.69, 95 % CI: 1.94-7.02), are potential risk factors associated with BVDV infection (P < 0.05). However, sex, faecal consistency and housing system were not associated with BVDV serostatus. The animal- and herd-level seroprevalence reports in Northwest Ethiopia can serve as a baseline finding for future BVD epidemiological investigations and to inform future control programs in the study region.