Isolation and identification of common bacterial contaminants in Malabari buck semen

Abstract

The present study was undertaken to isolate and characterise the predominant bacterial contaminants in semen from Malabari bucks maintained at the Artificial Insemination Centre, College of Veterinary and Animal Sciences, Pookode, Wayanad. Semen was collected using a sterilised artificial vagina and evaluated for macroscopic characteristics. Microbiological analysis involved enrichment in selective broths, sub-culturing on eosin methylene blue agar (EMB) and Baird-Parker agar (BP), followed by colony morphology, Gram’s staining and biochemical identification. The average ejaculate volume was 0.88 ± 0.02 mL, with colour ranging from creamy to creamy yellow and consistently high sperm density (DDDD). Cultural characterisation revealed two predominant colony types, which after Gram’s staining appeared as Gram-positive cocci in clusters and Gram-negative rods. Biochemical profiles confirmed the isolates as Staphylococcus aureus (catalase positive, oxidase negative) and Escherichia coli (IMViC pattern: + + - -).