Biological and chemical contaminants in extended porcine semen: Outcomes and diagnosis

Abstract

Animal studs that provide extended semen for breeding have a significant contribution to reproductive outcomes. This report highlights several biological and chemical contaminants in extended semen that were found to be the causative agent for disturbances to herd reproductive performance, along with the diagnostic approach used in contaminant identification. Biological contaminants of concern include bacteria, viruses, and molds. From our investigations, opportunistic bacteria of mammalian and purified water origin appeared to be the most common biologic contaminant in stud operations. Chemical contaminants were another major cause of disrupted herd subfertility. A variety of chemical contaminants with spermatoxic activities were identified, with their source being residual detergents and disinfectants, inferior semen extender (e.g., inclusion errors, impurities, inferior ingredients), reconstitution water quality, and plastic toxicity. Success in contaminant identification was best achieved through the combined use of objective pre-use data on the extended semen product along with post-use fecundity data from the breeding farm(s). Using a temporal overlayment and point of time determination, targeted in vitro diagnostics were employed, including spermiogram analyses, microbiological methodologies, and analytical chemistry. Investigation outcomes included establishing robust stud hygiene and sanitation procedures, implementation of scientifically-based quality assurance/quality control programs that use sperm-safe screening to validate quality and consistency of supplies prior to acceptance and use, and stud-specific input monitoring practices.