By Raúl González Urdiales, Global Senior AI Specialist
Bacterial contamination in semen significantly impacts reproductive efficiency and herd productivity. Bacteria can degrade semen quality, even when the semen has been properly selected during fresh semen assessments. This makes contamination control a critical factor in maintaining the quality of semen doses.
Traditionally, antibiotics have been used in semen extenders to control bacterial growth. However, there are growing calls worldwide to reduce such antibiotic use due to antimicrobial resistance. This trend raises concerns about how AI centers can continue to manage semen contamination risks.
Raúl González Urdiales has been Global Senior AI Specialist at Topigs Norsvin since 2020. He is a veterinarian and holds an MBA and a PhD in boar reproduction. He provides international technical support in boar reproduction in Southern Europe, China, and Latin America. He also collaborates with Topigs Norsvin’s research department on boar reproduction projects.
How bacteria degrade semen
Do all bacteria degrade semen in the same way?
“No, bacteria degrade semen in different ways. Gram-negative bacteria, such as Escherichia coli and Pseudomonas species, are particularly harmful because they contain lipopolysaccharides that destabilize sperm membranes and cause inflammatory responses in the sow’s reproductive tract. They also produce toxins that reduce sperm motility and viability. Staphylococcus species consume extender nutrients and Proteus species alter semen pH, further compromising quality. Additionally, some species like Serratia replicate rapidly at lower temperatures, which means they can significantly damage semen quality after just 24-48 hours.”
Effective management of bacterial contamination
What should AI centers do to effectively manage bacterial contamination in semen production?
“There are two key complementary approaches to managing bacterial contamination in semen:
– Minimize the presence of bacteria during semen production through strict hygiene protocols, daily disinfection, sterile materials, proper staff training to prevent cross-contamination, and robust monitoring to reduce contamination risks.
– Inhibit bacterial growth in semen by incorporating antibiotics in extenders and reducing the temperature.
Unfortunately, I often see that AI centers do not invest enough in hygiene and monitoring programs. Although the operation might seem to be effective, the critical issues often lie in the details. Effective control and sustainable bacterial management cannot be achieved without the proper monitoring of critical control points and comprehensive hygiene practices.”
Biggest challenge in preventing contamination
What is the biggest challenge AI centers currently face in preventing semen contamination?
“In my view, the biggest challenge is the rise of antibiotic-resistant bacteria. Whereas centers with strong hygiene protocols and monitoring systems effectively control bacteria, others rely on antibiotics, which mask deficiencies in their process control. These hidden shortcomings may lead to sporadically high numbers of bacteria in semen, which can compromise the reproductive performance on farms.”
Alternatives to antibiotics
Are there viable alternatives to replace antibiotics?
“Several alternatives to antibiotics have been explored. Antimicrobial peptides and natural compounds, such as essential oils and plant extracts, have shown promising results due to their broad-spectrum activity. Enzyme-based treatments and bacteriophages are also under investigation because they can inhibit the growth of specific bacteria. Advanced semen filtration systems and antibiotic-free extenders for use at 5ºC are also being developed. These alternatives require optimization to balance efficacy, cost, and compatibility with semen quality. Nevertheless, I believe some of them could be viable options for reducing antibiotic dependency.”
Short-term solutions
Which of these alternatives will be implemented in the short term?
“I think combining storage at 5ºC with antibiotic-free extenders and strict hygiene protocols is the most feasible approach for widespread implementation. However, implementing the approach might require the inclusion of more cells per dose, and the approach might not be suitable for some boars. Other alternatives are in the pipeline, and once these have been sufficiently validated, we’ll have a broad range of solutions to maintain semen quality.”
