Breeding dogs without antibiotics
RESEARCH PROJECT

Breeding dogs without antibiotics

Updated: August 2026

Project overview

The official name of the project:
Alternatives to antibiotics in extenders for canine semen cryopreservation
Project start: October 2025 Ending: October 2027
Project manager: Eva Axnér
Contact: Eva Axnér
Funded by: Sällskapsdjurens Forskningsfond, SLU

Participants

Short summary

Antimicrobial resistance is a growing veterinary problem, and semen preservation is a less well-known source of antibiotic use. We evaluate whether this is necessary for canine semen cryopreservation, and whether colloid centrifugation can reduce bacterial growth without harming sperm quality.

Antimicrobial resistance (AMR) is an increasing global health concern. This problem affects both human and veterinary medicine, and resistant bacteria are increasingly being detected in animals.

International dog breeding and frozen semen

Dog breeding is an international activity, with dogs frequently travelling between countries for breeding. Frozen semen makes it possible to preserve and transport valuable genetic material without moving the dog itself. However, this also raises questions about bacteria present in semen and the use of antibiotics during semen preservation.

Bacteria in dog semen

Healthy male dogs naturally carry many different types of bacteria on the penis, prepuce and lower urinary tract. These bacteria can also be found in semen. Although they are usually harmless to the male, bacterial contamination can sometimes reduce sperm quality. There is also concern that bacteria could be transferred to the female during artificial insemination, although bacterial exchange also naturally occurs during mating.

The role of antibiotics in semen freezing

When dog semen is prepared for freezing, it is mixed with a protective solution called a semen extender. This helps sperm survive cooling and freezing, but its nutrients, such as egg yolk and sugars, can also provide an environment where bacteria may multiply. Antibiotics are therefore commonly added to semen extenders to control bacterial growth. However, repeated exposure to antibiotics may contribute to the development of antibiotic-resistant bacteria.

A possible alternative: centrifugation

Freezing semen to –196°C stops bacterial growth, but it does not necessarily kill bacteria. They may become active again when the semen is thawed for artificial insemination. An alternative approach, called single-layer centrifugation, can help separate sperm from bacteria and other unwanted material before freezing.

About the study

Our study will investigate how bacteria behave during the freezing process of dog semen. We will examine whether antibiotics are really necessary and whether single-layer centrifugation could provide a safer alternative. The long-term goal is to develop methods that preserve sperm quality while reducing unnecessary antibiotic use and helping combat antimicrobial resistance.

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