Double semen collection at a 1-h interval in dogs decreases the bacterial contamination of canine ejaculates

Dominik Lechner; Jörg Aurich; Joachim Spergser; Christine Aurich

doi:10.1016/j.theriogenology.2023.06.002

Double semen collection at a 1-h interval in dogs decreases the bacterial contamination of canine ejaculates

Theriogenology. 2023 Sep 15:208:126-131. doi: 10.1016/j.theriogenology.2023.06.002. Epub 2023 Jun 7.

Authors

Dominik Lechner¹, Jörg Aurich², Joachim Spergser³, Christine Aurich⁴

Affiliations

¹ Artificial Insemination and Embryo Transfer, Department for Small Animals and Horses, Vetmeduni Vienna, 1210, Vienna, Austria.
² Obstetrics, Gynecology and Andrology, Department for Small Animals and Horses, Vetmeduni Vienna, 1210, Vienna, Austria.
³ Institute of Microbiology, Department of Pathobiology, Vetmeduni Vienna, 1210, Vienna, Austria.
⁴ Artificial Insemination and Embryo Transfer, Department for Small Animals and Horses, Vetmeduni Vienna, 1210, Vienna, Austria. Electronic address: christine.aurich@vetmeduni.ac.at.

PMID: 37315442
DOI: 10.1016/j.theriogenology.2023.06.002

Abstract

Semen extenders usually contain antibiotics with the aim to minimize bacterial growth, but the indiscriminate use of antibiotics increases the emergence of multidrug-resistant bacteria. A limiting factor of semen processing in dogs is the low total sperm count that limits the number of insemination doses that can be obtained from one ejaculate. Therefore, two ejaculates collected at a short interval can be combined to increase the number of AI doses. In this study, semen was collected from dogs either once or the same dogs (n = 28) were submitted to dual semen collection 1 h apart. All ejaculates were submitted to bacteriological analysis. We hypothesized that bacterial contamination of semen is low but that a dual semen collection might increase contamination. A sample for bacteriological examination was taken from raw semen immediately after semen collection. Bacteria including mycoplasmas were isolated using conventional cultivation procedures and isolates were identified to the species level by matrix-assisted laser desorption ionization - time of flight (MALDI-ToF) mass spectrometry. In total, 22 bacterial species were identified in the 84 ejaculates with Mycoplasma cynos, Streptococcus canis and Canicola haemoglobinophilus being most frequent. Bacterial growth was sporadic in 16 and absent in 10 ejaculates. The overall bacterial growth was lower in the second than in the first ejaculate of dual semen collections (p < 0.05). The percentage of motile and membrane-intact spermatozoa in frozen-thawed ejaculates was not associated with the degree of bacterial contamination of raw semen. In conclusion, there was only limited microbial contamination in dog semen and the microorganisms isolated are considered part of the normal genital bacterial flora. Repeated semen collection reduced bacterial contamination in the second in comparison to the first ejaculate. The use of antibiotics in canine semen should be questioned.

Keywords: Collection frequency; Dog; Microbial flora; Semen.

MeSH terms

Animals
Anti-Bacterial Agents
Bacteria
Body Fluids*
Dogs
Male
Semen*
Spermatozoa

Substances

Anti-Bacterial Agents