The Interaction between Canine Semen Bacteria and Semen Quality Parameters

Abstract

Assessing canine semen quality helps to detect infertility in males, but identifying factors that influence canine semen quality is a complicated task. The objective of this study was the assessment of the potential influence of bacteria found in canine semen samples on the characteristics of dogs' semen. In this study, semen samples were collected manually from 30 dogs and subjected to a comprehensive examination. The results of sperm motility, concentration, viability, and morphology were statistically analysed in relation to the number of bacteria in the semen (CFUs/mL) and the seminal microbiota. Samples with an increased bacterial count per millilitre were associated with lower-quality sperm motility (p < 0.05). The most frequently isolated bacterial genera from the analysed semen samples were Staphylococcus spp. (26.0%), Corynebacterium spp. (17.8%), and Streptococcus spp. (16.4%). The presence of β-haemolytic Escherichia coli bacteria was linked to suboptimal semen samples, characterised by significantly reduced semen viability and a lower proportion of morphologically normal spermatozoa (p < 0.05). Corynebacterium spp. was associated with reduced bacterial load and superior semen quality (p < 0.01). These findings highlight the importance of bacterial cell counts and microbiota diversity in relation to various factors influencing canine semen quality, providing a more comprehensive understanding of canine reproductive well-being.

Keywords: canine; semen quality; seminal bacteria.

Figure 1

A diagram illustrating the bacterial contamination in semen samples, expressed as colony-forming units (CFUs) per millilitre of sample. Semen samples are classified into higher (H, blue colour) and lower (L, red colour) quality groups according to their quality parameters: viability, morphology, and motility. H VIABILITY represents samples with 50% viability and higher, while L VIABILITY represents samples with less than 50% viability. H MORPHOLOGY indicates samples with 70% morphologically normal spermatozoa and higher, and L MORPHOLOGY represents samples with less than 70% morphologically normal spermatozoa. H MOTILITY designates samples with motility higher than 75%, and L MOTILITY represents samples with 75% motility and lower. H QUALITY and L QUALITY represent general quality groups. * Significant differences between groups when p-value < 0.05.

Figure 2

A diagram illustrating the percentage distribution of identified bacteria in semen samples of two quality groups, according to their viability, motility, and morphology.