Canine and feline epididymal semen provide an additional source of gametes to preserve the genetics of valuable breeding dogs and tomcats, especially for those that fail to ejaculate, need castration as a therapy or die unexpectedly. Moreover, since it is quite common to perform castration of non-breeding dogs and cats, the development of a gene bank of epididymal semen collected after castration would greatly contribute to increase the genetic diversity in dogs and cats. Collection and cryopreservation of epididymal semen necessitates a full understanding of the function of the epididymis and of the characteristics of epididymal spermatozoa as opposed to ejaculated semen. During collection of epididymal semen, specific factors may have a negative effect on epididymal semen quality and freezability. Accordingly, the elimination of these triggers could enhance epididymal semen freezability and consequently positively influence post-thaw semen quality and outcome for different ARTs.

Anti-Müllerian hormone (AMH) has been suggested to be involved in spermatogenesis. The aim of this study was to investigate the relationship between blood serum AMH concentration and semen quality in dogs. Moreover, this study sought to find the optimal cut-off point value of serum AMH with the greatest sensitivity and specificity to predict semen quality. Forty-five clinically healthy dogs were included in the study and their age as well as the following semen parameters were determined and correlated to serum AMH concentration: total sperm output, normal morphology, plasma membrane integrity, total motility, progressive motility, and velocity parameters. Statistical analysis for correlations were performed using Spearman’s correlation coefficients. Moderate negative associations were found between serum AMH and semen total motility (r = −0.38, p = 0.01), progressive motility (r = −0.36, p = 0.01), and normal morphology (r = −0.36, p= 0.02). Based on these associations, an AMH concentration of 5.54 µg/L was found to be the optimal cut-off point value to obtain the greatest summation of sensitivity (86%) and specificity (63%) to predict semen quality. The serum AMH assay may therefore be a potential hormonal marker to predict which dogs would require further semen analysis. Future research is however needed to confirm these preliminary results.

Small animal reproduction (SAR) is a main research field in veterinary medicine and bibliometric analyses are useful to investigate trends in specific research areas. The objective of the present study was to conduct a bibliometric analysis of the literature of the last decade on SAR. A search equation was created, and documents were retrieved from the Web of Science database. Documents were manually revised, categorized and R software version 4.1.2 with Bibliometrix R package version 3.1 and MS Excel were used to perform the analyses. The included documents (n = 1470) were mainly research articles (78%). The top countries for the number of documents and citations were Brazil, United States, Italy, Poland, and Korea. These also account for the most prolific authors and institutions. Analyses by author keywords, categories, and recent reviews of the literature suggest that research on the canine species is more abundant than research on the feline one and that reproductive biotechnologies are a main research focus. Some clinical topics are still considered niche or neglected themes (e.g., semen collection in tomcats, neonatology). However, heterogeneity and ambiguity in keywords and categories are undeniable. This study offers interesting insights, providing definitions for main keywords in the field of SAR.

The iSperm^® is a portable device for semen analysis. This study aimed to investigate its correlation with a conventional computer-assisted sperm analyzer (ISAS^®v1) for the assessment of semen concentration and kinematic parameters in dogs (n = 224). The intra-assay variability of both devices and their ability to estimate semen concentration at a fixed value of 40 × 10⁶/mL were also investigated. Results showed that the intra-assay variability was lower for the ISAS^®v1 for all parameters compared to the iSperm^®. Hence, iSperm^® estimates were more variable in-between fields. Both the iSperm^® and the ISAS^®v1 were not reliable in estimating semen concentration (ISAS^®v1: median 30 × 10⁶/mL, interquartile range (IQR) 12, p < 0.01; iSperm^®: median 35.12 × 10⁶/mL, IQR 11.11, p < 0.01). Finally, positive correlations were found between both devices with stronger correlations obtained when four fields were analyzed by the iSperm^®. However, the low number of spermatozoa analyzed per field and the inability to avoid artifacts are downsides that currently limit the reliability of the iSperm^®. Therefore, the software of iSperm^® needs some improvement to make it a valid and practical alternative to automated computerized systems for the analysis of canine semen.

This study evaluated how semen selection by single layer centrifugation (SLC) with Canicoll affects semen freezability in dogs. A total of eighteen ejaculates, collected from dogs with optimal and suboptimal semen quality (optimal: normal morphology (NM) ≥ 80%, n = 9; suboptimal: NM between 60 and 79%, n = 9), were divided into two aliquots and subjected to standard centrifugation or SLC before cryopreservation. Motility, NM, membrane integrity, mitochondrial membrane potential (MMP), and DNA integrity were improved in fresh samples after SLC, regardless of semen quality, but at the expense of some good quality spermatozoa. After thawing, NM and membrane integrity were improved in SLC-selected semen in both semen qualities. Interestingly, MMP was also higher but only in optimal quality semen. Still, spermatozoa from suboptimal quality semen did not survive freezing to the same extent as spermatozoa from optimal quality semen, even after selecting superior spermatozoa. Semen selection with Canicoll is, therefore, an effective technique to isolate a subpopulation of high-quality spermatozoa and obtain sperm samples of better quality after thawing, but is not sufficient to improve the intrinsic inferior freezability of suboptimal quality semen. So far, eighteen pups were born after insemination with SLC-selected frozen-thawed semen, proving that these selected spermatozoa remain fertile.

Benign prostatic hyperplasia (BPH) is a common condition in intact male dogs, often progressing from subclinical to symptomatic stages with increasing clinical and structural impact. This study evaluated canine prostate-specific esterase (CPSE) as a biomarker for BPH progression, focusing on clinical severity, complexity, and ultrasonographic features. Seventy-one dogs were included: subclinical-BPH (n = 14), clinical-BPH (n = 26), BPH-prostatitis (n = 9), and controls (n = 22). CPSE levels, measured using a canine-specific enzyme-linked immunosorbent assay, were significantly correlated with clinical severity (ρ = 0.800, p ≤ 0.001) and complexity (ρ = 0.818, p ≤ 0.001). CPSE predicted mild (OR = 1.260, B = 0.231, p ≤ 0.001) and moderate severity (OR = 1.300, B = 0.262, p ≤ 0.001), as well as low (OR = 1.225, B = 0.203, p ≤ 0.05), moderate (OR = 1.235, B = 0.211, p ≤ 0.01), and high (OR = 1.346, B = 0.297, p ≤ 0.001) clinical complexity. CPSE showed a trend toward predicting structural alterations (OR = 1.227, B = 0.204, p = 0.069) and was associated with larger stippled areas, increased prostatic volume, and larger cysts/abscesses (all p ≤ 0.001). CPSE appears to be a promising marker for BPH progression.