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.

Despite the widespread use of cryopreserved dog semen, reliable predictors of individual semen freezability are still not available. This study investigated the relationship between post-ejaculatory blood plasma concentrations of canine prostate-specific esterase (CPSE) and semen quality following cryopreservation. The CPSE levels were quantified using a canine-specific sandwich-type immunoassay, and sperm quality was evaluated in fresh and frozen–thawed samples using motility, kinematic, and morphological sperm parameters. Cryopreservation resulted in a significant decline in sperm motility and morphology, with marked variability in the magnitude of post-thaw changes among individuals. CPSE showed significant correlations with several morpho-functional parameters in both fresh and frozen–thawed sperm (p ≤ 0.05). However, its strongest predictive value for freezability was observed for total motility (p = 0.004), with a minimum threshold of 53 ng/mL identifying dogs showing a ≥20% post-thaw motility decline (AUC = 0.785, p = 0.010). These findings suggest that post-ejaculatory CPSE levels in blood plasma may reflect sperm cryoresilience and serve as a potential biomarker of canine sperm freezability.

Gonadectomy is performed in bitches to prevent unwanted reproduction and reduce the risk of sex hormone-related conditions. However, growing evidence suggests that the timing of spaying may influence long-term susceptibility to non-reproductive diseases. This retrospective case–control study (2013–2023) evaluated the association between timing of spaying and the development of orthopedic and neoplastic disorders in a Belgian referral-hospital population. Cases included bitches diagnosed with cranial cruciate ligament rupture, hip dysplasia, elbow dysplasia, lymphoma, mast cell tumor, osteosarcoma, or hemangiosarcoma, while disease-free bitches served as controls. Associations between disease occurrence and spaying status were assessed using multivariable logistic regression adjusted for age, weight category, and body condition score. Age at gonadectomy (<12 vs. ≥12 months) and timing relative to the first estrus were evaluated in separate models. Spaying <12 months of age was associated with increased odds of all conditions compared with intact females. Spaying ≥12 months of age was associated with lower odds of several orthopedic and neoplastic outcomes compared with early spaying, although odds were not always comparable to those in intact females. Large body size and higher body condition score were independently associated with increased odds of orthopedic outcomes. These findings support individualized spaying strategies rather than a universal age threshold.

Semen cryopreservation is widely used in canine breeding, but individual variation in post-thaw semen quality limits its efficiency. This study investigated whether testicular artery Doppler-derived blood-flow parameters and circulating vascular endothelial growth factor (VEGF) concentrations are associated with semen quality and sperm freezability in clinically healthy dogs. Sixty-four privately owned male dogs underwent reproductive screening, semen collection, testicular Doppler ultrasonography, blood sampling, fresh and post-thaw semen analysis, and plasma VEGF quantification. Testicular artery Doppler parameters were not significantly associated with fresh or post-thaw semen quality or with most freezability outcomes. Plasma VEGF concentration was positively correlated with fresh linearity (LIN) (p = 0.034), straightness (STR) (p = 0.031), and beat-cross frequency (BCF) (p = 0.043). Higher VEGF concentrations were associated with greater post-thaw declines in progressive motility (PM) (p = 0.036), straight-line velocity (VSL) (p = 0.032), LIN (p = 0.001), STR (p = 0.005), and wobble (WOB) (p = 0.010). In multivariable analysis, VEGF was associated with linearity decline (B = 0.595, 95% CI: 0.254–0.937; p = 0.001). Circulating VEGF may therefore be associated with individual variation in canine sperm cryotolerance, whereas testicular artery Doppler assessment showed limited value.