Animals

Cryopreservation of bovine ovarian cortical tissue offers a promising strategy for preserving female fertility and genetic resources, yet outcomes remain variable and influenced by both protocol and tissue size. This study investigated how slow freezing-thawing (SFT) and two vitrification-warming procedures (VW1 and VW2) affect preantral follicle morphology and granulosa cell proliferation in bovine ovarian cortex fragments of two dimensions (1 × 10 × 5 mm and 1 × 10 × 10 mm). Tissue from six cows was processed for histological evaluation and Ki67 immunostaining. Small fragments subjected to SFT showed no significant reduction in the proportion of morphologically normal follicles compared with fresh controls, representing the best overall preservation. In contrast, vitrification decreased morphological integrity, with VW2 performing better than VW1 in both fragment sizes. Small SFT pieces contained more morphologically normal follicles than large ones. Granulosa cell proliferation capacity was largely maintained across cryopreservation protocols, increasing with follicular stage; a size-related difference only appeared on VW2, where small fragments displayed higher Ki67 positivity. These findings underscore the relevance of jointly evaluating cryopreservation protocol and fragment size to optimize bovine ovarian tissue preservation, strengthening the evidence supporting SFT of small fragments as a robust option for safeguarding cortical integrity and improving tissue-based fertility preservation strategies.

Trace elements are essential for organisms, and their involvement in diverse diseases is increasingly recognised. Interest is increasing in veterinary medicine, particularly in relation to canine diseases. However, reference intervals for trace elements in dogs remain scarce. Plasma samples from 140 dogs were analysed by inductively coupled plasma mass spectrometry to determine the levels of 13 trace elements. Reference intervals (µg/L) were established for the following 12 elements: As, 0.417–8.17; Co, 0.039–1.33; Cr, 2.41–13.3; Cu, 296–790; Fe, 846–3643; Hg, 0.235–2.33; Ni, 0.567–9.04; Mn, 1.90–7.28; Mo, 1.43–12.7; Pb, 0.285–2.82; Se, 200–434; and Zn, 415–1095. However, Cd was below the limit of quantification in 77% of the samples. No differences in trace element concentrations were observed in relation to breed or reproductive status. Statistically significant differences were found in relation to sex (Cu, Mo, Zn), age (Co, Cu, Mo, Mn, Se, Zn), and size (Cu, Mo, Se, Zn); however, the magnitude of these effects varied among elements and was generally weak. Nevertheless, these factors should be considered when assessing trace element status. These reference intervals constitute an important resource for both clinical evaluation and future research.

Hemotropic mycoplasmas (hemoplasmas) are uncultivable, cell wall-less bacteria that parasitizeon the surface of red blood cells of mammals, potentially causing anemia and other systemic signs. While widely distributed among domestic and wild animals, their occurrence in equids remains poorly understood, and no species has been identified as host-specific to horses or donkeys. This study presents the first systematic survey of hemoplasmas in equids from southeastern Europe and only the second molecularly confirmed case in horses in Europe. A total of 843 equids (817 horses and 26 donkeys) from different regions of Croatia, representing various ages, uses, and husbandry systems, were screened for hemoplasmas by PCR targeting the 16S rRNA gene. Only one horse tested positive, identified as Mycoplasma wenyonii, a hemoplasma typically associated with cattle. The estimated prevalence was 0.12% (95% CI: 0.003–0.68%). No donkeys were infected. The extremely low prevalence observed here—the lowest reported in any study detecting hemoplasma-positive horses—supports the hypothesis that equids do not harbor host-specific hemoplasma species and may only sporadically acquire infections from other hosts via spillover. This finding underscores the apparent absence of persistent hemoplasma lineages adapted to equids and highlights the need for further research on their epidemiology, host specificity, and transmission dynamics.