Placenta is essential for the development of the fetus, and its impaired function can lead to a negative outcome (i.e., neonatal mortality). In dogs, investigations on placenta histology and neonatal outcome in healthy bitches are lacking, and a contribution is provided in this study to emphasize the use of placenta histology in practice. Fifty-one placentas from 11 litters were collected during cesarean section, classified according to the litter size (large (L) or small (S)) and the outcome, this latter as healthy (Group 1) or dead within 7 days (Group 2). The placenta/puppy weight ratio (PPR) was calculated, and specimens were formalin-fixed and paraffin-wax embedded, and on the resulting histological slides, capillary density (CD) was quantified. Among necrosis, calcification, and intravascular leucocytes, only the presence of multifocal-confluent necrosis (significantly more frequent in Group 2) was associated with a higher risk of death within 7 days (odds ratio = 30.7). Mixed logistic regression ruled out the effect on death both of a bitch and cesarean type (programmed vs. emergency). PPR and CD values were associated with litter size; large litters had lower PPR (p < 0.01) and higher CD (p < 0.05) than small litters. The relationship between PPR and CD was negative and significant (p < 0.01). Necrosis was a frequent finding in canine placentas, but only when multifocal-confluent was it associated with a poor outcome. The litter size influenced PPR (lower in L) and CD (higher in L), and this is likely due to the plasticity of placenta adaptation.

High dose medetomidine 0.13 mg/kg can be used for semen collection in cats with variable results in terms of quantity and quality. Therefore, a variation in terms of distribution and elimination among patients has been hypothesised. The aim of the study was to characterise the pharmacokinetics of medetomidine (0.13 mg/kg) administered intramuscularly (IM) in healthy male cats. Eighteen male cats undergoing castration were included, and medetomidine (0.13 mg/kg) was administered IM. Venous blood samples were collected at 20, 30, 40, 50, 60, 75 and 90 minutes after medetomidine administration. Before orchiectomy, at T20, sperm collection was attempted. Plasma medetomidine concentrations were determined by liquid chromatography/mass spectrometry analysis. Semen collection was successful in 15/18 cats. The medetomidine plasma concentration following the IM administration of a bolus was best described using a non-compartment model. Time of maximum concentration was observed at 40 minutes (range 20–90); maximum concentration was 32.8 ng/mL (range 26.8–51.2). The median apparent clearance was 11.9 mL/kg/minute (range 0.7–43.8). In conclusion, medetomidine administered IM at 0.13 mg/kg reached its peak plasma concentration slowly and with variability among patients. In addition, it was characterised by low total body clearance probably due to the cardiovascular alterations associated with medetomidine administration.

Feline calicivirus (FCV) is widespread in multi-cat environments and typically causes acute upper respiratory tract disease (URTD). FCV also causes outbreaks of virulent systemic disease (VSD), mainly in adults, with multiple organ involvement. In this study, an FCV-VSD infection was described in a less-one-month-old Maine Coon kitten originating from a cattery where an outbreak of FCV-URTD had previously been reported. After spontaneous death, post-mortem examination as well as histopathological, immunohistochemical, bacteriological and virological investigations were carried out. Pathological findings were consistent with severe pneumonia and cutaneous oedema of the footpads. No concomitant bacterial infection was detected. FCV RNA was detected in several organs and the highest amount of viral RNA was observed in the lung sample, in which the presence of the FCV antigen was confirmed by immunohistochemistry. With the same immunohistochemical technique, the IBA-1 antibody detected sparse alveolar macrophages, the main viral target cell and pulmonary replication site. The nucleotide sequences of the viral ORF2 gene amplified from all positive tissues were identical with each other and phylogeny confirms that highly virulent FCV strains are not distinguishable from FCV-URTD phenotypes. Our findings reinforce the hypothesis that VSD outbreaks can occur even in small populations, due to the high genetic variability of FCV.

Ovarian remnant syndrome (ORS) is a recognized postoperative complication in spayed dogs and cats, resulting from incomplete excision or inadvertent revascularisation of ovarian tissue during gonadectomy. Affected animals typically exhibit recurrent oestrous behaviour and may develop serious sequelae, including stump pyometra, mammary neoplasia, and granulosa cell tumours. This retrospective study evaluated 93 cases (70 dogs, 23 cats) diagnosed with ORS referred to the University Veterinary Hospital of Bologna, Italy, focusing on signalment, clinical presentation, diagnostic protocols, and treatment outcomes. Diagnosis relied on a multimodal approach combining clinical history, vaginal cytology, serum progesterone assays, ultrasonography, and histopathological examination of excised tissue. Surgical excision of residual ovarian tissue was the only curative treatment, with improved outcomes when performed during hormonally active phases of the oestrous cycle to optimize remnant localisation. Histopathology confirmed ovarian tissue in the majority of cases, with neoplastic transformation identified in 10% of dogs. Bilateral ovarian remnants were more prevalent than previously reported. Surgical revision was complicated by adhesions involving vital abdominal structures, emphasizing the need for meticulous technique. These findings highlight the critical importance of precise surgical technique during initial gonadectomy, early recognition of ORS, and comprehensive surgical management to prevent severe complications and promote companion animal welfare.

Data from three cases of uterus masculinus were retrieved from 2014 to 2018. Two out of three cases presented clinical signs compatible with systemic infection, as observed in bitches with pyometra. Ultrasound examination revealed a tubular fluid-filled structure with a thin irregular wall located cranially to the prostate and in continuity with the cranial part of the gland. In two cases, two other tubular fluid-filled structures were visualized in the caudal part of the abdominal cavity, ventrally to the prostate gland and urinary bladder. After surgical removal of these, histological examination revealed the presence of a uterine structure morphologically similar to the female counterpart. Various types of epithelial cell lining were found, including simple columnar, simple stratified and squamous epithelium associated with glands in the underlying stroma. Immunohistochemistry to anti-Müllerian hormone (AMH) produced a positive result on glands, while multifocal expression was found in the lining epithelium. AMH seems involved in the pathogenesis of uterus masculinus, but its role is not fully understood. Thorough clinical and ultrasonographical examinations, followed by a histological confirmation, are necessary to properly diagnose uterus masculinus in dogs.