Search Results (91)

Aggressiveness in dogs is a complex behavioral trait with implications for animal welfare and public safety. Despite domestication, dogs retain aggressive tendencies shaped by both genetic and environmental factors. This systematic review synthesizes the literature from 2000 to 2024 on the genetic and environmental bases of canine aggression. Using PRISMA 2020 guidelines, 144 articles were retrieved from Scopus and PubMed and screened in two phases, resulting in 33 studies selected for analysis. These were evaluated using a 20-question grid across seven categories, including phenotyping, genetic analysis, population structure, and future directions. The studies support a polygenic model of aggressiveness, with associations reported for genes involved in neurotransmission, hormone signaling, and brain function. However, inconsistencies in phenotyping, small sample sizes, and a limited consideration of environmental factors hinder robust conclusions. Most studies focused on popular companion breeds, while those commonly labeled as aggressive were underrepresented. The findings highlight the relevance of gene–environment interactions but underscore that aggression is often poorly defined and measured across studies. Future research should prioritize standardized phenotyping tools, broader breed inclusion, and the functional validation of genetic findings. These efforts will improve the understanding of dog aggression and inform breeding, behavioral assessment, and public policy. Full article

Brachycephalic head shape in dogs has been associated with behavioural traits that may enhance their appeal as companion animals, contributing to their popularity. However, it remains unclear whether these behavioural differences are directly linked to head shape or are mediated by factors such as body size, demographics, and dog-keeping practices. Drawing on two large-scale owner surveys (N = 5613) and cephalic index estimates for 90 breeds, we investigated the relationship between head shape and eight behavioural variables (four personality traits and four behavioural problems), while controlling for 20 demographic and dog-keeping characteristics, as well as body size. Our results show that behavioural differences among head shapes are only partly attributable to head shape itself; some are explained by confounding variables. Specifically, brachycephalic dogs appeared predisposed to positive behaviours (e.g., calmness, fewer behavioural problems), but these traits were often obscured by their small body size and low training experience. These findings highlight the complex interplay between morphology, behaviour, and environment, and emphasize the role of training and management in supporting the behavioural well-being of popular brachycephalic breeds. This has important implications for owners, breeders, and welfare professionals aiming to align aesthetic preferences with behavioural and welfare outcomes. Full article

Prophylactic gastropexy is increasingly recommended in large-breed dogs predisposed to gastric dilatation-volvulus (GDV), particularly when combined with other elective procedures such as ovariectomy to reduce surgical trauma and anesthesia exposure. This prospective clinical study aimed to evaluate the feasibility, safety, and outcomes of a combined laparoscopic ovariectomy (LOVE) and total laparoscopic gastropexy with absorbable fixation straps (TLG-SS) using a standardized three-port minimally invasive approach. Six female dogs of GDV-prone breeds underwent the combined procedure. Surgical times, intraoperative and postoperative complications, and follow-up outcomes were recorded. The mean total operative time was 29.0 ± 3.52 min, with ovariectomy and gastropexy requiring 7.5 ± 1.38 and 9.33 ± 2.58 min, respectively. No major intraoperative complications occurred, and no conversion to open surgery was necessary. Postoperative recovery was uneventful in all cases, with only one minor portal site reaction observed. Owner satisfaction was excellent. The use of absorbable fixation straps simplified the gastropexy procedure and reduced operative time compared to other laparoscopic techniques. These findings suggest that the combined LOVE and TLG-SS procedure is technically feasible and well-tolerated in a small cohort of large-breed dogs, supporting its potential integration into clinical protocols pending further validation. Full article

This study analyzes 209 dog skeletons from two sites in Wolin (9th–mid-13th century AD) using 100 standard metric variables covering cranial, mandibular, and postcranial elements. Estimated withers height, body mass, age at death, and sex were derived using established methods. The results indicate the presence of at least two to three morphotypes: small spitz-like dogs (40–50 cm, 4–6 kg), medium brachycephalic forms (50–60 cm, 10–15 kg), and larger mesocephalic individuals (up to 65 cm, 20–40 kg). Dogs lived 3–10 years, with both sexes represented. Signs of cranial trauma and dental wear suggest utilitarian roles such as guarding. The size range and morphological diversity point to intentional breeding and trade-based importation. Small dogs likely served as companions or city guards, while medium and large types were used for herding, hunting, or transport. These findings highlight Wolin’s role as a dynamic cultural and trade center, where human–dog relationships were shaped by anthropogenic selection and regional exchange. Full article

Cutaneous neoplasia is among the most common illnesses in dogs and can pose significant risks. Accurate morphological diagnosis of these conditions is vital for effective treatment and management. In this retrospective study, a total of 3746 canine skin biopsies were submitted to a veterinary reference diagnostic laboratory and evaluated using histopathology. The variables assessed included age, sex, breed, lesion, location, and histopathological diagnosis. Non-neoplastic lesions accounted for 61% of all analyzed samples, while neoplastic tumors accounted for 39%. When looking at age, dogs ranging 3–6 years and 7–9 years had at least six times higher risk of developing malignant neoplasia compared to those aged 0–2 years. Among the malignant neoplasms, mast cell tumors, hemangiosarcoma, and squamous cell carcinoma were the most observed, representing 30%, 18%, and 12% of cases, respectively. The breeds most frequently affected by malignant neoplasms included Pit Bull Terriers, Boxers, and mixed breeds, all of which comprised the majority of mast cell tumor cases at 50.54%. These findings are novel in this field and may assist small animal veterinarians in making preliminary diagnoses, while also helping pet owners understand the importance of skin cancer and its early detection. Full article

Myxomatous mitral valve disease (MMVD) is the most common heart disease in small-breed dogs, and accurate assessment of the left atrial (LA) size is essential for diagnosis and management. The traditional echocardiographic method, LA-to-Aorta (LA/Ao) ratio, is widely used, but evaluates LA size in only one view. This study introduces a novel index—the modified-LA/Ao (M-LA/Ao) ratio—which combines two echocardiographic views to better reflect the true LA size. This study retrospectively analyzed thoracic radiographs and echocardiograms from 136 dogs, including healthy controls and dogs with MMVD classified into stages B1, B2, and C according to ACVIM guidelines. The ability of the M-LA/Ao ratio is compared to conventional indices using correlation analysis and receiver operating characteristic (ROC) curves. The M-LA/Ao ratio showed a strong correlation with existing indices and slightly improved discrimination between ACVIM stages B1 and B2, although performance between stages B2 and C was similar to the LA/Ao ratio. Intra- and interobserver variability were also acceptable. Our findings suggest that the M-LA/Ao ratio may provide a practical and sensitive method to evaluate LA enlargement in early-stage MMVD, helping clinicians detect subtle cardiac remodeling before progression to advanced disease. Full article

Patellar luxation is common in small breed dogs and is often treated surgically. This study compares the long-term outcomes of two surgical techniques, trochlear wedge recession (TWR) and trochlear block recession (TBR), for medial patellar luxation (MPL) with regard to osteoarthritis (OA) progression. High inter-observer agreement was hypothesized for the use of a modified OA scoring system and fewer OA changes in the TBR group. This study included 25 dogs (<15 kg) with grade-2 or -3 MPLs treated at the University of Veterinary Medicine Vienna (2016–2021). A total of 32 stifle joints (TWR Group n = 11, TBR Group n = 21) were evaluated pre-operatively and at least one year post-operatively using a modified OA scoring system. A statistical analysis was conducted to compare OA progression between the techniques. The inter-observer agreement was high. The OA scores increased in both groups post-operatively, with TBR demonstrating a greater progression at specific points. Overall, no significant differences were found between the techniques. These findings suggest that OA progression does not significantly differ between TWR and TBR. The modified OA scoring system has shown to be reliable for assessing OA progression after treatment. Further prospective studies with larger study populations incorporating clinical assessments are needed for a better understanding of the surgical impacts on OA development. Full article

The patella plays a vital role in stifle joint function by contributing to limb extension and joint stabilization. While its clinical significance in small animal orthopedic surgery is well established, detailed comparative data on patellar morphology in domestic cats and dogs remain limited. This study aimed to investigate interspecific and intraspecific variation in patellar shape and size using three-dimensional geometric morphometric techniques. Computed tomography images of 18 cats and 55 dogs were used to construct 3D models, and a total of 14 anatomical landmarks were manually placed on each patella. Generalized Procrustes Analysis was applied, followed by principal component analysis to explore patterns of shape variation. The results revealed a significant difference in shape between cats and dogs, with dogs exhibiting broader variation and larger centroid sizes. Regression analysis indicated that 12.2% of the observed shape variation could be attributed to centroid size, reflecting the influence of patellar size. This strong link suggests that size has a significant influence on how the patella’s shape varies, especially in dogs. These findings highlight the importance of individual variation in patellar morphology, particularly in dogs. A single standardized implant or surgical technique may not be appropriate for all cases. Integrating shape and size evaluations into preoperative imaging can help improve implant fit, joint stability, and overall surgical success. In the absence of breed-specific data, individualized planning remains the most reliable approach. Full article

Congenital defects are among the leading causes of neonatal mortality in small animals. Among them, cleft palate is one of the most commonly found malformations in dogs. Appropriate clinical management and surgical correction are determining factors for the survival of puppies affected by this alteration. Thus, the objective of this study is to describe 10 clinical cases of successful clinical management of cleft palate, highlighting the therapeutic strategies used, the results obtained, and the evolution of patients after treatment. Ten neonatal dogs of three breeds were treated by the Small Animal Reproduction Service of FMVZ, Unesp—Botucatu: French Bulldog (6), Pug (3), and American Bully (1) presented with cleft palate at birth or during the first week of age. Patients underwent clinical and nutritional management, in addition to immunological support. At four months of age, the patients underwent medially positioned flap repair. The animals were fed via an esophageal tube for 10 days after surgery. The clinical management proved to be effective since, throughout the follow-up, the animals showed good development and did not present complications arising from the cleft palate, and the surgical procedures were successful, restoring the quality of life of the animals. Full article

This study explored the complications and prognosis of modified tibial plateau leveling osteotomy with tibial tuberosity transposition (mTPLO-TTT) for simultaneously correcting high-grade medial patellar luxation (MPL) and cranial cruciate ligament disease (CCLD) in small-breed dogs. This retrospective study evaluated patient data, lameness scores, radiographic outcomes, and complications over a median follow-up period of 10 weeks. Additionally, an owner interview was conducted 6 months postoperatively. Nine stifles from seven dogs were included in this study. All cases showed satisfactory patellar alignment and stability after surgery, with no major complications or reluxations. The lameness scores improved, and radiographic assessments confirmed implant stability and appropriate bone healing. Owner-reported outcomes at 6 months were also favorable. These findings suggest that simultaneous mTPLO-TTT is an effective surgical option for small-breed dogs with concurrent CCLD and Grade IV MPL. Full article

This study, which involved 868 patients, focused on size-dependent features (body size, pinna formation, brachycephaly, overweight) and their associations with the occurrence of canine Otitis externa. Breed, sex, and neuter status were also included. Canine patients diagnosed with Otitis externa presented between 1 January 2019 and 31 July 2022 in a referral small animal hospital were included, while dogs with matching categories presented at the Unit for Reproductive Medicine in the same time period functioned as a randomized control group. Statistical analyses included Pearson–Chi² test, Fisher’s exact test, and Bonferroni correction. p-values of <0.05 were considered statistically significant. Rhodesian Ridgebacks, non-brachycephalic breeds, intact female dogs, dogs with semi-erect ears, and large-sized breeds had a significantly reduced risk of developing Otitis externa. Conversely, Pugs, French Bulldogs, Cocker Spaniels, medium-sized breeds, dogs with erect ears, brachycephalic breeds, neutered female, and neutered male patients were more frequently diagnosed with Otitis externa. The study concluded that large breed dogs showed a reduced risk of developing Otitis externa in our data set as well as meso- and doliocephalic breeds and dogs with semi-erect pinna formation. Particularly, the Rhodesian Ridgeback and intact female dogs showed a significantly low risk of suffering from Otitis in the current study. Full article

Background: Histiocytic sarcoma (HS) is a highly aggressive malignancy characterized by the excessive proliferation of histiocytes in dogs and humans. A subset of dog breeds, including the Bernese Mountain Dog (BMD), show a remarkably high prevalence of HS. Previous work by us and others has identified somatic driver mutations of HS in the PTPN11 and KRAS genes that activate the MAPK pathway in about 60% of canine HS. However, no somatic driver mutations have been identified in the remaining 40%. Objectives: Our goals are to study HS in BMDs to gain insight into the molecular pathogenesis of the disease, and identify rational approaches to therapy. Methods: Here, we report our whole transcriptome analysis of 18 well-characterized BMD HS tumor tissues, as well as three HS cell lines. Results: Our analysis reveals the significant upregulation of molecular pathways involving the FOXM1, AURKB, PLK1, and E2F genes, in HS as well as hemophagocytic HS, providing new information regarding pathways that may be targeted with inhibitors. In addition, we document the expression of multiple checkpoint genes, suggesting the option of treatment with small-molecule inhibitors together with checkpoint inhibitors. Further, we show that the transcriptomes of three canine HS cell lines mirror those of canine patient tumors, further highlighting their potential use in drug discovery and efficacy studies. Finally, we demonstrate, for the first time, that aurora kinase inhibitors are effective in curtailing the growth of HS cells in vitro and show synergism with MAPK inhibition. Conclusions: This study provides the most detailed analysis of the canine HS transcriptome to date, highlighting key pathways in its pathogenesis and suggesting new avenues for both single and combination treatment strategies, which may be pertinent to the treatment of human HS. Full article

The reproductive cycle in domestic dogs involves prolonged phases of hormonal activity, making the endometrial tissue vulnerable to degenerative changes. One common result of these changes is cystic endometrial hyperplasia (CEH), which often leads to pyometra. Another, though rarer, condition is pseudo-placentational endometrial hyperplasia (PEH), characterized by abnormal proliferation of the endometrial glands and stroma, forming placental-like structures without the presence of pregnancy. Case presentation: An 8-year-old female Golden Retriever, healthy and intact, was presented for a routine ultrasound examination to confirm pregnancy after natural breeding 25 days earlier. Two previous pregnancies of this bitch have resulted in small but live litters. The ultrasound examination revealed multiple bilateral thickenings of the uterine horns, with ampullary-shaped enlargements measuring approximately 2.5 × 3.0 cm 25 days after breeding. The endometrium was conspicuously thickened, hypoechogenic, and either homogeneous or with scattered hyperechoic markings and faint striations. The mucosal surface ranged from regular to slightly irregular, and a small amount of hyperechoic condensed fluid was present in the lumen of the horns. No embryos were observed. Based on these findings, two primary diagnoses were considered: PEH or embryonic resorption sites, with a possible segmental uterine inflammation. A diagnosis suggestive of PEH was established through histopathological examination of the uterus after ovariohysterectomy, supported by consistent ultrasound findings that showed no progression or changes over time. Full article

Body awareness allows the individual to negotiate spatial tasks by referencing their own body. Here, we tested whether biologically meaningful factors, such as an alternative solution (detour around an obstacle) and learning from a human demonstrator, would affect dogs’ reliance on their body size in an aperture test. We hypothesized that the dogs would choose the socially reinforced solution over a shortcut, and they would choose the shortcut when the opening was comfortably large. We tested N = 45 adult, mixed-breed dogs, by using a 3 m long, transparent fence. The dogs had three trials with closed doors and then three trials with either a small (but passable) or a large open door. In the demonstration group the experimenter performed a detour before the first three trials, then we opened the large door. The dogs preferred the shortcut, where they relied on body awareness, as they either hesitated or opted for a detour when the small door was open. The dogs who watched the demonstration for longer in trial 3 chose the door less often in trial 4, which indicates social learning. By testing mixed-breed dogs, our results are minimally influenced by functional breed selection and serve as valuable baseline for testing complex socio-cognitive traits in companion dogs. Full article

Platelet-rich fibrin (PRF) is a recent regenerative biomaterial applied in clinical wound healing. This study aims to evaluate the safety and efficacy of allogeneic PRF therapy as a regenerative methodology for treating skin wounds in two small dogs. A Miniature Pinscher and a mixed breed dog weighing 3.6 and 9.5 kg, aged 5 and 10 years, with extensive skin wounds implicating significant tissue loss and with abundant yellow exudate were allocated to this study. Each allogenic PRF treatment was derived from screened donors and consisted of grafting PRFs at the wound recipient area. Nevertheless, the blood group of the donor or recipient was not considered. The wound from case 1 received three PRF treatments during the initial two weeks of treatment, and case 2 received four PRF treatments, followed by single weekly ones. The utilization of PRFs was suspended as soon as relevant wound contraction and epithelization were observed. Both animals received systemic antibiotics prescribed at the emergency room by the first clinician. The wounds were cleaned using sterile saline only. Two weeks later, the lesions had reduced by more than 80%. All lesions exhibited aesthetic and uneventful healing. No rejection, necrosis, or infection signs were observed. PRF acted as a regenerative biomaterial, forming vascularized granulation tissue, followed by epithelization and wound resolution. Full article