Gender-Related Differences in Pelvic Morphometrics of the Retriever Dog Breed

Evaluation of sex differences in pelvis and femur x-ray images in British shorthair cats by geometric morphometric method

The study covers British Shorthair cats, which is a popular domestic cat breed in our country and defined as 'brachycephalic' in terms of skull structure. Article focuses on the pelvis and femur region of cats which gynaecological and orthopaedic diseases of this cat breed, which are frequently encountered in clinical practice, is found to be important. It is aimed to reveal the shape differences between male and female individuals using geometric morphometric method. X-ray images were used to examine the pelvis and femurs of cats via geometric method. Radiological images were obtained from a total of 40 British Shorthair cats (20 females and 20 males) in two positions, ventro-dorsal (VD) and latero-lateral (LL), and shape differences between the sexes were examined. As result, it is seen that the measurement points taken from the males are more outward and have sharper angles than the females. Study also shows pelvis is a better choice than femur when it comes to sex discrimination. Although traditional morphometric methods are more useful in clinical practice, it is thought that is important to support or re-evaluate the data with the geometric morphometric method in academic field for a further approach.

Radiographic measures of the pelvis differ in British shorthair cats with dystocia and eutocia

The size of an animal's pelvis can have a substantial impact on the ease or difficulty of giving birth, which can vary depending on the breed. Radiography is a medical imaging technique that is commonly utilized in clinical cases to assess pelvic dimensions. The present retrospective, observational study was designed to evaluate pelvimetric differences in radiographic images of British Shorthair (BS) cats with dystocia and eutocia. Pelvimetric values (linear distance, angle, area, height/width) for ventrodorsal and laterolateral radiographic images were recorded in 15 BS cats with dystocia and 15 BS cats with eutocia. Statistical analysis of the obtained measurement values was performed. When the pelvimetric data were examined overall, it was seen that mean values, except the PL (pelvis length) measurement, were higher in cats with eutocia than in cats with dystocia. Vertical diameter, conjugate vera, coxal tuberosities, transversal diameter, acetabula, pelvic inclination, ischiatic arch, pelvis inlet area (PIA), and pelvic outlet area (POA) values were significantly higher in cats with eutocia than in cats with dystocia (P < 0.05). Mean PIA and POA measurement values in cats with dystocia were 22.89 ± 2.38 cm2 and 19.59 ± 1.90 cm2 , respectively; in cats with eutocia, the mean was calculated as 27.16 ± 2.76 cm2 and 23.18 ± 1.88 cm2 , respectively. In conclusion, the present study revealed that pelvimetric values, except the PL measurement, were higher in cats with eutocia than in cats with dystocia. Findings can be used to assist veterinarians in future clinical decision-making for pregnant BS cats.

Sex differences in pelvic and sacral size in wildcat from the Western Carpathians

Sexual differences in the wildcat were evaluated on 15 variables in 49 pelvic and 38 sacral bones in wildcat from the Western Carpathians. Our data confirmed a male-biased sexual size dimorphism (SSD) in the pelvic and sacral bones. The effect size was very large for two pelvic (SB, smallest width of the shaft of the ilium; and LAR, length of the acetabulum) and two sacral traits (GB, greatest width across the wings; and BFcr, greatest width of the cranial articular surface). Our different allometric patterns in pelvic and sacral measures in both sexes may also be important in mode of locomotion. These findings highlight the need for morphometric analysis of species at the regional as well global level.

A pilot study: Can calcaneus radiographic image be used to determine sex and breed in cats?

This study examined whether radiographic images measurements of the calcaneus in cats are determinative of sex and breed. For this purpose, radiographic images of 70 cats (37 male and 33 females) of different ages (from one to 18 years) and different breeds (41 mix-breed, 18 Scottish Fold and 11 British Shorthair cats) without orthopaedic problems were used. Right tarsal joint radiographs of these orthopaedically healthy cats were taken. Four linear measurements and two angle values of the calcaneus were obtained from the radiographic images. The MANOVA result showed that the most determining factor between the three groups was the greatest width (p value = 0.001). Calcaneal body length, calcaneal greatest length and calcaneal shortest depth were higher in mix-breed cats. Calcaneal tuber length was higher in Scottish Fold cats. The only statistically significant difference between Scottish Fold and British Shorthair was in the calcaneal tuber length (p value = 0.04). In the comparison made between the sexes regardless of species, the linear measurements in males were higher than in females. It was determined that these parameters are statistically significant in terms of sex differentiation in cats. Dorsal and plantar calcaneal angles are not sex determinants in cats. The effect of age on other measurements was analysed by correlation test. However, the effect of age on the measurements was not statistically significant. Mix-breed cats were examined in four groups according to their colour (grey, black-white, yellow, tri-colour). No statistically significant difference was found between calcaneal measurements of cats with different skin colour genotypes. In this study, calcaneus measurements were both determinative between breeds and sexes in cats.

Radiographic pelvimetry in free-ranging Eurasian lynx (Lynx lynx carpathicus) from Switzerland

The observation of pelvic anomalies in two Eurasian lynx (subspecies Lynx lynx carpathicus) from a population reintroduced to Switzerland raised the question of the frequency of such anomalies, but no anatomical reference values were available for comparison. This study aimed at providing baseline data on the pelvic morphology of Carpathian lynx from Switzerland, and at detecting potential pelvic anomalies. Measurements of 10 pelvic parameters were performed on the radiographs of 56 lynx taken from 1997–2015. Two ratios (vertical diameter/acetabula; sagittal diameter/transversal diameter) and two areas (pelvic outlet and inlet) were calculated to describe pelvic shape. The results showed that the Eurasian lynx has a mesatipellic pelvis, with a pelvic length corresponding to approximatively 20% of the body length. We found growth-related pelvis size differences among age classes and evidence of sexual dimorphism in adults: two parameters reflecting pelvic width were larger in females, likely to meet the physiological requirements of parturition. By contrast, pelvis length, conjugata vera, diagonal conjugata, sagittal diameter, and tendentially also vertical diameter, were larger in males, in agreement with their larger body size. Outliers were found in five individuals but apparently without clinical significance. Extreme values were likely due to inter-individual differences and the limited sample size rather than to possible congenital or developmental pathological morphology of the pelvic cavity. We present baseline data of the pelvic morphology, including growth and sexual dimorphism, which may be useful for health monitoring and for determination of age and sex in skeletal remains of Carpathian lynx.

A three-dimensional reconstructive study of pelvic cavity in the red fox (Vulpes vulpes)

Three-dimensional (3D) reconstructive techniques are being used in many morphometric studies and clinical applications. The red fox is a wild animal localized in a wide geography. This study has been performed to determine morphometric properties of the pelvic cavity and reveal differences between sexes via 3D reconstruction obtained by multi-detector computed tomography images (MDCT) of the red fox. A total of 12 adult red foxes of both sexes were used in this study. Two-dimensional (2D) MDCT images of the pelvic cavity obtained and stored in DICOM format were used to reconstruct the 3D model. Mimics 13.1 program was used to perform the 3D reconstruction. A total of 24 dimensions were measured from the reconstructive model of the pelvic cavity. Twenty two dimensions were found to be significantly different (p < 0.05) between sexes. In conclusion, according to the pelvimetric data, it was determined that the red fox has sexual dimorphism and these data may be useful in wild animals morphological and gynaecological research. The authors hope to help in the diagnosis and treatment of the pelvic cavity-related orthopaedic and gynaecological disorders in the wild animals.

Pelvic bone morphometric analysis in the dugong (Dugong dugon)

The dugong (Dugong dugon Müller) is recognized as an endangered marine mammal. There is limited available anatomical data on the dugong's skeletal system, while what is available has not been well established due to the limited number of archived samples and limited access to them. Importantly, there are certain key questions that should be answered when examining the bones and/or remains of animals such as; what kind of bone is it?; what species does it belong to?; what sex was the animal?; how old was the animal? or how big was it?, etc. In this study, we have focused on the pelvic bone of the dugong by asserting the hypothesis that pelvic bone morphology is related to age, sex, and body size. Here, we have established certain morphometric data encompassing 8 parameters and 5 indexes to analyze the morphology of the pelvic bones obtained from 88 specimens (45 dugongs). We will present three main findings: (1) the pelvic bone in mature male subjects is larger than it is in female subjects, (2) a high rate of accuracy can be established for sex identification using morphometric data obtained from the pelvic bone, and (3) the pelvic bone has the highest degree of correlation with body length, followed by body weight and age. Notably, the important data on the pelvic bone of the dugong acquired in this study can be reliable and extremely useful in sex identification and body size estimation.

Sexual dimorphism in limb long bones of the German Shepherd Dog

The study of sexual dimorphism in dog anatomy, especially with regard to skeletal elements, has received little attention. The present work focuses on elements of the canine stylo- and zeugopodium, less documented than the skull or pelvis in the literature. In order to identify only sex-dependent effects, we analysed a single breed: the German Shepherd Dog. Data come from 25 dogs, with a balanced sex ratio (12 males and 13 females). Four skeletal elements of the forelimb and hindlimb (humerus, radius, femur, tibia) were each measured using seven linear morphometric variables. Univariate and multivariate analyses were then performed on these 28 variables. For all measurements, males are on average larger than females, with a mean sexual dimorphism ratio of 1.07. Sexual dimorphism is significant for 92.8% of the variables. Except of femoral measurements, diaphyseal values show the highest grade of sexual dimorphism. The mean level of disparity is higher in the forelimb (1.08) than in the hindlimb (1.05). A significant dimorphism is shown for the first component of principal component analyses conducted on each skeletal element, and for the second component with humerus measurements. Discriminant functions for sex identification give success rates included between 82% for the radius and 93% for the femur, the latter providing the highest reported score for sex identification in dogs from any skeletal element. These complementary statistic methods highlight a more dimorphic forelimb in size and a more dimorphic hindlimb in shape.

Determination of whether morphometric analysis of vertebrae in the domestic cat (Felis catus) is related to sex or skull shape

In many mammals, gender and skull shape are related to the bone morphology of the entire body; however, this has not been well established in the domestic cat (Felis catus). This study aims to find a relationship between cervical, thoracic and lumbar vertebrae morphometrics with regard to the sex and skull shape of domestic cats. A total of 79 samples obtained from 92 dried bones of domestic cats were used to determine morphometric measurements for a total of 29 parameters. Hierarchical clustering was used to cluster the vertebral bones found in three groups: C3-T1, T2-T11 and T12-L7. The skull shape identification process employed discriminative analysis and revealed the highest training data accuracy rate at up to 86.20% in T4 followed by L1 (86.04%) Axis (85.71%) and C5 (85.18%). Sex identification employed discriminative analysis and displayed the highest training data accuracy rate at up to 75.58% in L1 followed by, T7 (71.87%) and C6 (71.79%). Moreover, we found that 14% of the samples had one vertebra missing (T13 or L1). In conclusion, domestic cat vertebral morphometrics were found to be more related to skull shape than gender. In addition, bone clustering employed morphometric data and yielded a result that was similar to that of traditional cluster analysis involving body regions.

Genetic mapping of principal components of canine pelvic morphology

Background

Concentrated breeding effort to produce various body structures and behaviors of dogs to suit human demand has inadvertently produced unwanted traits and diseases that accompany the morphological and behavioral phenotypes. We explored the relationship between pelvic conformation and canine hip dysplasia (HD) because purebred dogs which are predisposed, or not, to HD share common morphologic features, respectively. Thirteen unique bilateral anatomical features of the pelvis were measured on 392 dogs of 51 breeds and 95 mixed breed dogs. Principal components (PCs) were derived to describe pelvic morphology. Dogs were genotyped at ~183,000 single nucleotide polymorphisms and their hip conformation was measured by the Norberg angle and angle of inclination between the femoral neck and diaphysis.

Results

No associations reached genome wide significance for the Norberg angle when averaged over both hips. PC1 was negatively correlated with the Norberg angle (r = -0.31; P < 0.05) but not the angle of inclination (r = -0.08; P > 0.05). PC1, 2, 4, and 5 differed significantly between male and female dogs confirming pelvic sexual dimorphism. With sex as a covariate, the eigenvector contribution to PC1 reflected the overall size of the pelvis and was significantly associated with the IGF-1 locus, a known contributor to canine body size. PC3, which represented a tradeoff between ilial length and ischial length in which a longer ischium is associated with a shorter ilium, was significantly associated with a marker on canine chromosome 16:5181388 bp. The closest candidate gene is TPK1, a thiamine-dependent enzyme and part of the PKA complex. Associations with the remaining PCs did not reach genome wide significance.

Conclusion

IGF-1 was associated with the overall size of the pelvis and sex is related to pelvic size. Ilial/ischial proportion is genetically controlled and the closest candidate gene is thiamine-dependent and affects birth weight and development of the nervous system. Dogs with larger pelves tend to have smaller NAs consistent with increased tendency toward HD in large breed dogs. Based on the current study, pelvic shape alone was not strongly associated with canine hip dysplasia.

Electronic supplementary material

The online version of this article (doi:10.1186/s40575-017-0043-7) contains supplementary material, which is available to authorized users.

Feline (Felis catus) Skull and Pelvic Morphology and Morphometry: Gender-Related Difference?

This study demonstrates sexual dimorphism of feline bones, based on a morphometric analysis of 38 dried feline skulls and pelvic bones (20 males, 18 females). A total of 44 parameters (skull = 12, mandible = 10, pelvis = 22) were measured using a digital vernier calliper. In morphological observation of these bones, there were three hallmarks indicating a remarkable difference between sexes: the coronoid process of the mandible (accuracy rate = 88.2%); and the os coxae - caudal ventral iliac spine (accuracy rate = 94.4%), and the angle of the ischiatic arch (accuracy rate = 74.3%). In addition, based on morphometric characteristics, six parameters were found to be significantly different (P < 0.05) between males and females, consisting of one in the mandible and five in the pelvis, but no parameters in the skull. Effective equations to discriminate gender were generated through a stepwise discriminant analysis from feline mandible and pelvic bones. Our findings showed that an equation from the pelvic bones, Y = [-16.066*T/O] + [2.559*IC/PS] + [13.357*TTL/ISA] - [4.478], appeared to be more applicable with a 97.3% accuracy rate, while a function from the mandible gave a 64.9% accuracy rate. In conclusion, we suggest that an equation from feline pelvic measurements and three hallmarks, one on the mandible and two on the os coxae, can be used for sex estimation.