Pelvis shape analysis with geometric morphometry in crossbreed cats.

In this study, the geometric morphometry of the pelvis of 32 (16 male, 16 female) crossbreed cats was investigated. Pelvis images of cats were obtained by computerized tomography method. Then, these images were modelled and geometric morphometry was applied. Shape variations of the pelvis of all individuals were obtained by principal component analysis. The first principal component (PC1) value explained 18.44% of the total variation. Second principal component (PC2) and third principal component (PC3) values explained 16.84% and 13.60% of the total variation, respectively. The difference in the shape of the pelvis of female and male cats was more pronounced in PC2 and PC3, which differed in the linea terminalis. The centroid size difference in terms of sex in the Procrustes ANOVA result is statistically insignificant (p > 0.05). However, the shape difference was statistically significant (p < 0.001). As a result of discriminant analysis, the pelvis of female and male cats was completely separated from each other. The crista iliaca of males was more lateral than females. Linea terminalis was wider in shape in females. The edge of the acetabulum was higher in shape in males. Regression analysis was performed to see whether the age and weight of the cats had an effect on the centroid size of the cats. Age and weight were not found to be effective on centroid size. The shape variations of the anatomical formations obtained by geometric morphometry method can be revealed, and it can be examined whether there is a shape difference between the groups.

Detection of sexual dimorphism of the foramen magnum in cats using computed tomography.

The foramen magnum is a large round or oval opening surrounded by parts of the occipital bone. It connects the cranial cavity with the vertebral canal. The foramen magnum is an important structure having various applications in veterinary practice and forensic medicine. The variability of its shape and sexual dimorphism allow it to be exploited for sex and age identification in different species. This retrospective study used computed tomographic (CT) images of the caudal region of the 102 mixed-breed cat heads (55 males and 47 females). Eight linear measurements of the foramen magnum (FM) and occipital condyles were performed on CT images. The aim of the study was to find out if the linear measurements of the CT images of the foramen magnum showed variability between the sexes of the cats. In general, the values of the linear measurements in male cats were higher than in females. The mean maximum length of the foramen magnum (MLFM) was 11.18 ± 0.84 mm and 10.63 ± 0.72 mm in male and female cats, respectively. The mean maximum internal width of the foramen magnum (MWFM) was 14.43 ± 0.72 mm in males and 13.75 ± 1.01 mm in females. The difference between FM measurements in female and male cats was statistically significant (p value; FML: 0.001, FMW: 0.000). The MLFM confidence interval was 10.41 mm to 10.86 mm in female cats and 10.97 mm to 11.39 mm in males. The confidence interval of MWFM was 13.5 mm to 14.0 mm in female cats and 14.2 mm to 14.66 mm in male cats. With these intervals, we can predict the probability of sex in cats with 95% confidence. It was noted that measurements of the occipital condyles were not sex-determining. The difference in foramen magnum index in female and male cats was statistically insignificant (p value; 0.875). As a result of the study, it was seen that the linear measurements of the foramen magnum were sex-determining.

Examination of Shape Variation of the Skull in British Shorthair, Scottish Fold, and Van Cats.

A variety of skull shapes are frequently used for discrimination between animal species, breeds, and sexes. In this study, skulls of three different breeds of cats were examined by the geometric morphometric method, with the aim of revealing skull shape differences. For this purpose, 27 cats (6 British Shorthair, 7 Scottish Fold, and 14 Van cats) were used. The skulls of cats were modeled by computed tomography. Geometric morphometrics was applied using dorsal (8 landmarks, 63 semilandmarks) and lateral (8 landmarks, 63 semilandmarks) skull projections on these models. Centroid size differences between the breeds were statistically insignificant. However, the differences in shape were statistically significant for both the dorsal view and lateral view. Shape variation was less in the British Shorthair than in other breeds. Shape differences generally occurred around the orbit. In the skull of Scottish Folds, the orbit was situated more caudally than in other breeds. The British Shorthair had the largest orbital ring. In dorsal view, the Scottish Fold had the largest orbital diameter. The orbital ring of Van cats was smallest in both dorsal and lateral views. In the canonical variate analysis, it was seen that the breeds were separated from each other. The shape difference in the skull between different cat breeds could be revealed by geometric morphometrics. The results of this study provide useful information for taxonomy.