This study investigates skull shape variation and allometry among three different chicken breeds: Broiler, Lohman Brown, and Leghorn. Geometric morphometrics analysis was employed to analyse skull morphology, focusing on facial bones and the neurocranium. The study aims to understand how skull shape differs between these breeds and how it relates to size variation. Results show significant differences in skull morphology among the chicken breeds. Following PCA analysis, it was observed that PC1 explained 21.7% of the total variation. The PC1 values of Broiler chickens were notably lower compared to other breeds, indicating distinct morphological differences in their cranial shape. Increasing PC1 values corresponded to a more rounded head shape, with individuals possessing high PC1 values exhibiting a higher neurocranium. In contrast, Lohman Brown and Leghorn chickens show similarities in skull shape, with a more elongated appearance. Broiler chickens were found to be the smallest among the breeds studied, with statistical analysis confirming their distinguishability based on centroid size. In contrast, Lohman Brown and Leghorn chickens exhibited similar sizes, with no significant difference between them. Allometric analysis reveals that skull shape changes with size, particularly in the neurocranium and facial bones. These findings suggest that evolutionary adaptations and breeding practices have influenced the skull morphology of these chicken breeds. Overall, this study provides insights into the skull shape variation and allometry of different chicken breeds, highlighting the importance of considering both genetic and environmental factors in understanding morphological diversity in poultry.

This study aimed to reveal the morphological characteristics of pure Holstein and Simmental skulls and to obtain reference values for morphometric analysis. Moreover, 54 skulls from 12- to 14-month-old male Holstein (n = 25) and Simmental (n = 29) cattle were collected from Turkey’s Southeastern Anatolia Region between 2023 and 2024. Linear measurements indicated that Holsteins had longer skulls compared to Simmentals. Holsteins exhibited significantly higher values for the greatest length of nasals and the shortest skull length. The facial breadth was wider in Holsteins and statistically distinctive between the breeds. Holsteins had a more oval orbital bony roof, while Simmentals exhibited a wider orbital structure. The orbital index was higher in Holsteins, distinguishing between the two breeds. It was observed that Simmental cattle had a wider occipital region. This difference is likely due to the larger lateral appearance of the Simmental skull, which has more body weight and provides a larger surface area for muscle attachment. These differences not only aid in breed identification but also offer insights into the functional adaptations of each breed. Future research should explore the genetic and environmental factors contributing to these morphological traits, further enriching our knowledge of cattle morphology and its implications for breeding and conservation efforts.

The neurocranium in birds provides valuable insights into their morphological diversity, including adaptations related to brain size, facial shaping, and environmental factors. This study analyzes the neurocranial shape characteristics and size of chickens with similar genetic backgrounds. By examining the neurocranial shape variation in chickens of the same age and sex, the study aims to understand the factors contributing to morphological diversity within this specific group. 3D geometric morphometrics was used to analyze 235 neurocrania from four chicken breeds. The analysis revealed significant differences in centroid size among the chicken breeds. The largest neurocranium centroid size was found in Sasso chickens., which were statistically separated from Atak-S. Additionally, centroid size effectively differentiates between Lohmann Brown and Lohmann Sandy chicken breeds. The most significant shape variation concerned the width of the rostral part of the frontal bone. However, according to the PC1 value, the shape variation was observed within rather than between groups. Lohmann Sandy chickens exhibited higher variability in neurocranial shape, suggesting greater shape diversity within this breed than others. As for shape analysis, the breeds showed closer similarity to each other. Lohmann Sandy chickens are characterized by positive PC1 value, with the rostral end of the frontal region inclined more ventrally, and a more extensive basioccipital region. Sasso chickens have a more dome-shaped middle part of the frontal region than other breeds. The study also identified the most significant shape variation among the study samples, observed at the rostral part of the frontal bone. These findings contribute to understanding the genetic and environmental influences shaping neurocranial morphology in chickens. Similar studies in different bird species and subspecies offer valuable insights into avian biology and adaptation.

The calcaneus plays a critical role in balance, locomotion, and muscle attachment, making it a key structure for biomechanical adaptations. This study examined interspecies differences between sheep and goats, as well as intraspecies variations among different sheep breeds, in calcaneus morphology. A total of 128 right calcanei were analyzed using 3D geometric morphometric methods to allow detailed assessments of calcaneus shape and size. Among sheep, the Hamdani sheep displayed the largest calcaneus among the breeds, distinguishing them significantly from the others. In contrast, goats had a bilaterally narrower calcaneal body, while sheep featured a more pronounced distal portion that articulates with the talus and a deeper articular surface. Additionally, the sustentaculum tali were more developed in sheep. The bilaterally compressed calcaneal body in goats likely reflects their agility and ability to navigate steep, rocky terrains. In contrast, sheep’s broader and more robust calcaneus may support their grazing lifestyle on flatter terrains, emphasizing their stability and weight-bearing capacity. These findings highlight the functional significance of calcaneal morphology in the locomotor strategies and physical capabilities of goats and sheep, providing valuable insights for comparative anatomy and veterinary science.

The astragalus acts as a crucial intermediary in the tarsal joint, facilitating the transfer of body weight to the lower extremities while also ensuring both stability and mobility through its articulation with adjacent bones, enabling efficient movement. This study investigates the morphological diversity of the astragalus in three modern cattle breeds, one goat breed, and three sheep breeds using three-dimensional geometric morphometric methods. A total of 225 specimens were analyzed in this study. Large bovids, such as the Holstein and Simmental cattle breeds, had a more developed lateral edge of the proximal trochlea and a more rounded astragalus. In small bovids, the Akkaraman and Morkaraman sheep breeds displayed a more prominent medial edge and a rounded astragalus form, while the Hair goat breed exhibited a rectangular structure with a well-developed lateral projection. The results of this study demonstrate that the astragalus serves as a reliable morphological marker for differentiating between large and small bovids, as well as between closely related taxa such as sheep and goats. These shape variations, particularly observed in the proximal trochlea, reflect functional adaptations to size, body mass, and locomotor demands, making the astragalus a critical element for taxonomic identification and biomechanical analysis.

This study aimed to investigate the skull morphometry and morphology of East Anatolian Red (EAR) and South Anatolian Red (SAR) cattle breeds using advanced 3D modelling techniques to establish comprehensive reference values. The study was based on 27 measurements and eight indices of the 42 skulls of male cattle collected from slaughterhouses in Türkiye. Craniometric measurements were analysed to identify potential morphological differences between the two breeds. Despite some observed differences in specific measurements, no statistically significant variations in skull morphometry between East Anatolian Red and South Anatolian Red cattle were found. SAR cattle exhibited a larger neurocranium than EAR. SAR cattle generally have a broader and more robust skull with a more pronounced nuchal crest and greater breadth of the foramen magnum. High variability within the EAR group suggested significant intra‐breed diversity, possibly due to genetic or environmental factors. The reference values established in this study serve as a crucial benchmark for monitoring morphological changes across generations and assessing the impact of selective breeding on skull structure. These findings contribute to the broader understanding of evolutionary developments and adaptations in cattle breeds, with significant implications for veterinary morphology, taxonomy, and breeding programs.