This study aimed to characterize and compare the aspects involved in the microstructural formation of the Holstein and Gir breed hoof wall by histomorphometry, three-dimensional microtomography and microhardness test techniques. Seventy-two (18H/18G thoracic and 18H/18G pelvic) Holstein (H) and Gir (G) breed hooves were collected in slaughterhouses. The hooves were divided into six groups according to breed and age group: 24 to 36 months (C1H/C1G), 36 to 60 months (C2H/C2G) and over 60 months (C3H/C3G). The normality and homogeneity analysis of morphometric variables by the Kolmogrov-Sminov and Bartlett tests was conducted as a statistical model. Once the assumptions were met, the Sigmastat 3.5 software was used and the means were compared by T test. The 5% probability level is considered. When the assumptions were not met, the means were compared by the Mann-Whitney nonparametric test, considering the 5% probability level. When comparing the Holstein and Gir breeds, no differences were noticed between them as to the length of the dermal papillae; young animals showed thicker papillae than adult animals; the Holstein breed hooves showed higher amount of 7pores on the wall and on the sole compared to the Gir breed; Holstein cattle hooves showed greater microhardness than Gir cattle; there was no microhardness difference between pigmented and non-pigmented hooves of Holstein and Gir cattle.Keywords: diseases of cattle, digits, three-dimensional microtomography, dermal papillae, podiatry RESUMO O presente estudo objetivou caracterizar e comparar os aspectos envolvidos na formação microestrutural do estojo córneo de bovinos das raças Holandesa e Gir pelas técnicas de histomorfometria, microtomografia tridimensional e teste de microdureza. Foram coletados em frigoríficos, de forma igualitária entre as raças Holandesa (H) e Gir (G), 72 cascos (18H/18G torácicos e 18H/18G pélvicos). Os cascos foram divididos em seis grupos de acordo com a raça e a faixa etária: 24 a 36 meses, (C1H/C1G), 36 a 60 meses (C2H/C2G) e acima de 60 meses (C3H/C3G

The aim of this study was to describe the microstructure of hoof capsules of the buffalo. In addition, the study emphasized the morphometric aspects of the horn tubules, the Vickers nanohardness of the dorsal and abaxial walls and sole of the digits of the thoracic and pelvic limbs of the buffalo. The abaxial wall in the thoracic and pelvic digits showed larger diameter of the horn tubules when compared to all dorsal wall and sole. In addition, the abaxial wall of the thoracic digits showed larger diameter of the horn tubules when compared with the pelvic digits. According to the three-dimensional microtomography, the dorsal wall was higher in density compared with the abaxial wall. The latter exhibited an intermediate density, while the sole showed the lowest density. The Vickers nanohardness test showed that there was no difference in hardness and resistance between the experienced regions. However, the elastic modulus was greater on the transversal section of the hoof capsule. In conclusion, the results of the current study show that modern technologies such as microtomography and subsequent imaging can be used to investigate details of the basic morphology in different regions of the buffalo's hoof.

The aim of this study was to describe the microstructure of the pigmented and depigmented hoof capsule of Girolando cattle by bi- and tridimensional microtomography and nanoindentation, analysing the possible relation between these findings and the susceptibility of such animals to podal diseases. To carry out the microtomography and the nanoindentation, duplicated samples were collected from the dorsal wall, abaxial wall and pre-bulbar sole of the hoof capsule. Material collection was performed in 40 medial digits of thoracic limbs and 40 lateral digits of pelvic limbs. The bidimensional microtomography showed that the dorsal wall of the thoracic and pelvic limbs presented higher density, followed by the abaxial wall, and finally by the sole, with the lowest density. Moreover, the hoof capsule of cows of Girolando breed is a compact, non-porous material, and constituted by extratubular and intratubular keratin. By the tridimensional microtomography, it was possible to measure the angles of the corneal tubules in relation to the periople and the claws in the different regions of the hoof capsule, which were 90° for the dorsal wall, 55° for the abaxial wall and 70° for the sole. The tridimensional microtomography also showed corneal tubules of different diameters: 17, 51, 85, 119 and 153 μm. The nanoindentation test, when performed in different regions of the hoof capsule, did not reveal significant difference of Vickers hardness in the evaluated areas. However, we verified a larger elastic module of these regions on the transversal cut of the corneal tubules compared to the longitudinal cut.