Morphological differentiation of bovine and equine hair for species’ identification in forensic veterinary investigations

Abstract

In this paper a morphological differentiation tool of bovine and equine hair for their identification in forensic investigations is provided. 30 animals were used, fifteen adult bovines of the “Siboney de Cuba” breed and fifteen adult equines of the “Criolla” breed. These species are the most bred in Cuba and, at the same time, the most exposed to poaching and theft crimes. Hair from the cows was sampled from the dorsal region, the lateral region and the ventral region; on the other hand, the horses’ hair was sampled from the dorsal region of the body, of the mane and of the tail. The sampled areas, different for bovine and equine, have been chosen because they represent the different types of hairs present in the two species under examination. Getty et al. (2004), infact, reported that both in cattle and horses the length and thickness of the hair is reduced in a dorsal-ventral direction towards the abdomen, increasing its density. The samples were observed at an optical microscope with LCD display, at lens 4X, 10X, 40X and 100X, to determine cuticle scales, cortex, medulla and medullary index. As a result, it was noticed that both bovine and equine hair show a morphological and histomorphometric pattern based on the characteristics of the constitutive structures: cuticle scales, cortex and medulla. The bovines show a thin cuticle, coronal scales in mosaic with serrated edges and flattened irregularly, while in the equines it is thin and imbricated with irregular waves and intermediate spaces. The cortex in the bovines is thin crust dark brown and not pigmented; in the equines the cortex is dark brown, with light texture and isolated dark brown and black pigments. In both species, the white hairs do not show pigments. Through this investigation it can be noticed that one of the most important aspects in the species identification in forensic analysis is the medullary index, since it allows differentiation between animal and human species. In the bovine it is shown with an average of 0.60, while the equine shows an average medullary index of 0.49.