Diagnostics and identification of cryptosporidia are, especially in the agricultural sector, very important to prevent from or at least to minimize economic damage. In cattle, there are five different species of Cryptosporidium, which are able to cause cryptosporidiosis, a disease able to severely harm or even to kill the affected animals. This bachelor thesis describes an in situ hybridization for general detection of cryptosporidia in formalin-fixed paraffin-embedded tissue samples and a polymerase-chain-reaction with subsequent sequencing especially for these five cattle-relevant Cryptosporidium species. With these methods 16 out of 20 investigated samples were found to be infected with cryptosporidia and the pathogen was identified in all cases as Cryptosporidium parvum. Some genotypes of this species have a zoonotic potential.