Progress in elucidating the mechanisms regulating the immune response to infectious agents and derived vaccines in domestic species especially camels and water buffalo, has been impeded by the lack of monoclonal antibody (mAb) reagents needed to study the immune response in the species of interest. As a first step to address this problem we conducted a study to determine how many mAbs developed against leukocyte differentiation molecules (LDM) in various species recognized conserved epitopes on orthologous (identical) molecules in two or more species of Artiodactyla. Analysis of 490 monoclonal antibodies raised against leukocyte differentiation molecules (LDM) in cattle, sheep, goats, lamas, pigs, dogs and humans revealed that many epitopes have been conserved in the speices in the course of evolution in closely related species in the suborder Ruminatia (cattle, buffalo, bison) and fewer related species (sheep and goats). Only few of the epitopes conserved in Rumintia were conserved in the pig, lama and camels. The highest level of conservation in all suborders was found with major histocompatibility complex class 1 (MHC1) and class 11 (MHC11) molecules. These findings show the potential as well as the limitations of screening existing monoclonal antibodies to investigate disease conditions. These findings show the potential as well as limitations of screening existing mAbs for mAbs useful for research in less well studied species. Importantly, the findings also provide further insight into the composition of the immune system in Artiodactyla and factors to be considered when studying the immune response to infectious agents and vaccines in the different suborder of artiodactyla.