It all shows that the Influenza A virus is much more versatile than previously thought. If it can infect so many species, we can ask the question: can it infect even more animals?
Scientists then tried to infect calves with Influenza A(H5N1) and they found that the virus had potential to infect calves. The animals did not fall visibly ill but could shed the virus. That means that there is a problem because in regions like Asia and Egypt, where the Influenza A(H5N1) virus is endemic and probability of contact between poultry, pigs and cattle is high, the virus might adapt, evolve and mutate more rapidly.
 Crawshaw et al: Significant rising antibody titres to influenza A are associated with an acute reduction in milk yield in cattle in Veterinary Journal - 2008
 Kalthoff et al: Experimental Infection of Cattle with Highly Pathogenic Avian Influenza Virus (H5N1) in Dispatches - 2008