Introduction Rabies provokes acute and fatal encephalitis in all worm blooded mammal hosts; it is caused by a neurotropic, RNA virus belonging to the order Mononegavirales, family Rhabdoviridae, genus Lyssa-virus (Fauquet et al., 2005). Rabies infection usually occurs through infected saliva reaching a bite wound or skin scratches and breached mucous membranes. The severity, location, multiplicity of bites inflicted on the victim, biotype of the virus and the susceptibility of the recipient influence the outcome of potential exposure to infection. Bites on head and neck are associated with the shortest incubation period (Green and Rupprecht, 2006) The disease represents a serious public health problem in developing countries, where approximately 35000 to 50000 human deaths occur due to rabies each year (WHO, 1996). Control of diseases causing significant mortality has made outstanding progress and immunization of one individual is to prevent diseases (Mohanty et al, 2007). Post exposure vaccination against rabies along with anti-rabies immunoglobulin prevents the development of the disease. In this respect Al-Behwar (2009) concluded that the best immunization of farm animals post exposure to rabies infection could be achieved by administration of rabies vaccine and anti-rabies serum on the suitable time (1-3 days post exposure). There is a great attention directed toward animal protection against fatal diseases as rabies infection. In this aspect many studies were carried out including prophylactic vaccination with potent vaccine and post exposure intervention using specific antiserum and immunoglobulin (Khodeir and Daoud, 2008). Freeze-drying is a process used to improve the stability of pharmaceutical proteins, including snake anti-venoms. This additional step confers these with a higher stability in comparison to liquid formulations, especially in tropical regions where high temperatures could affect the activity of immunoglobulin. Freeze-drying confers stability to proteins, particularly at high temperatures. However, during this procedure antibodies can experience physical and chemical modifications, which may cause irreversible changes and have a negative