Abstract: We studied the use of specific transfer factor as a modulator of the immune system, with special respect to its effectiveness in the improvement of antibody production and serum biochemical indexes. A total of 21 adult male Beagle dogs were assigned randomly into 3 test groups. After immunized with a multivalent vaccine, dogs in two groups were fed with different dosages of canine parvovirus-specific transfer factor oral liquid products. Laboratory tests to assess the immune profile of experimental animals were performed till 27 days after initial treatment. Present results showed that dogs in the two groups treated with transfer factor products after vaccination had better antibody responses. Dogs receiving larger amount of transfer factor products exhibited more favorable serum biochemical parameters. Transfer factor could also promote growth significantly. The fact that specific antibody level rose and maintained for longer time in the transfer factor treated groups confirmed the immunomodulating properties of transfer factor. We concluded that transfer factor could enhance immunal response to vaccines, modify biochemical indexes in blood serum, decrease the response caused by stress and improve the health of dogs.