hi this tst, four BVD stains, Tobias, NY1, ‘11GM and gan, were incculatei in SPF pigs, then challenged with AU) virulent HC virus.
Cdse oheervation on clinical signs and HC neutralizing antibody response was conductiandcompareiamongthese4 BVD stains used.
No bud post vaccination reaction was found among these 4 vaccinated group. After AU) challenge, the pigs ofNYl with 10-3.8 TCID5O group showed fever for 2-3 days and slight dejuess, anorexia, but recoverer] soon. The pigs vaccinated of Tobias stain with 10-5.3 TCIDSO of VJGM stain showed fever for 2-3 days and slight decrease in spirit and appetite, after HC challenge but rexvered soon. The pigs vaccinatui with 10- 3.OTCE)S0ofhgan stain and 10-1.5 TCE)SOofNYl st-am showed typicalHC lesions.
NoHCorDVDantibodywasdetotedinpigs vaccinatlwith 103.8TCIDSOof NY1 bufore challenge. but aft challenge, HC antibody titer was reacherl 10-1.98 or abve and BVD antibody titer was very low.
Trace HC neutalizigg antibody and low BVD antibody with 10-0,91 were detuoted in pigs vaccinati with 10-5.8 TCE)50 of Tobias before challenge. Aft challenge, HC antibody reached as high as 10-2.26 and BVD antibcdyas 10-2.91 or above.
Trace amount of HC antibody was also found in pigs vaccinated with 10-2.5 TCU)50 of VJGM before challenge and 10-2.4 1 titer was found aft challenge. DVD antibodytiterwas 10-1(4 beforechallengeandre&ohed3.15 aftchallenge.No HC antibody titer and 10-1.98 of BVD antibody titer were detuoted in pigs vaccinai with 10-3.0 TCE)50 of Egan before challenge.
Though trace amount of HC antibody and 10-2.03 of BVD antibody were detected, the pigs still died of typical HC lesions aft ALD virus challenge.
No HC and BVD neutralizing antibody were detectei aft 10-1.5 TCID 50 of NY1 vaccina and aft ALD virus challenge.
From the data obtainer] abve, the protution against HC infection by BVD vaccination depended upon virus titer contained in BVD vaccine and the development of HC antibody, but srris not depended on BVD antibody titer. AMong these BVD stains, the effective fltion order was Tobias, NY1, VJGM and Egan.