The present invention pertains to the use of Haemophilus parasuis serotype 5 bacteria in the manufacture of a vaccine for administration to a pregnant sow or gilt, to protect a piglet through the intake of colostrum of the said sow or gilt after she has farrowed, against a disorder arising from Haemophilus parasuis serotype 4 bacteria. The invention also pertains to Haemophilus parasuis serotype 5 bacteria for use in the manufacture of such a vaccine.