Influence of parity of birth and suckled sows on piglet nasal mucosal colonization with Haemophilus parasuis.

Litters of primiparous and multiparous sows were switched at 12 d and nasally swabbed at 12, 18, and 23 d for detection of Haemophilus parasuis. At lactation days 12 and 23, mucosal colonization rates for multiparous and primiparous litters were 0% versus 33% and 26% versus 60%, respectively.