Young suckling piglets are protected by passive immunity from the sow.In most systems they receive little challenge from the sow herself, since she is actively immune to the diseases she carries.

• 新生仔猪可从母体获得被动的免疫力.；母猪对自身携带的疾病有较强免疫；小猪因获得了母体的免疫力；从而很少受到来自母猪的疾病威胁