M. hyopneumoniae specific immunity is transferred to piglets. M. hyopneumoniae specific AMI (panel A) and CMI (panel B) were measured in piglet blood before (n = 7/group) and 24 hrs after (n = 10/group) colostrum ingestion. Black bars represent piglets from vaccinated sows; gray bars represent piglets from nonvaccinated sows. Error bars are SEM; *: p < 0.05. A. M. hyopneumoniae-specific antibody S:P ratios were measured in serum of piglets pre-suckling and 24 hrs after suckling using the Idexx HerdCheckTM ELISA. B. M. hyopneumoniae specific CMI was measured in piglet blood via lymphoproliferation. Antigen-specific lymphoproliferation was determined by subtracting percent unstimulated lymphoproliferation (media only) from percent M. hyopneumoniae-specific lymphoproliferation.