Effect of vaccination against Mycoplasma hyopneumoniae on health, growth, and pubertal status of gilts exposed to moderate ammonia concentrations in all-in-all-out versus continuous-flow systems

Objective: To determine whether vaccination against Mycoplasma hyopneumoniae during exposure to ammonia alters prevalence and severity of lung lesions, lean tissue weight, and onset of puberty in gilts reared in all-in-all-out (AIAO) or continuous-flow (CF) production facilities. Methods: Two hundred and sixteen Yorkshire x Hampshire x Chester White gilts were reared in either AIAO or CF facilities at the Purdue University Animal Research Center during exposure to ammonia from 2.5-6 months of age. Half of the gilts in each environment were vaccinated against Mycoplasma hyopneumoniae. Lean tissue weight, prevalence and severity of lung lesions, and onset of puberty in gilts were determined at slaughter. Sera titers of Mycoplasma hyopneumoniae and Actinobacillus pleuropneumoniae were measured as gilts entered and exited the study. Correlations of sera titers with severity of lung lesions and with days-to-104.5 kg (230.4 Ib] were calculated. Results: Average daily gain was greater (P < .001) for gifts raised in AIAO versus CF facilities, but was not significantly greater for vaccinates than nonvaccinates. Feed:gain ratios were similar among AIAO and CF gifts, with or without vaccination. Gilts reared in AIAO facilities tended (P = .08) to reach 104.5 kg (230.4 Ib) bodyweight (BW) in fewer days than those raised in CF facilities (172 versus 180 days) and than those gilts that were not vaccinated (173 versus 179 days; [P = .07]). Fewer lung lesions were present in AIAO gilts than in CF gilts (P < .001). Vaccination did not reduce (P = .15) prevalence of lesions in either environment. Antibody titer of M. hyopneumoniae and A. pleuropneumoniae were positively correlated (P < .05) with severity of lung lesions at slaughter but no relationship (P > .05) was found between antibody titer and days-to-104.5 kg (230.4 Ib) BW Neither animal flow strategy (AIAO versus CF) nor vaccination affected (P > .05) ovarian weight, uterine weight or length, or percentage of gilts cycling after exposure to boars. Implications: Lung lesions detected at slaughter were less numerous and growth of gifts was improved by using AIAO facilities rather than CF facilities. Vaccination of gilts against Mycoplasma hyopneumoniae did not produce significant benefits.