41,8 % of the sows have antibodies against K 88, 59,5 % against K 99, 78 % against 987 P and 62,5 % whose 87,5 % against several pili.After discussion of respective importance of these antibodies and of their share, among one herd a same animal. the authors conclude in favor of existence in France of enteropathogenic strains with new pili and of the interest of incorporating these structures in the bacterines for the fighting against neonatal colibacillosis.