2009-06-242009-06-241979https://hdl.handle.net/10365/5226Based on blackleg vaccination results it would appear that 1) the optimum age to vaccinate nursing calves and immune dams for blackleg would be after four months of age, 2) that a second or booster vaccination will extensively enhance the immune status of nursing calves indicating that initial vaccination of calves six weeks older or younger will not interfere with booster vaccine administration, 3) that the immunological response of the six-week-old or younger calf to the Cl. chauvoei bacteria is variable indicating that maternal interference is not always exhibited or may even stimulate antibody production.North Dakota State UniversityAnimal diseasesArticle