Field vaccination trials against turkey coryza using a temperature-sensitive mutant of Alcaligenes faecalis

In field trials, 14 flocks of turkeys were vaccinated against coryza (rhinotracheitis) with a temperature-sensitive mutant of Alcaligenes faecalis via drinking water. Vaccine doses of 5 to 250 million bacteria per turkey were used. Turkeys ranged in age from 2.5 to 13 weeks. Doses of 5 to 7 million bacteria did not induce complete protection. Doses of 50 million bacteria or more appeared to induce substantial immunity in most flocks. Six-week-old birds receiving doses of 90 million bacteria developed a high degree of protection against challenge with virulent A. faecalis.