At the end of November 1899 during the war the burghers of the Utrecht district chosen J.T. Bierman as adjutant and relieve his Veldkornet a few times during his absence
On 18 November 1901 he was promoted to Veldkornet when the burghers of his district all voted for him.
He was promoted to Commandant of his district commando by General M.W. Myburgh close to the end of the war.