After the break, Beard and Neil Broom set about forming a match-defining partnership for the fourth wicket before Beard brought up his maiden first class ton midway through the middle session.
Broom joined him with three figures late in the afternoon being dismissed for 103 by Colin de Grandhomme, breaking the partnership at 239.
Beard continued unabated after the loss of his partner, ending the day on 160 not out to help his team to a lead of 217.
With their total of 438-4 accruing the full four batting bonus points, Otago closed the gap on CD to nine points. And it may get even closer after Canterbury did their southern neighbours a favour while facing the Stags.
After being bundled out for 252 by a Doug Bracewell-inspired CD attack, Canterbury roared back into the match on the second day in Rangiora
The Wizards' bowlers struck early and often at the Mainpower Oval, and it wasn't until Bracewell joined Keiran Noema-Barnett that the visitors managed a partnership of any real significance. The pair were the only men to surpass 50 and Bracewell backed up his 7-35 with the ball by top-scoring with 61.
Todd Astle and Ben McCord combined to take six wickets as Canterbury restricted CD to 249 and emerged with a slim first-innings advantage.
However, some of the good work was undone late in the day when the Wizards lost both openers to Andrew Lamb to finish on 55-2.
Peter Fulton's double failure (1 and 5) turned up the heat in the race for New Zealand's vacant opening spot for the upcoming test series against England.
Daniel Flynn, another main candidate to replace Brendon McCullum when he drops down the order, showed his ability in the position with a century on the second day of Northern Districts' clash with Wellington in Whangarei.
Flynn made 102, his 14th first class century, as the Knights ended the day on 344-6, still trailing Wellington's first innings total of 423.
ND, the third side still in contention for the trophy, will begin tomorrow with Daryl Mitchell (71no) and Tim Southee (41no) at the crease.