Shadman struck 10 fours to guide his side to 3-213 at stumps. Liton Das, returning from a hip injury, was also unbeaten, on 10.
Bangladesh captain Najmul Hossain Shanto had won the toss and opted to bat first, a decision that was justified by the patient Shadman.
New-ball bowlers Jayden Seales and Shamar Joseph put Bangladesh under pressure with probing lines and lengths.
Their persistency paid off when Tanzid Hasan edged a delivery from Seales to second slip on seven.
Unlike Tanzid, Shadman resisted the temptation to repeatedly drive outside the off stump and steadied the innings with Mominul Haque.
They kept West Indies at bay by sharing 59 runs for the second wicket.
Left-arm spinner Jomel Warrican broke the partnership when Mominul sliced a ball to mid-off on 28.
Warrican then dismissed Shanto on 19 after a successful lbw review, the skipper missing a paddle sweep.
Shadman had raised his 10th half-century, and fourth against West Indies, by taking a single.
Shadman found an able partner in Tawhid Hridoy, who was playing his first match since making his debut against Zimbabwe in Harare four months ago.
The pair put on 88 before Hridoy was forced off the field after suffering cramp in the humid conditions. He was unbeaten on 42.
Bad light first interrupted play for around 30 minutes when Shadman was on 96. After the resumption, he appeared set for his third test century but was denied by the early close.
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