[header] How to tell a horse's age by its teeth [title] Look a the color of the horse's teeth. [step] The color of a horse's teeth provide a general clue as to horse's age. The milk teeth are white, and the permanent teeth (which erupt at 2 ½ to 5 years of age) that replace them are cream-yellow. 
With increasing age they turn brown (20 years plus). [title] Examine the shape of the chewing surface.