Continuous Eruption and Loss
A horse's incisors, premolars, and molars, once fully developed, continue to erupt as the grinding surface is worn down through chewing. A young adult horse's teeth are typically 4.5–5 inches long, but the majority of the crown remaining below the gumline in the dental socket. The rest of the tooth slowly emerges from the jaw, erupting about 1/8" each year, as the horse ages. When the animal reaches old age, the crowns of the teeth are very short and the teeth are often lost altogether. Very old horses, if lacking molars to chew, may need soft feeds to maintain adequate levels of nutrition.
Older horses may appear to have a lean, shallow lower jaw, as the roots of the teeth have begun to disappear. Younger horses may seem to have a lumpy jaw, due to the presence of permanent teeth within the jaw.
Read more about this topic: Horse Teeth
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