DENTITION.
Age of Horse from One to Nine Years, as Indicated by Teeth (Incisors) in Lower Jaw.—The age of a horse is determined by:
1. The character of the teeth, i.e., whether they be temporary or permanent.
2. The period at which they are cut.
3. The condition of the teeth themselves.
Temporary or milk teeth are distinguished from the permanent teeth by being smaller, whiter, and having more distinct necks. The fangs are small and have little attachment to the gums. The jaws are plump, fleshy, and round, and the teeth are arranged in something like a semicircle. Permanent teeth are larger, broader, wider in the necks and more discolored than milk-teeth. The plumpness and circularity of the jaw is less than in the young colt, and gradually decreases. In old age the teeth are arranged in a nearly straight line.
During the first ten months the six incisors appear. At twelve months the teeth show little signs of wear, the corner teeth are mere shells, having no inner walls, and the teeth are close together.
At two years the corner teeth have grown up to level of others; the centre teeth are worn. The teeth stand wide apart at necks because of growth of jaw.
Shortly before three years old the two centre milk-teeth are shed and replaced by permanent teeth.
Shortly before four years old the next two milk-teeth on either side are shed, and permanent ones appear.