Horse Teeth - Tooth Growth

Tooth Growth

Horses are diphyodontous, erupting a set of first deciduous teeth (also known as milk, temporary, or baby teeth) soon after birth, with these being replaced by permanent teeth by the age of approximately five years old. The horse will normally have 24 deciduous teeth, emerging in pairs, and eventually pushed out by the permanent teeth, which normally number between 36 and 40. As the deciduous teeth are pushed up, they are termed "caps". Caps will eventually shed on their own, but may cause discomfort when still loose, requiring extraction.

It is possible to estimate the age of a young horse by observing the pattern of teeth in the mouth, based on which teeth have erupted, although the difference between breeds and individuals make precise dating impossible.

Common ages for tooth eruption.
Type of tooth	Number	Deciduous	Permanent
Incisor	First (central)	birth to 8 days	2.5 yrs
Incisor	Second (intermediate)	4.5–6 weeks	3.5–4 yrs
Incisor	Third (corner)	6–9 months	4.5–5 yrs
Canine		Absent	3.5–5 yrs, some around 6 yrs (if ever)
Premolar	First (wolf)	Absent	6 months to 3 years (if ever)
Premolar	Second	birth to 2 weeks	2–3 yrs
Premolar	Third	birth to 2 weeks	2.5–3 yrs
Premolar	Fourth	birth to 2 weeks	3–4 yrs
Molar	First	Absent	9–12 months
Molar	Second	Absent	2 yrs
Molar	Third	Absent	3–4 yrs

All teeth are normally erupted by the age of five, at which point the horse is said to have a "full mouth", but the actual age this occurs will depend on the individual horse, and also by breed, with certain breeds having different average eruption times. For instance, in Shetland ponies the middle and corner incisor tend to erupt late, and in both draft horses and miniature horses, the permanent middle and corner incisors are usually late appearing.