Telling how old an animal is by its teeth is an art that must be practiced in order to be good at it. The information is vast and can seem overwhelming at first but in fact, it is quite simple as the rules apply to all animals with just minor variations.
Not all animals have all teeth. For example, cows have no upper teeth and the pig is the only domestic animal that has a full dentition (all of the teeth).
The number of teeth an animal has is expressed by the formula: 2(I #/# C #/# P #/# M #/#) = total teeth
2( Incisors #on upper/# on lower Canines #upper/#lower Premolars # upper/# lower Molars # upper/# lower)= total teeth
The "2" tell you to multiply the numbers by 2 as they represent only one side of the mouth and we all know that we have the same number of teeth on both sides.
Example: Pig dental formula 2(I 3/3 C 1/1 P 4/4 M 3/3) = 44
The 2 indicates matching on both sides of the mouth
I = incisors or the front teeth-- 3 upper and 3 lower
Adult teeth are indicated with capital letters. I = incisors, P = pre-molar and M = Molar. Deciduous teeth (baby) teeth are labeled beginning with a "D" for deciduous and the letter indicating the type tooth is in small case. i.e..... I for incisor, p for premolar and m for molar.
When applying a dental formula to an animal that does not have a complete dentition, you have to determine between molars and premolars. Molars are the big teeth in the back of the mouth and premolars are the smaller teeth between the canines (pointed teeth/fangs) and the molars. All molars and premolars are having "baby teeth" precursors called deciduous teeth. This is not true for P1 as it has developed differently in different species. P1 does not have a deciduous precursor (baby tooth), cows and cats don't have a P1 and in the horse it is only on the top jaw and is the vestigial wolf tooth. Luckily, P1 is the only one that is so confusing. All other molars and premolars are in the same place if the animal has them.
In order to understand what the descriptions mean, refer to the photos or look at the animal you are reading about. The descriptions sound difficult and you will say "what is a dental star?" or "what is the neck?" but I assure you when you see one you will know what it is because it will look exactly as described.
The more you practice and the more teeth you look at, the better and more accurate you will become.
canine -- One of the pointed, conical teeth located between the incisors and the first bicuspids. Also called cuspid.
cusp -- A pointed or rounded projection on the chewing surface of a tooth.
deciduous --Falling off or shed at a specific season or stage of growth: baby teeth
dentition -- The type, number, and arrangement of a set of teeth
eruption --The emergence of a tooth through the gums.
incisor -- A tooth adapted for cutting or gnawing, located at the front of the mouth along the apex of the dental arch.
molar -- tooth with a broad crown used to grind food, located behind the premolars.
premolar -- one of eight bicuspid teeth located in pairs on each side of the upper and lower jaws behind the canines and in front of the molars.
rostral -- indicates a direction toward the nose
wear -- To damage, diminish, erode, or consume by long or hard use, attrition, or exposure
After the permanent teeth are in wear, the estimation of age becomes highly speculative. The various systems that have been devised do not agree, and the actual age of the individual may not be indicated by the amount of wear of the teeth. Often the ages are rounded for easy memorization. An estimate of age should always be cautiously phrased. One should never say that the animal is X years old but that it has the teeth of an average animal of X years.
Every animal has a dental formula that tells you how many of each teeth they should have as a baby and as an adult. In applying the dental formula to other species in which several teeth are missing, one must distinguish between molars and premolars. Molars are the back teeth and have no "baby" version. Premolars are in front of the molars and all except P1 have "baby" versions. P1 is very unstable: cats have none, it is the wolf tooth on the upper jaw only.
The most rostral cheek tooth in in dogs are the sectorial (cutting) teeth, which are always P 4 above and P 1 below, regardless of the number of cheek teeth that fail to develop. Beginning at the middle of the front teeth, the permanent incisors are designated I 1, I 2, I 3. Deciduous incisors are Di 1, Di 2, Di 3. Premolars are "P" and molars are "M". The numbers are set over each other to indicate upper teeth and lower teeth.
Special terms of direction are used in dentistry to refer to the borders, or contact surfaces, of the teeth. On the first incisor the mesial surface is next to the median plane; on all other teeth it is directed toward the first incisor. The opposite contact surface is the distal surface.
Brachydont teeth are short or low-crowned teeth that have a distinct crown, neck, and root(s) and stop growing after eruption. These include all the teeth of the dog and cat.
Hypsodont teeth have a large crown called the body and small late-forming root(s). These teeth continue to grow for a variable number of years after birth, which accounts for their unique pattern of wear and for the clinical problems that occur when the wear is abnormal. All of the horses teeth are hypsodont except for P1.
How to age sheep, goats, cattle and buffalo
The age of animals can be determined by examination of the front teeth. You will not be able to determine the exact age, especially in older animals.
How to hold (restrain) the animals to check their teeth
(1) Animal under one year old (no permanent teeth)
(2) One year old (2 permanent teeth)
(3) Two years old (4 permanent teeth)
(4) Three years old (6 permanent teeth)
(5) Four years old (8 permanent teeth)
(6) Old animal, more than four years old
Age of goats and sheep
Age of cattle
(1) Under two years old (No permanent teeth)
(2) Two years three months (2 permanent teeth)
(3) Three years old (4 permanent teeth)
(4) Three years six months (6 permanent teeth)
(5) Four years (8 permanent teeth)
(6) Old animal, over four years old.