Determining Age of Calf by Examination of Teeth

Determination of age of calf is important for effective sale / purchase and cost decisions.  It is quite easy to determine age in calves by examining teeth. At birth, a cow calf will have 20 temporary ‘milk’ or deciduous teeth, and as the animal grows these are replaced by permanent teeth. In order to describe numbers and types of teeth a ‘dentition formula’ is used. In case of newborn calves the dentition formula is:

teeth-in-bovine-calves 

   2(Di 0/4, Dc 0/0, Dp 3/3)

How to read dentition formula?  For purpose of dentition the mouth is considered as two halves but the formula describes only one half, and hence it is always multiplied by ‘2’. The numbers in numerator and denominator indicates the number of each type of tooth in the upper and lower jaws. ‘D’ indicates deciduous (milk) teeth and the lowercase ‘i, p, and c’ indicate incisors, premolar, and canine tooth types, respectively. The formula given above can be read as: The calf has total 8 incisors, all in the lower jaw, no canine teeth and total 12 premolars (six in each jaw) each jaw.   

How to differentiate between deciduous and permanent teeth:

Deciduous incisors are smaller in size than permanent incisors. The crown of deciduous incisors are also narrower, diverges more from the base (at the gum line) of the tooth to the apex as compared to permanent incisors. There is also a difference in the shape and size of teeth and the jaw width. The first permanent tooth in calves erupts at 12 months, hence from 2 weeks to 12 months it is difficult to age an animal by dentition alone; height and weight being more useful criteria.

 

        Teeth                                    Age of eruption

First incisor Di-1                          Birth to 2 weeks

Second incisor Di2                      Birth to 2 weeks

Third incisor Di3                         Birth to 2nweeks

Fourth incisor Di4                       Birth to 2 weeks

First cheek teeth Dp1                  Birth – 1 week

Second cheek teeth Dp2            Birth – 1 week

Third cheek teeth Dp3               Birth to 1 week

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