Dentition and ageing of livestock
AGEING OF SHEEP AND GOATS
Purpose : Determination of the age accurately enables the farm manager to take up appropriate managemental practices suitable for different age groups.
Sheep : The ages of sheep which are from 1 to 4 years old can be determined by observing the changes which take place in the incisor teeth on their lower jaws. At best this can only be an approximation of the exact age. The changes in teeth after 4 years of age will depend upon the longevity of the breed and the management and nutrition they have received.
§ Lamb : 8 temporary incisors that begin to erupt at 2 months of age and remain until about 12 months of age
§ Yearling : At approx. 12 months (range 10-14) of age, the two central temporary incisors are replaced by 2 larger, wider, permanent teeth
§ 2-year old : The second pair of temporary incisors, one on either side of the centre pair, are replaced by permanent incisors
§ 3-year old : The third pair of temporary incisors are replaced by permanent teeth.
§ 4-year old : All the incisor teeth have been replaced by permanent incisors, and the mouth shows. These animals are said to have a "full mouth".
§ Beyond 4 years : As the animal ages beyond 4 years, the teeth appear to be longer due to receding of the gums, and there is a greater space between the teeth. Such an animal is referred to as a "spreader" if no teeth have been lost, but its exact age cannot be determined.
§ 7-8 years : Some teeth may be lost. Sheep with missing teeth are referred to as "broken mouth".
§ In sandy areas, the teeth may be worn down by grazing, and sheep in which this has occurred are referred to as "short mouth" animals. This can occur at any time after the sheep is 4 years old.
§ Sheep that have lost all their incisor teeth are referred to as "gummers". They have difficulty in grazing forage and usually show the effects of poor nutrition.
Goats : The eruption of permanent incisor teeth in goats is as follows:-
Age ( months) Teeth
12-14 First - central
24-26 Second – middle
36-38 Third – lateral
48-50 Fourth – corner
30-35 Wearing of incisors starts
42-48 Table of tooth leveled
66-72 Teeth reduced in size
over 84 months Teeth reduced to stubs or broken/absent
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Disclaimer : The information on this site is meant as an aid to students and fellow veterinarians and should be used for educational purposes only. The views expressed are solely that of the author and should not be construed to be that of his employer or any other organization.