How to Estimate the Age
of Goats and Sheep

Determining the age of an animal is a relatively simple process, and can be done by examining the incisor (front) teeth. Sheep and Goats of up to four years of age can be identified by looking for the numbers of permanent incisor teeth on the lower jaw. Checking the molar teeth may also be required to identify problems that may be causing disease.

Teeth and Aging in Sheep and Goats Checking the Molar teeth Tooth Health and Animal Health Teeth and Jaw Problems   Poor Apposition   Excessive Incisor Wear   Peridontal disease References and Further Reading

Sheep, goats and cattle all have front teeth on the lower jaw and a dental pad on the upper jaw. They also have molars for grinding their food. These molars are located on both upper and lower jaws in the back of the mouth.

Sheep have 32 permanent teeth. Eight lower incisors, no upper incisors, 12 molars on the top jaw and 12 molars on the bottom jaw.

In first year animals, all teeth are small and sharp. They will gradually be replaced by larger, permanent teeth, and this process is used to help determine the age of the sheep or goat.

		Lambs and Kids, "Milk teeth", less than one year	0	When lambs are born, they have four pairs of baby or "milk" teeth. All teeth are small and sharp.
		"Two Tooth", about 1 to 1.5 years	2	When they are approximately one year old, the middle pair will be replaced by a pair of permanent incisors.
		"Four Tooth", about 1.5 to 2 years	4	When they are two years old, they will have two pairs of permanent incisors.
		"Six Tooth", about 2 to 3 years	6	By age 4, they will have four pairs of permanent incisors.
		"Eight Tooth" or "Full Mouth", about 3 to 4 years	8	After age 5, their teeth will begin to spread apart, break, then fall out. The age of the goat beyond 5 years should then be estimated from the amount of wear on the teeth, including the wear on the molars.

Once all eight permanent incisors are fully erupted the sheep can also be referred to as "aged", and once teeth are lost or broken, they are referred to as "‘broken-mouthed".

The condition of a goat's or sheep’s teeth varies considerably according to their diet and the type of land they live on. Animals on a rough, coarse diet will grind their teeth away faster than animals on an easily eaten diet. As a result, aging sheep and goats by the condition of the incisor teeth once all teeth have erupted is unreliable.

The molar teeth are far more important than the incisors since they do the important and crucial task of grinding up the roughage in the diet during the process of chewing the cud. If the molar teeth are damaged, and especially if they are causing pain, there will be a major effect on the ability of the animal to maintain body condition.

However, sheep and goats looked after well can in fact manage without any incisors at all providing the molar teeth are in good condition.

Problems with molar teeth are often associated with disease, for example the animal may be loosing condition for no apparent reason. Dental problems are also an important cause of premature culling of sheep before they reach the end of their natural reproductive life, and are recognised as an important source of economic loss to the sheep industry (due to high flock replacement costs).

Checking the molar teeth:

• Never put your fingers inside the animals mouth to check the molar teeth - you will get badly bitten, and there is a considerable power in the jaws.
  
• First check some young adult sheep or goats, so that you know what a normal jaw should feel like. Only by practicing on normal young individuals, and then comparing with older animals, will it be possible to become adept at recognising the abnormalities.
  
• Feel the thickness and sharpness of the jaw bones all the way along to the angle of the jaw. Normal healthy jaw bones are slim with well defined edges. There should be no pain, no thickenings or swellings, and the two sides should be symmetrical.
  
• In animals with molar tooth disease, the jaw bones are thickened and have rounded edges. There may also be more thickening on one side than the other.
  
• Feel the teeth through the cheeks. There should be no pain, and no displacement or movement of the molar teeth. Sometimes it is easy to feel that the teeth are longer than normal, displaced and pushing the cheeks out, or gaps where there are teeth missing.
  
• If you suspect that the teeth are not healthy, smell the animal's breath. If there is food debris trapped on or around unhealthy teeth, this may smell bad.
  

In this case "Apposition" refers to how the incisor teeth on the lower jaw meet the dental pad on the upper jaw. The teeth should not protrude in front of the pad when the mouth is closed. If the teeth do protrude ("overshot jaw") they are likely to become too long and will fall out earlier than they would normally if they meet the pad a few millimetres behind the front of the gums of the upper jaw. However, if the lower jaw is abnormally short, then the incisor teeth will be too far back ("undershot jaw"), and if this is severe the animal will have difficulty eating.

With excessive wear, the incisors become short and may be worn down to the level of the gums. This happens when soil or sand on pasture gradually files away at the teeth until they are worn, so it is usually only a problem in older animals. Livestock with very worn incisors can do well as long as they don’t have to eat very short or stringy pasture. They can be fed long soft pasture or hay or silage or concentrate feed.

Peridontal disease is a disease of the mouth involving the gums, mouth lining, and bony structures supporting the teeth and is caused by infection and plaque formation round the teeth.

In any animal, periodontal disease of the incisors causes them to become long and loose and they may be missing. This is caused by infection around the teeth (periodontitis). If an animal has only a few very loose incisors, they are probably best removed, either with your fingers or with pliers. The animal will then be gummy, but it can still stay in good body condition if it is offered long soft pasture or hay or silage or concentrate feed. Don’t attempt to remove any teeth that are not already very loose. Peridoontal disease can affect the molar teeth as well as incisors.