Estimated reading time: 4 minutes
- Counting teeth remains the best indicator of a sheep or goat’s age.
- Counting teeth helps producers to determine flock composition, spot dental defects and identify diseases.
- Once animals’ reach the wear and tear age, they would have already lost condition because they’re unable to take feed in the way they used to.
- The breed of an animal can have an influence on the rate at which teeth are shed.
Counting teeth might seem like a silly exercise but in a sheep or goat kraal it is a necessity. If the guessing game regarding the age of newly purchased animals yields false numbers, there is only one option: count those teeth. It remains the best indicator of a sheep or goat’s age, says Jan-Louis Venter, production advisor at the National Wool Growers’ Association (NWGA).
According to the NWGA’s guidelines, counting teeth is not only important for age determination, but it helps producers to:
- Determine flock composition.
- Spot dental defects.
- Identify diseases.
The way to do it
If you want to count an animal’s teeth you must start at the beginning: Open the lips to expose the teeth. Do this in a way that will keep tension and discomfort in the animal to an absolute minimum, explains Jan-Louis.
“The producer should preferably use his/her index and middle finger or thumb to pull back the animal’s lips.” Also make sure there is no confusion between a one-year-old animal that has not yet begun to shed teeth, and a mature four-year-old animal with a full set of teeth.
“Telling the difference is quite easy, as a mature animal is physically bigger and has bigger teeth,” he explains. Just as permanent teeth in humans are larger than milk teeth, the same applies to small stock.
An indicator of age
Once the animal’s mouth is open, start by counting the number of permanent teeth in the animal’s lower jaw. If the animal has two permanent teeth, he/she is probably, according to the NWGA’s official guidelines, approximately 12 to 15 months (one year) old.
An animal with four permanent teeth is around 21 to 24 months (two years) old and a six-tooth animal is approximately 30 months (two and a half years) old. By the time a sheep or goat has eight permanent teeth, the animal is 36 months (three years) old and known as a full-mouth.
Between six and eight years of age, the animal’s teeth begin to wear down (usually on harsh veld). Very long, thin and loose teeth, on the other hand, mean there is a lack of wear because the animal is grazing soft pasture. The teeth of ewes that graze soft feed will only start to wear at an older age.
Figure 1: Age determination in small stock. (Source: NWGA/RPO Guidelines for Livestock Farming)
Wear and tear, and condition
“Once animals’ reach the wear and tear age, they would have already lost condition because they’re unable to feed the way they used to, which consequently leads to poor feed consumption,” says Jan-Louis. It pays to feed them so that they can regain condition for slaughter purposes. Ewes with worn teeth can no longer consume the amount of feed necessary to raise their lambs and therefore, as a rule, breeding animals should not be retained in the flock for more than six to eight years.
There is not as much wear on teeth when animals have access to lush, soft feed (intensive systems). Teeth will grow long and become loose, with an accompanying negative impact on feed intake. Teeth filing was commonly practised in the past, but according to NWGA standards this is not acceptable as it causes unnecessary pain.
Influence of breed
The breed of an animal can have an influence on the rate at which teeth are shed. Some breeds, such as Dormers or Suffolks, are early-maturing breeds that shed sooner. Others, such as Merinos, start shedding at a later age and are known as late-maturing breeds.
“However, the time it takes for these different breeds to start shedding is weeks rather than months, and hence this is not really significant,” says Jan-Louis. It is important to take note of the fact that animals’ physiology can vary and that producers will never be able to determine the exact day of shedding with absolute certainty. – Susan Marais, Stockfarm
For more information, contact Jan-Louis Venter on 083 650 1131.