Understanding the age of common livestock species

By Shane Brody | 1 June 2024 | 7:00 am

Looking at teeth in common livestock species such as sheep, goats and cattle in order to judge their age can be quite tricky for the novice farmer, says Shane Brody.

I was recently asked whether a cow with eight teeth can be regarded as an old cow.

It is a complex question, because livestock, unlike horses and donkeys that have incisors or cutting teeth on both the top and bottom gums, have incisors only on the bottom gums.

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While sheep, goats and cattle do have molars on the back aspects of the upper gums in order to crush grass or grains, the top gum in front has a toothless pad that is assisted by a course tongue in gripping grass before the bottom incisor teeth are used to cut such grass in a sideways motion, and then the chewing or crunching process begins.

When people talk of “looking at the teeth” in order to judge the age of livestock, they are referring to the bottom row of teeth.

Young animals will however have baby or milk teeth and these are not the teeth that I’m referring to.

Milk teeth are visibly smaller and shorter than permanent adult teeth and will (with some exceptions) still be present in sheep and goats up to a year of age and in cattle up to two years of age. Feedlots generally want to produce A-grade meat.

While there are sometimes remarkable time-span differences between certain breeds within a given species, and even due to environmental differences, generally, sheep lambs (A-grades) will cut their first two adult teeth at about one to one-and-a-half years of age (making them A/B

grades), four teeth at between one-and-a-half and two years (B-grades), six teeth at about two to three years (still B-grades), and eight teeth from a few months over two years of age to four years (C-grades).

Some research has shown that goats may age at a slightly slower rate than sheep, and generally, this rate can be anything from five to 12 months slower in cutting various adult teeth.

Cattle, on the other hand, probably due to being larger animals, will generally have longer life spans than sheep and goats, and their rate of cutting or having adult teeth erupting also differs somewhat.

Calves may cut their first two adult teeth at about two years of age, four teeth at two-and-a-half years old, six teeth at three-and-a-half years, and eight teeth at four-and-a-half years.

The meat grade classification of cattle is the same as for sheep, two adult teeth being an A/B-grade and so forth.

In returning to the question of whether an eight-tooth cow is old, it will be regarded as mature rather than being old.

It will, on the other hand, not be regarded as a young animal as is the case in two- and four-tooth animals.

Six-tooth animals will be regarded as still being quite young, but heading toward maturity.

Essentially, in order to judge whether a cow is truly “old”, it will indeed have eight teeth but there will be very definite signs of tooth degradation or wearing. The same counts for sheep and goats.

This wearing of teeth due to usage in the grazing or chewing process will on average start showing from five to six years of age in cattle, with advanced wearing that is clearly evident in what seems to be damaged, darkened or shrunken teeth occurring between seven and 10 years of age.

‘Slating’ of teeth

Severe wearing or “slating” is known to start at about 12 years of age, but some breeds and animals fed easy-to-consume rations may slate at a more advanced age.

Generally, cows showing advanced tooth wearing can be regarded as old, while those with teeth worn right down to gum level (often dark in colour and broken in places), called “gummers” by some farmers, can be regarded as being very old.

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Particularly when buying livestock for breeding purposes where you’ll be wanting younger animals, merely looking at livestock, particularly as a novice farmer, can be a tricky exercise and potentially costly for you.

Basically, older animals with degraded or no teeth and compromised biological systems will not be able to raise offspring functionally, so they do not constitute viable breeding propositions.

In respect of choosing animals for slaughtering purposes, you will also probably want to buy a mature or younger animal rather than buying a very old animal whose meat may be tougher and that shows poor carcass conformation.

By keeping livestock birth records while remembering the livestock ageing time spans I’ve listed above, you will have a way better chance of tracking the age of your livestock and thereby becoming a more successful and functional farmer.

There are numerous online advice sites that show livestock teeth in drawing or photographic format; it may benefit you to visit such sites.