Age of a Horse

This poem is not mine, the origins are unknown and it's been around for years, but a favorite of mine none the less.

The Age of a Horse

To tell the age of any horse
Inspect the lower jaw of course;
The six front teeth the tale will tell,
And every doubt and fear dispel.

Two middle nippers you behold
Before the colt is two weeks old;
Before eight weeks two more will come
Eight months the corners cut the gum.

The outside grooves will disappear
From middle two in just one year.
In two years from the second pair 
In three years "corners" too are bare.

At two the middle "Nippers" drop
At three the second pair can't stop;
When four years old the third pair goes,
At five a full new set he shows.

The deep black spots will pass from view
At six years from the middle two;
The second pair at seven years;
At eight the spot each corner clears.

From middle "Nippers" upper jaw
At nine the black spots will withdraw.
The second pair at ten are bright,
Eleven finds the corners light.

As time goes on the horseman knows
The oval teeth three sided-grows,
The longer get project before
Till twenty, when they know no more