This is a "memory rhyme" that apparently enables anyone who can remember it to determine the age of a horse by looking at its teeth. It was published in a one volume encyclopedia in 1894. —fadedpages.com

          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, the 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 white;
          Eleven finds the "corners" light.

          As time goes on, the horsemen know,
          The oval teeth three-sided grow;
          They longer get, project before
          Till twenty, when we know no more.

Warning - This information has been transcribed from a source that is well over 100 years old. It may be incorrect or outdated in some cases. It is also possible that errors were made during the transcription process. This information is being made available for entertainment purposes only.