My Highland Goat is a popular song often taught to and sung by children in Boy Scouts, Girl Guides, schools, etc. The version I learnt as a child is as follows:

My highland goat
Was feeling fine
Ate three red shirts
Off my back line

I took a stick
And gave a whack
And tied him too
The railroad track

The whistle blew
The train drew nigh
My highland goat
Was sure to die

I took a knife
And cut that rope
And saved the life
Of my highland goat

 

The song is sung in a major key, with the chord progression for each verse as I, IV, V, I. Each chord changes on the last word at the end of each line. For instance, if you were singing in C Major, the first line's chord would be Cmaj the whole way, the second line's would be Cmaj and then Fmaj on "fine", the third line's chord would be Fmaj then Gmaj on "shirts", the fourth line's would be Gmaj then back to Cmaj on "line". Repeat for each verse.

The whole song is quite often sung twice through. The first time through is a call and response; a leader will sing a line and the line will be repeated by the group before the next line is sung, much like a military cadence except with a different melody. The second time through, everyone sings each line with nonsense rhymes in between the lines.

For instance, the first time through:
My highland goat (my highland goat), was feeling fine (was feeling fine), he ate three shirts (he ate three shirts), off my back line (off my back line). Etc.

The second time through:
My highland goat-ee-oatee-oatee-oatee-oat, was feeling fine-ee-ine-ee-ine-ee-ine-ee-ine, he ate three shirt-y-irty-irty-irty-irts, off my back line-ee-ine-ee-ine-ee-ine-ee-ine. Etc.

I have since discovered a different version, in which the group replies to the leader's lines with smart aleck answers, much like often happens with the popular christmas song Rudolph the Reindeer. This goes as follows:

My highland goat (Not a chicken but a goat)
Was feeling fine (Had a glass of wine)
Ate all my shorts (Red white and blue)
Right off the line (T'was made of twine)

I took a stick (Not a tree but a stick)
And gave a whack (Smack smack smack smack)
And tied him to (With a knot not glue)
The railroad track (No time to pack)

The whistle blew (Not a beep but a toot)
The train drew nigh (It started to fly)
My highland goat (Not a chicken but a goat)
Was sure to die (Goodbye goodbye)

He gave a groan (AHHHHH)
Of mortal pain (AHHHHH)
Coughed up my shorts (Red white and blue)
And flagged the train (Begin again)

 

There are a great number of other versions out there, as is the nature of children's songs. Other titles for the song include Bill Grogan's Goat and Old Hogan's Goat. Other lyrics include a master or father called Jack, the time of the train, or the goat nearly dying of fright before coughing up the shirts.