I could not find it in either the DT or the forum, though it is mentioned in some threads, so here are the lyrics minus the camel verse (sometimes included, although the magi aren't part of the nativity scene, per the Bible) and including the tabby cat verse.
This is just in case the link posted by Wildlone expires.

Sonja

Jesus, Our Brother  (The Friendly Beasts)
 

Jesus our brother, strong and good,
Was humbly born in a stable rude,
And the friendly beasts around him stood.
Jesus our brother, strong and good.

"I," said the donkey, shaggy and brown,
"I carried his mother uphill and down,
I carried her safely to Bethlehem town."
"I," said the donkey, shaggy and brown.

"I," said the cow, all white and red,
"I gave him my manger for his bed,
I gave him my hay to pillow his head."
"I," said the cow, all white and red.

"I," said the sheep with curly horn,
"I gave him my wool for his blanket warm.
He wore my coat on Christmas morn."
"I," said the sheep with curly horn.

"I," said the dove, from the rafters high,
"I cooed him to sleep that he would not cry;
We cooed him to sleep, my love and I."
"I," said the dove, from the rafters high.

"Wait, neow," said the tabby cat, silken-furred,
"To keep him from crying took more than those birds!
 So to lull him to slumber, I softly pur-r-r-r-r-r'd."
 "I," said the tabby cat, silken-furred.

And all the beasts, by some good spell,
In a stable dark were glad to tell
Of the gifts they gave Emmanuel,
The gifts they gave Emmanuel.

Words:  English translation of traditional 12th C. French carol.
Sixth (tabby cat) verse by Sonja W. Oates   © 1994
Music: Orientis Partibus French melody (13th C)