The meaning of the words on the collar of Banks' goat - see below?

Here's the spelling, I think:
PERPETUI, ambita bis terra premia lactis
Haec habet, altrici capra secunda Jovis.

Here's Boswell's context
http://books.google.com/books?id=Xvc_AAA...

Banks was a naturalist who had sailed all around the world
http://en.wikipedia.org/wiki/Joseph_Bank...

According to this translation, the Latin poem says:

"In fame scarce second to the nurse of Jove,
This Goat, who twice the world had traversed round,
Deserving both her master's care and love,
Ease and perpetual pasture now has found."

This incident and letter refer to the goat which had supplied the First Voyage with fresh milk.
http://www.captaincooksociety.com/ccsu41...