"Mon second chien est noir."

Translation: My second dog is black.

[AussieFrench]

Could you use "deuxième" instead of "second"

[Sitesurf]

Absolutely, "deuxième" and "second" are strictly synonymous.

[tjtomi]

Isn't second only used if there is a particular amount of sth.? Like "la second guerre mondiale".

[Sitesurf]

No, there is only one expression I can think of, where "deuxième" cannot replace "seconde", it is to refer to the 1st year in highschool: "la seconde"