oh my god. 放羊means shepherd. translated by words, "my lucky star" should be “我幸运的星星”， and "放羊的星星" is "the star that shepherd" if the name is translated by words, i guess you will ask why the title mentioned shepherd and star? then why the drama translated into "lucky star", i'm not sure. after studing the drama, i guess "星星" refers to the girl named "阿星" ， and “放羊”... god, I don't know why they use "放羊"。maybe her husband likes the sheep that need to be treated tender. (i just guess. and everyone can has his own idea about this.) anyway, we can say it's a sort of chinese expressioin ___ it seems that there's nothing to do with each other literally, but their stories are the same, or can be compared to. generally speaking, the producer will give a drama a really deeply name that you can't know the story only through the name, then you 'll have the interest to know what exactly told by the drama. yeah, this is one of chinese way. just forget the title, and try to understand the drama. that's enough.

Lucky means 幸运的 not 放羊, don't believe translations by taiwanese, they are always liking to change the original meanings.