Well, someone else could've warned you but since no one has stepped up to the plate it's my time:
You'll be at least two years in waiting to get any milk from this heifer calf IF she's fertile (not a freemartin) and IF she survives the first few months or year in your care.
I too am surprised to hear you got a heifer calf for free, because most times dairy farmers aren't too eager to let them go (except if they're freemartin, which most likely may be the case here), much less for free.
Crossbred Jersey calves--crossed with Holstein--are usually almost always all black, and will retain the characteristics of a Jersey, but also have the characteristics of a Holstein, which will show up when she reaches sexual and adult maturity. Pure jersey calves are usually fawn with brown eyes, nose and hooves, but they can also be black too and get a light saddle. Usually, if I'm right, the saddle doesn't show up until they're older.
ETA: So you're saying that she was born right on the processing floor from this Holstein cow? Then it's very likely she's merely a cross-bred, not a full blown Jersey as, I'm sure you know, it's impossible to get a pure Jers from a Holst.
for big family!
