Sam,
It is always advisable to have your own land to start milk production dairy.
Major investments in dairy is Land for growing green fodder, Cattle & Cattle shed. Getting success without any of these are highly impossible pls. note.
If really interested in animal husbandry, then why can't you try in other divisions like transport facilities and cold chain,Cold storage for milk/milk products, Private veterinary clinic, Mobile Units, Dairy parlor etc
Regards,
SWAMY