The Collaborative International Dictionary of English v.0.48:

Fatling \Fat"ling\, n. [Fat + -ling.]
   A calf, lamb, kid, or other young animal fattened for
   slaughter; a fat animal; -- said of such animals as are used
   for food.
   [1913 Webster]

         He sacrificed oxen and fatlings.         --2 Sam. vi.
                                                  13.
   [1913 Webster]