The Collaborative International Dictionary of English v.0.48:

Yearling \Year"ling\, n. [Year + -ling.]
   An animal one year old, or in the second year of its age; --
   applied chiefly to cattle, sheep, and horses.
   [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Yearling \Year"ling\, a.
   Being a year old. "A yearling bullock to thy name small
   smoke." --Pope.
   [1913 Webster] yearlong

WordNet (r) 3.0 (2006):

yearling
    n 1: a young child [syn: toddler, yearling, tot,
         bambino]
    2: a racehorse considered one year old until the second Jan. 1
       following its birth
    3: an animal in its second year

Moby Thesaurus II by Grady Ward, 1.0:

61 Moby Thesaurus words for "yearling":
   Brahman, Indian buffalo, aurochs, babe, baby, baby bunting,
   bambino, beef, beef cattle, beeves, bison, bossy, bovine,
   bovine animal, buffalo, bull, bullock, calf, carabao, cattle, cow,
   critter, dairy cattle, dairy cow, dogie, heifer, hornless cow,
   incubator baby, infant, kine, leppy, little angel, little darling,
   maverick, mewling infant, milch cow, milcher, milk cow, milker,
   muley cow, muley head, musk-ox, neat, neonate, nursling, ox, oxen,
   papoose, preemie, premature baby, preschooler, puling infant,
   steer, stirk, stot, suckling, toddler, weanling, wisent, yak,
   zebu