External Anatomy
Domain 2: External Anatomy
This domain examines the external regions, points and body parts used to describe, judge, identify and age farm animals. Questions ask you to label regions, relate structure to function, or estimate age from incisor teeth.
Body regions and points
- Head and neck: poll, forehead, muzzle, nostrils, jaw, dewlap in cattle, neck and crest.
- Trunk: withers, back, loin, rump, tail head, pin bones, hips, barrel, brisket, flank and abdomen.
- Udder and teats: four functional quarters in cattle and buffalo; supernumerary teats are a defect to record.
- Forelimb: shoulder, elbow, knee (carpus), fetlock, pastern and hoof. Hindlimb: stifle, hock, cannon, fetlock. The hock corresponds to the human heel.
- Skin derivatives: horns, hooves, hair and sweat glands; horns arise from the frontal bone, not the poll.
Age by dentition
Cattle and buffalo have 32 permanent teeth and no upper incisors; they have a dental pad. Temporary incisors are replaced from about 1.5 to 2 years, and the full permanent set is usually complete by about 4 to 5 years. Ageing is approximate and is affected by breed and feed.
Worked example
A cow shows two broad, permanent central incisors and the neighbouring teeth are still temporary. Reason: the central pair erupts first, so the animal is roughly 2 years old, not 4. Record two permanent centrals and note that exact age needs a dentition table; do not claim a precise month from one pair alone.
Traps
The commonest error is writing that cattle have upper front teeth. Others: calling the poll the horn base; confusing the hock with the stifle; and counting temporary teeth as permanent.