Sheep Origin, Classification, Anatomy, and Management

A set of vocabulary flashcards based on lecture notes covering sheep origins, taxonomy, body condition, wool characteristics, genetics, dental anatomy, glands, hooves, internal digestive and reproductive systems, vital signs, and behavioral biology.

Asiatic Mouflon

The wild ancestor of domesticated sheep, bearing the scientific name Ovis gmelini.

Ovis aries

The zoological classification for domesticated sheep, belonging to the genus Ovis and species aries.

Fertile Crescent (Sheep Origin)

The southwest Asia region, specifically Anatolia and adjacent areas, where sheep were domesticated approximately $10,000 - 12,000\,\text{years}$ ago.

Artiodactyla

The taxonomic order of even-toed ungulates with hollowed horns, to which sheep belong.

Bovidae

The taxonomic family consisting of ruminant mammals, which includes sheep.

Lanolin

The oily secretory product of sebaceous glands distributed across the sheep's body, consisting primarily of cholesterol.

Suint

Dried perspiration deposited in sheep wool that gives fleece its greasy texture.

Yolk

The substance formed on fleece when cholesterol (lanolin) from sebaceous glands combines with suint.

Polled

The genetically hornless trait found naturally in sheep breeds such as Suffolk, Polypay, and Katahdin.

Scurred

Having small, underdeveloped, and moveable horn remnants.

Polled Dorset Genotypes

Genetic determinations in Polled Dorsets where $PP$ results in both rams and ewes polled, $Pp$ results in scurred rams and polled ewes, and $pp$ results in both rams and ewes horned.

Dental Pad

The firm tissue on the upper front jaw of sheep that replaces upper incisors, against which lower incisors press to bite and tear forage.

Solid Mouth

A sheep aged $7 - 8\,\text{years}$ that retains a complete and intact set of permanent incisors.

Broken Mouth

A sheep around $10\,\text{years}$ of age that has lost some of its permanent incisors or exhibits severe dental wear.

Gummer

A sheep around $10\,\text{years}$ of age or older that has lost all of its front incisors.

Parrot Mouth

An overbite (overshot jaw) condition in sheep where lower incisors sit behind the upper dental pad.

Monkey Mouth

An underbite (undershot jaw) condition in sheep where lower incisors extend forward past the upper dental pad.

Suborbital Gland

A pouch located in the shallow pit in front of the eye lined with sebaceous and sweat glands that secretes a waxy, pheromone-containing fluid for territorial marking and communication.

Interdigital Gland

A deep glandular pouch located between the toes on each foot that secretes an odorous waxy substance used for trail recognition, flock signaling, and sexual communication.

Rumen

The largest of the four stomach compartments in sheep, acting as a fermentation vat where microbes break down fiber.

Reticulum

The honeycomb-lined stomach compartment that works alongside the rumen to form cud for regurgitation and trap foreign objects.

Omasum

The stomach compartment known as 'many piles' that absorbs water, minerals, and volatile fatty acids (VFAs).

Abomasum

The 'true stomach' of ruminants, which functions similarly to a human stomach by performing chemical digestion using acids and enzymes.

Esophageal Groove

A specialized anatomical channel in young lambs that shunts milk directly to the abomasum, bypassing the underdeveloped rumen, reticulum, and omasum.

Cervical Barrier

An anatomical feature of the ewe reproductive tract that prevents traditional transcervical artificial insemination, necessitating laparoscopic AI to deposit semen directly into each uterine horn.

Normal Sheep Vital Signs

Standard baseline values for healthy adult sheep: average rectal temperature of $102.5^\circ\text{F}$, heart rate of $75\,\text{beats/min}$, and respiration rate of $20\,\text{breaths/min}$.

Estrous Cycle (Sheep)

The reproductive cycle lasting $16 - 17\,\text{days}$, featuring a standing heat duration of $20 - 42\,\text{hours}$ and ovulation $12 - 24\,\text{hours}$ before the end of heat.

Gestation Period (Sheep)

The duration of pregnancy in ewes, ranging from $143 - 150\,\text{days}$ with an average of $147\,\text{days}$ (approximately $5\,\text{months}$).

Gregarious Behavior

The strong flocking instinct in sheep that causes them to synchronize actions with the herd and follow a leader.

Diurnal

Active primarily during daylight hours, reflecting the grazing patterns of sheep during morning and early afternoon.