🐎Horse - Types (Horse, Mule, Zebra), Terminology and Equine Science

• Family: Equidae. The Equidae family includes all modern horses, donkeys, and zebras. These animals are odd-toed ungulates, meaning they bear their weight on a single central toe on each foot, which has evolved into a hoof.
• Gestation: 320–365 days, average ~340 days (approximately 11 months). This is one of the longer gestation periods among domesticated livestock. Understanding gestation length is essential for breeding management and planning foaling dates.

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Types

Horse

The domesticated horse (Equus caballus) has been selectively bred for thousands of years for riding, draught work, racing, and agricultural purposes. Horses are valued for their speed, strength, and intelligence.

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Mule

A mule is the offspring of a male donkey (jack) and a female horse (mare). Mules are known for their remarkable endurance, sure-footedness, and disease resistance.

• Male mules (johns) are always sterile; female mules (mollies) are fertile in extremely rare documented cases. For exam purposes: mules are considered sterile.
• They are a classic example of interspecific hybridization in animal husbandry.
• Mules are larger than hinnies and have more horse-like characteristics.

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Hinny

A hinny is the offspring of a stallion (male horse) × jenny (female donkey).

• Both mules and hinnies are considered sterile for exam purposes.
• Hinny is smaller than a mule and resembles a donkey more in temperament and appearance.
• Hinnies are less common because jennies are harder to breed than mares.

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Zebra

Zebras are wild members of the Equidae family, native to Africa. They are easily recognized by their distinctive black and white striped coat, which is thought to serve as camouflage, temperature regulation, and protection against biting flies. Unlike horses and donkeys, zebras have not been widely domesticated.

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Important Terms

Understanding the correct terminology is fundamental when studying equine science. Each term describes the animal’s sex, age, or reproductive status:

• Equine: Relating to horses, mules, zebras, and asses. General adjective for any member of the horse family.
• Stallion: A sexually intact male horse over 3 years old. Used for breeding; typically more muscular and temperamental than geldings.
• Stud: A stallion used for breeding purposes. A stud farm is an establishment dedicated to selective horse breeding.
• Mare: A mature female. Mares are used for both riding and breeding.
• Filly: A young female up to 3 years of age.
• Gelding: Castrated male. Generally calmer, more manageable, preferred for riding and work.
• Colt: Intact male up to 3 years of age.
• Foal: Young male or female under one year of age.
• Weanling: A weaned young horse (male or female), typically separated from mother at 4–6 months.
• Jack / Jackass: Male donkey.
• Jenny / Jennet: Female donkey.
• Pony: Horse measuring ≤14.2 hands at the withers. Not a breed — a size classification. Most Indian mountain breeds (Manipuri, Spiti, Zanskari, Bhutia) fall in this category.

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Equine Terminology — Quick-Reference for MCQs

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Horse Conformation and Measurement

• Height is measured in “hands” — 1 hand = 4 inches = 10.16 cm
• Measurement is taken from the ground to the withers (highest point of the back, between shoulder blades).
• Key body parts:
  • Withers — highest point of back between shoulder blades; reference point for height measurement
  • Hock — ankle joint of the hind leg
  • Fetlock — joint above the hoof on each leg
  • Cannon bone — the bone between knee/hock and fetlock

Classification by Type

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Indian Horse Breeds

Indian horse breeds are a frequently tested topic in IBPS AFO, NABARD, and other agriculture exams. All breeds listed are recognized by ICAR-NCA (National Commission on Agriculture).

Marwari

• Origin: Rajasthan
• Distinctive feature: Unique inward-curving ear tips that touch each other; can rotate ears 180°
• Historically used as a war horse; known for courage, loyalty, and spirited temperament
• Height: ~14.2–15.2 hands
• Considered one of the most distinctive horse breeds in the world

Kathiawari

• Origin: Gujarat (Kathiawar peninsula)
• Distinctive feature: Similar inward-curving ear tips like Marwari; slightly lighter built
• Well-adapted to desert terrain; good endurance
• Height: ~14–15 hands
• Often confused with Marwari — both have curved ears, but Kathiawari is from Gujarat while Marwari is from Rajasthan

Manipuri

• Origin: Manipur (Northeast India)
• India’s oldest indigenous pony breed
• Height: ~11–13 hands
• Origin of the sport of polo in India; used in traditional Manipuri polo known as Sagol Kangjei
• Sure-footed, agile, and hardy

Spiti

• Origin: Himachal Pradesh (Spiti Valley)
• Small mountain pony; highly adapted to high altitude and cold climate
• Height: ~11–12 hands
• Extremely sure-footed on mountain terrain; used as pack animal
• Named after the Spiti Valley in the Himalayas

Zanskari

• Origin: Jammu & Kashmir (Zanskar Valley)
• Small mountain pony; stronger than Spiti; used as pack animal in extreme altitudes
• Height: ~12 hands
• Adapted to some of the harshest terrain in the world

Bhutia

• Origin: Sikkim / Darjeeling (Himalayan region)
• Mountain pony used as both pack and riding animal
• Height: ~12–13 hands
• Hardy breed adapted to Himalayan conditions

Thoroughbred (Exotic)

• Origin: England (exotic breed introduced to India)
• Used for racing in India; the fastest horse breed
• Registered with the Indian Stud Book
• Tall, lean, and built for speed

Arabian (Exotic)

• Origin: Arabian Peninsula; oldest pure breed in the world
• Distinctive features: dished (concave) face, high tail carriage, fine coat
• Has 17 pairs of ribs (most horses have 18) — a unique anatomical fact tested in MCQs
• Renowned for endurance racing; exceptionally sound hooves and dense bones

Przewalski’s Horse

• The only truly wild horse (never domesticated); native to Central Asia
• 2n = 66 (vs domestic horse 2n = 64)
• Listed as Endangered on the IUCN Red List; conservation breeding programmes ongoing

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NRCE — National Research Centre on Equines

• Full name: ICAR-National Research Centre on Equines (ICAR-NRCE), Hisar, Haryana
• Established: 1986
• Focus areas: Equine health, breeding, nutrition, disease management, genomics
• Notable achievement: Developed Lumpi-ProVacInd vaccine (jointly with IVRI, Bareilly) for Lumpy Skin Disease in cattle — announced 2022
• NRCE is the nodal institute for equine research in India under ICAR

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Horse Physiology — Unique Facts for MCQs

• Chromosome number: 2n = 64 (Donkey: 2n = 62 | Mule/Hinny: 2n = 63)
• Digestion: Horses are monogastric hindgut fermenters — single stomach, but a large caecum and colon ferment fibrous feed. Different from ruminants (multi-chambered stomach) and from pigs (hindgut fermenter but much smaller caecum).
• Vomiting: Horses cannot vomit — the cardiac (lower oesophageal) sphincter is very strong and the stomach angle prevents reflux. This is why equine colic is a veterinary emergency.
• Sleep: Horses can sleep standing up due to the stay apparatus — a passive locking mechanism in the hind (and front) limbs that prevents collapse without muscle effort. Full REM sleep requires lying down, but horses lie down only briefly.
• Normal heart rate: 28–44 beats/minute (resting); athletic horses may reach 240 bpm at gallop.
• Unique feature of Arabian: 17 pairs of ribs (most breeds have 18), 5 lumbar vertebrae (others have 6).

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Equine Diseases

Glanders

• Causative agent: Burkholderia mallei (bacterium)
• Primarily affects horses and donkeys; severe respiratory and skin disease
• Zoonotic — transmissible to humans; classified as a potential bioterrorism agent due to extreme danger
• Notifiable disease in India; sporadic outbreaks have been reported
• Characterized by nodular lesions in the lungs, nasal passages, and skin (farcy)
• No vaccine available; no reliable treatment — policy is test-and-cull
• Diagnosis: Mallein test (intradermal or ophthalmic) — equivalent of tuberculin test in cattle

Equine Infectious Anaemia (EIA / Swamp Fever)

• Causative agent: Retrovirus (Lentivirus)
• Transmitted by blood-sucking insects (horse flies, stable flies)
• No cure and no vaccine available
• Diagnosis: Coggins test (AGID — Agar Gel Immunodiffusion)
• Affected horses must be euthanized or isolated for life

Surra

• Causative agent: Trypanosoma evansi (protozoan parasite)
• Transmitted by Tabanus (horse flies) and other biting flies
• Affects horses, camels, cattle, and dogs; causes progressive weakness, anaemia, oedema
• Also known as “Tibarsa” in India; one of the most economically important animal diseases

Strangles

• Causative agent: Streptococcus equi subsp. equi
• Highly contagious upper respiratory disease
• Causes swelling and abscess of submandibular lymph nodes — the classic “strangles” sign under the jaw
• Treatment: Penicillin; vaccine available

Equine Influenza

• Causative agent: Influenza A virus (H3N8, H7N7 subtypes)
• Common respiratory disease; spreads rapidly in dense horse populations
• Vaccine available

Tetanus

• Causative agent: Clostridium tetani
• Horses are highly susceptible to tetanus
• Prevention: Tetanus toxoid vaccine is essential

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Key Reproductive Parameters

References & Sources

1

G.C. Banerjee: A Textbook of Animal HusbandryBook

2

ICAR-NRCE Official WebsiteWeb

3

Wikipedia — Animal HusbandryWeb

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Summary Cheat Sheet

Indian Horse Breeds

Mule vs Hinny

Key Reproductive Parameters

Major Equine Diseases

Other Key Points