Horses Flashcards
When were horses domesticated
Domestication of horses in Eurasia (8000-5000BC): may have saved species from extinction due to heavy hunting (prior to 8000BC)
- Horse become particular useful: 2000 BC (pull chariots) and by 1000BC complete domestication: Europe Asia and North Africa
True or False
Horses have never been food animals
False
Horses were initially used for food (30 000 BC)
Male intact adult horse
Stalion
Male sterilized (no testes) Adult Horse
Gelding
Baby Male Horse
Colt
Adult Female Horse
Mare
Baby Female Horse
Fille
Baby horse (gender neutral)
Foal
What is 1 Hand in inches
Horse industry
1 Hand = 4 Inches
Withers
Horse
What you measure for height in horses
- Located near front shoulders
What are the three broad catagories of horse? | Size
- Ponies: less than 14.2 hands at withers and less than 8oolbs
- Light Horse: 15-17.2 hands and 900-1200 lbs, majority of breeds
- Heavy horse: 16-18 hands, heavy muscle, large bones and sturdy legs, greater than 1400 lbs
Hot Bloods
Horses
Hot Bloods: Lighter bodies, idea for speeds (racing):
- Temperament is high strung and flighty: Arabian, Thoroughbred, Quarter Horse
Warm Blood
Horses
Warm Blood: Named for the area the horse was located. No true breed of warm blood (as hot bloods - Arabians):
- Mild temperament and calm spirt:
- Dressage ,Jumping, 3 day eventing: Hanoverian, Irish Sport Horse (Irish Hunter), Trakehner
Cold Bloods
Horses
Cold Blood: Mild manner, docile good with children:
- Heavy work (Agriculture; pulling equipment) Draft
- Breeds; Percheron, Clydesdales, Shire
- intelligent
Arabian Horses
- Oldest breed of horse in world (ancestry 5000 years old)
- Classified by ancestry nation of origin: Polish, Spanish, Russian, Egyptian, Domestic
- Agile and excellent stamina
- Dish face prominent eyes and arched neck
Thoroughbred
Horse
Breed developed from 3 Foundation Arabian Stallions
- Fastest Horse: Intermediate distance: (three-quarter mile -1.5 mile races)
- Cross breeding: influenced the development of breeds (Quarter horse, Standardbred and some Warm bloods- Irish Sport Horse)
Quarter Horse
Created: Initially English Horse Breeds crossed with Arabians (Arabs and Barb descent)
- Later: These horses crossed with Thoroughbreds: stronger and faster
- In NA: these new horse breeds crossed with Mustangs- quick horses and used for cattle work
- Strong hind quarters
- Fastest Horse: Short distance (quarter mile races)
Standardbred Horses
- Foundation: Sire from Thoroughbred (name): Messenger
- Harness racing: Pacers and Trotter: what is the difference (Video)
- Dressage and Hunter jumpers
Mule vs Hinny
Male Donkey x Female Horse = Mule
Female Donkey x Male Horse = Hinny
What do horses stand on
Their middle fingers
- Coffin bone
- DP or P3
White Coat Colors
Horses
True white horses valued throughout history
- Lethal White Foal Syndrome: Dominant white gene (homozygous): often lethal in utero and intestinal neurological abnormalities- colic first 12 hours of life
- Heterozygous: pink skin- colored eye
Horse Teeth
Teeth: important of digest cellulose, helps in hind-gut fermentation
- In grazing animals: good dentition is key to survival
- Uneven wear of teeth mouth injuries
- Wolf teeth: extra set of small premolars in front of large grinding premolars- 70% have Wolf teeth
- vestigial tooth - forest dwellers eating for brush plant products to now plains dwellers
- not involved in fighting- unlike canine or swine
Teeth will grow throughout life
- Must be grinded down
- “Float teeth”
Horse Digestion
Digestive system:
- Prehensile lips (Video)
- Hind gut fermenters (cecum and colon) for fiber digestion (similar bacteria populations as rumen in ruminants). Fermentation
releases volatile fatty acids- a major feed source for forage-based diets
Horse Reproduction
- Gestation: 340 days
- Labours short: 10-15 minutes
- 50-80% breeding efficiency
- Seasonal polyestrous: short breeding season spring and summer
- Estrus: 5-7 days and to improve breeding efficiency, breeding starts Day 3 of estrus and continues every other day until mare refuses breeding
- Colostrum (first milk): critical first hours following delivery, if not foals often succumb to infection
Horse Vision
Vision: wide field of vision and eyes see independently (monocular vision): cannot see directly in-front (forehead) or behind (tail)
Horse Hearing
14 Hz - 25 Hz (20Hz-20KHz): responds well to low tone commands: Don’t like high or shrill commands
- Ears rotate 180º: 10 muscles (people 3 ear muscles)
Horse Taste
Like salt and sweet. Dislike bitter and sour:
- protective against poisonous plants and water
Horse Smell
better sense of smell than people: use smell for pheromone detection (stallion) and predator detection.
- Foals and mares bond through sense of smell
Flehmen reaction
Horses
Horse rolls upper lip (expose sensitive membrane of lips and nose) to detect unusual smell.
- Allows ‘scent’ to interact with vomeronasal organ (important in pheromone detection)
Colic
abdominal pain: many causes
- Horse is listless or varying degrees of distress
- Signs: curling lips, pawing, kicking at belly, lying down, rolling
- Pulse rate elevated, sweating, pink to blue gums
- Emergency in horses
- Stats: 4.2 colic/ 100 horses: 11% are fatal
What are the 2 general catagories of cholic
- Colic by cuase
- Colic by location
Cholic by cause
- Digestive Colic: too much feed or change in feed
- Spasmodic or gas colic: eating too fast or toxin in feed
- Sand colic: sand in feed
- Impaction colic: not enough water
- Others: ‘Intestinal accident’
Colic: Stomach
- Gastric colic’ (gastric dilatation and rupture): stomach small (8-10 liters).
- Stomach will rupture as fluids content increase -as horses can not vomit
- Intestinal obstruction (fluid build up) or too much gas . Very common
- Horse stomach rupture (Stomach Impaction): impacted with feed. Less common
Colic: Intestine
Most common causes of colic:
- obstruction
- strangulation
- intussusception
- inflammation
- volvulus (180º rotation around mesenteric axis)
- ascarid impaction
- cranial mesenteric arteritis (verminous arteritis)
- Enteroliths and cecal impaction (many more)
Strangulation: Pedeunulated lipoma
A type of cholic that occurs in old horses
- Fat gows on fiberous tissue
- Starts swinging →Wraps around and strangles intestines
- Must be surgicaly removed
Colic: Prevention and Treatment
- Mild exercise (walk or jog): gas colic
- Pain meds (NSAIDS)
- Stomach tube
- Fluid rehydration
- Better feed and access to water
- Surgery
- Deworm
Pathology and Incubation
EIA
- EIA: Acute – Chronic incidence of fever anemia (low RBC), edema and cachexia (wasting), jaundice,
- Many horses are asymptomatic or only have mild clinical symptoms and thus are carriers
- Virus: lives in leukocytes for life and in plasma during periods of viremia
- Infects: different cell lineages: RBC ,
macrophage, monocytes, endothelial cells: leads to destruction - incubation period: 7-45 days
Equine Infectious Anemia (Swamp Fever) (EIA)
Reportible Disease
- Retrovirus (RNA virus)
- Lentivirus
- Associated with high morbidity and mortality
- Found worldwide
Is considered a sporadic disease and
incidence is low (CFIA, 2014)
- Hot Spot: Northeast Alberta: Cold Lake region
EIA: Transmission
- Mechanical transmission: Biting flies (Horse, Deer flies; painful), main method of transmission.
- Local infection more likely than distant animals
- Other transmission: contaminated equipment, milk, semen, in utero
Diagnosis and Treatment
EIA
Use Clinical signs (above slides)
Tests:
- Antibody tests Coggins test (AGID) and ELISA: Horses are seronegative for 2-3 weeks and thus the Coggins test usually doesn’t work in early infection
- Molecular tests: PCR: Good for testing foals to infected mares
- Vaccine: none
- Vaccine: 1975-1990 China developed vaccine, not recommended strategy (OIE, Govt. of Canada)
- Terminate animal or permanently isolate for other equids (is this good to isolate)
Laryngeal Hemiplegia
Roaring/Wistling Horses
- Exercise intolerance in horses
- Left side is mainly affected.
- Right side and bilateral nerves affected is uncommon
- Left recurrent laryngeal nerve: Due to extended length of left recurrent nerve travelling around aortic arch (base of the heart)
- Progressive loss in distal myelinated fibers that innervate that laryngeal muscles (left side)
- Left arytenoid cartilage and left vocal fold (chord) becomes weak and can progress to paralysis.
- Arytenoid cartilage collapsed medial (into the tracheal lumen) and the vocal fold will not open.
- Reduced glottal cross-section area (airway area is smaller)
The greater the exercise greater the air resistance and the louder the ‘roaring’
- More exercise will further collapse the
trachea and more difficulty breathing
- Greater exercise intolerance and poorer horse performance
- Most horses with laryngeal hemiplegia sound normal (no roaring) at rest
Treatment and Complications
Roaring Horses
Treatments
- Prosthetic laryngoplasty: best for performance horses- horses usually never reach potential
- Laryngeal ventriculectomy: reduces roaring
Complications:
- Chronic cough
- Aspiration of feed (aspiration pneumonia)
- Implant failure/infection
How many horses will get laminitis?
1:7 horses will have an incidence of laminitis in its life-time
What does Founder mean?
Laminitis
Founder: means to give away or collapse
Laminitis
Inflammation of structures attaching the hoof to the 3rd phalanx bone (coffin bone)
- Failure or loss of attachment of the laminar basal epithelial cells of the epidermal laminae with dermal laminae
- The 3rd phalanx rotates toward the sole of the foot and can penetrate through the sole: ‘Sinking’
Mechanisms of Laminitis
1) Matrix molecules of the basement membrane and dermis breakdown by metalloproteinases
2) dysregulation of hemidesmosomes-adhesion molecules that used to attach epithelial cells to matrix molecules
Causes of Laminitis
List all 5 Common types (5 bonus types)
- Endocrine Disease: Cushing’s disease (Hyperadrenocorticism) or Equine Metabolic Syndrome: Possibility due too much insulin produced, this may injure laminae
- Excessive grain intake (common)
- Grazing on pasture (grain overload): of high sugar content such as spring/fall growth (very common)
- Excessive or concussive exercise in adult horses (common)
- Obesity - risk increases greatly as body score increases (common)
- Stress from disease or trauma: excessive bearing of weight on 1 leg - post injury to other limb(s)(common)
- Use of corticosteroid drugs
- walnut shavings in a load of bedding: 1% walnut in shaving in bedding will lead to laminitis
- Small hooves or poor hoof quality
- Infections: diarrhea (bacterial[salmonella], rickettsia [Potomac Horse fever], retained placenta, septicemia etc (sporadic)
Diagnosis of Laminitis
- Clinical exam and history
- Radiographs
- Nerve blocks
What are the types of laminitis
- Acute: <3 days; hot hoofs, painful to walk, depressed, decrease appetite , prominent digital pulse: only severe incidence leads to 3rd phalanx rotation and sinking
- Subacute:> 3 days, similar to symptoms and manifestation as acute laminitis
- Chronic: intermittent periods of acute and subacute laminitis, will eventually lead to rotation and sinking of 3rd phalanx
Acute Laminitis
<3 days;
hot hoofs, painful to walk, depressed, decrease appetite , prominent digital pulse:
only severe incidence leads to 3rd phalanx rotation and sinking
Subacute Laminitis
> 3 days
similar to symptoms and manifestation as acute laminitis
- depressed
- low appitite
- prominent digital puls
Chronic Laminitis
Intermittent periods of acute and subacute laminitis, will eventually lead to rotation and sinking of 3rd phalanx
