ANS270: Equine Science
Fall 2003
Colic
General term used to describe an abdominal pain that is usually gastrointestinal in nature.
Overeating, internal parasites, rapid diet changes, lack of water, reproductive events in mares, general stress, etc. are all causes of colic.
Signs:
Elevated heart rate
Distension of abdomen
Slowed capillary refill time
Cold and clammy-feeling to extremities
Biting of flanks/sides
Lying down with/without rolling
Treatment:
Call the vet
Treatment will depend on which part of GI Tract affected and degree/severity
Severe colic can lead to gastric rupture, complete impaction, intestinal twists & death
Usually colic is something we do wrong in feeding & care management
Founder or Laminitis
Causes are many and are created from many of the same things associated with colic
Ultimately this condition directly affects the foot of the horse
Vaccinations
Purpose: 1 protect against disease 2 decrease severity of disease
Vaccination program:
Consult with your veterinarian
Consider location, season, horses (how many, activity, etc)
Not 100% effective
*Influenza
*Tetanus
Rabies
Strangles
Botulism
*Encephalomyelitis (“sleeping sickness”): eastern, western, and venezuelan strains.
Neurological disease caused by bacteria, can be transmitted to humans
Potomac Horse Fever
Rhinopneumonitis: critical for broodmares, vaccinate at 5, 7, 9 months of gestation;
appears as an upper-respiratory infection, aborts months afterwards.
Equine Protozoal Myeloencephalitis (EPM)
Equine Viral Arteritis (like Rhino, but immediately aborts)
*West Nile Virus: inflammation of the central nervous system, spread via birds from
mosquito bites, can also affect humans.. not all will show encephalitis-like signs,
can be lethal.
Others as subscribed by geographic region
30-60 days pre-parturition, give boosters of all needed vaccines
Equine Infectious Anemia (EIA)
Only in horses, infected for life
Coggin’s Test, regulations
Low prevalence in Arizona
General Averages
Temperature: 100.5’
Heart Rate: 30-40bpm
Respiratory Rate: 8-16epm
Parasite Control
Control by treatment with anthelmintic agents (dewormers)
At minimum, most hoses should have 2x per year (spring & fall)
Many owners will deworm every 45-60 days
Some use feed-through daily along with 2x invermectin
Strongyles (bloodworms), ascarids (roundworms), bots, pinworms
Hoof Care
Routine trimming or showing of the horse is desirable to maintain a healthy foot
Foot grows 1/8-1/4 inch per month
Farrier work ever 6-8 weeks may be desirable
Dental Care
Have teeth evaluated at least annually
If sharp points develop, floating may need to be done
If a horse cannot chew, they probably will overtime become unthrifty and malnourished
Horses with poor teeth tend to slobber food, turn head sideways to chew and one might see the whole, undigested particles of feed in feces
Nutrition of Horses
Horse is a non-ruminant herbivore
Digestive tract designed to consume small meals frequently
Stomach is small and rate of movement though stomach and small intestine occurs rapidly (4hrs)
Cecum and large intestine is site of fiber digestion via microbial fermentation
In times of shortage or low-quality foodstuffs suck as low-quality grass, horses may practice coprophagy.
Heartgirth x Length
330
Hay is a structural carbohydrate fiber
Glucose
Volatile fatty acids end product
65-72hrs to completely pass through the system
Horses have nutritional requirements for:
Energy – from carbohydrates, fats, & protein
Water
Protein – quality vs. quantity
Minerals – Macro & micro, or trace
Vitamins – Fat-soluble & water-soluble
General feeding recommendations:
Feed at least 1% of horse’s body weight daily in long-stem roughage (hay or pasture)
When designing a feeding plan, you must first know:
Class/physiological state (maintenance, growth, gestation, lactation, work)
Age
Weight
Body Condition Score
Feeds available, how much feeding
Nutrient composition
Nutrient requirements
Energy requirements
Greatest proportion of the diet is hay (at least 1% of the horse’s body weight fed in hay daily)
Lactating mare produces 3% of her body weight worth of milk every day… these mares need 32-35 mcal during this time.
Feed
RoughagesConcentrates
Alfalfa Grain
Timothy
Bermuda
Fats and oils have 2.25 times greater energy than protein & carbohydrates
Commercial grains have 1.3-1.6 mcal DE/lb
Two cups of corn oil equates to three pounds of oats (in terms of DE)
Example daily feeding requirement for 1100 pound maintained horse:Digestible energy (DE)Crude protein (CP)CaP
16.4 mcal1.2 lb24g14gDE would increase to 21 mcal for light work, 30mcal for heavy work
Sleep
9 periods of REM that each last about 5 min… so 47 min of REM
REM: mind active, muscles not (rapid eye movement = REM), slight increase in heart & respiratory rates but less than drowsy state
Slow wave: mind not active, muscles are
Drowsy state: heart, respiratory rate and muscle tone go down & continue to decline into slow wave
2 hrs, 52 min of sleep per day
1hr 55 min in drowsy state
19 hrs, 13 min awake & active
So, 21 hrs, 8 min awake/day total
Can sleep standing-up due to the locking effect of the stay apparatus in all four legs
Gets help from check apparatus in front legs and reciprocal apparatus in rear legs
Vision
340’ field of vision
Monocular vision: each eye works independently
Binocular vision: eyes work together
Horse has fairly continuous focus from a distance of three feet forward
Horse must position its head to focus due to the shape of the retina
Poor depth perception (objects tend to look flat)
Color blindness (nearly total)
The horse is a creature of habit and, therefore, a well-trained horse can perform well without the ability to use all of its senses if it has been taught to respond and understand rider cues.
Hearing
Hearing is well-developed and is capable of hearing at frequencies above those perceived by man
Horses can localize sound in part due to the ability to move ears via ten muscles that control them
Usually horse can detect sound before it visually detects the source
Smell
Olfaction (sense of smell) is also well-developed and used for identification purposes.
Flehman response: curling upper lip
Vomeronasal organsis part of olfactory system located in nasal cavity relates to sex behavior and social activity, may be involved with urinalysis in stallions
Training
Three-second response time
Imprinting: handling and accustoming a foal to human stimulation during the first 48hrs
Response that occurs without practice is an unconditioned response (instinct)
Response that is learned is a conditioned response
Primary reinforcers have natural reinforcement properties (feed)
Secondary reinforcers are learned (petting, kind voices)
Positive reinforcement/reward training is effective because the horse wants to give a desired response; negative reinforcement the horse will respond to avoid or get rid of stimuli.
Equine Psychology
Flight response or instinct behavior
Horses are sensitive to pressure, pain and temperature, especially around the eyes, ears, legs and belly; thus understanding touch aspects is important in good horsekeeping.
Abnormal behaviors
Reactive: weaving, head nodding and shaking, pacing and pawing, self-mutilation, tail rubbing, destructive behavior
Abnormal ingestive behaviors
Crib biting, tail biting, tongue dragging, wind sucking, wood chewing, eating feces (coprophagy), eating hair or soil
Behavioral Types
Horse behavior is usually modified during training
Contactual: seeking affection or protection, gregarious, concept of more eyes/ears/etc (horses huddle together during bad weather or danger)
Ingestive: taking in anything (coprophagy, cribbing, windsucking)
Eliminative: excretions, horses interrupt activity… territorial, stress, patterns differ with gender
Reproductive: all acts associated with fertilization, sex behavior, geldings can show signs of sex behavior, mare in heat or estrus 5-7 days out of 21day estrous cycle with diestrus about 16 days and ovulation occurs about 2 days prior to end of heat, photoperiod responses
Epilemetic: giving care & attention (mare & foal bond, helping each other w/ flies)
Allelomimetic: mimicry, contagious behavior (a herd of horses run because one does)
Investigative: sensory inspection of environment, excitable, involves movement and one or more senses
Agonistic: all actions resultant of conflict, hierarchy, dominance via aggression
Et-epilemetic: signal for care & attention by calling or movement, strong pair bonding (conditioning response human/horse at feeding time, separation of mare & foal)
Fight or flight syndrome: self-protective behavior
History
Kingdom: Animalia
Phylum: Chordata
Class: Mammalia
Order: Perissodactyle
Family: Equidae
Genus: Equus
Species: Caballus
Eohippus (“dawn horse”, 50-60mya)
Otohippus
Mesohippus
Merychippus
Pliohippus
Equus (modern horse)
Byerly Turk Tennessee Walkers, Morgans… first sire to have influence on speed
Darley Standardbreds, Saddlebreds
Godolphin Quarter Horses
Evolution
- Eohippus had four functional toes on each foot (three on behind).an elongated skull, arched back, & shortened tail
- Four trends in the evolution to Equus:
- Reduction in number of toes
- Increase in size of cheek teeth
- Lengthening of face
- Increase in body size/extremity elongation
Purchasing a Horse
Questions to ask yourself:
What type of horse will best fit my needs or simply what is my intended use?
Am I buying a horse for hobby or investment?
Where can I find a suitable horse?
How much am I wiling to spend?
What will it cost me annually to keep a horse?
The costs of a horse:
Initial purchase price
Transportation
Basic tack, grooming supplies, misc.
Corral, shed, & storage area (or board)
Feed
Farrier
Veterinary care
What to look for in a horse:
Breed
Age
Level of training
Health
Temperament
Conformation
Quality
Location
Where to look for a horse:
Auctions… can make comparisons, see what the “going rate” is
Private owners… buy directly from the “factory”, can talk to current owner
In either case, make sure you are dealing with a reputable company or person and if you are a novice, get expert help
Rewards of owning a horse:
Young people can learn responsibility
Development of skills, greater coordination, strength, agility, & self-confidence
Promotes family unity, stronger bonds & relationships, improved social skills
Provides relaxation, decreases stress, and improved personal discipline
Equine Industry
$112 billion total impact on US economy (GNP)
6.9 million horses in the US… 54,000 donkeys & 28,000 mules
7 million people in the US involved with horses
Most amount of horses are in Brazil
27%-Asia 25%-S. America 10%-Mexico 8%-USA 8%-Africa 7%-Europe
World population today is about 58 million (61 million in 1960)
Value of goods and services in US is $25.3 billion
Full-time horse-related jobs in the US: 338,500
Total FTE jobs generated: 1.4 million
In the US…
Horse industry is above motion pictures ($24.8 billion)
Average fixed cost to own a horse annually is $2,000
38% of owners have household incomes of less than $50,000/yr
21% of owners have household incomes of more than $100,000/yr
1915: peak year of horses (20mil)
Horse numbers by state:
1 Texas: 678,0001 California: $11.4bil
2 California: 642,0002 Texas: $7.1bil
3 Florida: 299,0003 Florida: $6.5bil
4 Oklahoma: 278,0004 New York: $4.8bil
5 Illinois: 278,0005 Illinois: $3.8bil
6 Colorado: 194,0006 Kentucky: $3.4bil
Arizona: 166,500 (not including reservation horses), $1.2bil
In Arizona…
More than 45% of horses are boarded
Over 100,000 people are horse owners
78% pleasure, 16% racing, 6% show
Breed rankings:
1 Quarter Horse2 Paint 3 Thoroughbred 4 Standardbred 5 Tennesee Walker
Breeds
Breed: defined as a group of animals having a common origin with certain distinguishable characteristics such as function, conformation, and color.
These characteristics are not common to other members of the same species.
Prepotency: the ability of the parents to uniformly transmit characteristics to offspring
*Appaloosa – color breed
Registration requires coat coloring
Nez Pierce Indians: one of first to practice selective breeding
White sclera, mottling
*Buckskin – color breed
Buckskin, grullo, dun, red dun
No dorsal stripe
Can be Quarter Horse
*Morgan – only breed named after a specific horse
*Palomino – color breed
*POA – Pony of the Americas
1955, Black Hand (#1, foundation sire)
Sire: Shetland Pony, Dam: Appaloosa
Shorter than 56”
*Saddlebred
*Thoroughbred – Jockey Club, NY
Race 6 furlongs-1.5 miles
Breeder’s Cup
Coat Colors
Bay: six black points
Brown: light areas
Buckskin: no dorsal stripes
Cremello: cream color, double-diluted chestnut
Albino: no pigment
Dun: red dun… buckskin-like, dorsal strips legs & back
Gray: dominant color
Grullo: smokey color, black points
Palomino: single dilution of chestnut
Red roan: red & white, black & white (blue roan)
Sorrel: chestnut, lighter
Markings
Face
Star: white marking on forehead
Snip: between nostrils
Stripe: down face between eyes & nose
Star & stripe combo
Blaze: broad stripe
Bald face: very broad stripe
Star, stripe, & snip combo
Legs
Coronet
Half-Pastern
Pastern
Sock-half cannon
Stocking
Selection Criteria
Balance & symmetry
Balance is defined as how the horse’s body parts blend & fit together
Muscling
Gaskin & forearms are best indicators of muscle
Structural correctness
Type & quality
Travel or way of going
Structure
Skeletal system creates shape of the horse, in addition to providing support
Bones act as levers, store minerals, and site of blood cell formation
205 bones in the body
34 bones are flat bones, united by sutures & constitute the skull
Front leg: shoulder, arm forearm, knee (carpus), canon bone, fetlock, long pastern, short pastern, coffin bone (1, 2, 3 phalanx)
Knee; structure set-up with many small bones, help with anti-concussion
Ligaments attach bones (ex. splint bones attached to cannon by ligament)
Stay apparatus: keeps fetlock up, larger joint puts more pressure on legs
Patella (kneecap) is the largest sesamoid bone
Effects Exercise on Bone
Competence – stress level is within horse’s capacity
No new demand, no new capacity
Adaptation – stress is at level sufficient to “alarm” system, developing new capacity with no damage
Fatigue – stress sufficient to weaken horse temporarily but not disable him. Need to give system time to have “rebound effect”
A single major overload = failure
Classification of Bones
According to gross appearance
Long: grows in length (epiphyseal cartilage)
Short: cuboid-absorption of shock
Flat: relatively thing, expand two dimensions, serve in protection
Irregular: paired bones, vertebrae
Sesamoid: reduce friction (along course tendon)
Pneumatc: air spaces or sinuses
Nasal: pneumatic
Scapula: modified long (old flat)
Vertebrae: Irregular
Carpal/Tarsal: short
Cannon (metacarpal): long
Navicular, patella: sesamoid
Skull: flat
Characteristics of Bone
- Approximately 66% mineral matter
- About 33% organic matter
- Ca & P in about 2:1 ratio
- Organic material is chiefly collagen, a protein… it forms within the framework
- Organic material gives toughness & elasticity while minerals add hardness
- Bone is never static, constantly changing… only static when dead
- Osteoblasts: aid in the incorporation of Ca
- Osteoclasts: aid n the removal of Ca (from work/concussion)
- Blood from Ca level goes down, hormones tell to remove Ca from bones to go back into blood
- Too much Ca, hormones to put Ca back in or to restore injured bones
Ossification & Growth of Long Bones
Epiphysis
Diaphysis
Epiphyseal cartilage or growth plate
The provision for continued ossification at either end of the diaphysis is made by the actively growing cartilage
When the epiphyseal cartilage ceases to differentiate bone growth ceases.
Joints
Hind Limb Joints
System of angles aid in shock absorption like front leg
Injuries, luxation (dislocation)
Hip joint: best enarthrodial / ball & socket
Stifle joint: corresponds to human knee
Tarsus or hock joint: many disorders
Fetlock joint: similar as front leg
Synovial Joints – freely moveable
Horse’s ball bearings
Consist of two bone ends covered by articular cartilage
Cartilage within joint is smooth and resilient which allows for frictionless movement
Joint stability is maintained by a fibrous capsule, which attaches to both bones & collateral ligaments
Collateral Ligaments
Maintain stability in joints like the fetlock, knee, elbow, hock, and stifle
Other ligaments within the joint itself such as the cruciate ligaments which truly help stabilize joints like the stifle joint.
Other ligaments outside the joint cavity also lend support, ie distal sesamoidean
Ligaments & suspensory ligaments along with the sesamoid bones hold fetlock
- In addition to the fibrous joint capsule, the joint capsule itself also contains an inner layer called the synovial membrane
- Joint is very well engineered to provide frictionless movement via the combination of structures including articular cartilage, subchondral bone (one beneath the cartilage), & soft tissues (joint capsules & ligaments)
- Articular cartilage by nature is resilient and has the ability to compress thus is a good shock absorber by itself
- Resiliency of the soft tissue is important for normal motion as well as shock absorption
- Problem with articular cartilage is that it is less thick and has far less overall volume than either bone or soft tissues
- If any disease affects the bone (fracture) or soft tissue (fibrosis due to chronic inflammation) results in interference with shock absorption
Hyaluronic acid provides lubrication to the synovial membrane surface along with lubricin, another protein structure, it also lubricates articular cartilage surfaces
The substance moving over the surface of the joints is called boundary lubrication
Second mechanism of lubrication of cartilage is affected by fluid being squeezed out of the cartilage onto the surface when weight-bearing occurs
When weight-bearing ceases, the fluid is absorbed back in the cartilage, ready for the next cycle of weight-bearing.
Composition of cartilage within joint
Normal microscopic section: articular cartilage appears as a glasslike structure containing cells. The glasslike structure outside the cell is called a matrix.
The matrix is made-up of a framework of collagen
Within the framework are proteoglycans and water from the water molecules
Both proteoglycans and collagen important for articular cartilage function