Horses Notes

Horses

Domestication and Early Uses

  • First domesticated 5000 years ago.
  • Early uses in warfare:
    • Assyrians used horses to pull chariots in 2000 B.C.
    • Genghis Khan used horses to transport soldiers in the conquest of China.

Horses in the Americas

  • Columbus: Brought 5 horses to the West Indies in 1493.
  • Cortez: Brought hundreds of horses to Mexico for fighting the Aztecs.
  • Escaped horses reproduced rapidly.
  • Native Americans captured wild horses, calling them cayuses.
  • Impact on Native American Lifestyles:
    • Increased travel distance and speed.
    • More efficient hunting (e.g., bison).
Continued
  • Cowboys: Caught wild horses called mustangs (Spanish for wild mustengo).
  • Essential for working cattle.
  • Needed for the Pony Express.
  • Draft horses used in farming.
  • Impact of Tractors: Temporary decline in horse numbers.
  • Resurgence: Horse numbers increased with the popularity of pleasure riding, racing, shows, and sports.
  • Economic Value: Value of live horses exported from the United States now exceeds that of cattle.
  • Total Economic Impact: Exceeds 112billionintheUnitedStates112 billion in the United States.
  • Employment: More than 1.4millionfull−timejobs1.4 million full-time jobs associated with the horse industry in the USA.

Contributions of Horses

  • Pleasure riding
  • Racing
  • Showing/Eventing/Rodeos/Polo
  • Cattle and farm work (e.g., ranches, Amish)
  • Police work
  • Therapeutic Riding Programs
  • Production of vaccines and hormones

Classification of Horses

  • Order: Perissadactyla
  • Family: Equidae
  • Genus: Equus
  • Species: caballus (domestic horse)
  • Related Species: Asses, donkeys, zebras, and onagers.

Types of Horses

  • Ponies: Below 14.5 hands (58 inches), weighing 300-600 pounds.
  • Horses:
    • Light horses (900-1200 pounds).
    • Heavy horses (may exceed 1600 pounds).
    • "Hot bloods" (sports breeds, most saddle horses).
    • "Warm bloods" (dressage horses and jumpers).
    • "Cold bloods" (draft horses).

Examples of Breeds

Saddle and Sport Horse Breeds
  • American Saddlebred
  • Appaloosa
  • Arabian
  • Lipizzan
  • Missouri Fox Trotter
  • Morgan
  • Mustang
  • Paint
  • Palomino
  • Paso Fino
  • Pinto
  • Quarter Horse
  • Tennessee Walking
  • Thoroughbred
  • Morgan
  • Standardbred
Draft Breeds
  • Belgian
  • Clydesdale
  • Friesian
  • Percheron
  • Shire
  • Suffolk Punch
Harness Breeds
  • Cleveland Bay
  • French Coach (Normand)
  • German Coach (Oldenburger)
  • Hackney
Warmblood Breeds
  • Hanoverian
  • Holsteiner
  • Trakehner
  • Warmblood (American, Australian, Dutch, Swedish)
  • Westphalian
Pony Breeds
  • American Miniature Horse
  • Connemara
  • Dartmoor
  • Hackney
  • Haflinger
  • Pony of the Americas
  • Shetland
  • Welsh

Horse Gaits

  • Slow Gait: A slow “showy” pace.
  • Running Walk: Four beat, ipsilateral.
  • Fox Trot: Four beat, diagonal.
  • Rack: Rapid four beat, diagonal.
  • Walk: Slowest (4 mph), four beats.
  • Trot: Speed of 9 mph, two-beat (diagonals together); riders often post on outside diagonal.
Continued
  • Canter or Lope: 10-12 mph, three-beat gait. "Lead" refers to which foreleg is the farthest ahead (right lead canter starts with left hindleg, then right hind + left fore, then right foreleg).
  • Gallop: Speeds of up to 40 mph, four beat (right lead steps are left hind, right hind, left fore, right fore).
  • Pace: Two beat, ipsilateral legs move together.

Development of Senses

  • Keen eyesight: Can focus in two fields of vision; blind spots in front of head and rear of body.
  • Keen hearing
  • Highly developed sense of touch
  • Primary defense: "Flight", but in some circumstances will also "fight".

Horse Coat Colors

Solid Colors
  • Black
  • Brown
  • Bay
  • Buckskin
  • Chestnut
  • Sorrel
  • Palomino
  • Gray
  • White
Mixed Colors
  • Piebald (black with white spots)
  • Skewbald (another color with white spots)
  • Pied (solid with only a few spots)
  • Tobiano (white with large color spots)
  • Overo (colored w/ jagged white spots)
  • Paint (restricted breeds)
  • Pinto (any spotted horse)
  • Roan (intermixed dark and white hairs)
Continued
  • Appaloosas: Frost, leopard, marble, snowflake, spotted blanket, white blanket; have stripped hooves.
  • Palominos: Golden with white mane and tail.
  • Buckskin: Golden with dark mane and tail.
  • Cremellos: Pale cream, almost white, with blue eyes.

Markings

Facial
  • Snip
  • Star
  • Strip
  • Blaze
  • Bald
Legs
  • Coronet
  • Half-pastern
  • Lightening mark
  • Pastern
  • Sock
  • Stocking

Horse Reproduction

  • Lower reproductive rate compared to other farm mammals.
  • Long gestation period.
  • Seasonal estrus cycles.
  • Produce only one foal per gestation.
  • Mares often not bred until after racing and show careers have ended.

The Stallion

  • Reaches puberty at 1 year, rarely used for breeding until 3 years of age.
  • Ejaculate volume is 50−150cc50-150 cc.
  • Sperm concentration is 30−800millionpercubiccentimeter30-800 million per cubic centimeter.
  • Average of 10mares10 mares can be bred from one ejaculate (using a semen extender).
  • Mature stallions may have semen collected once per day, rarely twice in a day.
  • Fresh cooled semen can be shipped in the Hamilton-Thorn container for use within 3 days.
  • Stallion semen varies in its ability to maintain fertility when froze.

The Mare

  • Reach sexual maturity at 10-18 months.
  • Rarely bred before 3 years old.
  • Estrus cycles 19-21 days.
  • Length of estrus (standing heat) is 2-9 days.
  • Ovulation occurs 1-2 days prior to end of estrus.
  • Up to 20% have double ovulations but rare to have live twin births (often abort one).
  • "Teasing" determines receptiveness to male.
  • Typically breed every other day during estrus.
  • Pregnancy diagnosis:
    • Lack of estrus
    • Rectal palpation
    • Rectal ultrasonography
    • Serum progesterone levels
Continued
  • Gestation length 335-345 days.
  • Udder becomes distended, “beads of wax” form on teats 24-48 hrs prior to parturition.
  • Muscles around tailhead and vulva relax.
  • Normal presentation is front legs first with head and chin resting between them.
  • Normal delivery time is 10-15 minutes.
Continued
  • Placenta should be expelled within 6 hrs.
  • Retained placentas predispose to uterine infections and laminitis.
  • If normal delivery and foal mare may be rebred on “foal heat” approximately 5-10 days post parturition.

Neonatal Foal Care

  • Umbilical cord dipped in disinfectant.
  • Tetanus antitoxin given if mare has not been recently given tetanus toxoid booster.
  • Healthy foals stand within 30 minutes.
  • Must receive colostrum within 12 hours to absorb antibodies.
  • Watch for infections (“joint ill”) and constipation (may require enema).

Care of the Young Horse

  • Early “imprinting” and handling important.
  • Parasite control program.
  • Regular hoof care.
  • Horse colts castrated at approximately 1 year of age.
  • Pasture is ideal (for exercise and high fiber diet).

Common Conformation Faults

  • Plain-headed
  • Weak jaw
  • Parrot mouth
  • Lacking femininity or masculinity
  • Narrow chest
  • Crooked legs
  • Winging, forging
  • Interfering
  • Lacking balance
  • Short, thick neck
  • Ewe-necked
  • Straight shoulders
  • Sway-backed
  • Straight pasterns
  • Roman nose

Nutrition of Horses

  • Nonruminant herbivores
  • Protein, fat, vitamins, and minerals digested and absorbed in the stomach and small intestines
  • Plant fibers digested and absorbed in the cecum and large intestines (cecum is a bacteria-rich vat where fiber is broken down into volatile fatty acids and carbohydrates).

Nutrient Requirements

  • Influenced by:
    • Age
    • Size
    • Amount of work performed
    • Reproductive status

Concentrates (Grains/Mixes)

  • Oats:
    • Most popular grain for horses in the USA
    • Highly palatable
    • High enough fiber that minimum risk of carbohydrate overload-induced colic or founder
    • High phosphorus:calcium ratio
Continued
  • Wheat bran: Used for bulk, palatability, laxative
  • Molasses: Added to decrease dustiness, increase palatability
  • Beet pulp:
    • A highly fermentable fiber, promotes healthy GI flora (bacteria)
    • Good source of energy
  • Corn:
    • Low fiber, high carbohydrate
    • Excellent source of energy
    • Low in protein
  • Barley, Milo, Wheat:
    • Rarely used for horses
    • Limited amounts may be added to mixed grains or incorporated into pellets
Continued
  • Linseed meal:
    • Source of protein and omega 3 fatty acids
    • Popular in early 1900s, rarely used today
  • Soybean meal: High protein supplement
  • Flaxseed meal: Rich in omega 3 fatty acids
  • Corn oil:
    • High energy food
    • Up to 2 cups may be fed twice daily
  • Extruded grains: Easy to digest (good for older horses)
  • Complete feeds:
    • Contain forage products
    • Popular diets for older horses
Continued
  • “Life Stage Grains”
    • Foals
    • Yearlings
    • Brood mares/Stallions
    • Working horses
    • Pleasure horses
    • Idle horses
    • Elderly horses (“Senior” diets)

Harvested Forages

  • Grass hays:
    • Ideal diet for most horses
    • Relatively low in protein, supplements needed
    • Timothy, Bermuda grass, Orchard grass, Prairie, and Oat Hay are excellent for horses
  • Legumes:
    • High in protein and calcium
    • Caution in feeding to growing horses to avoid too rapid growth and Ca:P imbalances
Continued
  • Should be free of weeds, bugs, dust, and molds
  • Should be harvested before the plants have produced mature seedheads
  • Silages may replace up to 50% of forage
  • Plant products incorporated into extruded and pelleted foods prolong longevity in horses with poor teeth

Pasture

  • Most natural feed for horses
  • Fewest digestive and behavioral problems
  • Pasture management is essential to avoid overgrazing, contamination with parasite-rich manure, and overgrowth of weeds
  • Rotational grazing is recommended
  • Depending on conditions may need 1-20 acres per horse if the sole source of nutrients

Salt and Minerals

  • Working horses may lose 75gNaCl75 g NaCl per day
  • Free choice salt blocks or granular salt should be provided
  • Diet should have Ca:P ratio balanced, horses do not self-regulate these minerals
  • Iodine and selenium supplements may be required, check with local Extension Office

Vitamins

  • Supplements not needed if fed high quality hay or pasture and access to sunlight
  • B-complex vitamins are synthesized in cecum and large intestines and are also found in green plants and hays

Water

  • A vitally important nutrient
  • Average consumption is 10-12 gallons/day

Nutritional Diseases

  • Anemia:
    • Deficiency of iron, copper, cobalt, vitamins
    • Signs include loss of appetite, emaciation, death
    • Worldwide
  • Azoturia (Monday morning disease, tying up):
    • Associated with faulty carbohydrate metabolism
    • Signs include profuse sweating, pain, reluctance to move, wine-colored urine
    • Prevent by decreasing grain and daily exercise
Continued
  • Calcium deficiency:
    • Signs include infertility, decreased milk production, fragile bones
    • Calcium deficient soils in parts of Florida, Louisiana, Nebraska, Virginia, West Virginia
    • Prevent by fertilizing soils and analyze diet to ensure adequate and balanced Ca:P
Continued
  • Colic:
    • Signs include excruciating pain, distended abdomen, violent rolling and kicking
    • Many causes include impaction (too little water, sand, enteroliths), damage to intestinal blood supply by parasites, intestinal torsions, mold, and toxins
    • Prevention includes good water source, good parasite control, feed only high quality feeds
Continued
  • Developmental Orthopedic Bone Disease:
    • Result of overfeeding protein or calcium or improper Ca:P balance
    • Signs include lameness, joint disease, joint effusion, and contracted tendons
    • Surgery sometimes required to remove abnormal bone and cartilage
    • Prevent by watching Ca:P and do not overfeed young horses, add copper and zinc to diet
Continued
  • Laminitis (founder):
    • Associated with endotoxemia from carbohydrate overload or metritis
    • Signs include fever, extreme pain, reluctance to move, abnormal stance
    • Chronic cases have separation of hoof laminae
    • Consult veterinarian to treat, prevent by avoiding causes
Continued
  • Heaves (Chronic Obstructive Pulmonary Disease):
    • Signs include forced expirations, flared nostrils
    • Associated with feeding of dusty and/or moldy feeds or environments
    • Treat with bronchodialators or corticosteroids and modify diet (may wet hay before feeding or use pelleted feeds)
Continued
  • Iodine Deficiency (Goiter):
    • Inadequate iodine results in the inability to produce thyroxin and enlargement of thyroid glands
    • Foals are weak, adult animals have poor performance
    • Iodine deficient soils in the Northwestern United States and Great Lakes regions
    • Prevent by feeding salt with 0.01% KI
Continued
  • Osteomalacia:
    • Weak bones, poor appetite, depraved appetite (chewing wood, metal, bones), stiff gait
    • Most often associated with phosphorus deficiency (soils of Southwestern USA)
    • Prevent by feeding adequate amounts and balanced Ca:P
Continued
  • Periodic Ophthalmia (moon blindness):
    • Multiple causes of this condition include immune-disease, Leptospira organisms, parasites, trauma, and rarely riboflavin deficiency
    • Signs include painful, cloudy eye, these symptoms wax and wane
    • Consult a veterinary ophthalmologist for treatment, add riboflavin to diet
Continued
  • Rickets:
    • Result of inadequate calcium, phosphorus, vitamin D, or imbalances of Ca:P
    • Signs include joint enlargements, bowed tendons, bulges on bones, stiff gait or reluctance to move, pathological fractures
    • Treatment and prevention is feeding adequate amounts and proper ratio of Ca:P and sun exposure or supplemental vitamin D
Continued
  • Salt Deficiency:
    • Inadequate intake of NaCl
    • Signs include loss of appetite, rough hair coat, poor performance, decreased milk production
    • Salt-starved animals should have slow reintroduction of salt to their diet
Continued
  • Urinary calculi:
    • Signs are dribbling urine, frequent attempts to urinate, abdominal pain
    • Improper Ca:P balance or too high minerals in diet may predispose animals to calculi
    • Males most often affected, may require surgery to remove stones and open the urethra
Continued
  • Night Blindness:
    • Vitamin A deficiency
    • Signs are impaired vision, especially when the light is dim
    • Provide leafy green hays or pasture as a source of carotene (precursor of vitamin A) or supplement vitamin A (especially in winter)

Feeding Horses

  • Variability in individual needs:
    • "Easy keepers" do well on forages alone
    • "Hard keepers" need supplemental grains or fats
  • "Rule of thumb" for horses doing light work:
    • One pound of grain/100 pounds body weight
    • One pound of hay/100 pounds body weight (free choice grass hay or pasture is recommended)
  • Increase or decrease the amount of grain or fat if necessary to maintain body weight
Continued
  • Idle horses do well on high-quality pasture or grass hay
  • Hard-working horses and stallions during the breeding season often require concentrates fed at 1.5% of body weight
  • Young horses are typically fed 0.5% of body weight as concentrates plus high-quality pasture or grass hay

Training Horses

  • Foals should be groomed and halter trained
  • Many popular methods of training (e.g., clicker training)
  • Young horses are rarely ridden before 2 years of age (January 1st being considered the “universal birthday” for horses)

Grooming of Horses

  • Currycombs are useful in removing mud, soil, and loose hair
  • A stiff brush is used next to remove more dirt and loose hair
  • A soft brush and/or cloth are used to polish coat
  • Vacuums popular remove dirt and keep it from being redeposited on coat
Continued
  • Cornstarch or baby powder to enhance white markings
  • Bathing as needed to remove sweat, soil
  • Blanketing keeps coats clean, smooth, and short
  • Artificial lighting is used to prevent the growth of long “winter” coats in show horses
Continued
  • Manes and Tails should be handpicked following liberal use of conditioners to avoid breakage
  • Some breeds/shows require braiding, banding, or even roaching of manes
  • “Bridle path” is usually trimmed short

Defects of Movement

  • Cross-firing
  • Dwelling
  • Interfering
  • Lameness (claudification)
  • Paddling
  • Pointing
  • Pounding
Continued
  • Rolling of shoulders
  • Scalping
  • Speedy cutting
  • Stringhalt
  • Trappy stride
  • Winding (rope-walking)
  • Winging

Blemishes and Unsoundness

  • Blindness
  • Blood spavin
  • Bog spavin
  • Bone spavin (jack spavin)
  • Bowed tendons
  • Calf-kneed
  • Capped elbow
  • Capped hock
Continued
  • Cocked ankles
  • Contracted heels
  • Contracted tendons
  • Corns
  • Curb
  • Developmental bone diseases (osteochondritis dessicans, osteochondrosis)
Continued
  • Fistulous withers
  • Founder (laminitis)
  • Knee-sprung (bucked-kneed)
  • Moon blindness (periodic ophthalmia)
  • Navicular disease
  • Parrot mouth
  • Poll evil
Continued
  • Quarter crack (sand crack)
  • Quittor
  • Ringbone
  • Scratches (grease heel)
  • Sidebones
  • Splints
  • Stifled
Continued
  • Stringhalt
  • Sweeney
  • Thoroughpin
  • Thrush
  • Undershot jaw
  • Wind puffs

Stable Vices

  • Bolting food
  • Cribbing
  • Halter pulling
  • Stall kicking or striking
  • Tail rubbing
  • Weaving

Bad Habits of Horses

  • Balking
  • Rearing
  • Striking out
  • Shying
  • Running away (cold-jawed)
  • Hard to catch
  • Hard to tighten girth (“swelling up”)
  • Bucking

Care and Trimming of the Feet

  • Proper trimming is prophylactic against many leg and hoof problems
  • Corrective trimming may compensate for some conformational faults
  • When shoes are used should be reset every 4-8 weeks depending on use and rate of hoof growth

Determining the Age of Horses

  • Aging is based on the shape and appearance of teeth
  • Permanent incisors replace temporary ones
  • Wear of incisors shows “cups” on the surface
  • Cups are worn down and dental stars appear
  • Teeth become more triangular
  • The angle of teeth also change
  • Galvayne’s groove

Normal Horse Physiology

  • Pulse rate at rest 36-42 beats per minute
    • Exercise may increase to >200beatspermin200 beats per min
  • Respiratory rate at rest 9-12 per minute
    • Exercise may increase to >100breathspermin100 breaths per min
  • Body temperature at rest ~ 100F100 F
  • Defecations average 8-10 per day

Symptoms of Disease

  • Loss of appetite
  • Fever (rectal temperature > 101F101 F)
  • Rapid respiratory rate
  • Rapid heart rate
  • Sweating, stiffness, lameness, nasal discharge, coughing, diarrhea, constipation, pawing, rolling groaning, etc.

Most Common Injury

  • Wire cuts (especially severe when barbed wire, high tensile wire may also cause injury)

Communicable Diseases

  • Encephalomyelitis (“sleeping sickness”)
    • Eastern, Western, and Venezuelan
  • Equine infectious anemia (EIA, “swamp fever)
  • Influenza (many strains)
  • Potomac horse fever (Ehrlichia risticii)
  • Protozoal myelitis (Sarcocystis neurona)
Continued
  • Rabies
  • Rhinopneumonitis
    • EHV-1
    • EHV-4
  • Strangles (Streptococcus equi)
  • Tetanus (Clostridium tetani, “lockjaw”)
  • West Nile Encephalitis

Internal Parasites of Horses

  • Botflies (Gasterophilus spp.)
  • Ascarids (Parascaris equorum, roundworm)
  • Large Strongyles (Strongylus spp.)
  • Small Strongyles (cyanthostomes)
  • Threadworms (Strongyloides westeri)
  • Pinworms
  • Tapeworms

Prevention of Intestinal Parasites

  • Interrupt lifecycles through deworming
  • Remove manure from stalls/lots/pastures
  • Compost or scatter manure on fields not grazed by horses
  • Pasture rotations alternating grazing with ruminants

Control of Intestinal Parasites

  • Management to decrease exposure to ova and larvae
  • Anthelmintics (many forms: pastes, liquids, granules, feed additives)
    • Different classes for different parasites
    • Rotational schedule to minimize the development of resistance

Anthelmintics

  • Avermectin (e.g. Ivermectin):
    • Efficacy against bots 99%, ascarids 100%, large strongyles 100%, small strongyles 100%, pinworms 100%
  • Milbemycin (e.g. Moxidectin):
    • Efficacy against bots 90%, ascarids 100%, large strongyles 100%, small strongyles 100%, pinworms 100%
Continued
  • Benzimidazole (Fenbendazole, Oxibendazole):
    • Efficacy against bots 0%, ascarids 85%, large strongyles 95-97%, small strongyles 97%, pinworms 97%
  • Pyrimidines (Pyrantel Pamoate):
    • Efficacy against bots 0%, ascarids 95%, large strongyles 70-77%, small strongyles 95%, pinworms 50%
Continued
  • Daily Dewormers:
    • Pyrantel tartate
    • Protective against large and small strongyles, roundworms and pinworms
    • Twice yearly administration of purge dewormers effective against bots
Continued
  • Pinworm treatment:
    • Double dose of pyrantel pamoate on two consecutive days
  • Treatment of tapeworms and encysted small strongyles:
    • Double dose of fenbendazole (Panacur, Safe-Guard) for five consecutive days

Control of External Parasites

  • Fly control:
    • Good sanitation (removal of manure)
    • Parasitic wasps
    • Feed-through larvicides
    • Baits, traps, fly strips
    • Numerous topicals for use on horses
  • Mosquito control:
    • Eliminate stagnant pools of water
Continued
  • Lice:
    • Topical pyrethrins/pyrethroids
    • Topical carbamates (“Sevin”)
    • Ivermectin
  • Ticks:
    • Topical pyrethroids