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 $112 billion in the United States$.
• Employment: More than $1.4 million full-time jobs$ 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 $50-150 cc$.
• Sperm concentration is $30-800 million per cubic centimeter$.
• Average of $10 mares$ 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 $75 g NaCl$ 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 >$200 beats per min$
• Respiratory rate at rest 9-12 per minute
  • Exercise may increase to >$100 breaths per min$
• Body temperature at rest ~ $100 F$
• Defecations average 8-10 per day

Symptoms of Disease

• Loss of appetite
• Fever (rectal temperature > $101 F$)
• 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