Equus caballus

Gender Terms• Male = stallion• Female = mare• Castrated male = gelding• Newborn/young = foal (until weaned)• Giving birth = foaling• Young female = filly• Young male = colt• Group = herd or band

Breeding

• Seasonally polyestrous spontaneous ovulators• Estrous cycle 21.7 days• Estrus 6.5 days, ovulation in last 24-48h of estrus• Most horses at our latitude naturally begin cycling in March, but ideal to

breed in February for Jan 1 foal birthday• Provide artificial lighting to start cycling (14.5-16h/day light starting 12/1)….

• ~25% of mares cycle in winter / throughout year• Gestation = 340 days• Birth usually at night

Breeding

• Age recorded as January 1st of the year born• Wean @ 5-6 months• Puberty = 10 to 24 months (~18 months)

General Equine Information

• Life span: 20 to 30 years – Oldest I’ve seen was 38 years old (‘Boomer’)

• Measurement is hh = hands high– 1 hand = 4 inches

• Peak usefulness is 3 to 13 years (plenty of exceptions)

• Range horse can travel up to 30 miles a day.

Gaits

• Four natural gaits:

Walk - 4 beat Trot – 2 beat

Canter – 3 beat Gallop – 4 beat

Complete Book of the Horse p32

Anatomy

Anatomy

• Hind gut fermenter: large cecum (like rabbits)

• Relatively small stomach capacity – needs to eat throughout the day

• Large lung area• Well-developed muscles in shoulders and

hindquarters

Anatomy

• 340 degree vision – blind spot directly behind them

• Acute hearing – 16 muscles in each ear to move ears independently & pinpoint sound source

• Can sleep standing upright – stay apparatus

Natural Behavior

• Prey animal• Startle easily• Flight instinct stronger than fight• Naturally live in groups• Numerous vocal sounds• Well developed sense of touch

Behavior

DO NOT:• Handle roughly• Try to modify undesirable behavior with

negative reinforcement

Behavior

DO:• Rule out medical causes of behavior• Provide counterconditioning based on

positive reinforcement, classical conditioning and desensitization

Common Equine Behavior ProblemsStereotypic Behavior • Locomotor

• Stall pacing, walking, kicking• Weaving • Pawing at ground

• Oral• Wind sucking * (don’t confuse with wind suckers…

pneumonvagina 2nd to poor conformation, Caslick’s procedure used to help)

• Cribbing• Wood chewing

Common Equine Behavior Problems

• Aggression• Towards other horses• Towards humans

• Stable Vices (Stereotypic Behavior)• Locomotor • Oral

• Transporting Problems• Loading/unloading, particularly

Common ProblemsUCD Equine Behavior Service

2005-07

• 25% - underlying medical problem• 33% - aggression• 14% - fear• 10% - procedure aversion • 5% - compulsive disorders

Body Language

WATCH:• Ear position• Head position• Mouth• Feet

Restraint

• Halter/lead rope• Distraction • Lift front foot• Twitch• Blindfold• Hobbles• Stud chain

Housing• Need shelter from wind, snow & rain• Adequate stall/paddock size

– At least 12’ x 12’ for one horse– Behavior & health issues result from too

small a space or over-crowding• Adequate ventilation• Appropriate bedding – (no black walnut shavings - toxic)

– Clean daily– Bed deeply

• Sturdy & Safe Fencing

Nutrition / Feeding

• Feeding should be according to amount of activity in horses life– Pasture pet needs less energy (food) then a

race horse

• When multiple horses together, watch to make sure no one is out competing the others for food

Nutrition / FeedingINTAKE:• 1.5% - 3% of body weight (lb) daily• 20-70L (5-20gal) water daily

NEEDS:• Clean, fresh water all the time• Salt/mineral block• Forage – pasture, hay

Nutrition / Feeding• Pasture grass

– May be adequate for nutritional needs of low activity horses (pasture pets)• Depends on stocking density and quality of forage

• Hay – Grass hay preferred for many horses– High quality alfalfa best to slowly re-feed starved

horses

Nutrition / Feeding• Grain

– Some do not need supplementation with grain, depends on age, activity level

– Excessive supplementation could lead to obesity, laminitis

– Older horses often require supplementation• Equine Senior• Beet pulp• Vegetable oil

Toxic Plants

• Yellow Star Thistle

Health Concerns

Legs and Bellies (Orthopedic & GI)• Dentistry • Colic• Injuries• Lameness

– Laminitis – acute & chronic– Navicular dz– Thrush (moist dermatitis of frog)

http://www.equipodiatry.com/podiatry.html

AAEP.org

Laminitis• Acute & Chronic versions• Often occurs secondary to overfeeding

– lush pasture, horse broke into grain room, abrupt diet change

• Also can be 2nd to other illness, excessive steroid administration

• PAINFUL• Often both front feet, but any/all can be

affected

Laminitis• “founder” – lay people use

interchangeably with laminitis, more accurately refers to chronic laminitis

• “sinker” – P3 (coffin bone) rotated through sole…VERY BAD

ColicAbdominal pain / discomfort•Signs can include:

– Rolling, kicking / looking at abdomen, not eating/drinking/defecating, sweating, unsettled, stretching, increased HR

•GI & extra-GI causes, including– Sand– Parasites– Enterolith– Strangulating lipoma

Colic• Medical vs. Surgical colic• Mild to life threatening

Prevention:• Quality diet, primarily forage• Regular exercise• Clean water• Don’t feed directly on dirt

Strangles, ‘equine distemper’

• Streptococcus equi equi• Highly contagious• Consider barns contaminated for 2m post outbreak• Signs include:

– Fever (103-106)– Mucoid to mucopurulent nasal discharge– Submandibular lymphadenopathy– ‘bastard strangles’ – internal LNs abscessed

• http://www.merckvetmanual.com/mvm/index.jsp?cfile=htm/bc/121309.htm

Pigeon Fever, Dryland Distemper

• Corynebacterium pseudotuberculosis• External abscesses – pectoral region, ventrum• Internal abscesses • Late Summer / early Fall• When draining abscesses, do not let discharge

contaminate ground/stall/barn

http://www.aaep.org/health_articles_view.php?id=358

EHV-1, EHV-3, EHV-4

• EHV-1– Respiratory disease– Abortion (9-120 days post exposure)– Myeloencephalopathy / neurologic

• EHV-4– Respiratory disease

• EHV-3 – Coital exanthema (STD)

EHV-1, EHV-3, EHV-4

• HIGHLY CONTAGIOUS– Beware nasal droplets – lots of virus– Incubation & Shedding for ~21-28 days– ISOLATE NEW ARRIVALS FOR AT LEAST ONE

MONTH• Some may remain infected lifelong• No vaccination for neuro form (there is a

vaccination for respiratory & abortion

Equine Infectious Anemia

• EIA, Coggins• Viral dz RBC destruction anemia • Regulatory disease• Infectious for life, no cure, carriers• Transmitted via blood sucking insects –

horse flies, deer flies, mosquitoes, fomites (needle re-use)

• http://www.aphis.usda.gov/animal_health/animal_diseases/eia/

‘Normal’ Vitals

• Temperature: 99.5 to 101.3°F (37.5 – 38.5°C)• Heart Rate:

– Young 65-75 beats per minute– Adult 28 to 45 bpm

(when racing, up to 250bpm)• Respiration Rate:

– Young 14-15 breaths per minute – Adult 10-14 bpm

Recommended Vaccinationshttp://www.vetmed.ucdavis.edu/ceh/currenthealth.cfm

• Rabies• 3-way (EWT) – EEE, WEE, Tetanus +/- VEE• WNV (West Nile Virus)

Pregnant mares:

EHV – vaccinate at 5, 7, & 9 months of gestation

IM Injection Sites

• Neck*, gluteal, semi-tendinosus muscles

http://www.aces.edu/pubs/docs/A/ANR-1018/

Parasitism

• Large strongyles – Strongylus vulgaris, S edentatus

• Small strongyles - Tridontophorus

• Tapeworms - Anoplocephala

• Pinworms – Oxyuris equi

• Bots - Gasterophilus sp.

• Stomach worms – Habronema • Ascarids – especially young – Parascaris equorumhttp://www.merckvetmanual.com/mvm/index.jsp?cfile=htm/bc/toc_22500.htm

Parasite Control

• Clean!!!• Manure management / muck stalls daily• Pasture rotation• Lower stocking densities

Deworming

• Ivermectin PO q 2 months – For example - March, May, July, September

• 2x pyrantel q1y in ~January

– Tapeworms• Moxidectin* or 2x fenbendazole q1y in ~November

– Encysted larvae