Equine Rotation Block

What is the total percent of BW?

60%

Where is blood volume calculated in (ECF vs. ICF)?

ECF

What percent of BW is blood volume?

8%

What is the formula for a fluid deficit or volume needed?

% dehydration + maintenance + ongoing losses

What is the difference in dehydration and hypovolemia?

Dehydration = Loss of total body water

Hypovolemia = Decrease in circulatory volume (blood)

An animal can be dehydrated but not hypovolemic. An animal can pull water from the ______________ space to maintain circulatory volume

Interstitial

What are some signs of dehydration?

- Tachycardia

- Reduced jugular fill

- Cold extremities

- Tacky mucus membranes

- Sunken eyes

- Reduction in body weight

What diagnostic tools can we use to measure dehydration? Which is the most sensitive?

- PCV/TP

- Creatinine

- USG (most sensitive)

What is important for monitoring fluid output/losses?

- PCV/TP

- Lactate

- Urine output

- Body weight (very important for foals)

What are maintenance fluid rates for adult horses? Foals?

Adults: 60 mL/kg/day

Foal: 100-120 mL/kg/day

What is the formula for replacement fluids?

BW in kg x % dehydration

*This answer is in L

What are ways horses can have ongoing losses? What is the only one we can truly measure?

- Diarrhea

- Sweating

- Urine output

- Reflux (only one we can measure)

What type of fluids do we want to give to an impaction colic?

- Enteral fluids

- IV fluids

What type of fluids should we not give to a horse that is refluxing?

Enteral fluids

*Give IV fluids

Lactated Ringers are (acidifying/alkalinizing) and should not be used with ____________ dysfunction

Alkalinizing, hepatic

When do we not want to use enteral fluids?

- Ileus

- Strangulating lesions

- Esophageal obstruction

- Recumbent horses

What are the four wound classifications?

- Clean

- Clean contaminated

- Contaminated

- Dirty/infected

There are four types of wound closures. When would we use each?

Primary: Clean or Clean-contaminated wounds that are made and have no tension

Delayed Primary: Clean-contaminated or maybe infected wounds. Debride first then close a few days later

Secondary closure: Dirty/infected wounds. Closure about 5 days after (after granulation tissue and start of epithelialization)

Which phase of healing do we as vets have the most control over?

Inflammatory/lag phase

If a horse has a wound, what vaccine do we need to give?

Tetanus

If there is dead space in a wound, what needs established?

Ventral drainage

What are two reasons for a non-healing wound?

Motion and infection

Corticosteroids generally have a (POSITIVE/NEGATIVE) effect on wound healing

Negative

Colostrum should ideally be given within __________ hours but need to be given in _________ hours

12,24

At what age does the foal start to make its own antibodies? Also when the maternal antibodies are waning?

5 weeks

*We want to protect the foal between the 5-15 week period to reduce exposure to disease during this time

What age do we typically start to vaccinate foals?

4-6 months and then booster in 3-4 weeks

*This is about weaning time

How long do antibodies in adult horses (>1 year old) last according to the current vaccine studies?

12 months

An ideal vaccine will stimulate ___________ mediated immunity and will be a (killed/MLV) vaccine

Cell, MLV

True or False: There are no labeled MLV for gestating mares

True

When is the best time to vaccinate pregnant mares? Why?

Last 30-45 days of pregnancy because this helps transfer antibodies

What are the three parts to the infectious disease triad?

- Animal

- Disease

- Environment

What type of virus is Equine Infectious Anemia (EIA)? How is it transmitted? Diagnostics?

Virus: Lentivirus (HIV)

Transmission: Blood born - flies, needles

Diagnostics: Coggins test

What happens if a horse is positive on a noggins test for EIA?

It will be reported then the horse will be most like euthanized

What virus is it especially important to practice good biosecurity with? Why?

Influenza - it is very hardy, can be aerosolized, and can be picked up rom horses who are just traveling down the road

What are the injection sites for vaccinated horses?

- Neck

- Pectoral (adults only)

- Low hip

What size and length of needle should be used for vaccines?

Size: 18g, 19g

Length: 1.5 inches

*An 18g will work for most IM injections. This larger needle size will have less force when injecting the liquid into tissues

What are the core vaccines?

- Tetanus

- Eastern/Western Equine Encephalomyelitis

- West Nile Virus

- Rabies

Why is clostridium Setani a normal inhabitant of the GI tract in horses?

Because they graze on the ground and eat dirt (lives in soil)

What is the prevention and treatment of tetanus?

Prevention: Tetanus toxoid vaccine

Treatment: Tetanus Antitoxin

What do we have to be careful of with tetanus antitoxin?

Theiler's Disease (acute serum hepatitis)

When do we give the core vaccines to pregnant mares?

4-6 weeks pre-partum

What kind of viruses are Eastern/Western Equine Encephalomyelitis? How do humans and horses get it?

Virus: Togaviruses

Transmission: Mosquitos

*This is reportable, horse is an incidental host

Out of WEE, EE, and VEE which one has the best prognosis for survival? Which one can transmit to humans directly from horses?

Best prognosis: WEE

Horses to humans: VEE

When do we give the core vaccines to foals?

Tetanus: 1-6 months, booster 4-6 weeks

Eastern/Western: 3-6 months, booster 4-6 weeks

West Nile: 3-4 to 5-6 months, booster 4-6 weeks

Rabies: 3-6 months, booster 4-6 weeks

What kind of virus is West Nile? How is it transmitted? What season is highest?

Virus: Flaviviruses

Transmission: Mosquito

Season: Late summer to fall

True or False: West Nile virus cannot be shared between horses and humans so you do NOT need to euthanize positive horses

True

What type of virus is Rabies? How is it transmitted?

Virus: Rhabdoviridea

Transmission: Saliva-contaminated wounds

What are the two different routes on inoculation with rabies?

- Replicates in myocytes (remain undetectable for weeks to months)

- Directly enters peripheral nerves (incubation period very short)

Equine Herpesvirus (EHV 1 and 4) are the strains we worry about in horses. What does each one cause?

EHV 4: Upper respiratory (rhinopneumonitis)

EHV 1: Neurological, later term abortion

What are clinical signs of EHV1 (neurologic and abortion)? Clinical signs of EHV4?

EHV1 Neurologic: Hind limb ataxia, dribbling urine, xanthochromia on CSF

EHV1 Abortion: Later term abortion

EHV4 Respiratory: Serous nasal discharge, cough, mild fever

When do we vaccinate foals and adults for EHV 1 and EHV 4?

Foals/Weanlings: 4-6 months, booster 4-6 weeks and again at 10-12 months

Broodmares (abortion strain): 5, 7, 9 months gestation

What type of influenza do we see in horses?

Type A (subtype H7N7 and H3N8)

*In the US we see the H3N8

What age of horse do we see influenza? Clinical signs?

Horse: Young but > 9 months

Clinical signs: Serous nasal discharge, cough, fever (103-105), lower limb edema (vasculitis)

What is the rule on treatment/rest after horses have influenza?

Cilia get destroyed in the trachea by the virus so for every day they have a fever, they need a week of rest so the cilia can regenerate

When do we vaccinate foals/weanlings and adults for influenza?

Foals/weanlings: 6-7 months, booster 4-6 weeks then 10-12 month old (inactivated) or booster 11-12 months old (MLV)

Broodmares: 4-6 weeks pre-partum

Adults: Semi-annual

What does Equine Viral Arteritis (EVA) cause? How is transmitted?

Cause: Respiratory disease, abortion, limb edema

Transmission: Aerosol or venereal or semen

What must we do before vaccinated for Equine Viral Arteritis (EVA)?

Serological testing to prove negativity

*This WILL show up positive after we vaccinate

When do we vaccinate for Equine Viral Arteritis (EVA)?

Colts: 6-12 months

Stallions: 2-4 weeks prior to breeding season

Mares: When open

How do we handle mares bred to shedding stallions of EVA?

- Vaccinate/isolate mare 21 days prior to breeding

- Isolate mare 21 days after breeding (first year only)

What is the most common cause of viral diarrhea in foals less than 2 months of age?

Rotavirus

*They can develop severe electrolyte disturbances and death may occur due to dehydration

When do we vaccinate mares for Rotavirus?

8, 9, and 10 months of gestation to ensure adequate passive transfer

Strangles (Streptococcus equi var equi is a gram (POSITIVE/NEGATIVE)

Positive

What are clinical signs of strangles?

- Lethargy/fever

- Enlarged lymph nodes

- Purulent nasal discharge

*Strangles doesn't live in the environment, it lives in horses so find the horse that is a carrier (has chondroids)

Why is the strangles vaccine not a strategy to mitigate an outbreak?

They can have an allergic reaction if previously exposed (purport or myositis)

What titer level of strangles DON'T we want to vaccinate if over?

Do not vaccinate if > 1,600

The MLV of strangles needs to be administered by which route only?

Intranasal

*If you give in the muscle it can cause a major abscess

When do we vaccinate foals/weanlings for strangles?

Killed: 4-6 months

MLV: 6-9 months

Booster 4-6 weeks for both

Booster 4-6 weeks after 2nd dose for killed

Booster 11-12 months of age for MLV

When do we vaccinate adults for strangles?

Broodmare (killed): 4-6 weeks pre-partum

Semi-annual

What is Botulism commonly called in foals and what clinical signs will we see?

Shaker foal syndrome. Will see dysphagia so milk coming from the nose

When do we vaccinate mares for Botulism?

8, 9, 10 months of gestation

Single 10th month booster in subsequent years

What are the high risk geographic regions for botulism?

OH, KY, VA, NY, PA

What causes Potomac horse fever and what do we see?

- Neorickettsia risticii

- Fever, luekopenia

- Diarrhea, laminitis, abortion

*This is seasonal during late summer, early fall

Where do we see Potomac horse fever?

Where there is water (MI, IN, IL, OH, MO)

When do we vaccinate for Potomac horse fever?

- Initial and booster 3-4 weeks apart

- Revaccinate every 3-6 months

- Broodmares: 4-6 weeks pre-parturm

Leptospirosis is a spirochetes bacteria that has zoonotic potential. What clinical signs do we see in horses?

- Pyrexia

- Icterus

- Periodic uveitis (moon blindness)

- Renal disease and abortion

*75% of healthy horses have been exposed to lepto but very few horses get it

What does anthrax cause?

Highly fatal septicemia, blood from orifices

*Don't necropsy

How do we vaccinate for anthrax?

- 2 doses SQ 2-3 weeks apart then annually

- Don't use in conjunction with antibiotics

- Don't vaccinate pregnant mares

Horses get roundworms from a fecal-oral transmission. What are the clinical signs? What are the two types?

Types: Ascrids, Strongyles

Clinical signs: Weight loss, colic, diarrhea

*If you have a horse less than 3 years of age with a dry cough, consider ascrid migration to the lungs

What are clinical signs of pinworms?

Itching hind end, rough tail head

What internal parasite can foals get from their mom? What does it cause?

- Strongyloides Westeri (threadworm)

- Foal diarrhea (1-3 weeks old)

- Zoonotic potential

True or False: Bots generally cause no problems

True

What is the equine tapeworm? Lifecycle is fecal to orbitatid mite to oral

Anaplocephala perfoliata

*This can possibly cause colic and the pasture mite is the intermediate host

What is the lung worm in horses? How do they contact it? Clinical signs?

Lung worm: Dictycaulus arnfieldi

Transmission: From donkeys

Clinical signs: Coughing

If a horse has low to no parasites, how many times a year should they be wormed?

Twice a year

Should we rotate dewormers?

No

Where is the problem with PPID? What is its? Typical age?

- Pituitary Pars Intermedia Dysfunction

- Problem is in the Pars intermedia

- Average is 20 years old

What are clinical signs of PPID?

- Hypertrichosis

- Laminitis

- PU/PD due to hyperglycemia

- Hyperhydrosis

- Muscle wasting (abaxial)

- Immunosuppression (due to excessive steroid in the body)

How do we diagnose PPID?

- Endogenous ACTH (recognize seasonality)

- TRH (better in spring, not great in fall)

How do we treat PPID?

- Pergolide with is a dopamine agonist (DA2 agonist)

- Ice boots to decrease risk of laminitis

*The disease is due to a lack of dopamine

What is the difference in clinical signs between PPID and Equine Metabolic Syndrome?

- The hair coat will be normal with equine metabolic syndrome

- EMS is younger horses (5-20 years vs. on the older side)

- EMS will have abnormal fat deposits

What is the most sensitive test for equine metabolic syndrome?

- Oral sugar test

- Measure insulin (and glucose) at 60 and 90 minutes

- Insulin > 45 uU/mL = insulin dysregulation

How should we feed an EMS horse?

- Prairie hay, alfalfa okay

- Decrease to 1.5% of their body weight

- Thyroid supplement until they are at their ideal weight

What are some things that can cause laminitis?

- PPID/iatrogenic steroids

- Endotoxemia (colitis, retained placenta)

- Black walnut

- CHO overload

- Idiopathic

- Equine metabolic syndrome

What are the 4 pathogenesis of laminitis?

- Ischemia (lack of blood flow)

- Mechanical

- Enzymatic (MMP enzymes)

- Metabolic (insulin & glucose)

*We think high insulin is what causes it in EMS and PPID horses. We can't induce laminitis with steroids but it can push the insulin higher

What is the best NSAID for laminitis?

Bute

What are some drugs that cause ileus?

Opioids and Alpha 2s

Which radiographic views can be helpful for diagnosing laminitis?

- Lateral

- AP

Which drug has an anti-platelet effect (prevent thrombus) and is still used to improve blood flow with laminitis?

Aspirin

True or False: Glucose tends to be normal to high normal on a chemistry with equine metabolic syndrome and the rest of the chemistry will be WNL

True

What vitamin is important to supplement in horses with equine metabolic syndrome since they aren't on green grass?

Vitamin E