Equine clinical pathology, random, passports (notifiable diseases, anaemia, protein, microchips)

Question 1

What equine notifiable diseases are there?

Answer 1

Equine Infectious anaemia (EIA)
Equine viral arteritis
Rabies
Vesicular stomatitis
Dourine
Epizootic lymphangitis
Equine viral encephalomyelitis
Glanders
West Nile Virus
African Horse Sickness
Contagious equine metritis

Question 2

Examples of equine endemic contagious infectious diseases?

Answer 2

Equine herpesviruses 1 and 4
Equine coital exanthema (EHV 3)
Strep equi equi
Rhodococcus equi
Salmonella and Clostridial diarrhoea
Equine influenze
Etc

Question 3

Zoonotic infections from horses?

Answer 3

Salmonella enterica
CLostridium difficile
Crytosporidium parvum
Rhodococcus equi
MRSA
(Rabies)

Question 4

Normal horse rectal temperature?

Answer 4

36.5 - 38.5C

Question 5

Define positive and negative predictive values?

Answer 5

PPV = number of positive results that are actually positive
NPV = number of negative results that are actually negative

Question 6

What is the adiponectin test?

Answer 6

= hormone from fat

Concentration can be used for diagnosis of laminitis risk in ponies

Question 7

What happens with a strangulation obstruction of bowel in horses? How will this be detected by clinical pathology?

Answer 7

1. Water and electrolytes move into the bowel
   - > High PCV (“haemoconcentrated”)
2. No blood supply to bowel -> anaerobic metabolism, ischaemic necrosis -> increased permeability of blood vessels -> leakage of blood and protein into peritoneal fluid
   - > High lactate in blood/peritoneal fluid (from anaerobic resp)
   - > High RBCs and protein in peritoneal fluid
3. SIRS -> margination off neutrophils, activation of coagulation, low BP -> poor renal perfusion, reduced GFR
   - > Increased creatinine and urea

Question 8

How much blood do horses have?

Answer 8

8-9% BW

500kg horse has about 40-45L

Question 9

How to get serum and plasma from a blood sample?

Answer 9

Serum: plain tube, allow to clot, centrifuge and take fluid = plasma with the coagulation proteins removed
Plasma: mix with anticoagulant, centrifuge and take fluid

Question 10

Normal horse PCV?

Answer 10

Hot blooded: 32-48

Cold blooded: 24-44

Question 11

Role of spleen with PCV?

Answer 11

Huge reserve of RBCs in spleen
At rest, approx 1/3 RBCs are in the spleen
Exercise/stress -> adrenaline -> spleen contracts and releases RBCs into circulation
Can increase PCV from 30-40% to 50-70% at max exercise

Question 12

Normal blood smear findings in a horse?

Answer 12

Rouleax formation - horses have weaker surface negative charge on RBCs so tend to clump more
Lack of peripheral signs of regeneration (reticulocytes not a reliable sign)

Question 13

Types and causes of erythrocytosis?

Answer 13

Relative: dehydration or splenic contraction
Absolute primary: polycythemia vera
Absolute secondary: chronic hypoxia

Question 14

Causes of anaemia in horses?

Answer 14

Acute haemorrhage: 
- trauma
Chronic haemorrhage:
- parasites
- gastric ulceration
- guttural pouch mycosis
Intravascular haemolysis:
- immune mediated disease
- intracellular RBC parasites
- plant and chemical poisoning (e.g. red maple leaves, onions, phenothiazine)
- bacterial infections (e.g clostridium)
Extravascular haemolysis:
- fragmentation of RBCs (DIC, vasculitis)
- immune mediated disease (EIA virus, penicillin)
Primary non-regenerative:
- bone marrow disorders
Secondary non-regenerative:
- chronic disease
- lack of erythropoietin, chronic renal failure
- iron deficiency

Question 15

How to tell if red urine is haemoglobinuria or haematuria?

Answer 15

Centrifuge and if Hb stays red???

Question 16

What is the test for IMHA?

Answer 16

Coomb’s test

Question 17

What is neonatal isoerythrolysis?

Answer 17

Mare has been sensitised to a RBC antigen some time in the past: previous foaling or blood transfusion
Stallion has that RBC antigen
Foal born with that RBC antigen
Mare’s Abs absorbed by foal from colostrum -> haemolysis

Question 18

What affects the results of TP?

Answer 18

Icterus
Lipaemia
Haemolysis

Question 19

What is the most common cause of panhyperproteinaemia in horses?

Answer 19

= high TP due to high albumin and globulin

Dehydration

Question 20

What is the most common cause of hyperglobulinaemia?

Answer 20

Chronic inflammation

Also plasma cell myeloma

Question 21

Causes of panhypoproteinaemia and hypoalbuminaemia?

Answer 21

Panhypoproteinaemia:
- aggressive IVFT
- severe protein loss (e.g. haemorrhage, diarrhoea)
Hypoalbuminaemia:
- most commonly lost across glomerulus/intestinal mucosa
- decreased production by liver

Question 22

Define colloid oncotic pressure of blood?

Answer 22

Ability of blood to retain water

Albumin is major determinant of this

Question 23

Initial investigation of ventral oedema?

Answer 23

Clinical exam (CHF? Other systemic disease?)
Blood sample - particularly consider low albumin

Question 24

How to test for myopathy?

Answer 24

AST and CK

Question 25

How much of liver mass has to be lost before function affected -> liver failure?

Answer 25

80%

Question 26

How is clinical pathology used for the liver?

Answer 26

Damage to liver -> increased GGT, GLDH, AST, ALP, LDH Loss of >80% liver function -> liver failure -> increased bile acids and clinical signs (also low albumin, increased bilirubin and ammonia) Poor association with aetiology and prognosis - biopsy is better

Question 27

Rules for when a horse must have a passport?

Answer 27

Passport must be issued within 6 months of birth or by 31st December of the year of birth (whichever is latest) If foal is sold before 6mo, the new owner must get it a passport within 30 days A foal under 6 months needs a passport if it is exported without it mum or sent for slaughter It is an offence to keep a horse without a passport - applies to keepers with primary responsibility for care of the horse

Question 28

Rules for microchipping of horses?

Answer 28

All horses born on or after 1st July 2009 must be microchipped Any horse born before this that has not received a passport, must be microchipped when passport

Question 29

Who is allowed to complete the silhouette in a horse passport and to implant a microchip?

Answer 29

Silhouette - vet or person deemed competent by the PIO | Microchips - vets only

Question 30

When must a horse be accompanied by its passport?

Answer 30

At all times except: - emergency situations - when stabled or at pasture - when being moved on foot - participating in a competition/event which requires the horse to leave the venue (e.g. endurance) Passport must be made available within 3 hours if requested by an enforcement agency

Question 31

What must be done when giving medications if a horse has not been signed out the food chain?

Answer 31

Must keep a medicines book and record all medicines given: - batch numbers - date of administration - withdrawal periods Includes most wormers, creams and shampoos (No need if signed out)

Question 32

What can food producing horses be treated with?

Answer 32

A veterinary medicine containing a substance in the ‘legally permitted essential substance list for horses’ (withdrawal period 6 months) A veterinary medicine that contains a substance listed in ‘table 1 of the commission regulation 37/2010’ (drugs used off the cascade that are licenced in other food producing animals.

Question 33

What must be done if a prohibited substance in food producing animals is given to a horse that has not been signed out the food chain?

Answer 33

Vet, owner or keeper must sign them out (vet must sign if owner refuses) If needed on welfare grounds in emergency, can ask owner to sign a disclaimer which will detail all treatment that you have administered (responsibility then falls on keeper)

Question 34

What must be done if a horse is issued with a passport when >1yo?

Answer 34

Automatically excluded for human consumption

Question 35

Method of microchip implanting? What to do after?

Answer 35

Clip and scrub small area on left hand side of neck over mid section of nuchal ligament Place local anaesthetic Second scrub Put on gloves Check microchip reads and matches number on paperwork Insert chip into nuchal ligament Check microchip reads after insertion Put microchip number on passport and indicate position of implant with capital M with circle around it on silhouette and sign and stamp Fill out paperwork

Question 36

When must an owner hand over a horse's passport to a buyer? What must the buyer do?

Answer 36

At time of sale Buyer must notify the transaction to the passport issuing organisation for registration of the new ownership within 30 days

Question 37

What must an owner do with a horse's passport if it dies?

Answer 37

Return it to the passport issuing organisation within 30 days of the death

Question 38

Rules for identification of features on a silhouette in a horse's passport?

Answer 38

Narrative in black ink and capital letters Whorls = X Feathered whorl = X with line Linear whorl = line White areas = outlined in red and lightly hatched with red lines Flesh marks = solid red Acquired marks = black arrow Prophets thumb mark = black triangle Microchips = black M in a circle with an arrow Bordering (regions of mixed white and dark hairs at edge of a patch of white) = red double ring with hatch centre

Question 39

What is a wall eye?

Answer 39

Unpigmented iris