Food Animal Clinical Chemistry

Question 1

What enzyme is best evaluated to determine the presence of liver disease in the ruminant?

Answer 1

GGT +/- SDH

Question 2

How does age play a factor in liver enzyme counts?

Answer 2

neonates tend to have high GGT, but this is related to colostral intake NOT liver disease

Question 3

What are the 2 most common tubes used for bloodwork in food animals?

Answer 3

1. purple top (EDTA) - plasma for CBC
2. red top - serum for chemistries

Question 4

How does time, hemolysis, and leakage from RBCs affect bloodwork results?

Answer 4

if left out for longer than an hour, blood glucose decreases due to RBC glycolysis

increases AST and LDH

elevates potassium if serum/plasma is not separated within 1 hour of collection

Question 5

What are the 2 most common causes of hyponatremia and hypernatremia?

Answer 5

HYPONATREMIA - excessive water intake or retention, excessive loss from diarrhea

HYPERNATREMIA - lack of water, water loss/dehydration/salt poisoning

Question 6

What is the normal range of sodium in ruminant bloodwork?

Answer 6

130-155 mEq/L

Question 7

What are the 2 most common causes of hypokalemia nad hyperkalemia?

Answer 7

HYPOKALEMIA - diarrhea, third space problems (displaced abomasum = alkalosis)

HYPERKALEMIA - renal crisus, acidosis

Question 8

What is the normal range of potassium in ruminant bloodwork?

Answer 8

3.5-6 mEq/L

Question 9

How do forestomach problems alter ruminant bloodwork?

Answer 9

decreases potassium and chloride

(think HCl and alkalosis!)

Question 10

What are the 2 most common causes of hypochloremia and hyperchloremia?

Answer 10

HYPOCHLOREMIA - 3rd space sequestration (displaced abomasum), diarrhea

HYPERCHLOREMIA - lack of water, water loss/dehydration (salt poisoning)

Question 11

What is the normal range for chloride in ruminant bloodwork?

Answer 11

97-111 mEq/L

Question 12

What is the preferred method of administration of fluids in ruminants? What 2 major electrolytes are given?

Answer 12

oral (IV typically saved for emergencies or abomasal disease)

1. NaCl - 150 g
2. KCl - 50 g

“As long as the kidneys are working, the dumbest kidney is smarter than the smartest clinician”

Question 13

What are the main causes of hypocalcemia and hypercalcemia?

Answer 13

HYPOCALCEMIA - milk fever (parturient paresis) common immediately after calving

HYPERCALCEMIA - previous treatment with calcium, excessive vitamin D supplementation

Question 14

What is the normal range of calcium in ruminants?

Answer 14

9-12.5 mEq/L

Question 15

What are the main causes of hypophosphatemia and hyperphosphatemia?

Answer 15

HYPO - parturient paresis, chronic renal disease

HYPER - acute renal disease

Question 16

What is the normal range of phosphorus in ruminants?

Answer 16

5-6.5 mEq/L

Question 17

What are the main causes of hypomagnesemia and hypermagnesemia?

Answer 17

HYPO - nutritional due to rapidly growing green grass that is low in magnesium

HYPER - excessive treatment with Epsom` salts or IV magnesium

Question 18

What is the normal range of magnesium in ruminans?

Answer 18

1.8-3 mg/dl

Question 19

Rank the following electrolytes from highest to lowest ranges in the ruminant:

Cl, P, Mg, K, Na, Ca

Answer 19

• Na - 130-155
• Cl - 97-11
• Ca - 9-12.5
• P - 5-6.5
• K - 3.5-6
• Mg - 1.8-3

Question 20

What causes an elevation in SDH? How does it compare to other liver enzymes?

Answer 20

hepatocellular damage and enzyme leakage

• short half-life, so an elevation indicated active and on-going liver disease
• labs do not commonly run panels with SDH on it

Question 21

What causes CK elevation? What are the 2 most common examples?

Answer 21

muscle disease —> short half-life, commonly returns to normal within 12 hours

1. downer cows - smaller cows will have lower elevations
2. skeletal white muscle disease - ongoing will cause CK elevation to be chronic

Question 22

What 3 liver enzymes are not as helpful clinically for ruminants? What causes their elevations?

Answer 22

1. AST - liver and muscle disease, longer half-life
2. ALP - liver and bone disease
3. LDH - liver and muscle disease

Question 23

What causes elevations in GGT?

Answer 23

hepatobiliary disorders and cholestasis (long half-life)

• high levels normal in neonates

Question 24

What are the main causes of hypoglycemia in neonates and adult cattle?

Answer 24

NEONATES - bacterial septicemia (E. coli), lack of nutrition

ADULT - lack of intake, ketosis, pregnancy toxemia

Question 25

What are the main causes of hyperglycemia in ruminants?

Answer 25

• stress
• sickness

Question 26

What is the normal range of glucose in ruminants?

Answer 26

40-80 mg/dL

Question 27

What are the main causes of increased and decreased creatinine in ruminants?

Answer 27

INCREASED - pre-renal (dehydration, decreased perfusion), renal (renal damage), or post-renal (urolithiasis) disease —> better indicator of renal failure in ruminants compared to BUN

DECREASED - muscle wasting, starvation

Question 28

What is the normal range of creatinine in ruminants?

Answer 28

0.7-1.3 mg/dL

Question 29

What are normal causes in increased and decreased BUN?

Answer 29

INCREASED - pre-renal, renal, post-renal disease

DECREASED - liver failure, normally low in neonates

Question 30

What are the normal ranges for BUN in bovines, ovines, and caprines?

Answer 30

8-23

14-37

19-31

(larger range = less useful compared to creatinine)

Question 31

What bloodwork parameter is indicative of metabolic disturbances?

Answer 31

bicarbonate concentrations

• low bicarb, low pH = metabolic acidosis (calf diarrhea)
• high bicarb, high pH = metabolic alkalosis (displaced abomasum)

Question 32

What is the normal range of bicarbonate on ruminant bloodwork?

Answer 32

21-32 mEq/L

Question 33

A Jersey cow is down in milk and has a normal physical exam. Interpret the following bloodwork results.

Answer 33

• liver disease due to increased GGT and BILIs (AST can be increased due to muscle OR liver)
• calcium not incredibly low, likely due to being off feed
• increased TP and globulins indicative of inflammation

Question 34

What is the only approved extra-label usage of ceftiofur in cattle?

a. extralabel indications
b. increased dosing amount
c. increased dosing frequency
d. altered route of administration

Answer 34

A