Ch 4 Fluid Therapy

Question 1

Maintenance fluids for adult cattle

Answer 1

3.5-5%bwt/d for nonlactating = 40-60ml/kg/day

Additional 80-90% milk production in lactating cows

Question 2

Maintenance fluids for calves/preruminant cattle

Answer 2

80-100ml/kg/day

Don’t exceed 80ml/kg/hr during rehydration

Question 3

Parameters assoc with 8% dehydration

Answer 3

1. 6 second skin tent

2. 4mm eyeball sinking

Question 4

The 8% rule

Answer 4

Cattle >8% dehydrated likely req. IVFT vs oral or intra-ruminal

Question 5

Guide for estimating calf dehydration

Answer 5

% dehydration, eyeball recession (mm), skin tent (sec)

0 % - 0mm - 2secs
2% - 1mm - 3 secs
4% - 2mm - 4s
6% - 3mm - 5s
8% - 4mm - 6 s
10% - 6mm - 7secs
12% - 7mm - 8secs
14% - 8mm - 9secs

Question 6

Most common metabolic derrangements in cattle with GI dz

Answer 6

METABOIC ALKALOSIS

Much more common than metabolic acidosis

Question 7

Conditions assoc. w development of acidosis in ruminants

Answer 7

1. Calf diarrhoea
2. Carbohydrate engorgement (V high VFA absorption)
3. Choke/dysphagia (salivary loss - rich in bicarb)
4. Acute small intestinal obstruction (volvulus)

Question 8

Conditions usually alkalotic

Answer 8

Abomasal displacement/volvulus
Caecal displacement/torsion
Intussusception

Question 9

Fluid therapy for metabolic acidosis

Answer 9

Simply restoring extracellular fluid volume is insufficient to rapidly correct acidosis in calves with naturally occurring diarrhoea

Alkalinising agents can be added incl sodium bicarb, or metabolisable bases such as lactate, acetate, gluconate, and citrate

Lactate probably most commonly used (LRS) L-isomer is the only one efficiently metabolised

Question 10

Properties of citrate

Answer 10

Chelates calcium so can only be used in ORAL rehydration, unsuitable for IV

Question 11

Properties of gluconate

Answer 11

Used in combination with acetate, ineffective in calves as alkalinising agent

Question 12

Recommendations for oral fluid therapy in calf scour

Answer 12

Avoid v high bicarb - >70mM - abomasal alkalinisation may encourage growth of enteropathogenic bacteria.

Isotonic electrolyte solutions containing the alkalinising agents acetate or propionate may be more appropriate.

Question 13

Calculating base replacement required (bicarb?)

BD

Answer 13

BD × 0.3 × BW = Base required

BD - mEq/L
0.3 is a conversion factor (extracellular water or the “bicarbonate space,”)

The base required is expressed as total mEq of base.

Use conversion factor of 0.6 is used for calves - higher % body water

Question 14

Base deficit calculation example

Answer 14

When acid-base status not measurable, can correct for a base deficit of 10 mEq/L without sig risk.
Eg for 500-kg cow

10mEq L×0.3×500kg=1500mEq

Question 15

No of mEq of HCO3- in 1g sodium bicarb

Answer 15

12

Therefore in 10mEg base deficit, req 1500mEq base replacement - = 125g bicarb

Since 13 g of sodium bicarb made upto 1 L of water is isotonic solution, it would require just under 10 L of isotonic (1.3%) sodium bicarbonate solution to correct a BD of 10 mEq/L. Therefore about 10 L of isotonic sodium bicarbonate solution, or 125 g of sodium bicarbonate, is needed empirically to treat moderate acidosis in an average-sized cow.

Question 16

Potassium in acidosis

Answer 16

Becomes extracellular (exchanged for H+) so may be hyperkalaemic, altohugh subsequent urinary excretion can rx in total body deficit

Serious hypokalemia may result when potassium moves from extra to the intracellular compartment while acidosis is being corrected. For this reason, potassium should be included in alkalinising fluids or should follow immediately after correction of acidosis.

A moderate concentration of 10 mEq of K+/L is safe for hyperkalemic acidotic cattle, even at the 20 L/h rate, if it is administered simultaneously with bicarbonate

Question 17

Summary for fluid therapy for metabolic acidosis

Answer 17

Most common in diarrheic neonatal calves - not common in adults

Bicarbonate is the most efficient IV alkalinising agent, but lactate and acetate are also effective. In acidotic calves, oral electrolyte solutions containing acetate or propionate may be more appropriate alkalinising agents than those containing bicarbonate.

Question 18

Fluid therapy for normal acid-base or metabolic alkalosis

Answer 18

Much more common in adult cattle

Treated by providing extracellular anions in relative excess to cations (the strong ion theory)

This is accomplished with chloride-rich, potassium-rich solutions

Question 19

Conditions commonly causing metabolic alkalosis

Answer 19

Vagal indigestion, abomasal displacement or volvulus, traumatic reticulitis, abomasal ulcer disease, peritonitis, renal disease, and almost any condition that results in anorexia and gastrointestinal stasis

Question 20

Common electrolyte abnormalities with metabolic alkalosis

Answer 20

Hypochloraemia and hypokalaemia

Question 21

Solutions used for volume replacement in metabolic alkalosis

Answer 21

0.9% NaCl and ringers solution (NOT lactated as alkalinising); normal saline is acidifying

Add potassium chloride to either solution at a rate of 20 to 40 mEq/L.

1 g of potassium chloride contains about 14 mEq of potassium ion.

2 g of potassium chloride/L yields 28 mEq/L

Oral potassium supplementation should be provided as well because safely administering adequate IV potassium replacement is often difficult

Question 22

Glucose supplementation

Answer 22

5% glucose solution can be administered at a slow IV rate for several days.

It is usually preferable to infuse 2.5% to 5% glucose in 0.45% to 0.9% sodium chloride or other electrolyte solution

Useful for ketosis etc

Question 23

Calcium supplementation

Answer 23

Advised for all lactating cattle

500 mL of a commercial calcium borogluconate solution may be added to 20 L of solution for IV administration. Alternatively, 10 g of calcium chloride may be substituted

Question 24

Intra-ruminal fluid recipe

Answer 24

140g NaCl
25g KCl
10g CaCl2 or
500ml 23% Calcium Gluconate 
20L Water

Question 25

Hypertonic saline dose

Answer 25

4-5ml/kg (4ml/kg horse dose)

Need to combine with 20 L of water administered orally

Question 26

Summary of fluids in metabolic alkalosis

Answer 26

IV fluids should contain approximately 300 to 500 mOsm/L.

The solution should contain sodium (135-155 mEq/L), chloride (150-170 mEq/L), and potassium (10-20 mEq/L).

Lesser concentrations of electrolytes may be included if glucose is added to the solution.

In dairy cows, calcium borogluconate (5-8 g/L) or calcium chloride (0.5 g/L) should be added. Cattle with ketosis, fatty liver, or negative energy balance may benefit by adding 10 to 50 g/L glucose.

Hypertonic-saline (2400 mOs/L) solution administered at a dose of 4 to 5 mL/kg body weight intravenously and accom- panied by intraruminal fluid is an alternative to large-volume IV isotonic fluid therapy.

Question 27

Intra-ruminal fluid techniques

Answer 27

Frick speculum and ororumen tube

Nasogastric tube

Pump and oesophageal probe

Question 28

IV catheter sites

Answer 28

Jugular - easiest and best suited to high volumes

Auricular vein - lower volumes, better suited to longer term (upto 96hr) administration