Treatment of Viral Calf Scours

(Adapted from Reference 21)

There is no specific treatment for calf scours caused by corona and rotavirus.  The treatment plan will focus on supportive care while the calf’s immune system clears the virus.

Important considerations during the physical exam of the calf:

a.   
Temperature: calves with neonatal diarrhea are often hypothermic.

b.  
Dehydration: the level of dehydration in these calves should be estimated as a percentage of body weight.  This is easily done by assessing the skin tent response and the eyeball sunkenness.


Dehydration (%BW)

Eyeball sunkenness

(distance between globe and orbit)

Skin Tent

(middle of neck)

Normal

0 mm

< 2 seconds

4%

2 mm

< 4 seconds

8%

4 mm

< 6 seconds

12%

7 mm

> 8 seconds


c.  
Acidosis: the degree of metabolic acidosis in a calf can be assessed by its mental state.  The following chart is handy in estimating the degree of acidosis as a function of the base deficit.  Knowing the base deficit is important when developing treatment plan to correct the acidosis.

Base Deficit (in mmol/L) as a function of Calf age and Attitude

 

Less than 8 days

Older than 8 days

Standing, sucking

0

5

Standing, not sucking

5

10

Sternal Recumbency

10

15

Lateral Recumbency

10

20



d. Hypoglycemia: this is assessed by taking a blood sample from the calf and getting the blood sugar levels.   These calves are often hypoglycemic because of the malabsorptive diarrhea.

scouring calf (23)

Treatment Plan:

1.    Warming  

A scouring calf is often hypothermic.  It is important to move the calf to a warm, dry environment where the calf will be able to stay until the end of treatment. Blankets, heating pads and lamps may be used to warm the calf.  Be careful not to overheat or burn the calf as it may be too weak to change position or get away from the heat source.  It is important to monitor temperature throughout the course of treatment.

2.    Fluid Therapy to correct dehydration, acidosis and hypoglycemia

All scouring calves will be dehydrated and a fluid therapy plan should be in place even if the calf does not appear to be dehydrated.  Fluid therapy will increase perfusion to all of the vital organs and avoid hypovolemic shock. A specific fluid therapy plan should be tailored in each case with careful consideration of the severity of dehydration, metabolic acidosis and hypoglycemia. 

Calves can often be grouped into the following treatment plans. 

a)    Oral fluid and electrolytes: Every calf with diarrhea should be given oral fluids and electrolytes as soon as thy start showing signs.  This may prevent the need for more aggressive treatment later in the course of infection.

Oral electrolytes will contain sodium, chloride, an alkalizing agent (acetate, proprionate) and carriers that will facilitate the uptake of sodium and water in the intestinal tract (ie. glucose and glycine).
 
Oral therapy is appropriate for any calf with neonatal diarrhea that fits th following description:
-        standing
-        suck reflex present
-        alert
-        good muscle tone

Therefore, oral therapy may be appropriate as the first defense if the calf is not presenting severe signs or it may be appropriate after more aggressive treatment has taken place and the calf has begun to respond.

b)   Oral fluid and intravenous hypertonic saline (7.5%): Calves that fit the following description are good candidates for this treatment plan:
-       
weak suck reflex
-       
slight acidosis
-       
warm mouth
-       
standing
This therapy will allow them to correct their electrolyte imbalances more quickly.  This therapy should be followed by oral electrolyte therapy once the strong suck reflex returns (re-evaluate in 6 – 8 hours). 

c)    Intravenous fluid, electrolytes, bicarbonate and dextrose: Calves that are showing more severe symptoms (such as the following) are good candidates for this therapy:
-        severe dehydration
-        no suck reflex
-        recumbency 
The correct amount of fluid to be given can be calculated by considering the level of dehydration, the maintenance requirements of the calves and its ongoing fluid losses due to the diarrhea.

Iso-osmotic saline is often given as a source of electrolytes to correct imbalances. 

Bicarbonate ions may be added to the fluid therapy to correct for the acidosis. The correct amount of bicarbonate ions to add to the treatment plan can be calculated by identifying the base deficit of the calf.
 

A 5% dextrose solution may also be given as part of IV fluid therapy to provide a quick energy source to the calf.  It is also helpful in decreasing the level of hyperkalemia.
 
*Please note that doses and rates are not given. These will be dependant on the size of the calf and the severity of symptoms. Veterinary medicine: a textbook of the diseases of cattle, horses, sheep, pigs, goats (Radostits, 2007) should be consulted for equations required to calculate type of fluid, dose and rates.*

3.    Antibiotic Therapy 
Calf scours do cause damage to the intestinal tract of the calf, making it possible for normal flora of the intestinal tract to escape into the blood.  Antibiotic therapy is therefore an important part of treatment plan, not for the treatment of the scours but rather, for the prevention of bacteremia.


calves (23)

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