According to Elizabeth Homerosky, DVM, MSc, DABVP of Veterinary Agri-Health Services Ltd, the ‘skin tint’ test is one way to identify dehydration levels in calves.
In a video – which the Beef Cattle Research Council in Canada released – she explained how to perform the in-field clinical test.
“You can pinch the skin right over the neck area, make a tent and then measure the number of seconds it takes for that skin to return to normal.”
“So, based on these two parameters, you can estimate the & dehydration.”
Skin tint test
The following information is from Geof Smith, DVM, MS, PhD, Department of Population Health and Pathobiology, North Caroline State University:
|Percent Dehydration||Demeanor||Eyeball Recession:||Skin Tenting|
|None (<5%)||Normal||None||<1 seconds|
|Mild (6-8%)||Depressed||2-4 mm||2-4 seconds|
|Moderate (8-10%)||Depressed||4-6 mm||4-6 seconds|
|Severe (10-12%)||Comatose||6-8 mm||>6 seconds|
In summary, she outlined that for healthy calves, the skin will return to normal in two seconds. Anything longer is a sign that the calf is dehydrated and should be treated with electrolytes.
“That calf will appear clinically normal until they are about 6% dehydrated. Once that calf becomes dehydrated, the eyeball may start to recess back into the head.”
She advises that providing oral fluids with electrolytes solution can help calves that are mildly dehydrated to make a recovery.
In terms of a moderately dehydrated calf, she advises farmers to maintain oral fluids “quite frequently” throughout the day to keep them hydrated.
Calves in the 10% bracket become “severely dehydrated”, and Homerosky advises farmers to involve their vet at this point.
“We often see dehydration, electrolyte disturbance, and acidosis all happening simultaneously. One of the really clear indicators of a calf that is experiencing acidosis is when they get up, they will stagger around, or they fall down very easily.”
“When you check the suckle reflex on those calves, it is quite weak or not rhythmic at all. Because these calves are experiencing dehydration, there is often not adequate blood flow. Therefore, these calves are very susceptible to hypothermia.”
“Those calves are not profusing properly, which means that they are not getting oxygen distributed throughout the body.”
“Frequently, check rectal temperatures and make sure that you are providing warmth and some other way if they are not able to maintain an adequate body temperature.”
According to this vet, most electrolyte solutions are designed to replace the electrolytes that are leaving the body rapidly in an animal that is experiencing diarrhoea.
She added that while sodium is the main one, chloride and potassium are often included. Others that vets commonly look for are acetate or propionate.
“These are ingredients that will help that calf retain sodium and water and correct those electrolyte imbalances. They could potentially correct the acidosis as well.”
She explained that electrolyte powders have very low energy compared to milk and, therefore, advises alternating between electrolytes and milk throughout the day.
Concluding, she said: “Most of these scour outbreaks can be prevented by working with your vet.”
She explained that diagnosing calf dehydration includes:
- Performing a skin-tent test (as outlined above);
- Looking for sunken eyes;
- Watching for signs of depression;
- Testing its sucking reflex.
According to the vet, many calves experiencing neonatal calf diarrhoea or scour do not actually die from the virus, bacteria or protozoa that causes the scour.
Instead, she explained that they will die from resulting dehydration, electrolyte imbalances and, in some cases, acidosis.
Note: Always consult and seek advice from your vet.