Dehydration in calves

By Leonardo Bringhenti – Technical Services Consultant

Dehydration, loss of electrolytes and decrease in blood pH are the three biggest challenges for calves facing intestinal challenges. Dehydration, in level of percentages is best explained as the percent of water loss relative to total body weight. Rehydrating those calves is therefore critical. Rehydrating means supportive administration with fluid and electrolytes. This is vital, regardless of the cause of the intestinal challenges.

When a calf is 5% dehydrated, the effect can start to become visible. The calf is dull —not as strong and perky — and may not run off as fast when you approach. If you pinch the upper eyelid or the neck or wherever the skin is thin and can be pinched [skin tenting], and see how fast it sinks back into place, this gives a clue. If the calf is less than 5% dehydrated, it falls back into place quickly. This is referred to as skin elasticity, or turgor. At 5% or more, the skin stays tented for a few seconds. The more dehydrated the calf, the longer the skin stays tented.

Also, in the dehydrated calf, the eyeball looks like it is sinking back into the head. That’s because tissues around the eye are also dehydrated. The more sunken the eyes look, the more dehydrated the calf is. If you roll down the lower lid and see a big space there, this indicates dehydration.

Ideally, you want to give fluids orally —while the calf still has a functional gut. When it gets severely dehydrated, fluids just sit in the stomach and cannot be absorbed because the gastrointestinal tract has shut down. If the calf can still stand and walk — even if it is slightly weak and wobbly — it may still benefit from oral electrolytes.

At about 12% dehydration, the calf is at a high risk. There is a small window of time between 5% [when you can tell it is dehydrated], to 10% or 12%, when the calf is severely challenged. Intervention needs to be as soon as possible, while the calf is still strong and can restore quickly. Chart 1 provides insight into how dehydration levels can be measured and what the best recommended way is to support the calf.

Chart 1: Determination of calf’s dehydration %. Demeanour is a description of the calf’s appearance and reaction to feeding and stimulation. Calves start to lose energy, become lethargic, and show signs of a non-optimal well-being at 8% dehydration. Oral administrations refer to providing electrolytes in the morning in addition to their meal. Also, leave a bottle in between feedings and feed another bottle at night in addition to their meal. When it comes down to providing an IV administration –when a calf is 8-10% dehydrated, and has a poor or no suckling reflex, fluids are provided subcutaneous instead or intravenous. The veterinarian is consulted at this stage.