This summer, it’s more important than ever to provide cows with ample supplies of clean, fresh water.  

Scientists estimate that a cow’s daily water intake will rise by 5 to 6 gallons on summer days when the minimum temperature is 68 F, compared to spring or fall days when the temperature drops to around 35 F for at least  part of the day. 

Robert Ovrebo, veterinarian from Arlington, Minn., offers the following ideas for handling dehydration. The following information is excerpted from the March-April 2010 issue of our sister publication, Bovine Veterinarian.

Be proactive

Not all situations of dehydration in the bovine are easy to recognize, Ovrebo points out. The rumen acts as a fluid reservoir by which body fluid balance can be maintained for a short period of time. This causes “shrink” of the animal’s normal body weight and, if not corrected, will lead into the stress observed as clinical dehydration.

Being aware of situations that cause shrink presents an opportunity to be proactive. 

Providing accessible high-quality water and anticipating increased maintenance needs from environmental heat and transportation are examples of situations that can be addressed to maintain hydration with the use of water or feed-added electrolytes on a pen or herd basis.

Recognize the clinical signs

Severely challenged cattle can dehydrate in excess of 10 percent of their bodyweight. Clinical signs include eyes sunken into orbits, skin remains tented indefinitely, dry mucous membranes, and depression is evident. This degree of dehydration is potentially life-threatening, and procedures of IV fluid therapy and oral rumen large-volume supplementation should be initiated immediately.

Cattle with dehydration of 5 to 10 percent of their bodyweight will exhibit partial sunken eyes into the orbit, skin tenting that is four to eight seconds in duration, tacky mucous membranes, and reduced dry matter intake with a corresponding decrease in productivity. University studies indicate that cattle with 7 to 8 percent dehydration levels have impaired immune response.

Cattle with 2 to 4 percent dehydration or less will have minimal observable clinical signs, but physiological and performance efficiency can be reduced.

Work with your veterinarian

Dehydrated adult cattle usually have a metabolic alkalosis and it is important to use non-alkalinizing fluids.

Fluid preparations, whether oral or IV, need to contain sources of chloride electrolytes when administered to dehydrated cattle.

Oral rehydration of adult cattle is sufficient in most cases where dehydration is less than 8 percent of bodyweight and the animal is not toxic. Oral administration is accomplished by using a full-length orogastic tube (14-foot tube marked at the 10-foot length to insure rumen placement) and pumping in 20 to 50 liters of fluid, depending on rumen capacity and degree of dehydration. Non-chilled water when mixed with electrolytes is the preferred fluid choice and will replace the need for intravenous isotonic fluids for all but the severely dehydrated or toxic animal.

For adult cattle dehydrated 10 percent or more and compromised toxic cows, IV isotonic fluids are necessary. (Consult with your veterinarian on this.)

Bovine Veterinarian is a sister publication of Dairy Herd Management