Calf scours is one of the most important and costly calf health issues affecting dairy operations in North America. According to the USDA, scours, diarrhea and other digestive problems are responsible for more than half of all pre-weaned heifer calf deaths. The National Animal Health Monitoring Survey attributes six in 10 deaths of calves under the age of 2 months to calf scours. Calves that scour in the first 14 days of life are at a higher risk for mortality due to secondary infection during the first 90 days of life.
Calf scours is caused by any number of micro-organisms, ranging from viruses, such as rotavirus or coronavirus, to bacteria, such as E. coli, salmonella or protozoa. Scours can also be incited by nutritional challenges, including changing dietary inputs, unpasteurized waste milk, transport and vaccinations. Climatic factors such as wet environments, freezing temperatures and wind chill make calves particularly susceptible.
Whatever the cause, scours severely dehydrates newborn calves, whose bodyweight is around 70-percent water. Calves can lose 5 to 10 percent of their bodyweight in water within a single day of scouring. More than 14 percent loss of water can cause death.
Unfortunately, once a calf starts scouring, replacing lost fluids is not enough. An effective oral rehydration program must give the calf sufficient amounts of fluids, offer an effective solution for correcting acid-base balance and provide nutrition.
While dehydration significantly contributes to the overall poor condition of calves, it must be noted calves with diarrhea die from:
Electrolytes provided to scouring calves not only need to drive the rehydration of the calves but must also address the associated conditions.
An important concern for treatment of scours is the acidic nature of the blood caused by dehydration. Calves that suffer moderate to severe acidosis are less apt to eat and drink on a free-choice basis. Providing alkalinizing agents early on to scouring calves is paramount in their survival from a scour-causing infection. The challenge is that those same life-saving alkalinizing agents aren’t palatable. Thus, treatment of scours with an oral electrolyte solution must be done in tandem with our knowledge of calf behavior. To rehydrate calves and minimize on-farm labor requirements, calves must willingly drink an electrolyte solution, and it’s our job to provide a flavor, taste and formula calves will find appealing.
Be sure to detect dehydration early and correctly and ensure consistency in how the product is delivered. The industry has thought about electrolytes largely one way: dry powders. Arguably, the dry powders acted as a hindrance in providing the calf with all the critical nutrients it needs to recover from scours.
Scouring calves need fluid therapy, but what that fluid delivers can be the difference between life and death. Proper rehydration results from the supply of key nutrients at the proper concentration with the right alkalinizing agents to keep your animals drinking, eating and producing.
Characteristics of an effective oral electrolyte include:
- Sufficient sodium to replace fluids and restore blood flow. The optimal concentration is 90 to 130 mM (millimolar, a unit of concentration of a solution) per liter.
- Supplemental electrolytes such as potassium, which should be at 10 to 30 mM per liter, and chloride should be at 40 to 80 mM per liter.
- An excess of strong cations such as sodium, potassium, calcium, magnesium compared to the concentration of strong anions—chloride, bicarbonate, D-lactate.
- Neutral amino acids and/or fatty acids such as glycine, acetate or propionate to encourage absorption of the sodium and fluids in the intestine.
- Alkalinizing agents such as acetate or propionate to correct an acidotic blood pH.
- Non-milk energy sources to provide energy to hypoglycemic calves.
- Particle concentration to provide additional energy for scouring calves not receiving milk. The optimal concentration of 600 mOsm/L (milliosmoles per liter, which measures solute particles contained in a solution).
Work with your veterinarian and nutritionist to develop protocols for treating calf scours, including the use of an effective electrolyte supplement.