Scours: Make a list and check it twice

If our goal is to prevent scours rather than just treat the cases as they occur then how do we go about prevention?

What constitutes a scours “problem”? Is it the number of calves with diarrhea? Is it more than a certain percentage of calves that are sick? Or, is it the degree of dehydration from which calves are suffering?

No one answer to these questions will satisfy everyone. Regardless of your definition of a scours problem for your calves one fact remains true. We would all like less severe diarrhea in fewer calves. Occasionally, scours actually occur in a random fashion. One calf here now, another case several weeks later with no apparent pattern.

However, quite often scours do happen in a regular, predictable fashion. An example is the five to seven day window. Calves eat okay up to that age and have normal manure. Then, for two to three days, they are finicky eaters. If cryptosporidiosis is the only problem their manure is just lighter yellow and somewhat more loose than normal. Most of these calves require little, if any, treatment. They are only set back two or three days in growth.

But, if these five to seven day old calves have an underlying bacterial infection, then no rules apply. The manure may be any color and probably is liquid. Most of these calves require supplementary fluids in addition to their milk or milk replacer. Many of them are sufficiently immune suppressed to fall prey to a respiratory illness as well. The episode sets the calves back a week to ten days in growth.

If our goal is to prevent scours rather than just treat the cases as they occur then how do we go about prevention? First, keep a record of scours treatments. Next, look for some regular pattern. At some common age do many calves have scours? At some change in their life (food, housing, stress event) do many calves have scours?

Note: this advice does not apply to situations where all the calves get diarrhea at once. That is very likely an epidemic caused by a contagious rather than an environmental pathogen. The herd veterinarian should be consulted as soon as possible.

Make a List and Check it Twice

For patterns that occur early in life (less than two weeks) sanitation is the most frequent cause. The check list looks like this for both colostrum and milk handling equipment:

  •  I rinse all my equipment after every use in luke warm water to remove milk proteins and dirt before washing.
  • I wash all my equipment after every use in water that never gets below 120 degrees even at the end of the wash cycle (temperature checked with thermometer).
  • I wash all my equipment after every use in water containing chlorine either from bleach or a chlorinated cleaning powder.
  • I rinse all my equipment after every use in an acid solution to lower the pH to retard bacteria regrowth.
  • I let all my equipment dry on a rack after every washing to retard bacterial regrowth.
  • The water I use to wash equipment and mix milk replacer does not contain significant numbers of environmental bacteria (e.g., coliforms) or parasites (e.g., giardia).
  • I’ve collected “as-fed” samples of colostrum during the past 12 months and had them checked for bacterial contamination in order to evaluate the effectiveness of my sanitation program.

For patterns that occur between three and seven weeks of age infections from the coccidia parasite are the most common cause. The checklist includes:

  • If I’m feeding milk I am adding a coccidiostat no later than one week of age to suppress coccidial growth.
  • If I’m feeding milk replacer I either have a coccidiostat blended into the replacer or am adding it prior to feeding.
  • My calf starter grain contains a coccidiostat in a high enough concentration so that 2 pounds contains enough medicine for the size of my calves one week prior to weaning.


When refrigerating colostrum try covering it. The cover (lid, nipple, foil, and plastic wrap) will inhibit the formation of a cream scum. This often-discarded scum contains a lot of fat. This fat contains vitamins A, D and E. A calf is born with little or no reserves of these fat soluable vitamins. She depends on the fat in colostrum for these vitamins, especially vitamin E that stimulates the action of the immune system.


Sam Leadley

Sam Leadley
62 articles

Consultant on Calf/Heifer Management at Attica Veterinary Associates.

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Attica Veterinary Associates

Attica Veterinary Associates

Attica Veterinary Associates provide veterinary services and products, independent consultation in dairy management, nutrition and performance, and trainings.

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