Reduce The Risk Of A Calf Scours Outbreak

Reduce exposure to pathogens and increase immunity.

by Glenn Selk, Oklahoma State University Extension

Neonatal calf diarrhea (commonly called “calf scours”) is one of the most costly diseases in the beef cattle business. Fall-calving herds have the help of the hot, late summer/early fall sunshine to reduce the buildup and spread of the pathogens that cause calf diarrhea. However, whether you have spring- or fall-calving cows (or both), there are some key management procedures that will reduce the likelihood of a scours outbreak in your calves, both by decreasing the pathogen exposure and increasing the calf’s immune system.

1. 1) Calve in clean and dry areas.
2. 2) Calve heifers earlier than the cow herd.
3. 3) Avoid congregating and creating muddy, pathogen-infested areas in calving pastures.
4. a) If possible, avoid loose hay feeding in calving pastures.
5. b) If hay is fed, use bale rings or hay feeders and move feeders frequently.
6. c) Move pairs to larger pastures promptly. Larger herds may want to study and employ the Sandhills Calving System.
7. 4) Use biosecurity and biocontainment measures for all herd additions.
8. a) Isolate, quarantine and perform appropriate tests on all herd additions.
9. b) Introduce pregnant herd additions at least 30 days prior to the start of calving season. This will allow time for exposure to new pathogens, antibody development and secretion of antibodies into the colostrum.
10. c) Do not add calves to the herd until the youngest calf in the herd is more than 30 days of age. Buying a calf at a livestock auction or from a dairy for a cow that has lost a calf can introduce diseases that your herd may not have immunity against.
11. 5) Isolate and treat.
12. a) Remove sick calves from the herd immediately. One sick calf can produce overwhelming pathogen exposure by shedding as many as 100 million bacteria or viruses per milliliter of feces — 500 million bacteria and/or viruses per teaspoon of feces.
13. b) Visit with your local large-animal veterinarian to determine best treatment options for the pathogens affecting your calves.
14. c) Treating the sick calves should occur after handling the well calves. Clean and disinfect all equipment. Clothing, boots, gloves, etc., worn while treating sick calves should not be worn when handling well calves.

Boost immunity
Here are a few methods of increasing the immune status of the baby calf so that when the calf comes in contact with the pathogens, he will have a much better chance of fending off disease.

Make certain that calf gets passive immunity.

Baby calves are born without the presence of antibodies that fight disease organisms in the environment. They receive the antibodies via the first milk called colostrum that is provided (in most cases) by the mother. There are numerous factors that affect the success or failure of this passive transfer of immunity.

1. 1) The amount of colostrum produced and available to the calf.
2. a) First-calf heifers must be in good body condition at calving to produce the maximum amount of colostrum they are genetically capable of producing. Calves born to thin heifers have been shown to have lowered levels of disease-fighting antibodies 24 hours after birth compared to calves born to heifers in good body condition.
3. b) The calf must be vigorous enough to find the teat and nurse within a short time after birth.
4. c) Calves that do not have access to good-milking mothers need a commercial colostrum replacer or at least 2 quarts of properly thawed frozen colostrum from another cow.
5. 2) Calves need the colostrum (or replacer) within 6 hours of birth.
6. a) Calves born after a long, difficult delivery will often be sluggish and slow to get up. Plus they may have respiratory acidosis that will impair the ability of the calf to absorb the large proteins (antibodies or immunoglobulins). Use calving-ease bulls to reduce the risk of dystocia, and assist those calves that need help in a timely manner.
7. b) Feed sluggish calves the colostrum replacer or the natural colostrum from another source first. Do not feed them whole milk before the colostrum. Any milk product will speed up the process of intestinal closure (whereby the gut is losing its capability to absorb the large protein antibodies). Make certain colostrum or colostrum replacer is fed first. A second feeding of colostrum should follow within 12 hours of the first.
8. c) When purchasing colostrum substitutes, know the difference between a “replacer” and a “supplement.” A colostrum “replacer” should contain 100 grams (g) of immunoglobulin per dose, and research has shown can replace a feeding of natural colostrum from a cow. The colostrum supplements will contain much less than 100 g of immunoglobulin and will be used to supplement a poor-milking mother’s colostrum. Remember to give the supplement after the calf has consumed the natural colostrum first.
9. d) Timing is everything. Colostrum absorption by the intestine of the calf is declining rapidly after birth. Therefore it is critical that the baby calf receive a full dose of colostrum within the first six hours of life (the sooner the better).

If the management procedures to reduce exposure to pathogens and increase passive immunity in the calf do not solve most of the scour problems on your operation, then visit with your local veterinarian about other options. One additional option to consider would be a precalving vaccine for the cows and pregnant heifers. This is given far enough before the calving season so that the colostrum in your cows will contain more antibodies designed to fight calf diarrhea organisms.

Calf diarrhea continues to be one of the most costly diseases in the beef industry. Losing a calf to scours is always painful and expensive.

Editor’s note: This article is compiled and reprinted with permission from the Jan. 28 and Feb. 4 editions of Cow-Calf Corner, a newsletter published by the Oklahoma Cooperative Extension Service, for which Glenn Selk is an emeritus extension animal scientist. Research was shared from “Neonatal Calf Diarrhea Complex” by veterinarian John Kirkpatrick.