calf scours | calf diarrhea |

Hopefully by this time, calving season is well under way and you have most, if not all, of your calves on the ground. With the unusually wet and cold weather we’ve experienced in the Southeast so far this year, there’s a good chance we’ll see an increase in conditions such as calf scours.

A bad season of calf scours can wreak havoc on your entire calf crop. Calf scours, or calfhood diarrhea, is the leading cause of death in calves under three weeks of age, and a major cause of illness and death in calves from three weeks to weaning. Calf scours can cause significant losses to beef producers in terms of treatment costs, poor growth and production, and animal losses. Subsequently, studies have shown that calves who become sick in the first month of life weigh an average of 35 lbs. less at weaning than their healthy herd mates.

Causes

Calf scours is not actually a disease, but a sign of a disease which can have many causes. There are several infectious causes of calf scours, including viruses, bacteria and parasites. In reality, however, calf scours may involve a combination of pathogens, and results from a number of both infectious and non-infectious factors. In addition to pathogens, factors such as calf immunity and pathogen load, are areas that can be influenced by management and should be examined further. By understanding some of the causes of calf scours, prevention strategies can be made to help prevent future losses.

The most common infectious causes of neonatal calf scours are rotavirus, coronavirus, enterotoxigenic E.coli (ETEC), salmonellosis and cryptosporidiosis. Many of these pathogens act very quickly, causing clinical signs of calf scours within one or two days from exposure. Most calf scours will happen around two weeks of age. The earliest infections (less than five days of age) are usually caused by ETEC, and are often due to failure of passive transfer (FPT). The pathogens usually localize in the calf’s gut, causing the all too familiar white/grey to yellow watery diarrhea. Under most circumstances, however, it is not as important to identify the specific pathogen as it is to treat the animal and immediately prevent new cases of calf scours from occurring.

During wet, inclement weather, calves can get stressed and may not develop enough immunity to calf scours. Chilled calves may not nurse as aggressively as needed. Muddy and damp conditions can increase pathogen survival in the environment, resulting in increased pathogen exposure to the calves. It is important to point out that these scour-causing pathogens are commonly present in the pasture environment, which is why dirty calving areas can predispose calves to scours. Calves ingest these scour-causing pathogens mainly through the fecal-oral route, which includes nursing of a manure-covered udder. Animals will often lay and defecate around a hay ring or feeder, increasing the potential for ingesting pathogens in the feed.

Treatment

Rehydration of a calf with scours is the most critical aspect of treatment. Dehydration, with cold limbs, a poor suckle reflex and recumbency, is commonly seen in scouring calves and frequently life-threatening. Oral fluid therapy with electrolytes can be beneficial in mildly dehydrated or non-dehydrated calves. However, intravenous (IV) treatment is often necessary in severe or non-responsive cases. When giving oral electrolytes, most recommend alternating the fluids with milk (ideally) or milk replacer, waiting four to six house between feedings so that the electrolytes do not interfere with milk absorption. Follow the label directions on the package.

Calves will continue to need the energy and nutrients from milk, and the sooner you get his nutritional schedule back to normal, the better. Antibiotic treatment is not always recommend, and in some cases, such as salmonellosis, may worsen clinical signs in the calf. Be sure to check with your veterinarian for treatment recommendations in severe or outbreak conditions of calf scours.

Prevention

Prevention of calf scours, like any disease, should focus on optimizing your animals’ exposures to pathogens through proper management and biosecurity. Adequate colostrum intake within the first 12 hours of birth is the best prevention against calf scours. If calves do not receive adequate colostrum, or receive poor quality colostrum, they are at a higher risk for developing calf scours. This “passive immunity” from the dam is like providing a custom-made vaccine for the calf, since colostrum is rich in antibodies. Heifer development and proper nutrition of the dam are critical to the development of good quality colostrum. Vaccination of the dam against rotavirus, coronavirus and ETEC may provide additional protection against calf scours. Oral vaccinations are also available for the newborn calf and calves that are at high risk for calf scours. Check with your veterinarian to determine if these products are cost-effective for your operation.

Provide a clean and dry calving area to minimize risk of pathogen exposure. If adequate pasture is available, separating the close-up cows from new pairs every one to two weeks to avoid exposing new calves to the older calves can reduce potential spread of pathogens. The “Sandhills Calving System” basically minimizes the transmission of pathogens within a herd by 1) segregating calves by age so that older calves don’t pass pathogens to younger calves, and 2) regularly moving pregnant cows to clean uncontaminated pastures on a scheduled basis. Hay rings and feeders should be moved to clean and dry areas as necessary.

Other biosecurity measures include separating sick calves from the others, disinfecting all bottles and calf feeders between use, and wearing latex gloves when treating calves. Avoid new additions to the herd during calving season if at all possible. The implementation of good biosecurity measures, good nutrition and a good internal parasite program will also keep older calves protected against calf scours.

There is no silver bullet to prevent calf scours. By understanding some of the causes of calf scours, prevention strategies can be made to help prevent later losses. Work with your veterinarian to ensure that you are providing your herd with adequate immunity against calf scours and practicing good biosecurity to reduce and prevent disease transmission. You’ll find that many of these management practices will help control other potential disease conditions on your farm and can result in improved overall herd health.

This article about calf scours by Carla L. Huston, DVM, PhD., ACVPM, Mississippi State University College of Veterinary Medicine appeared in the April 2011 issue of the Gulf Coast Cattleman. Visit the Gulf Coast Cattleman website at www.gulfcoastcattleman.com to subscribe.