Calf Scour Prevention in Your Herd

Jerry Rusch, DVM

Neonatal Calf Diarrhea affects newborn calves and those less than 30 days old. It is responsible for 80% of sickness and 57%  of deaths in unweaned calves in the United States. This problem has a significant impact on the calves’ health and is a major driver in the profitability of a ranch or dairy.

The most common causes of acute diarrhea in calves are Escherichia coli, Cryptosporidium sp., Bovine rotavirus (BRV) and Bovine coronavirus (BCoV), accounting for 75-95% of infections worldwide. Other causes can include Salmonealla sp and Coccidosis.

E. coli is a bacteria that is commonly encountered in calves from three to five days of age. Although it is a normal resident of the intestines, disease-causing strains produce toxins that damage the intestinal lining resulting in diarrhea, dehydration, shock and death. Mortality can be especially high in younger calves. Diagnosis is made by culturing the organisms from the intestine on necropsy. Treatment can include antibiotics and nonsteroidal anti-inflammatory agents for their anti-toxin properties. Fluid and electrolyte replacement, warmth and probiotics should also be included. Vaccines are available for E. coli prevention that are given to the dam precalving. In addition, there are oral vaccines available to give the calf at birth. If a vaccine is used, it should include the K-99 antigen.

Calf Scour Prevention & Control at a Glance

1. Using MULTIMIN® 90 strategically to ensure adequate trace mineral level in the dam & calf

2. Vaccinating the cow/heifer for scours pre-calving

3. Cow/Heifer segregation

4. Ensuring a dry, clean calving environment

5. Moving pairs to fresh pasture posting calving

6. Ensuring adequate colostral intake

calf scoursCryptosporidium is a protozoal organism similar to coccidia and causes diarrhea in calves from two to five weeks of age. This organism affects all animals including humans so proper sanitation should be practiced while dealing with a scouring calf to prevent human transmission. Crypto is resistant to disinfectants and is not affected by most medications. Diagnosis is by a fecal examination. Supportive therapy of fluid and electrolyte replacement, warmth and probiotics are the treatments of choice.

Bovine rotavirus (BRV), and Bovine coronavirus (BCoV) are both viruses that cause diarrhea but at different ages. Both infect the intestinal cells and cause a variable degree of damage to the intestinal lining. Rotavirus usually affects calves at 7 to 10 days of age while Coronavirus is at 7 to 15 days of age. Both viruses are frequently found in feces of healthy adult cattle, which serves as a source of environmental contamination and herd transmission. Many cases of Rotavirus are fatal, especially in the younger calves. Coronavirus infected calves are usually not as ill as Rotavirus calves and the mortality is not as high. Both are diagnosed by fecal examination under an electron microscope. Treatment includes supportive therapy of fluid and electrolyte replacement, warmth and probiotics.

A combination vaccine against Coronavirus and Rotavirus is effective and commercially available. These are given to pregnant cows prior to calving to increase the antibody levels in their colostrum for the calf to consume. It is important to ensure that the calf nurses and intakes an adequate amount of the colostrum. An initial vaccination and booster followed by yearly vaccination is required. Most of these vaccines also contain E. coli as well. There are also oral vaccines and boluses available that are given to the calf at birth. Vaccination becomes more beneficial if used in conjunction with proper management practices. Many times, more than one pathogen is involved in a scouring calf. Treatment of these coinfections can include antibiotics if a bacterial component is identified.

An infected calf can be a multiplier and a spreader of the infectious agent to other calves and the environment. To help decrease this spread, there are some management practices that should be employed. Calving cows and heifers separately to facilitate monitoring the heifers closely and to decrease the exposure of pathogens from the cows is extremely important. Sorting the dams into groups based on the approximate calving date can also be very helpful. In addition, calving cows and heifers on calving grounds separate from the pre-calving pasture will decrease pathogen exposure to the newborn calf.

It is important to sure that the calving pastures are dry, well drained and devoid of any manure buildup, as pathogens need a moist environment to multiply and survive. If you have a dystocia area, make sure it is dry and clean to help prevent issues. Another way to avoid mud and calf illness is to adjust the calving dates to a time of year when the weather is less stressful and the environment is easier to manage. Lastly, make sure all treatment equipment including balling guns, tube feeders and nipple bottles are thoroughly cleaned and disinfected between each use to prevent disease transmission.

calf scours

There are many factors that affect whether a calf will get scours or not. Some important factors are the calf’s nutritional status, immune system status, trace mineral status and the ability of the intestinal barrier to prevent the colonization of organisms. Calves in a poor plane of nutrition either due to the dam’s milk production ability or the calf’s nursing ability are more susceptible to disease including scours. Closely tied to the nutritional status is the immune status of the calf. Calves receive their disease fighting antibodies from the colostrum they receive in the first 24 hours of life. The absorption of colostrum is optimal up to 6 hours and rapidly declines until no further absorption occurs after 24 hours of age.

Multiple studies have shown the correlation in the increase of risk of disease and death in calves that received inadequate colostrum amount or quality. In fact, this risk carries through all the way to the feedlot. Trace mineral status is integral to the development of the immune system and disease response in calves. Multiple studies have shown improvement of immune status and response in calves supplemented with injectable trace minerals at strategic times. During the last trimester of pregnancy, the dam recruits trace minerals from her liver into the blood stream that is then shared via the umbilical vein and deposited in the calf’s liver to stack the calf’s liver with trace minerals. When the calf is born, these trace minerals are mobilized and utilized for many functions including the development and differentiation of immune cells. Several of these trace minerals are utilized at an exponential rate and replenishment is necessary to maintain optimal growth and immune system function since the milk diet of a calf is a poor source of these trace minerals.

Another consideration in disease expression in the calf is the dam’s nutritional status, immune system status and her trace mineral status. Cows and heifers in poor nutritional status will produce lower quality colostrum and less milk, which will result in more disease incidence in their calves. This also affects her immune system and the quality and amounts of immunoglobulins in the colostrum she produces for her calf. Due to the nature of how trace minerals are transferred to the fetus during the last trimester of pregnancy, a cow or heifer with poor trace mineral levels in her liver will transfer less to her fetus. This results in a calf that is born with low trace minerals and can allow such issues as White Muscle Disease, due to low Selenium, and bone and cartilage deformities, due to low Manganese, to occur.

Using an injectable trace mineral (ITM) like MULTIMIN® 90 containing Copper, Zinc, Manganese and Selenium, offers the benefit of a known and controlled amount of these minerals that is delivered to the cow and calf. It is also well documented that this ITM results in a rapid and immediate absorption and liver storage following administration. In addition, the administration of ITM has shown beneficial effects on the immune response against viral and bacterial respiratory pathogens and improved response to administered vaccines.

A recent study using MULTIMIN® 90 at the time of scour vaccine administration to pregnant heifers suggested an increase immune response and higher, colostral immunoglobulin levels and higher antibody titers to Bovine Coronavirus in calves. This offers an additional management tool in the fight against calf scours.

Neonatal calf diarrhea is a major driver of profitability in beef herds due to treatment costs and death. Utilizing management practices including vaccination and MULTIMIN® 90 injectable trace mineral can help a herd decrease the incidence of calf scours and increase profits.

Republished with permission from MWI Animal Health. Source: Producer Outlook, Fall 2021