Byline Dr. Kevin Hill, Merck Animal Health
Getting calves off to a good start in the first few weeks of life can have a major impact on their long-term health and performance. However, newborns are vulnerable to many diseases, especially calf scours. According to the U.S. Department of Agriculture, scours accounts for 17.2 percent of annual nonpredatory calf loss in U.S. cattle operations annually,1 and it is the leading cause of death in the first 30 days of life.
Not only does the financial loss impact cow-calf producers, but so does the additional workload of caring for calves with scours. That’s why the best recipe for defending against calf scours is a year-round prevention effort including environmental management, colostrum management, proper nutrition, hygiene, and a solid vaccination program.
Common Signs of Scours
Scours most often occurs in the first three weeks of life. Symptoms are soft or watery stools that may be brown, grey, green, or yellow with occasional blood and/or mucus. Because calves are not absorbing fluids or nutrients from their mother’s milk, they can quickly become weak, dehydrated, and lethargic.
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Since a young calf with severe diarrhea can lose 5 to 10 percent of their body weight in water within one day of scouring, dehydration can occur very quickly. To test for dehydration, pull up a “tent” of skin on the neck. The skin should return to its normal flat position in about three seconds if the calf is in a normal state of hydration. A dehydrated calf’s skin will stay tented longer.
It is important to get replacement fluids with electrolytes into the calf as soon as possible. Utilize appropriate fluid therapy, with oral or IV fluids, in addition to other supportive therapy recommended by your veterinarian.
Factors That Predispose Calves to Scours
Calf scours can be caused by several infectious organisms including the following:
• Viruses: such as rotavirus (most common) and coronavirus which infect the lining of the intestinal track and damage the cells that digest and absorb milk
• Parasites: such as cryptosporidium and coccidia
• Bacteria: certain strains of Escherichia coli (E. coli), Salmonella, and Clostridum perfringens which invade the cells of gut wall.
Many factors can play a significant role in allowing these organisms to infect calves. Mud, overcrowding, contaminated lots, cold weather, rainfall and other environmental conditions are all stressful to the newborn calf and can increase its susceptibility to infectious agents. Other contributing factors can include inadequate colostrum intake at the proper time, poor nutrition and /or body condition of the dam which can compromise her colostrum quality, quantity and milk production.
Prevention and Management are Paramount
Because treatment is time consuming, costly, and sometimes ineffective, prevention is key to maintaining good herd health. Good biosecurity, hygiene, proper nutrition for the dam and calf, and an effective vaccination program are all important components of a prevention strategy.
Perhaps the single most important requirement for the newborn calf is to receive colostrum – the first milk mom makes – early in life. It is filled with nutritious protein, fat, minerals, vitamins and, most important, antibodies. Colostral antibodies are very important to help protect them from specific disease-causing agents. The calf’s digestive system allows for efficient absorption of colostral antibodies for a very limited time, so it is very important to ensure that the calf is up and nursing within two to four hours after birth. At 12 hours after birth a calf will only be able to absorb about 50 percent of the available antibodies, and by 24 hours antibody absorption from colostrum is nearly zero.
In addition to the quantity and timing of colostrum, the quality can vary and is dependent on a few factors:
• Nutrition – Provide adequate energy, protein and minerals to the dam throughout her gestation period, especially in the last 90 days.
• Immune status – Vaccinating the dam will stimulate antibody production and these antibodies will be delivered to the calf in colostrum. Proper vaccination timing is important to get the peak level of antibodies in the colostrum. Always follow label directions.
The bottom line: the first meal a calf takes is its most important one.
Even with proper colostrum management it’s still important to minimize a calf’s exposure to pathogens. If calves are born in a maternity pen be sure to sanitize pens, walls, and gates before calving season begins and between calvings. Eliminate muddy areas wherever possible so that udders stay clean and uncontaminated. Use plenty of clean straw or sand as bedding in these areas and change it as frequently as conditions dictate.
For calves born outside, pasture rotation – also known as the Sandhills Calving System (SCS) – can be utilized to minimize exposure to disease. Developed by the University of Nebraska-Lincoln, the SCS involves rotating through a series of calving pastures which can be modified based on the size of the herd and the amount of pasture available. This system was developed to reduce the pathogen load in the newborn’s environment and minimize contact with other cattle that carry a pathogen load.
In short, the system involves a series of rotating pastures.
• All late-pregnancy cows reside in a given pasture at the start of calving.
• After two weeks of calving, pregnant cows are moved to a new, clean pasture, leaving new pairs in the original pasture.
• For each week after that, pregnant cows are repeatedly moved to a new pasture.
• After the youngest calf is four weeks old, the animals can co-mingle.
This system keeps calves of different ages separated so that older calves are not allowed to be a source of infection for younger calves. Development of a pasture rotation plan should take place well in advance of calving season to ensure success.
Prepare for Adverse Weather
During calving season the only predictable thing about the weather is that it’s unpredictable. Producers should be prepared to provide shelter, especially from the wind and wet weather. If calves stay dry and out of the wind they can withstand cold temperatures. Wind breaks, deep bedding and shelter can reduce environmental stress and heat loss, in turn reducing risk of disease.
Implement an Effective Vaccination Program
Vaccination of pregnant cows can help reduce the risk of scours by supporting development of antibodies that will be passed to the calf in colostrum. A veterinarian can assist in developing a pre-calving vaccination program specific to the farm.
Vaccines such as Guardian® which includes two strains of rotaviruses, two coronaviruses, K99 Escherichia coli, and a bacterin-toxoid from Clostridum perfringens type C & D, provides broad spectrum protection as an aid in the control of the leading contributors to scours. Guardian is also the only scours vaccine administered to pregnant cows and heifers that includes both Coronavirus Type 1 and Type 3 and has been shown to produce higher K99 E. coli titer levels than other products on the market. Talk to your veterinarian about a pre-calving vaccination plan.
Calf scours is a complex disease that results from many factors. Reducing the risk of exposure to pathogens, managing environmental conditions, ensuring adequate colostrum intake and implementing an effective vaccination program will go a long way to getting calves off to a good start in life.
5 steps to enhancing calving season success
1) Provide adequate cow nutrition, especially in late pregnancy
2) Vaccinate pregnant cows with Guardian® to enhance antibody production
3) Rotate calving areas to reduce exposure to pathogens
4) Prepare for adverse weather conditions
5) Ensure adequate colostrum intake by calf
Copyright© 2018 Intervet Inc., d/b/a Merck Animal Health, a subsidiary of Merck & Co., Inc.
About Dr. Kevin Hill
Dr. Kevin Hill is a fifth-generation stockman residing in Kaysville, Utah. He graduated from Colorado State University and was in large animal practice for 27 years in Northern Utah. In 2005, he joined the technical services team for Merck Animal Health. He interfaces with R&D and field sales to provide input for development of enteric, ocular, reproductive, and respiratory disease prevention products. He is chairman of the biologics market support research committee and has been active in research related to neonatal immunology focused on respiratory and enteric pathogen protection.
1 USDA. 2011. Cattle and Calves Nonpredator Death Loss in the United States, 2010. USDA–APHIS–VS.
2 Penn State Extension https://extension.psu.edu/electrolytes-for-dairy-calves. Accessed Sept 12, 2018
3 Guardian product label
4 SPAH FSR MS-Guardian-03-11