By Dr. Brett Kroeze

Calf scours is a disease that many producers face in the first few months of life with their calves. The common causes of infectious scours in calves are rotavirus, coronavirus, BVD virus, coccidia, CryptosporidiumEscherichia coliSalmonella spp., and Clostridium perfringens.  Unfortunately, many of these pathogens do not have good treatment options; therefore, the best way to try and combat scour diseases is through prevention.

Prevention starts with the cow, so it is important to ensure that the mothers are getting the energy, protein, vitamins, and minerals that they need. Proper protein levels are important for volume, quality and maintaining antibody levels of the colostrum. Proper energy amounts are important to maintain the proper body condition.  Finally, vitamins and minerals are important for maintaining healthy cows and producing quality colostrums and providing the correct amounts of nutrients will help ensure this. If you don’t have a nutritionist that you work with, I would highly suggest finding one that can help you with a good ration and the proper amount of vitamins and minerals.  It is well worth the investment!

Proper vaccination of your herd is also an important part of calf scours prevention.  Cows start to produce colostrum five to six weeks prior to calving. At this time, the transfer of antibodies from the blood to the colostrum in the cow starts, but maximal transfer occurs two weeks before calving.  It is important to vaccinate with a scour vaccine prior to this in order to have the highest amount of antibodies present in the blood when they start to put antibodies into the colostrum.  I like using Scour Bos® 9 and Guardian® for vaccinating cows and heifers. Good time to vaccinate cows would be six to eight weeks before calving. Work with your veterinarian to set up a good vaccination protocol that works with your herd.

Calves are not born with a fully developed immune system and rely on passive immunity from the cow through colostrum to help their immune system for the first one to two months of life.  This is one of the reasons it is so important calves get high quality colostrum as soon as possible after birth.  When the calf is born, the GI tract is highly permeable to antibody absorption, but this permeability decreases rapidly in the first 24 hours.  Studies have shown that at six hours 66% of antibodies are absorbed and at 36 hours only 7% of antibodies are absorbed.  High quality colostrum will have 50g/L IgG and IgGs that are specific against calf diseases.  Colostrum should also be low in bacteria and contaminants (<100,000 cfu/ml total and <10,000 cfu/ml coliforms).  There are several ways of testing colostrum such as a brix refractometer (>22 brix) or a colostrometer (green indicator).  It is important to ensure cows are housed in clean, dry facilities when calving so that when the calf tries to suckle they do not get mouthfuls of manure and other contaminants.  If feeding colostrum to calves, make sure all feeding equipment is disinfected and free of pathogens beforehand.  If good quality colostrum is not available or you are unsure if the calf has nursed, it is advisable to use a colostrum replacer.  Good colostrum replacers will have high volumes of IgG or immunoglobulin proteins and made from dried colostrum. Colostrx® CR is a really good option. There are also several products available that can be given at birth to combat specific pathogens causing calf scours.  First Defense® boluses and Calf-Gaurd® are a few specific products.

The calf’s environment plays a huge role in the disease process as most of the pathogens are spread by the fecal oral route.   Calving areas should be clean, dry and disinfected to reduce the pathogen load in the environment of the calf.  A good way to make sure the bedding is dry enough is to kneel down and see if your knee gets wet.  If your knee is wet after kneeling down for 5-10 seconds the bedding is too wet.  Stocking density can play a role in calf scours as the more concentrated the animals are, the higher the pathogen load will be.  For dairy calves, 30 sq. feet minimum is required.  For beef herds in a dry lot calving situation the space requirements are quite variable but a minimum of 500 square feet per pair is recommended with 800-1000 square feet being desirable.  It is recommended to house heifers and cows separately.  Cows in general, will have better colostrum than heifers and their offspring, therefore, will in general have better immune defenses.  Heifers also require more monitoring as it is their first go-around at calving and they don’t have the experience of the cows. Cows and heifers also require different nutrient requirements and should be fed differently.

In general, prevention is the best way to combat calf scours.   The best methods of prevention are ensuring good quality colostrum, vaccination for good immune defenses, and reducing pathogen loads through clean and dry environments.  As always, work with your vet to develop a plan for your herd to help minimize calf scours.