Taylor Strickland, DVM
MFAM Candidate, ACVIM Resident
Emmanuel Rollin, DVM, MFAM, Clinical Associate Professor, Dairy Production Medicine – 706-202-7821/emmanuel@uga.edu
Department of Population Health, College of Veterinary Medicine
University of Georgia, Athens GA
Diarrhea, or calf scours, is the most common cause of sickness and death in dairy calves. Calves that develop and recover from diarrhea have a higher risk of developing respiratory disease and also have reduced average daily gain. For dairy calves specifically, calfhood diarrhea causes longer term economic and production consequences such as poorer reproduction and lower levels of milk production in the first lactation. Calves that develop neonatal or calfhood diarrhea are often treated with antimicrobials, which increases total antimicrobial use on the farm and the risk of developing antimicrobial resistance within the calf crop. Thus, there has been increasing interest in alternative therapies that can be utilized to combat diarrhea and potentially other illnesses in calves.
An alternative therapy that has recently garnered increased interest and investigation is feeding colostrum or colostrum replacement products to at-risk calves beyond the first day of life. Even if calves have excellent transfer of passive immunity as neonates, there are advantages to continued colostrum feeding or supplementation. This practice describes using bovine colostrum as a nutraceutical, a nutritional supplement that improves health outcomes, to reduce the incidence of diarrhea in pre-weaned calves under high disease pressure. Colostrum feeding has been described as a means of protecting calves from developing illness and also as an adjunct alternative treatment for diagnosed disease.
Calves should be fed at least 3 liters of high quality, clean colostrum within the first two hours after birth to ensure the best chance at adequate passive transfer of immunity. IgG, IgA, and IgM are immunoglobulin proteins present in colostrum, and each play a key role in the transfer of passive immunity in the calf’s first hours. While antibodies are only absorbed into the bloodstream during the first day of life, these globulins can also support local gastrointestinal health and productivity after gut closure, by binding to and inactivating pathogens. Colostrum contains many other bioactive components and has a composition that differs from the typical cow’s milk fed to calves daily. Colostrum contains twice as many solids, is richer in dietary fat, and has higher levels of vitamins A, E, and B12 when compared to whole milk. The bioactive components found in colostrum include those with antimicrobial properties such as lactoferrin, lactoperoxidase, and lysozymes. These bioactives inhibit microbial growth, reduce binding capacity of pathogens, and facilitate immune cell’s abilities to destroy intruding bacteria. Colostrum also contains peptides like casein which have the ability to improve tissue repair and mucosal integrity in the gastrointestinal tract. Some studies have also shown this may play a role in reducing overall inflammation in the gut.
A study at the University of Guelph investigated colostrum as an adjunct treatment modality for neonatal scours. This study provided colostrum to sale barn calves for eight feedings over two days after the calves were identified with diarrhea at the rearing facility. Calves that received colostrum were twofold more likely to have shorter durations of diarrhea. It should be noted that this study was investigated in the calf crop of a farm with a high diarrhea rate. More research is needed to further evaluate the effects of feeding colostrum to calves that are at a lower or more moderate risk of disease.
Researchers at the University of Kentucky even investigated colostral supplementation as a protective intervention strategy for illness other than scours. In that study, researchers fed colostrum replacer for three days to calves that were displaying behavioral signs consistent with developing respiratory disease. This strategy lowered the risk of respiratory disease for 14 days when compared to the control group that was not supplemented with colostrum. Additionally, calves that have been diagnosed with diarrhea in the past have a higher risk of developing respiratory disease making this similar area of research increasingly relevant when investigating the benefits of continued colostral feeding to scouring calves.
Utilizing colostrum as a nutraceutical for older calves also answers a common question from producers which is: how can I utilize excess lower quality colostrum? Lower quality colostrum with a BRIX score less than 22% is not fit for the first feeding, but the composition is still adequate for use as an alternative therapy in older calves experiencing diarrhea or as a protective strategy for those calves at high disease risk. Clean, lower quality maternal colostrum can be frozen in bottles or bags for efficient freezing and defrosting. Some farms have even tried freezing colostrum in ice cube trays, and add one or several cubes to each feeding. Alternatively, colostrum replacement powder can be used to better ensure that a clean, consistent dose of colostrum is offered. When adding powder to whole milk or milk replacer, it is important not to increase the total solids of the final product above 15%, since this can cause osmolar diarrhea or other digestive upsets.
In conclusion, utilizing colostrum as an adjunct therapy for treatment of calf scours or as part of a preventive plan is a promising new tool to boost producer’s ability to provide the best care to calves. It is a potential way to reduce the use of antimicrobials in dairy calf populations, improve production parameters throughout life, and reduce wasting clean colostrum that cannot be used for a first feeding to achieve transfer of passive immunity. This is an area in need of more research to determine the ideal dose and benefits to calves of low to moderate disease risk. Feeding colostrum as a nutraceutical is just one way to ensure calves have the guts to become the future of our herds.
