– Dr. Michelle Arnold – DVM, MPH UK Ruminant Extension Veterinarian
“Neonatal” calf diarrhea is defined as scours occurring within the first 3 weeks of a calf’s life. Viruses (rotavirus, coronavirus), certain bacteria (E. coli K99; Clostridium perfringens Types A and C, Salmonella spp.) and the protozoan parasite Cryptosporidium parvum are the most common causes in beef cattle operations. Controlling rotavirus, coronavirus, Clostridium perfringens Type C, and E. coli K99 scours through vaccination can significantly reduce calf sickness and death loss when given correctly. Scours vaccines are formulated to be given to pregnant cows and heifers during the third trimester of gestation so they will make the specific antibodies against the pathogens that cause diarrhea while colostrum is being formed. It is important to remember that scours vaccines given to pregnant cattle will only work if an adequate amount of good quality colostrum is consumed by her newborn calf within the first 12 hours (preferably the first 6 hours) of life. If unable to vaccinate the pregnant females in the herd, a variety of products can be given to newborn calves to help reduce the risk of sickness and death from scours as well.
The three most popular vaccines available for use in pregnant cattle are ScourBos®9 and 4 (Elanco), ScourGuard®4KC (Zoetis) and Guardian® (Merck). The first time scours vaccines are used, a two-shot series must be given in the third trimester of pregnancy consisting of a first or “primary dose” followed by a booster dose. After the first year, just one annual revaccination in late gestation is required every year throughout the cow’s reproductive life. Vaccination timing is critical to stimulating and optimizing antibodies in colostrum. If cows are vaccinated too early in pregnancy, the antibody response may start to fall off prior to the colostrum being made. Vaccinating too late and the colostrum may already be produced before an antibody response is mounted. Which product is chosen often depends on when cattle will be worked; Scour Bos® is administered earlier during pregnancy, ScourGuard® is used latest in gestation and Guardian® is in-between these two options. Obviously not all calves will be born the first week of calving season but plan to give the scours vaccine based on when the first calves of the season are expected. Consider administering an additional dose to those females who have not calved within 2 months of receiving their scours vaccine.

Table 1: Retrieved from : https://firstdefensecalfhealth.com/dual-force-bolus-gel/
It takes some planning to vaccinate correctly; timing is critically Continue reading Scours Vaccines*: What are the Options? →