First, let’s define some terms.
    Septicemia means invasion of the bloodstream by pathogenic organisms. In calves, these are usually bacteria, though they could be viruses or parasites.
    Bacteremia is a subset of septicemia where the infection is specifically caused by a bacterium.     Sepsis is often used interchangeably with septicemia. Septic shock is another similar term. However the Society of Critical Care Medicine defines sepsis as “a life threatening organ dysfunction due to dysregulated host response to infection,” and septic shock as “a subset of sepsis … with particularly profound circulatory, cellular and metabolic abnormalities that substantially increase mortality.”
    Thus sepsis and septic shock are more severe conditions that develop from septicemia.
    Why is this important in calves? Here are some examples from our practice.
    One farm had multiple cases of newborn calves showing very high fevers, rapid breathing, extreme arching of the neck, paddling of the legs and death. Calves were typically less than 2 days old. Another farm had several cases of newborns found down and depressed with fevers in the first 3 days of life. Calves were treated with a broad spectrum antibiotic, an anti-inflammatory and fluids. Some responded within hours, others died. A third farm had 1 to 2 week old calves with swollen joints and lameness. Often careful examination revealed that more than one joint was affected. Most survived, but some remained lame. They also had calves that sluffed the tips of ears, toes or feet. Yet another farm had multiple calves that appeared to be born unable to stand, though careful examination of history could not rule out the possibility that calves were standing in the first day of life. Most died or were euthanized.
    These cases are all examples of septicemia, most likely bacteremia. The severe ones are cases of sepsis or septic shock. Sepsis and septic shock often result in rapid death because of the body’s inability to respond correctly or quickly to infection. They all, however, have common origins. They all are also commonly misdiagnosed or attributed to incorrect causes on farms. For example, sometimes farmers say the animal was born with it or born that way. This seems reasonable since these calves may only be a few days old in some cases. Older calves may be diagnosed with pneumonia because they often breathe fast and have a fever. In reality, all cases start with bacterial infection somewhere in the body, and progress to a blood infection, and then possibly to sepsis and septic shock.
    The first farm was found to have a contaminated dip cup that looked like it had never been cleaned or washed. The cup was thrown away and the problem disappeared. The second farm, upon further investigation, was found to be only sporadically spraying navels and did not practice monitoring of blood total proteins for the purpose of identifying failure of passive transfer of antibodies. The third farm did an excellent job of monitoring total proteins and seldom reported failure of passive transfer but had been using a variety of products to dip navels. When they switched back to strong iodine as a dip the problem subsided. The last farm did not dip navels or measure blood total proteins. Only a couple of the farms had bacteria isolated from tissues submitted to a laboratory. E. coli was isolated in both cases. It is not always possible to isolate an organism in the live or dead animal, but it may not really matter since septicemia in calves is usually caused by common environmental organisms. There are some exceptions, however; Salmonella Dublin is the most notable.
    The source of the infection may be the navel, the mouth, the respiratory tract, or occasionally, a penetrating wound such as dehorning. The navel has a direct connection to internal organs at birth. If the entry is the mouth, however, the ingested organisms have to get through the body’s defenses in the gut and associated tissues. Fortunately, most of the time, bacterial infections in the intestine or lungs will not breach these defenses and calves do not develop septicemia. Circulating IgG antibodies absorbed from maternal colostrum are integral components of the body’s defense, too, and can be critically important in preventing the development of sepsis following septicemia.
    Bacteremia needs to be treated immediately with a broad spectrum antibiotic, copious amounts of (IV if possible) fluids and aggressive supportive care. Supportive care in colder months needs to include a warm environment or calves may develop severe hypothermia. Bacteremia can rapidly progress to sepsis and septic shock. These calves are much harder to save.
    Septicemia is probably much more common in calves than most producers appreciate. Proper prevention includes providing excellent hygiene in calving pens, calf housing, calf feeding and air. It also includes preventing failure of passive transfer. Prevention is much more effective than treatment. Today’s dairy veterinarians have many tools to help evaluate your farm’s prevention programs. Contact yours if you need help.
    Bennett is one of four dairy veterinarians at Northern Valley Dairy Production Medicine Center in Plainview, Minn. He also consults on dairy farms in other states. He and his wife, Pam, have four children. Jim can be reached at bennettnvac@gmail.com with comments or questions.