Rachel Endecott, Montana State University
As summer begins its journey into fall, planning ahead for fall chores like pre-weaning vaccinations for calves might start to appear on to-do lists in cattle country. This month, I'll focus on the differences and similarities among killed, modified live and chemically altered vaccines. Just what is a vaccine, anyway? A definition I like to use in class is this one: A suspension of attenuated or killed microorganisms or the antigenic proteins derived from them. That might sound a little overwhelming, so let's look at each piece separately.
Summer pneumonia in nursing beef calves is not uncommon, but it occurs somewhat randomly and with low frequency. A wide variety of risk factors for summer pneumonia exist. These include relative success of colostral antibody transfer, commingling of groups, weather changes, nutrition changes or deficiencies, pathogen exposure, stress and even operation-specific risk factors like lack of labor.
Blue-green algae, or cyanobacteria, are photosynthetic bacteria that live and grow in aquatic environments. Many species exist — while some are harmless, others produce neurotoxins that affect the nervous system, and others produce hepatotoxins that affect liver function. These toxins are known as cyanotoxins. Large blooms of cyanobacteria can occur when conditions are favorable, leading to elevated concentrations in water sources. When livestock or other animals ingest high concentrations of blue-green algae, death can occur within minutes or hours.
As we move into early summer, cattle producers may be noticing increased numbers of flies on their cattle. Horn flies are very common on beef cattle in our region and annual losses in production and control costs exceed $780 million in the U.S. alone. When horn flies are abundant, cattle experience pain and annoyance from fly bites, which interfere with normal activities such as grazing and resting. Cattle infested with horn flies may exhibit decreased milk production, reduced weight gain and poor feed efficiency.
Pinkeye is a common infectious disease affecting the eyes of cattle. Although pinkeye is not fatal, it has a marked economic impact on the cattle industry. It is known to occur at all seasons of the year and in all breeds of cattle. A bacteria, Moraxella bovis, is the primary infectious agent that initiates pinkeye. Factors causing irritation can allow for the invasion of the bacteria and thus, pinkeye formation. These may include excessive sunlight, face, house and stable flies, plant material and dust.
Proper pre-calving nutrition and good calving management practices play an important role in establishing passive immunity of the calf. Ensuring immediate and adequate intake of colostrum is a critical first step to lifetime calf health. Colostrum is the first milk given by a cow following delivery of her calf. It is high in antibodies that protect the calf from invading microorganisms. These antibodies are large proteins called immunoglobulins, and in addition to these, colostrum also contains the milk protein casein, the milk sugar lactose, fat, and vitamins A and E.