EARLY SIGNS OF DISEASE IN CALVES
1. Fever (over 39.5or 103F).
2. Slow or reduced milk intake.
3. Watery and/or bloody diarrhea.
4. Cough, nasal discharge, or heavy breathing.
5. Umbilical or joint swelling, head tilt.
6. Weakness, inability, or reluctance to rise.
Average mortality in beef calves between birth and weaning runs at about four to five per cent. For some producers, losses like this could mean that they can’t supply suitable replacements to maintain herd numbers. Causes of death are varied, but the major contributors are diarrhea, pneumonia, and septicemia. Knowing when to suspect each of these diseases, as well as how they are caused, treated, and prevented, can mean greater calf survival.
Calves under one month of age are particularly susceptible to diarrhea, or scours. It is the most common cause of mortality in young calves, yet it is also the easiest to avoid, or at least limit, with good management.
Though there are many different pathogens that trigger scours, veterinarians rarely try to figure out the exact organism involved. This is because calves are often infected with more than one pathogen, and no matter what the infectious agent, the disease is treated the same.
The only time identifying the pathogen is warranted is when you want to implement control measures. For example, knowing the virus or bacterium causing a scours outbreak can tell you if vaccines can help. It can also suggest what disinfectant, if any, will effectively clean the premises.
If the diarrhea is not resolving or the calf is showing signs of stress (not suckling, becoming weak), there is a risk it can progress to dehydration, metabolic acidosis, circulatory shock, and death.
Treatment begins with fluids to help restore water balance. Commercial oral rehydration products contain glucose (or a similar energy source), sodium chloride (salt), and other electrolytes. The glucose and sodium help the calf absorb the fluids. Sick calves require a minimum of two litres, given up to three times a day. Severely dehydrated calves need subcutaneous or intravenous fluids.
Though antibiotics rarely address the cause of the scours due to their inability to kill viruses and parasites, they can prevent secondary bacterial infections in the damaged gut. Also, bacteria that migrate from the gut through the bloodstream to other areas of the body can cause septicemia (more on this later). Antibiotics can help prevent these complications.
To limit the spread of bacteria, scouring calves should be moved away from the non-scouring ones to decrease transmission between them. Also, spreading out calves and their dams on pasture can reduce the scours incidence by lowering the environmental pathogen load.
When is it time to call in the veterinarian? If treatment is not working, more than five per cent of calves are scouring, or death loss is greater than two per cent, it’s time for help.
The most important step in preventing diarrhea is good colostrum management. If a calf fails to get its needed antibodies through colostrum (failure of passive transfer), it is susceptible to many infectious health problems.
The problem with colostrum-deficient calves is that they pose a risk to other calves — they shed pathogens into the environment at a much greater rate than calves with adequate immunity. But, these calves look like any other calf. They can only be identified with blood tests.
The most important factor determining antibody transfer is the quantity of colostrum the calf receives. The requirement for the average calf is about five per cent of body weight immediately following birth and the same amount again 12 hours later. If a calf weighs 40 kilograms (about 90 pounds), it needs four litres of colostrum in total. If there is any delay in feeding, the calf should receive the full amount at one time.
Calves can only absorb antibodies across the intestinal wall for the first 24 hours of life, so getting enough early on is paramount. But, colostrum does more than that. It also provides the energy the calf needs to remain vigorous and continue suckling.
If failure of passive transfer is suspected,
you can determine if the calf is at risk by measuring the calf’s total serum protein level. If it is done before a calf reaches 12 hours old, arrangements can be made to feed stored colostrum and (hopefully) rectify the problem.
If you are using frozen colostrum, it must be less than a year old and not been through more than one freeze-thaw cycle. Commercial supplements are also available to boost antibody levels. Ask your veterinarian for advice on these products.
Pneumonia is an inflammatory condition of the lungs caused by an infectious agent. This is usually one of several bacteria — Mannheimia hemolytica, Pasteurella multocida, or Mycoplasma bovis. Like scours, multiple agents are often involved and the etiologic diagnosis is rarely pinned down.
Calves that develop pneumonia usually have some of the same risk factors as calves with diarrhea. These include failure of passive transfer, prolonged exposure to adult cattle, and if they are indoor calves, poor ventilation.
Calves with pneumonia usually have a fever, nasal discharge, dry cough, heavy breathing, and decreased appetite. Treatment consists of antibiotics, and sometimes, anti-inflammatory therapy. It should begin as soon as possible to prevent the case turning chronic. Calves with chronic pneumonia seldom recover completely and the condition threatens future productivity.
The last disease, septicemia, is another condition that is highly linked to colostrum deficiency. It is a major cause of mortality of calves less than 14 days old. The major bacterial isolates from these cases are the bacteria E. coli and salmonella.
Signs consistent with septicemia include progressive depression, lethargy, and inappetance. Temperature, heart rate, and respiratory rate are usually all elevated, but there are exceptions. Some have one site of infection (e. g. the umbilicus); but others have multiple sites, including the joints, eyes, and brain.
Septicemia is usually diagnosed based on history and a physical examination. If a calf has not received colostrum (confirmed by history or a blood test), it makes septicemia that much more possible.
Septicemia is difficult to treat, expensive, and carries a poor prognosis. Broad-spectrum antibiotics are used as well as anti-inflammatory drugs. In some, joint lavages (flushes) are needed as well as surgical resection of an abscess.
The underlying theme in preventing all these diseases is colostrum.