Newborn and young calves are often vulnerable to systemic infection if they fail to obtain adequate passive transfer of temporary immunity from the dam’s antibodies in the colostrum. Systemic infection results when bacteria or their toxins overwhelm the body’s defenses and spread throughout the body via the bloodstream.
According to Claire Windeyer, an assistant professor of production health services at the University of Calgary’s faculty of veterinary medicine, bacteria circulating in the blood is called bacteremia. “Their toxins in the blood creates a serious condition called endotoxemia. When one or both of these situations results in systemic clinical symptoms, the medical term is septicemia,” she says. Unless this condition is quickly treated and resolved, the infection localizes in various organs and/or joints, resulting in joint ill (septic arthritis), meningitis, or shock and death due to organ failure.
Nathan Erickson, an assistant professor in large animal clinical sciences at the Western College of Veterinary Medicine in Saskatoon, says there are several ways the infection can enter the bloodstream, including scours, or an umbilical infection. “If these bacteria cross into the bloodstream, they can distribute through the body and settle in certain places. These calves need aggressive treatment and management with anti-inflammatories and antibiotics. This should be done in conjunction with help from your veterinarian,” he adds.
“If the infection gets into multiple joints, it can be really difficult to treat. We might be able to stop the infection, but the damage to the joints may be permanent. Sometimes these calves are so compromised that they should be euthanized. It’s best to prevent the infection, if possible,” says Erickson.
Elizabeth R. Homerosky, DVM, MSc., an associate veterinarian with Veterinary Agri-Health Services Ltd. in Airdrie, Alta., explains that septicemia is characterized by the presence of pathogenic bacteria in the blood. “It is commonly accompanied by signs of shock due to release of toxins from the bacteria. Numerous types of infections by numerous species of bacteria can result in septicemia; however, salmonella and E. coli are the most common pathogenic bacteria cultured from the blood of an ill newborn,” she says.
“Newborn calves that fail to absorb an adequate amount of gamma immunoglobulins (IgG) from consumption of colostrum are the most susceptible to septicemia. However, septicemia can result from a number of different types of infections such as navel ill, joint ill, diarrhea, pneumonia, or any other infection that allows pathogenic bacteria access to the bloodstream,” she says.
Calves that are several weeks old when a severe infection goes systemic must be closely monitored and quickly treated for any illness to avoid the possibility of septicemia, which can be fatal. Some types of G.I. tract infections, for instance, can readily produce an endotoxemia that may kill the calf within a few hours. Severe pneumonia can also turn fatal if the lung infection goes systemic.
Signs of sickness
“Common clinical signs associated with septicemia include fever greater than 104 F, rapid heart rate, laboured breathing, along with abnormal blood clotting which can appear as hemorrhage on mucosal surfaces throughout the body,” says Homerosky.
“Newborn calves with septicemia may be down and unable to get up with a generalized weakness. They may have diarrhea, dehydration, weak suckle reflex, dark red mucous membranes and prominent vessels in the sclera (whites) of the eyes. Severely affected newborn calves may exhibit neurologic signs (bizarre behaviour, aggression, head-pressing) or be in lateral recumbency (flat on their sides, unable to get up). Calves in cardiac failure may be hypothermic (low temperature) with cold extremities,” she says.
Windeyer says some of these calves may just seem dull and depressed. “Some will have fever while others will be cold. They may have high or low heart rate, increased or decreased respiratory rate, and poor appetite. Gums may be red, and blood vessels become apparent across the whites of the eyes. Onset is quick, and as they worsen, pulse becomes weak and extremities become cold. The calves with meningitis will often extend their head and neck,” she says.
Calves with scours can be at risk for septicemia, so they should be treated. Windeyer says that when the gut is compromised by infection, regardless of the type of diarrhea, E. coli bacteria commonly present in the gut can translocate from the compromised gut into the bloodstream.
“It is estimated that 30 per cent of calves with scours have circulating bacteria in the blood. Not all of these calves will develop septicemia; however, calves showing signs of systemic illness (fever, depression, etc.) or have blood or mucus in the manure are more likely to be septicemic. Antibiotic treatments for calves with scours are not so much for the scours as they are for reducing the risk of septicemia,” says Windeyer.
Early recognition of clinical signs associated with septicemia is critical to treatment success. “Broad-spectrum antibiotics and supportive care are recommended for treatment of septicemia. Any issues with dehydration, energy or electrolyte depletion, or other secondary issues should be promptly addressed to help promote treatment success and prevent organ failure,” says Homerosky.
“Treatment of calves with severe neurologic signs is generally unrewarding as the infection is likely present in the brain and has progressed beyond a cure. Calves dying from septicemia typically die as a result of multiple organ failure.
“Unfortunately, there are several neurologic diseases, especially in older calves, that resemble septicemia and need to be ruled out. These include polio (caused by either thiamine deficiency or sulphur toxicity) or nervous disease seen in association with coccidiosis. Often these cannot be distinguished in a timely manner or without examination by a veterinarian,” she says.
“Older calves with neurologic signs should receive a number of treatments to cover all potential causes, including a broad-spectrum antibiotic, thiamine and an anti-inflammatory such as meloxicam or dexamethasone,” says Homerosky. Your veterinarian can prescribe an appropriate broad-spectrum antibiotic, selecting one that might be most helpful in this particular case.
“Effective drug choices for septicemia include ampicillin, ceftifur or flurfenicol,” says Windeyer. “Intravenous administration is preferable so consider calling your vet. Anti-inflammatory drugs may also be necessary to help moderate the excessive inflammatory response that can result. Supportive care can make all the difference — keeping the calf warm and dry, providing deep bedding, fluids and nutrition (which is often more effective if administered IV). Consider calling your veterinarian to do a culture and sensitivity test if there is treatment failure during an outbreak affecting multiple animals to aid in selection of the appropriate antimicrobial,” she says.
Good management of calving cows and cows with young calves is crucial. Make sure their environment is as clean as possible. “Source of the bacteria for vulnerable calves is often from a contaminated environment, particularly through the umbilicus,” says Windeyer. Therefore, “dilution is the solution to pollution” by calving on clean, dry pasture, providing clean bedding, having clean equipment (such as esophageal feeders), keeping cows clean, dipping navels if need be, etc.
“Calving in a large pasture with natural shelter and windbreaks where newborns do not have exposure to older calves is ideal,” adds Homerosky. Older calves with scours can quickly contaminate the area, and spread infections to younger, more vulnerable calves.
“Ensuring timely and adequate colostrum consumption promoting adequate transfer of passive immunity is critical to helping prevent bacterial infections and subsequent septicemia,” Homerosky says. Ideally, you want calves up and suckling within a couple hours of birth, and definitely by the time they are four hours old.
“Any calves exhibiting a weak suckle reflex shortly after birth, or any calves that had to be delivered with a hard pull are less likely to consume enough colostrum on their own by the recommended four-hour cutoff.” These calves should be assisted in colostrum consumption before that four-hour period has elapsed.
Windeyer says any failure in the transfer of passive immunity via colostrum creates a major risk factor for septicemia, particularly in calves less than two weeks of age. “In beef calves, recent research says calves with more than 24 g/l of immunoglobulin G in their blood are less likely to get sick or die than those with inadequate passive immunity. Colostrum quality in beef cows is generally very good (with high concentrations of IgG) so failure is typically either due to poor vigour of the calf, inadequate volumes of colostrum generated by the cow, or environmental challenges such as cold, mud, etc. Dairy colostrum has, on average, 25 per cent the concentration of IgG compared to beef colostrum and is a poor substitute. Colostrum replacement products with at least 100-200 g or home-grown, frozen colostrum are an important resource to have on hand for these calves, to avoid the risk of septicemia,” she adds.