Calf diarrhea, also known as calf scour, is one of the major causes of neonatal calf mortality, which has been estimated to cost farmers around 60 to 80 Euros per calf,1 with up to three in four calves affected.2 Calf scour can result in a decrease in performance in the short term, and in the longer-term impact future production. It also has significant welfare impacts through the pain of the disease, combined with the risk of mortality, as well as increasing the use of antimicrobials.
Causes of Calf Diarrhea
Neonatal diarrhea is most commonly caused by infectious agents or nutritional disturbances. The main infectious agents are Enterotoxigenic E. coli (F5 adhesin) or ETEC, bovine rotavirus, bovine coronavirus, cryptosporidiosis, Salmonella, coccidiosis and other minor pathogens. It is important to note that the outbreaks often include multiple pathogens. For practitioners, it is worth considering the impact of determining the pathogen(s) involved in the outbreak in terms of changes to treatment and prevention protocols, as well as public health-related issues (e.g. zoonosis potential, identification of a reportable/notifiable disease).
Treatment of Calf Diarrhea
One of the key components of a treatment plan for calf scour is rehydration, as mortalities caused by infectious pathogens are a result of the lack of fluid replacement. The estimation of the volume of fluid required in a calf is based on clinical signs, which estimate the proportion of fluid lost by the calf, for example, a loss of 5% bodyweight for a 40 kg calf is 2 liters. Replacement of fluids can be delivered orally or by intravenous fluid therapy, depending on the severity of the clinical signs. Additionally, the use of non-steroidal anti-inflammatories (NSAIDs) is important for reducing intestinal damage, caused by the response of the immune system to the presence of an antigen. As part of the treatment, a single injection of meloxicam (Metacam®) was reported to improve all relevant clinical symptoms of diarrhea including fever, allowing a faster recovery. It was also shown to increase feed consumption, either milk or solid feed, and decrease the discomfort that is associated with sick behavior.3 Another important aspect is the isolation of sick calves, either as individuals or as a group. Biosecurity measures like the disinfection of tools, equipment and boots will also aid in reducing the transmission on the farm.
Ensuring the correct treatment protocol is in place is important for improving the success of treatment and reducing the degree of short and long-term production effects and overall mortality and morbidity.
Prevention is Key
The main enteric pathogens are found in adult bovine feces, which act as a reservoir of infection. Therefore, one of the key strategies to prevent the spread of calf diarrhea is hygiene through the reduction of exposure of calves to enteric pathogens in either the calving area or the calf rearing area. Calves need to be removed from the source of infection and other calves that are shedding the pathogen because of the current infection.