August 2019 Articles

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Dangers to Cattle Health after the Floodwaters Recede

Dangers to Cattle Health after the Floodwaters Recede Heidi Ward, DVM, PhD, Assistant Professor & Extension Veterinarian University of Arkansas
Now that Arkansas floodwaters are starting to recede, it is time to discuss some potential health issues that cattle may face in the next couple of months. Normally, special attention is paid to the actual flooding event – isolation of cattle, no access to feed or water sources, movement through contaminated water, etc. However, we must not forget the dangers that arise once the floodwater is gone. These threats can be divided into three main categories: bacterial disease, toxicities and physical hazards. Bacterial Disease Producers are always on alert for the potential of infectious diseases creeping into their herds. Most diseases associated with flooding are caused by bacteria – most often from species that are normally found in the environment such as Clostridia (soil) or Leptospira (water). Diseases caused by Clostridial bacteria include scours, tetanus, Red water disease and Blackleg. Clostridial bacteria can either actively invade and reproduce in damaged tissues of the host or cause toxemia when the bacteria is ingested and toxins are absorbed within the digestive system. Clostridial bacteria also have the ability to go dormant by forming spores that are very sturdy in the environment. Clostridial diseases are not transmitted from animal to animal. Flooding enhances the risk of Clostridia exposure due to wet hooves and legs being easily injured by rocks, branches or even long stemmed grasses. Luckily, cattle on a regular vaccine schedule are vaccinated for Clostridial diseases. If producers have cattle that are not fully vaccinated with a Blackleg vaccine, they should vaccinate them as soon as possible. Cattle may also be treated with antibiotics if an outbreak occurs. Leptospira is another bacterium that is commonly found in the environment. The bacterium is spread by urine of carrier animals (maintenance hosts) which include rodents, skunks, raccoons and wild boar. Any free-standing water, particularly water after flooding, should be considered as potentially contaminated by Leptospira. If cattle drink contaminated water, they may become infected. Many cattle do not show signs of infection, especially if they are not pregnant or lactating. In Arkansas, the most common sign of Leptospirosis is abortion. Because the organism can also infect humans and other animals, producers should take special care when handling aborted fetuses and placenta. Vaccination combined with antibiotics can be used in the face of an abortion outbreak. Toxicities The majority of cow-calf farms in Arkansas are nestled in areas surrounded by towns or industrial operations that produce waste products. Flooding is a common way for cattle to become exposed to toxins from a multitude of chemicals that can include petroleum products, industrial cleaning agents or discarded pharmaceuticals. Contaminated flood water may have an oily sheen or have an odd color. Regardless of how the water looks, residues can remain on pasture even after the water is gone. Producers should be aware of their surroundings to know what kind of toxins they may be facing. Toxic plants also become an enhanced risk post flooding. In Arkansas, perilla mint and water hemlock are the plants most likely to cause cattle toxicities. Perilla mint normally grows in shaded areas. If eaten in large enough quantities, cattle can develop a special type of pneumonia that is fatal. Water hemlock is normally found next to streams. Ingestion of the plant, the roots in particular, will cause severe seizures. Flood waters have the potential to allow these plants to germinate in unusual areas that may allow cattle better access. Displaced perilla mint poses an added risk as it becomes more palatable when it is dying from excess sun exposure. Physical Hazards Along with unwanted bacteria and chemicals, floodwaters can also bring hazardous objects such as sharp branches, nails, wires and various forms of trash. Cattle are curious creatures and will likely use their heads to probe any large objects they encounter. For this reason, producers should scan the pasture and remove any large objects before the cattle can interact with them. Unfortunately, there may also be small objects on the ground that are not as readily seen by the human eye. If cattle ingest small sharp objects while grazing, they may develop hardware disease or bovine traumatic reticuloperitonitis. This disease occurs when sharp metal objects settle in the animal’s reticulum where the objects punch through the lining and travel through the body. The disease can be fatal if the objects damage the heart. Hardware disease is usually thought to be a dairy cow problem, but floodwaters make the disease a beef cow problem as well. Pregnant animals are more at risk because the uterus compresses the reticulum. Again, producers should be aware of their surroundings. Nearby lumber yards, oil rigs or car parts dealers will increase the potential for small metal objects getting into floodwaters. If in a high risk area, producers should consider feeding any valuable animals a bar magnet to prevent hardware disease. Veterinary Involvement Producers who have been hit hard by flooding this season should consult with their veterinarian to develop an action plan. Your veterinarian will be the best source of information when dealing with the overall health of your herd. For information on Clostridial diseases, see the Extension publication FSA3073. For information on Leptospirosis, refer to Extension publication FSA3086. To learn more about common Arkansas plants that are toxic to cattle, see the Extension publication FSA3025 and to learn more about hardware disease, see the Extension publication FSA3071.