This article was originally featured in Progressive Cattle. 

For the cattle producer, managing a cattle operation requires more than just daily herd oversight. It demands a specialized knowledge of risk management and environmental toxicology. From a swallowed wire to the silent toxicity of a poisonous plant, the threats to herd health are often invisible until a loss occurs. These hazards can be devastating not only to the cow, but in certain instances can cause late-term abortions or permanent birth defects in the calf crop. 

1. Hardware Disease: The Internal Puncture 

Traumatic Reticuloperitonitis (TRP), or Hardware Disease, occurs in cattle because they use their tongues to wrap and pull forage into their mouths rather than using nimble lips to sort, making them prone to swallowing metal debris like wire, nails, and fencing staples. Once swallowed, these heavy objects settle in the reticulum. When the reticulum contracts, it can drive a sharp object through its wall. This can result in a few possible scenarios including local infection around the reticulum from leakage of fluid up to the most severe outcome, which is a puncture of the sac around the heart. Keeping your pastures free of debris is key to helping prevent hardware disease.  

Mixing your own feed or chopping hay makes it easy for metal debris to become hidden in the forage or feed, leaving cows unable to sort through and reject the hardware as they eat. Another source of this hazard is roadside hay harvested from highway ditches. Mowers operating in these areas shred objects such as aluminum cans and discarded wire or metal into small, sharp shards. These invisible fragments are then baled into the hay, where they become inescapable for the animal when fed. 

2. Water Quality: The Silent Killers 

Water is the most critical nutrient for beef cattle, as it is essential for growth, lactation, and replacing moisture lost through excretion or evaporation. However, it can also carry hidden toxins that can quickly turn fatal. 

 Nitrates, sulfates, and blue-green algae can affect water quality. A safe level of nitrate nitrogen (NO₃N) in the water for cattle is less than 100 parts per million (ppm). Tanks that are used to haul nitrogen-based fertilizer should not be used to transport drinking water for cattle as there is a risk of poisoning. It's very difficult to ensure all the nitrogen has been removed from the tank, even if you wash it thoroughly. The sulfate upper limit for calves is less than 500 ppm (167 ppm sulfur as sulfate). For adult cattle, the upper limit is less than 1,000 ppm (333 ppm sulfur as sulfate). Stagnant water, lakes and ponds are ideal environments for the growth of blue-green algae, which can be toxic to cattle. When in abundance, blue-green algae gives the water the appearance that someone has dumped a bucket of light green or turquoise paint in the water. Signs of blue-green algae poisoning are diarrhea, vomiting, lack of coordination, labored breathing, seizures, convulsions and possibly death. 

3. Botanical Hazards: Poisonous and Toxic Plants 

Pastures are rarely pure stands of grass and may contain poisonous plants or plants that can accumulate nitrates when stressed. Likewise, annual forages such as sorghum, sorghum-sudan hybrids, and sudangrass may produce hydrocyanic acid (prussic acid) when plant tissues are damaged, such as by freezing, chopping, or chewing. If used for grazing, select varieties that are known to have low potential for the production of prussic acid and do not begin grazing until plants have reached a height of 18-24 inches and exercise caution after a frost. Summer annual grasses may also accumulate nitrates when stressed. Table 1 lists some common plants and their toxins or potential toxins when stressed. Know your pastures and plants for the area of the country you live in and be diligent with any potential poisonous plants. Also be diligent as to any poisonous plants or high nitrates with any hay you purchase. Nitrates when grazing drought-stressed corn residue can also be a concern.  

Table 1. Some common examples of plants and their potential toxins. 

4. Terrain Hazards: The Risk of "Cast" Cattle 

Topography poses a significant physical hazard to cattle through the risk of becoming "cast." This occurs when an animal lies down or slips on a slope with its back oriented downhill, creating an "over-centered" position where gravity prevents it from rocking forward to stand. This is a critical medical emergency. The massive weight of the rumen compresses the diaphragm and lungs, while the animal’s inability to eructate (belch) leads to rapid, life-threatening bloat. 

Without immediate intervention to roll the animal into a sternal position (upright on the brisket), death occurs from respiratory failure or circulatory collapse. Furthermore, the weight of the rumen can compress the blood supply to the hindquarters; even if rolled sternal, the animal may be slow to recover or suffer permanent damage, leaving it unable to rise. 

Management Note: While steep slopes are primary risks, cattle can over-center on obstacles as small as the depression between corn rows during residue grazing or even frozen fecal pats. Diligence is required in any uneven terrain. 

5. Pasture Lameness: Physical and Infectious Threats 

Lameness is pain in one or more limbs that affects movement and can affect productivity. Generally, the causes fall into two categories: non-infectious (mechanical, genetic, or nutritional) and infectious. The trouble is that these often work together. Mechanical injuries from the environment frequently break the skin or scrape or puncture the hoof, creating an entry point for bacteria to take hold. Here are some causes of lameness in the pasture: 

• Puncture Wounds: Sharp rocks, metal scraps, or hard woody stalks can puncture the hoof sole or interdigital cleft. This introduces anaerobic bacteria into tissue which can lead to lameness and eventually possible abscess or joint infection if not treated. Tissues of the foot are softened when cattle stand in water or wet areas and stomping caused by flies can exacerbate the problem.
• Animal Burrows: Animal burrows, such as those from badgers, prairie dogs, or groundhogs, pose a physical threat to grazing herds. Stepping into these hidden holes can lead to acute lameness, ranging from joint sprains to leg fractures that often prove fatal.  

Managing a cattle operation requires navigating a complex landscape of invisible risks that extend far beyond basic daily care. From the physical hazards of hardware disease and animal burrows to the biological threats of poor water quality and botanical toxins, a producer's environment is full of potential "silent killers." These risks can lead to acute injury, permanent lameness, reproductive failure, or sudden death in the herd. While many common environmental and nutritional dangers were covered, this is not an exhaustive list of all hazards. 

References 

• Drewnoski, M. E., Anderson, B. E., Kononoff, P. J., & Reynolds, M. B. (2019). Nitrates in Livestock Feeding (G1779). Nebraska Extension. https://extensionpubs.unl.edu/publication/g1779/2019/pdf/view/g1779-2019.pdf
• Merck Veterinary Manual (2023). Traumatic Reticuloperitonitis. https://www.merckvetmanual.com/digestive-system/diseases-of-the-ruminant-forestomach/traumatic-reticuloperitonitis
• Rasby, R., & Walz, T. (2025). Water Requirements for Beef Cattle (G2060). Nebraska Extension. https://extensionpubs.unl.edu/publication/g2060/2025/pdf/view/g2060-2025.pdf
• Stubbendieck, J., Carlson, M. P., Dunn, C. D., Anderson, B. E., & Redfearn, D. D. (2018). Nebraska Plants Toxic to Livestock (EC3037). Nebraska Extension. https://extensionpubs.unl.edu/publication/ec3037/nebraska-plants-toxic-to-livestock-ec3037
• Walz, Troy. (2023). What to Know About Feeding Road Ditch Hay to Cows. UNL BeefWatch. https://beef.unl.edu/beefwatch/2023/what-know-about-feeding-road-ditch-hay-cows/