Podcast
Questions and Answers
What is a primary cause of bloat in cattle?
What is a primary cause of bloat in cattle?
- Lack of minerals in the diet
- Excessive water consumption
- High protein concentration in grass
- Formation of stable foam in the rumen (correct)
Which plants are known to rarely cause bloat in livestock?
Which plants are known to rarely cause bloat in livestock?
- Kudzu and perennial peanut (correct)
- White clover and birdsfoot trefoil
- Alfalfa and ladino clover
- Ryegrass and annual lespedeza
What is a recommended control measure to reduce the likelihood of bloat?
What is a recommended control measure to reduce the likelihood of bloat?
- Immediate grazing of lush legumes
- Feeding dry hay before grazing (correct)
- Allowing access to water before grazing
- Supplementing with high protein feeds
What is the initial symptom of bloat in cattle?
What is the initial symptom of bloat in cattle?
How quickly can death occur in cases of acute bloat?
How quickly can death occur in cases of acute bloat?
What happens to an animal's oxygen supply when bloat occurs?
What happens to an animal's oxygen supply when bloat occurs?
Which grazing conditions are NOT associated with a higher risk of bloat?
Which grazing conditions are NOT associated with a higher risk of bloat?
Which type of livestock other than cattle can be affected by bloat, although less frequently?
Which type of livestock other than cattle can be affected by bloat, although less frequently?
What is a primary cause of acute bovine pulmonary emphysema (ABPE)?
What is a primary cause of acute bovine pulmonary emphysema (ABPE)?
Which symptom is NOT associated with acute bovine pulmonary emphysema (ABPE)?
Which symptom is NOT associated with acute bovine pulmonary emphysema (ABPE)?
Which of the following is an effective prevention method for ABPE?
Which of the following is an effective prevention method for ABPE?
What toxin is responsible for ergot poisoning in cattle?
What toxin is responsible for ergot poisoning in cattle?
What symptom indicates that cattle may be suffering from ergot poisoning?
What symptom indicates that cattle may be suffering from ergot poisoning?
Bermudagrass staggers is caused by:
Bermudagrass staggers is caused by:
What is an immediate step to take if cattle are affected by bermudagrass staggers?
What is an immediate step to take if cattle are affected by bermudagrass staggers?
What environmental condition may promote the growth of toxin-producing fungi in bermudagrass?
What environmental condition may promote the growth of toxin-producing fungi in bermudagrass?
What is the optimal percentage of grass in a pasture to reduce bloat hazard?
What is the optimal percentage of grass in a pasture to reduce bloat hazard?
When is the period with the highest risk of bloat for grazing animals?
When is the period with the highest risk of bloat for grazing animals?
What type of blocks can be used to minimize the risk of bloat during grazing?
What type of blocks can be used to minimize the risk of bloat during grazing?
Which forage plants are known to have a high potential for nitrate accumulation?
Which forage plants are known to have a high potential for nitrate accumulation?
What is the consequence of nitrite formation from nitrates in livestock?
What is the consequence of nitrite formation from nitrates in livestock?
What symptom indicates an animal is suffering from nitrate poisoning?
What symptom indicates an animal is suffering from nitrate poisoning?
How can the risk of nitrate poisoning from hay be managed?
How can the risk of nitrate poisoning from hay be managed?
Why are nitrates stable in hay after harvest?
Why are nitrates stable in hay after harvest?
What management practice may help prevent bloat after grazing begins?
What management practice may help prevent bloat after grazing begins?
What effect does ensiling have on nitrate levels in corn?
What effect does ensiling have on nitrate levels in corn?
When are supplemental grain feedings beneficial in managing nitrates?
When are supplemental grain feedings beneficial in managing nitrates?
Which of the following conditions can contribute to high nitrate levels in plants?
Which of the following conditions can contribute to high nitrate levels in plants?
What is a common treatment for nitrate poisoning in livestock if diagnosed early enough?
What is a common treatment for nitrate poisoning in livestock if diagnosed early enough?
Large round bales of hay can increase the risk of nitrate toxicity due to what reason?
Large round bales of hay can increase the risk of nitrate toxicity due to what reason?
What moisture content range is recommended for harvesting corn for silage in bunker silos?
What moisture content range is recommended for harvesting corn for silage in bunker silos?
Which factor is NOT associated with an increased risk of prussic acid buildup in plants?
Which factor is NOT associated with an increased risk of prussic acid buildup in plants?
What should be done to assess the moisture content of drought-stressed corn?
What should be done to assess the moisture content of drought-stressed corn?
Under what conditions is grass tetany most likely to occur in cattle and sheep?
Under what conditions is grass tetany most likely to occur in cattle and sheep?
Which of the following animals is most prone to experiencing grass tetany?
Which of the following animals is most prone to experiencing grass tetany?
How does prussic acid toxicity primarily affect animals?
How does prussic acid toxicity primarily affect animals?
What is a safe level of magnesium in forage to avoid grass tetany?
What is a safe level of magnesium in forage to avoid grass tetany?
Which action can reduce the likelihood of high nitrate silage when chopping drought-stressed corn?
Which action can reduce the likelihood of high nitrate silage when chopping drought-stressed corn?
What should be avoided for at least a week after a frost regarding grazing?
What should be avoided for at least a week after a frost regarding grazing?
Which condition is NOT likely to cause prussic acid buildup in plants?
Which condition is NOT likely to cause prussic acid buildup in plants?
What is the primary control method for preventing grass tetany in livestock?
What is the primary control method for preventing grass tetany in livestock?
What is one of the symptoms observed in animals experiencing prussic acid poisoning?
What is one of the symptoms observed in animals experiencing prussic acid poisoning?
How long after ensiling high prussic acid forage is it generally considered safe to feed?
How long after ensiling high prussic acid forage is it generally considered safe to feed?
What results from the formation of stable foam in the rumen of livestock experiencing bloat?
What results from the formation of stable foam in the rumen of livestock experiencing bloat?
Which of the following legumes is most likely to cause bloat in cattle?
Which of the following legumes is most likely to cause bloat in cattle?
Which of the following practices can help minimize the risk of bloat when grazing?
Which of the following practices can help minimize the risk of bloat when grazing?
What is the main physiological consequence of bloat if it is not addressed rapidly?
What is the main physiological consequence of bloat if it is not addressed rapidly?
Bloat can occur with which of the following environmental conditions?
Bloat can occur with which of the following environmental conditions?
Which symptom is typically observed first in cattle affected by bloat?
Which symptom is typically observed first in cattle affected by bloat?
In which scenario is bloat most likely to occur in grazing animals?
In which scenario is bloat most likely to occur in grazing animals?
Which type of clover is noted for having low potential to cause bloat?
Which type of clover is noted for having low potential to cause bloat?
What is a symptom indicative of acute bovine pulmonary emphysema (ABPE)?
What is a symptom indicative of acute bovine pulmonary emphysema (ABPE)?
What condition may occur when cattle are removed abruptly from lush pastures?
What condition may occur when cattle are removed abruptly from lush pastures?
Which of the following is a method to prevent ergot poisoning in cattle?
Which of the following is a method to prevent ergot poisoning in cattle?
What is the characteristic symptom of bermudagrass staggers?
What is the characteristic symptom of bermudagrass staggers?
What immediate action should be taken if cattle are affected by an outbreak of ABPE?
What immediate action should be taken if cattle are affected by an outbreak of ABPE?
Which factor does NOT contribute to the development of bermudagrass staggers?
Which factor does NOT contribute to the development of bermudagrass staggers?
How can cattle suffering from ergot poisoning be treated effectively?
How can cattle suffering from ergot poisoning be treated effectively?
Which of the following statements regarding acute bovine pulmonary emphysema (ABPE) is false?
Which of the following statements regarding acute bovine pulmonary emphysema (ABPE) is false?
What is the primary time period when bloat is most likely to occur in grazing animals?
What is the primary time period when bloat is most likely to occur in grazing animals?
Which plant species is likely to accumulate nitrates, posing a risk for livestock?
Which plant species is likely to accumulate nitrates, posing a risk for livestock?
What role does the addition of salt-molasses blocks containing surfactants play in bloat prevention?
What role does the addition of salt-molasses blocks containing surfactants play in bloat prevention?
What effect does drought have on nitrates in corn plants?
What effect does drought have on nitrates in corn plants?
What is a safe nitrate level in hay to prevent toxicity to livestock?
What is a safe nitrate level in hay to prevent toxicity to livestock?
How can grazing on pastures with suspect plant species during drought conditions affect livestock?
How can grazing on pastures with suspect plant species during drought conditions affect livestock?
What happens to nitrates during the ensiling process?
What happens to nitrates during the ensiling process?
What symptom indicates a livestock animal is suffering from nitrate poisoning?
What symptom indicates a livestock animal is suffering from nitrate poisoning?
What treatment can be administered intravenously for nitrate poisoning if diagnosed timely?
What treatment can be administered intravenously for nitrate poisoning if diagnosed timely?
Which factor does NOT contribute to high nitrate levels in plants?
Which factor does NOT contribute to high nitrate levels in plants?
What method can help prevent bloat after grazing has begun?
What method can help prevent bloat after grazing has begun?
What is the consequence of consuming nitrate-rich hay months after harvest?
What is the consequence of consuming nitrate-rich hay months after harvest?
Which condition can increase the risk of bloat in livestock besides pasture composition?
Which condition can increase the risk of bloat in livestock besides pasture composition?
What moisture content range is recommended for chopping normal corn for silage in bags?
What moisture content range is recommended for chopping normal corn for silage in bags?
Which condition could increase the risk of prussic acid accumulation in plants?
Which condition could increase the risk of prussic acid accumulation in plants?
What should livestock producers avoid doing for at least a week after frost?
What should livestock producers avoid doing for at least a week after frost?
What is a sign that an animal may be affected by grass tetany?
What is a sign that an animal may be affected by grass tetany?
Which of the following is NOT a method of controlling prussic acid toxicity?
Which of the following is NOT a method of controlling prussic acid toxicity?
What happens to prussic acid levels in forage after ensiling high levels?
What happens to prussic acid levels in forage after ensiling high levels?
Which farming practice is advised to reduce the risk of grass tetany?
Which farming practice is advised to reduce the risk of grass tetany?
In what condition is prussic acid most likely to reach dangerous levels in plants?
In what condition is prussic acid most likely to reach dangerous levels in plants?
Which of the following nutrients is linked to the risk of grass tetany?
Which of the following nutrients is linked to the risk of grass tetany?
What is a consequence of feeding livestock hay that has been dried adequately?
What is a consequence of feeding livestock hay that has been dried adequately?
What moisture content is recommended for upright silos when chopping corn for silage?
What moisture content is recommended for upright silos when chopping corn for silage?
Which statement about high nitrate levels in forage is incorrect?
Which statement about high nitrate levels in forage is incorrect?
What precaution should be taken regarding livestock access to wild cherry trees?
What precaution should be taken regarding livestock access to wild cherry trees?
How can raising the cutter bar affect the silage of drought-stressed corn?
How can raising the cutter bar affect the silage of drought-stressed corn?
Which of the following describes a significant factor contributing to bloat in grazing cattle?
Which of the following describes a significant factor contributing to bloat in grazing cattle?
What is the primary consequence of untreated bloat in cattle?
What is the primary consequence of untreated bloat in cattle?
Which of these pasture management practices can reduce the risk of bloat in cattle?
Which of these pasture management practices can reduce the risk of bloat in cattle?
What type of legumes are associated with a higher risk of bloat in cattle?
What type of legumes are associated with a higher risk of bloat in cattle?
Which environmental condition may exacerbate the occurrence of bloat in livestock?
Which environmental condition may exacerbate the occurrence of bloat in livestock?
How quickly can acute cases of bloat lead to death in cattle?
How quickly can acute cases of bloat lead to death in cattle?
Which of the following practices should be avoided to decrease the chances of bloat development?
Which of the following practices should be avoided to decrease the chances of bloat development?
Which of the following plants is known to rarely cause bloat in livestock?
Which of the following plants is known to rarely cause bloat in livestock?
What is a key characteristic of acute bovine pulmonary emphysema (ABPE)?
What is a key characteristic of acute bovine pulmonary emphysema (ABPE)?
Which group of cattle is particularly susceptible to acute bovine pulmonary emphysema (ABPE)?
Which group of cattle is particularly susceptible to acute bovine pulmonary emphysema (ABPE)?
What is an effective prevention method for ergot poisoning in cattle?
What is an effective prevention method for ergot poisoning in cattle?
What symptom is commonly associated with bermudagrass staggers?
What symptom is commonly associated with bermudagrass staggers?
What should be the immediate action if cattle are affected by acute bovine pulmonary emphysema (ABPE)?
What should be the immediate action if cattle are affected by acute bovine pulmonary emphysema (ABPE)?
Which of the following describes the condition caused by ergot poisoning?
Which of the following describes the condition caused by ergot poisoning?
What is a long-term risk associated with feeding hay cut from toxic bermudagrass pastures?
What is a long-term risk associated with feeding hay cut from toxic bermudagrass pastures?
What is the main strategy to prevent bermudagrass staggers?
What is the main strategy to prevent bermudagrass staggers?
What is the recommended moisture content for harvesting corn for silage in upright silos?
What is the recommended moisture content for harvesting corn for silage in upright silos?
Which condition increases the risk of prussic acid toxicity in plants?
Which condition increases the risk of prussic acid toxicity in plants?
What should be done to evaluate the moisture content of drought-stressed corn?
What should be done to evaluate the moisture content of drought-stressed corn?
What is a common symptom of prussic acid poisoning in animals?
What is a common symptom of prussic acid poisoning in animals?
Which of the following is a strategy to control grass tetany in livestock?
Which of the following is a strategy to control grass tetany in livestock?
At what time frame is grazing or feeding green chop avoided after a killing frost?
At what time frame is grazing or feeding green chop avoided after a killing frost?
How does low available phosphorus affect magnesium uptake in forage?
How does low available phosphorus affect magnesium uptake in forage?
Which statements regarding the ensiling of high prussic acid forage is true?
Which statements regarding the ensiling of high prussic acid forage is true?
What physical change occurs initially when cattle go into tetany?
What physical change occurs initially when cattle go into tetany?
What nutrient combination in soil is likely to lead to grass tetany?
What nutrient combination in soil is likely to lead to grass tetany?
Which part of the plant tends to contain more prussic acid?
Which part of the plant tends to contain more prussic acid?
What is a critical factor in assessing drought-stressed corn before harvesting for silage?
What is a critical factor in assessing drought-stressed corn before harvesting for silage?
What happens to prussic acid levels in hay that has dried to 18-20% moisture?
What happens to prussic acid levels in hay that has dried to 18-20% moisture?
What is the effect of frost on prussic acid levels in plants?
What is the effect of frost on prussic acid levels in plants?
What is the main reason nitrate poisoning is prevalent in livestock?
What is the main reason nitrate poisoning is prevalent in livestock?
Which factor may increase the nitrate levels in pastures or hay?
Which factor may increase the nitrate levels in pastures or hay?
What is the immediate visual symptom of nitrate poisoning in livestock?
What is the immediate visual symptom of nitrate poisoning in livestock?
When is the risk of bloat in livestock typically the highest?
When is the risk of bloat in livestock typically the highest?
Which of the following practices can help prevent bloat when grazing legume pastures?
Which of the following practices can help prevent bloat when grazing legume pastures?
What is the primary physiological effect of high nitrate levels in livestock?
What is the primary physiological effect of high nitrate levels in livestock?
Which plant species is known to accumulate high levels of nitrates?
Which plant species is known to accumulate high levels of nitrates?
What is a recommended strategy for managing hay with high nitrate levels?
What is a recommended strategy for managing hay with high nitrate levels?
How does the ensiling process affect nitrate levels in crops like corn?
How does the ensiling process affect nitrate levels in crops like corn?
What type of blocks can help prevent bloat during grazing on legume pastures?
What type of blocks can help prevent bloat during grazing on legume pastures?
What is an important precaution when managing drought-stressed corn for forage?
What is an important precaution when managing drought-stressed corn for forage?
Which of the following is a symptom of nitrate poisoning in livestock?
Which of the following is a symptom of nitrate poisoning in livestock?
What should be monitored closely in livestock grazing pastures with high nitrogen fertilization?
What should be monitored closely in livestock grazing pastures with high nitrogen fertilization?
What is a common misconception regarding nitrates in hay after harvest?
What is a common misconception regarding nitrates in hay after harvest?
Flashcards
Fescue Toxicity
Fescue Toxicity
A common livestock ailment in the South caused by toxic substances or mineral imbalances in forages.
Bloat in Cattle
Bloat in Cattle
A serious livestock problem caused by a stable foam in the rumen preventing gas release.
Bloat Cause
Bloat Cause
Stable foam in rumen inhibits eructation (belching) of gases from microbial fermentation.
Bloat Symptoms
Bloat Symptoms
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Bloat Susceptibility
Bloat Susceptibility
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Bloat-causing Plants
Bloat-causing Plants
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Bloat Prevention
Bloat Prevention
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Bloat Monitoring
Bloat Monitoring
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ABPE Cause
ABPE Cause
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ABPE Symptoms
ABPE Symptoms
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ABPE Prevention
ABPE Prevention
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Ergot Poisoning Cause
Ergot Poisoning Cause
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Ergot Poisoning Symptoms
Ergot Poisoning Symptoms
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Ergot Poisoning Prevention
Ergot Poisoning Prevention
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Bermudagrass Staggers Cause
Bermudagrass Staggers Cause
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Bermudagrass Staggers Symptoms
Bermudagrass Staggers Symptoms
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Bloat hazard in pasture
Bloat hazard in pasture
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Bloat risk periods
Bloat risk periods
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Continuous grazing and bloat
Continuous grazing and bloat
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Surfactant blocks for bloat
Surfactant blocks for bloat
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Nitrate poisoning cause
Nitrate poisoning cause
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Nitrate accumulation factors
Nitrate accumulation factors
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Nitrate in hay stability
Nitrate in hay stability
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Nitrate reduction from ensiling
Nitrate reduction from ensiling
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Forage nitrate toxicity levels
Forage nitrate toxicity levels
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Nitrate poisoning mechanism
Nitrate poisoning mechanism
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Nitrate poisoning symptoms
Nitrate poisoning symptoms
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Preventing nitrate poisoning
Preventing nitrate poisoning
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Nitrate poisoning safety limit for hay
Nitrate poisoning safety limit for hay
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Drought-stressed corn and nitrate
Drought-stressed corn and nitrate
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Silage Moisture Content
Silage Moisture Content
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Drought-Stressed Corn Silage
Drought-Stressed Corn Silage
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Why Raise the Cutter Bar?
Why Raise the Cutter Bar?
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Prussic Acid Cause
Prussic Acid Cause
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Prussic Acid Symptoms
Prussic Acid Symptoms
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Prussic Acid Control
Prussic Acid Control
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Grass Tetany Cause
Grass Tetany Cause
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Grass Tetany Risk Factors
Grass Tetany Risk Factors
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Grass Tetany Control
Grass Tetany Control
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Grass Tetany Symptoms
Grass Tetany Symptoms
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Prussic Acid vs. Nitrate
Prussic Acid vs. Nitrate
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Prussic Acid in Different Forages
Prussic Acid in Different Forages
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Prussic Acid Breakdown
Prussic Acid Breakdown
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Lower Leaves & Prussic Acid
Lower Leaves & Prussic Acid
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Grazing After Frost
Grazing After Frost
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Bloat: What Causes It?
Bloat: What Causes It?
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Bloat: Which Plants?
Bloat: Which Plants?
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Bloat: How to Prevent It?
Bloat: How to Prevent It?
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Bloat: What to Watch For?
Bloat: What to Watch For?
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Bloat: Reducing Risk
Bloat: Reducing Risk
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Chronic Bloaters
Chronic Bloaters
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Bloat: Seasonal Risk
Bloat: Seasonal Risk
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Bloat: Continuous Grazing
Bloat: Continuous Grazing
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Bloat Prevention: Grass
Bloat Prevention: Grass
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Bloat Prevention: Salt & Water
Bloat Prevention: Salt & Water
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Bloat Risk: Spring Growth
Bloat Risk: Spring Growth
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Bloat: Frequent Pasture Changes
Bloat: Frequent Pasture Changes
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Bloat Prevention: Surfactants
Bloat Prevention: Surfactants
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Nitrate Accumulation: Drought
Nitrate Accumulation: Drought
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Nitrate Accumulation: Fertilizer
Nitrate Accumulation: Fertilizer
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Nitrate Poisoning: Hay
Nitrate Poisoning: Hay
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Nitrate Toxicity Level
Nitrate Toxicity Level
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Nitrate Poisoning: Hay Analysis
Nitrate Poisoning: Hay Analysis
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Nitrate Poisoning: Round Bales
Nitrate Poisoning: Round Bales
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Drought-Stressed Corn: Nitrate
Drought-Stressed Corn: Nitrate
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Raise the Cutter Bar?
Raise the Cutter Bar?
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Bloat: What's the Problem?
Bloat: What's the Problem?
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Nitrate Poisoning: Prevention
Nitrate Poisoning: Prevention
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Bloat Hazard
Bloat Hazard
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Bloat Risk: Spring
Bloat Risk: Spring
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Nitrate Accumulation: Hot & Dry
Nitrate Accumulation: Hot & Dry
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Nitrate Reduction: Ensiling
Nitrate Reduction: Ensiling
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Study Notes
Livestock Disorders from Forage
- Toxic Substances and Mineral Imbalances: Consumption of toxic substances or mineral imbalances in forages and weeds can result in reduced productivity, sickness, or death in livestock. Common Southern issues include fescue toxicity.
Bloat
- Cause: Bloat in cattle, and other ruminants to a lesser degree, is caused by stable foam formation in the rumen. This prevents eructation (belching), trapping gases produced by microbial fermentation of forage. Pressure builds, reducing oxygen supply and potentially leading to suffocation. Affected animals swell rapidly.
- Plants Linked to Bloat: Persian, ball, ladino, or white clover, and alfalfa are high-risk plants. Other legumes, like birdsfoot trefoil, sericea lespedeza, and tropical legumes, are less likely to cause bloat. This difference is thought to be due to leaf tannins in the latter group, which act as protein precipitants to break up the foam.
- Bloat Prevention: Limit access to lush legume pastures for hungry animals. Initially feed dry hay before grazing. Frequent checks are vital; remove animals showing bloat symptoms. Bloat hazard is reduced with a 50% or more grass component in a pasture.
- Factors Influencing Bloat: Bloat risk increases during rapid pasture growth (spring), potentially decreasing during summer. The period between mid-March and mid-May is a critical time. Continuously grazing an area is less likely to cause bloat during ongoing grazing than alternating grazing cycles.
- Treatment: Salt and water access is helpful. Surfactant blocks (detergent-type compounds), and ionophores, can reduce bloat risk, most important in early spring.
Nitrate Poisoning
- Cause: High nitrate levels in pastures or hay (pasture/hay high in nitrate-nitrogen) are the primary cause. Nitrates accumulate in plants in low moisture/humidity conditions (especially after periods of drought or cool, wet conditions and high/continuous nitrogen fertilizer use). High nitrate hay can be dangerous for months after harvest. Ensilage reduces nitrate levels somewhat.
- Susceptible Plants and Weeds: Sudangrass, sorghum-sudan hybrids, pearl millet, corn, wheat, oats are examples of plants susceptible to nitrate buildup. Wild plants such as pigweed, smartweed, ragweed, lambsquarter, goldenrod, nightshades, bindweed, Canada thistle, and stinging nettle may also accumulate toxic levels. Some herbicides (e.g., 2,4-D) can increase nitrate levels in plants.
- Toxic Levels: Plants with more than 1.5 percent nitrate (15,000 ppm) are highly toxic. Nitrates in the digestive tract reduce to nitrites, which hinder iron in blood hemoglobin, preventing oxygen transport. Symptoms include labored breathing, muscle tremors, and stagger. (bluish membranes).
- Prevention/Treatment: Monitor animals grazing heavily fertilized fields during periods of drought or wet, low-humidity conditions. Prompt treatment with methylene blue (intravenously) can prevent death. However, diagnosis is usually too late. Supplemental grain feeding can reduce risk. Proper nitrate analysis of hay is crucial.
- Hay Nitrate Levels: Hay with up to 2,500 ppm nitrate is typically safe. Levels from 2,500 to 5,000 ppm require caution; above 5,000 ppm is considered dangerous. Toxicity doesn't diminish with time. Large bales or stacks increase nitrate exposure risk. Mixing high-nitrate hay with other feed sources (15% or less) is a possible mitigation strategy.
Nitrates in Drought-Stressed Corn
- Forage vs. Grain: Drought-stressed corn is sometimes used as forage rather than harvested for grain to salvage planting investments.
- Ensiling: Ensiling (chopping and storing chopped corn as silage) is the best method; nitrates drop by at least 20%. Base of corn stalks contains the highest nitrate concentration.
- Moisture Content: Ideal moisture content for silage (horizontal, bags, upright silos, and upright oxygen-limiting structures) should be between 50-70% (varies slightly depending on silo type).
- Moisture Determination: Determining moisture content can be more challenging to evaluate without ears or with poor ear development on drought-stressed corn stalks. Using a microwave oven or moisture tester is advised. Adjustments to the cutter bar may be needed to decrease the likelihood of high-nitrate silage.
Prussic Acid Poisoning
- Cause: Glycosides in certain plants (johnsongrass, sorghum, sudangrass, sorghum-sudan hybrids, wild cherry; pearl millet does not contain prussic acid) can form prussic acid (HCN). High levels usually result after frost, drought, or rapid early growth. Young growth after these stresses poses a larger risk. Top leaves tend to have a higher concentration of prussic acid than lower leaves. Low phosphorus and high nitrogen soils increase the risk. Herbicides can temporarily increase levels.
- Mechanism: Prussic acid affects the oxygen-transferring capacity of red blood cells, leading to suffocation. Symptoms may include excessive salivation, rapid breathing, muscle spasms, and death (within 10-15 minutes).
- Prevention/Storage: Avoid grazing areas (and wilted hay) immediately after severe drought or frost. Hay that is dried (18-20% moisture or less) usually doesn’t contain toxic levels. Prussic acid degrades after ensiling (safe to feed after 3 weeks). Standing-frost-damaged plants are usually safe after one week.
- Control and management: If there is a prussic acid concern, then livestock should not be given access to freshly frosted plants, branches from wild cherry trees and avoid access to plants immediately after drought occurrences.
Grass Tetany (Hypomagnesemia)
- Cause: Low blood magnesium levels (hypomagnesemia) in cattle and sheep, especially during early lactation, causes this condition. This deficiency results from grazing plants on magnesium-deficient soils, especially during wet conditions which limit the plant's ability to take up the nutrient. This problem is most likely on soils low in phosphorus, but high in potassium and nitrogen (e.g., fertilized with broiler litter).
- Risk factors: Waterlogged soils prevent plants from absorbing sufficient magnesium.
- Symptoms: Initially, animals may exhibit nervousness, muscle twitching, staggering, and later collapse, muscle spasms, and convulsions, leading to death. Forage with 0.2 percent magnesium is generally safe.
- Prevention/Control: Pasture improvement (liming with dolomitic limestone and/or magnesium fertilization) may not completely prevent tetany in waterlogged conditions, so supplemental feeding of magnesium-fortified mineral mixes during high-risk periods is advised.
Other Disorders
- Acute Bovine Pulmonary Emphysema (ABPE): Respiratory distress in cattle related to sudden diet changes (dry to lush feed, grass to legume). Recent calving cows are especially vulnerable. The best prevention is avoiding sudden dietary changes. Symptoms include acute respiratory distress, labored breathing, frothy mouth, grunting, slight elevation in body temperature.
- Ergot Poisoning: Parasitic fungus in seed heads (small grains, ryegrass, bahiagrass, dallisgrass) disrupt circulation. Early symptoms are lameness (reduced blood flow), tail sloughing, and possible foot problems. Clipping pastures and providing ergot-free feed can reduce the risk.
- Bermudagrass Staggers (Bermudagrass Tremors): Nervous disorder (alkaloids from fungal infection of bermudagrass). Rare outbreaks, most possible during autumn/winter following damp, cloudy weather. Symptoms resemble ergot poisoning; recovery often occurs rapidly when animals are moved off pasture. Prevention is best in maintaining pastures in their early vegetative stage.
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Description
This quiz covers the various disorders in livestock caused by forages, focusing on toxic substances, mineral imbalances, and bloat. Learn about the causes of bloat, high-risk plants, and prevention strategies. Test your understanding of how forage quality affects livestock health.
