Cressleaf Groundsel in Hay

Source: Jason Hartschuh, CCA, Ted Wiseman, OSU Extension

Cressleaf Groundsel is in full flower currently in forage and unplanted fields across the state. While this is not a new weed prevalence has been increasing, causing concern for many livestock producers.

 

Toxicity

Cressleaf Groundsel is toxic to both cattle and horses. Cattle are 30-40 times more susceptible to poisoning than sheep or goats. Calves and younger cattle are more susceptible than older cattle, but it can be fatal at high enough doses to all age groups. Pyrrolizidine alkaloids are the principle toxin in these plants. It is known to cause liver disease in cattle, producing symptoms such as listlessness, decreased appetite, depression, anorexia, diarrhea, and photosensitization in extreme cases. It also appears that this species has been responsible for abortions in cattle, making control of butterweed a necessity. Cattle that consumed 4 to 8% of their body weight in the green plant over a few days developed acute liver necrosis and died within 1 to 2 days. Cattle that ingested 0.15% of their body weight (fresh weight) of a species in the same genus as butterweed for a minimum of 20 days resulted in 100% mortality. This comparative ratio equates to a 20-day cumulative dose of 2% of an animal’s body weight of dry plants (Knight and Walter 2001). Most beef cattle will consume 2-2.5% of their body weight in dry matter per day. Since these toxins are cumulative when hay is over 5% Cressleaf Groundsel dry matter weight, enough can be consumed within 20 days to cause mortality.

Cressleaf Groundsel

While toxicity decreases in some plants as they dry, that is not the case with Cressleaf Groundsel. These toxins are not decreased if the plants are dried and baled. Ensilaging will decrease the concentration of toxin but not eliminate them. Producers with high concentrations of Cressleaf Groundsel maybe forced to bale first cutting and throw it away so that livestock are not poisoned. Areas of sparse concentration may be baled and fed cautiously, ideally alongside hay that is free from poisonous weeds. Cattle may sort the weeds out. A new bale should be fed before the only thing left in the feeder is weeds. In grazing situations, cattle will usually not eat poisonous plants as long as they have access to other quality forages. Be cautious anytime drought conditions decrease forage stands.

Biology and Identification

Cressleaf groundsel reproduces only from seeds and emerges as a rosette in the fall, then bolts, flowers, and goes to seed in the spring.  Bolting stems are hairless, hollow, grooved, and can reach heights of three feet with inflorescences that have six to twelve yellow ray flowers.  The flowers are like other species in the Aster family, with ray (outside) and disk (center) petals.  The outer ray will normally consist of 5 to 15 petals that are bright yellow, and the inner disk will be a more golden yellow in color.  Plants will eventually produce seeds that resemble those of dandelions.  The seeds are small with a reddish to brown tint and have a feathery pappus that makes them easily carried by the wind.

Control

Cressleaf groundsel normally does not regrow after the first cutting of hay; however, our goal should be to prevent it from becoming established in the field. Take note of fields with Cressleaf Groundsel in them or nearby for increased scouting and control measures next year.  Effective chemical control is when the plants are still in the rosette growth stage in late fall or early spring.  Herbicides such as 2,4-D provide good control when applied at the correct growth stage.  Larger plants may require additional herbicides such as dicamba.  Products that can be used to control this weed and others can be found in the 2020 Weed Control Guide for Ohio, Indiana, and Illinois.  One caution using these broadleaf herbicides is that they also damage legumes such as alfalfa and clovers in pastures and hayfields.  For additional information on identifying weeds go to https://cpb-us-w2.wpmucdn.com/u.osu.edu/dist/7/3461/files/2014/04/Cressleaf_groundsel_article_-_p-zna9t9.pdf

Grass Tetany Could be Looming for Cattle and Sheep

Are your pastures ready for spring and your livestock ready for pasture?

As fast as this year seems to be going, pastures will be greening up and it will be time to start grazing again. Although we haven’t had much of a winter so far, and I hope I am not jinxing us by mentioning it here.

Spring arrives soon
Soon it will be time to start preparing our livestock for lush green pastures. Last year was a tough year for getting stored forages harvested, especially first cutting hay.

Supplement energy
Some hay analysis I have seen this past year would suggest that many need to supplement energy to maintain body conditions during this last trimester prior to the spring calving and lambing season. Continue reading

Is Fescue Toxicosis a Problem in Hay?

Gary Bates, Extension Forage Specialist and Director of the UT Beef and Forage Center, University of Tennessee
(Previously published in Hay & Forage Grower: November 25, 2019)

Tall fescue is the dominant forage species used in the eastern United States. Being a cool-season grass, it provides grazing during the spring and fall for many livestock producers around the nation.

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Multi-species Grazing can Improve Utilization of Pastures

Jodie Pennington, Small Ruminant Educator, Lincoln University, Newton County Extension Center
(Previously published on Extension – Goats, August 14, 2019)

Multi-species grazing is the practice of using two or more livestock species together or separately on the same pasture-land in a specific growing season. With an understanding of the different grazing behaviors of each species, various combinations of animals can be used to more efficiently utilize the forages in a pasture. Different species of livestock prefer different forages and graze them to different heights. Cattle tend to be intermediate grazers. They graze grasses and legumes and bite with their mouth and tongue. Sheep and horses graze closer to the ground than cattle.

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Control Pasture Weeds Now

Christine Gelley, OSU Extension Educator ANR, Noble County

With the combination of sunny warm days and more than adequate rainfall received so far in May, grasses and legumes in our hayfields are beginning to flower. Which means, according to our knowledge of grass maturity and forage quality, it’s already time to make hay. If the weather will cooperate, that is.

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How Much Rest Does Your Pasture Need?

– Victor Shelton, NRCS State Agronomist/Grazing Specialist (Sourced from the OSU BEEF Team Newsletter)

took the time to walk through most of my pastures a few days ago. I recommend doing this fairly often to keep a mental forage inventory. It is best to record the findings. Some use fancy electronic data sheets, some track on paper charts, some just have notes in their pocket datebook or smart phone. I use a combination. I like the paper charts for long term planning, but for a quick assessment, I like a white board.

More residual left and more rest; more roots, more production and animal performance

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When to Start Grazing: Don’t Rush It!

– Chris Penrose, Extension Educator, Ag and Natural Resources, Morgan County

Originally posted on the BEEF Newsletter

 

One goal I have had with livestock grazing over the years is to start as soon as I can. I put spring calving cows on stockpiled grass in early March to calve with the hope of not having to feed any more hay. Many years this works but not this year, grass is just starting to grow. The stockpile is about gone and I have started feeding them some more hay but hope to move the group with the fall calving cows this weekend. I then plan on starting a fast rotation around many of the paddocks and hay fields which is actually later than many years.

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Avoid Forage Toxicities After Frosts

Originally posted on the BEEF Newsletter– Mark Sulc, OSU Extension Forage Specialist

As cold weather approaches this week, livestock owners need to keep in mind the few forage species that can be extremely toxic soon after a frost. Several species contain compounds called cyanogenic glucosides that are converted quickly to prussic acid (i.e. hydrogen cyanide) in freeze-damaged plant tissues. A few legumes species have an increased risk of causing bloat when grazed after a frost. Each of these risks is discussed in this article along with precautions to avoid them.

Species with prussic acid poisoning potential

Forage species that can contain prussic acid are listed below in decreasing order of risk of toxicity after a frost event:

  • Grain sorghum = high to very high toxic potential
  • Indiangrass = high toxic potential
  • Sorghum-sudangrass hybrids and forage sorghums = intermediate to high potential
  • Sudangrass hybrids = intermediate potential
  • Sudangrass varieties = low to intermediate in cyanide poisoning potential
  • Piper sudangrass = low prussic acid poisoning potential
  • Pearl millet and foxtail millet = rarely cause toxicity

Species not usually planted for agronomic use can also develop toxic levels of prussic acid, including the following:

  • Johnsongrass
  • Shattercane
  • Chokecherry
  • Black cherry
  • Elderberry

It is always a good idea to check areas where wild cherry trees grow after a storm and pick up and discard any fallen limbs to prevent animals from grazing on the leaves and twigs.

Fertility can affect poisoning risk. Plants growing under high nitrogen levels or in soils deficient in phosphorus or potassium will be more likely to have high prussic acid poisoning potential.

Fresh forage is more risky. After frost damage, cyanide levels will likely be higher in fresh forage as compared with silage or hay. This is because cyanide is a gas and dissipates as the forage is wilted and dried for making silage or dry hay.

Plant age affects toxicity. Young, rapidly growing plants of species that contain cyanogenic glucosides will have the highest levels of prussic acid. After a frost, cyanide is more concentrated in young leaves and tillers than in older leaves or stems. New growth of sorghum species following a non-killing frost is dangerously high in cyanide. Pure stands of indiangrass can have lethal levels of cyanide if they are grazed when the plants are less than 8 inches tall.

Toxicity Symptoms

Animals can die within minutes if they consume forage with high concentrations of prussic acid. Prussic acid interferes with oxygen transfer in the blood stream of the animal, causing it to die of asphyxiation. Before death, symptoms include excess salivation, difficult breathing, staggering, convulsions, and collapse.

Ruminants are more susceptible to prussic acid poisoning than horses or swine because cud chewing and rumen bacteria help release the cyanide from plant tissue.

Grazing Precautions

The following guidelines will help you avoid danger to your livestock this fall when feeding species with prussic acid poisoning potential:

  • Do not graze on nights when frost is likely. High levels of toxic compounds are produced within hours after a frost, even if it was a light frost.
  • Do not graze after a killing frost until plants are dry, which usually takes 5 to 7 days.
  • After a non-killing frost, do not allow animals to graze for two weeks because the plants usually contain high concentrations of toxic compounds.
  • New growth may appear at the base of the plant after a non-killing frost. If this occurs, wait for a killing freeze, then wait another 10 to 14 days before grazing the new growth.
  • Don’t allow hungry or stressed animals to graze young growth of species with prussic acid potential. To reduce the risk, feed ground cereal grains to animals before turning them out to graze.
  • Use heavy stocking rates (4-6 head of cattle/acre) and rotational grazing to reduce the risk of animals selectively grazing leaves that can contain high levels of prussic acid.
  • Never graze immature growth or short regrowth following a harvest or grazing (at any time of the year). Graze or greenchop sudangrass only after it is 15 to 18 inches tall. Sorghum-sudangrass should be 24 to 30 inches tall before grazing.
  • Do not graze wilted plants or plants with young tillers.

Greenchop

Green-chopping frost-damaged plants will lower the risk compared with grazing directly, because animals are less likely to selectively graze damaged tissue. Stems in the forage dilute the high prussic acid content that can occur in leaves. However, the forage can still be toxic, so feed greenchop with great caution after a frost. Always feed greenchopped forage of species containing cyanogenic glucosides within a few hours, and don’t leave greenchopped forage in wagons or feedbunks overnight.

Hay and silage are safer

Prussic acid content in the plant decreases dramatically during the hay drying process and the forage should be safe once baled as dry hay. The forage can be mowed anytime after a frost if you are making hay. It is rare for dry hay to contain toxic levels of prussic acid. However, if the hay was not properly cured and dried before baling, it should be tested for prussic acid content before feeding to livestock.

Forage with prussic acid potential that is stored as silage is generally safe to feed. To be extra cautious, wait 5 to 7 days after a frost before chopping for silage. If the plants appear to be drying down quickly after a killing frost, it is safe to ensile sooner.

Delay feeding silage for 8 weeks after ensiling. If the forage likely contained high levels of cyanide at the time of chopping, hazardous levels of cyanide might remain and the silage should be analyzed before feeding.

Nitrate accumulation in frost forages

Freezing damage also slows down metabolism in all plants that might result in nitrate accumulation in plants that are still growing, especially grasses like oats and other small grains, millet, and sudangrass. This build-up usually isn’t hazardous to grazing animals, but green chop or hay cut right after a freeze can be more dangerous. When in doubt, send a forage sample to a forage testing lab for nitrate testing before grazing or feeding it.

Species That Can Cause Bloat

Forage legumes such as alfalfa and clovers have an increased risk of bloat when grazed one or two days after a hard frost. The bloat risk is highest when grazing pure legume stands and least when grazing stands having mostly grass.

The safest management is to wait a few days after a killing frost before grazing pure legume stands – wait until the forage begins to dry from the frost damage. It is also a good idea to make sure animals have some dry hay before being introduced to lush fall pastures that contain significant amounts of legumes. You can also swath your legume-rich pasture ahead of grazing and let animals graze dry hay in the swath. Bloat protectants like poloxalene can be fed as blocks or mixed with grain. While this an expensive supplement, it does work well when animals eat a uniform amount each day.

Frost and Equine Problems (source: Bruce Anderson, University of Nebraska)

Minnesota specialists report that fall pasture, especially frost damaged pasture, can have high concentrations of nonstructural carbohydrates, like sugars. This can lead to various health problems for horses, such as founder and colic. They recommend pulling horses off of pasture for about one week following the first killing frost.

High concentrations of nonstructural carbohydrates are most likely in leafy regrowth of cool-season grasses such as brome, timothy, and bluegrass but native warm-season grasses also may occasionally have similar risks.

Another unexpected risk can come from dead maple leaves that fall or are blown into horse pastures. Red blood cells can be damaged in horses that eat 1.5 to 3 pounds of dried maple leaves per one thousand pounds of bodyweight. This problem apparently does not occur with fresh green leaves or with any other animal type. Fortunately, the toxicity does not appear to remain in the leaves the following spring.

Autumn Grazing Tips for Extending the Growing Season

Originally Posted in the Sheep Newsletter- Victor Shelton, NRCS State Agronomist/Grazing Specialist

The older I get, the more I tend to philosophize about things. I’ve been asked a few times why I am such an advocate for sound grazing practices. Best management grazing practices, just like conservation practices for reducing or preventing soil erosion on cropland, help preserve and or regenerate resources not only for present generation, but also for future generations.                         

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Good Management Practices for Fall Grazing

Ted Wiseman, OSU Extension Educator ANR, Perry County
(Previously published in Farm and Dairy: August 9, 2018)

 

Fall pasture management is a critical period for pastures. For many of us we have had adequate rainfall up until recently and pastures have done well to this point.

As we transition into late summer and early fall it is critical to pay close attention to your forages. Some pastures may be stockpiled, but those intended to be grazed this fall still need time to rest.

It’s very tempting to use those forages that green up late in the fall. Management decisions made this fall will greatly impact forage growth next year.

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