I guess this topic gets addressed every year, but frost is just a few weeks away. It is a concern of mine.....I have lots of it. What are everyones thoughts and experience with Jgrass. Does it take a killing frost or is light frost enough to make it deadly? If the Jgrass is headed out and matured is it still toxic at that point or not, or does it need to be green and growing?
Johnsongrass/Prussic acid
- Thread starter Banjo
- Start date
Help Support CattleToday:
I'd mow it and turn them in now to eat it or just turn them in depending on the height.
Shanghai
Well-known member
Frost in worse than a freeze
Damage/mowed/grazed regrowth after a rain is when it's at its worst
Best as I can tell its suspect more times than not
I've had cattle on pasture before spring/summer growth and as long as there is enough cattle to keep it from taking hold and they will eventually graze it out
http://aces.nmsu.edu/pubs/_b/B-808.pdf
Damage/mowed/grazed regrowth after a rain is when it's at its worst
Best as I can tell its suspect more times than not
I've had cattle on pasture before spring/summer growth and as long as there is enough cattle to keep it from taking hold and they will eventually graze it out
http://aces.nmsu.edu/pubs/_b/B-808.pdf
Shanghai":3ni0kzrd said:
But if eaten dry it should be fine correct?
Shanghai
Well-known member
TennesseeTuxedo":36skgo7r said:
I'm not sure, its possible when drought stressed
After a hard freeze or cured for hay it's fine
Thanks.
1982vett
Well-known member
It will dissipate over time. Curing after cutting for hay...or drying out after frost. Everything I've read mentions 5 days curing for haying. Let it dry out after a frost and don't turn in for grazing for two weeks after moisture stressed forage gets a good rain. Another warning for young growth under 18 inches.TennesseeTuxedo":2yts0f59 said:
Always a heads or tails situation.....set up and stick to a pasture rotation plan and risk turning in on infested forage or let them run the place and graze where they want keeping problem grasses grazed. Usually by this time of the year they have the run of the place. I opened the gate to the last pasture Wednesday and it rained the first growth stimulating rain in 4 weeks Friday afternoon.
I realize that conventional grazing or continuous grazing will kill it out, but I do rotational grazing so it just seems to flourish along with the other grasses. It is good for summer grazing. my current approach is to feed hay in a designated lot for a couple of weeks starting with the first frost.
lavacarancher
Well-known member
Banjo, everything I've read on Jgrass says it's ok to feed IF it hasn't been highly fertilized and hasn't been stressed. I don't fertilize Johnson grass at all and my cows eat it (love it) and do just fine. Haven't lost one yet. If you have a lot of it get it tested to see if it's OK to feed.
sim.-ang.king
Well-known member
Frost a few week away?
Crap! there goes the beans!
Crap! there goes the beans!
If you want to know for sure about Prussic acid, buy cyantesmo strips. Get a Ziploc bag, pick Johnson grass from more than one spot, crunch it up add a small amount of water, add a short strip of cyantesmo paper. Put in the sun or a very warm spot, if Prussic acid
cyanide is present the paper will turn bright blue. Btw put all the above in the bag...
There is a good paper written about in on the university of Kentucky website.
Also you need to watch for nitrates, if it was fertilized,went through a dry spell then started growing.
I got my strips on Amazon from a chemical company.
Last fall we had a long discussion on here about it, if I was smart I could link to it.
Or you could search my old posts, I don't have that many so shouldn't be too hard.
cyanide is present the paper will turn bright blue. Btw put all the above in the bag...
There is a good paper written about in on the university of Kentucky website.
Also you need to watch for nitrates, if it was fertilized,went through a dry spell then started growing.
I got my strips on Amazon from a chemical company.
Last fall we had a long discussion on here about it, if I was smart I could link to it.
Or you could search my old posts, I don't have that many so shouldn't be too hard.
cross_7
Well-known member
Limit risk for prussic acid poisonin
By Jody G. Holthaus
Meadowlark Extension District Agent
The first few frosts of the fall bring the potential for prussic acid poisoning when feeding forages. Some forage species, primarily sorghums and closely related species, contain cyanogenic glucosides, which are converted quickly to prussic acid in freeze-damaged plant tissue. Historically in Iowa there are very few documented cases of prussic acid poisoning. However, the risk is present, and good management practices are necessary to minimize the risks.
Prussic acid, or more precisely, hydrocyanic acid, is a cyanide compound that can kill animals within minutes of ingestion under the right circumstances. Cyanide interferes with the oxygen-carrying function in the blood, causing animals to die of asphyxiation. Symptoms include difficult breathing, excess salivation, staggering, convulsions and collapse. Affected animals will have bright cherry red mucous membranes from the cyanide. Ruminants are more susceptible than horses or swine because they consume large amounts of forage quickly and the rumen bacteria contribute to the release of the cyanide from consumed plant tissue.
Sudan grass varieties are low to intermediate in cyanide poisoning potential, sorghum-Sudan grass hybrids and forage sorghums are intermediate to high, and grain sorghum has high to very high poisoning potential. Pearl millet and foxtail millet have very low levels of cyanogenic glucosides. A few other plants also can produce prussic acid, including cherry trees.
Prussic acid does not form in sorghum and Sudan grass plants until the leaf tissue is ruptured, as with grazing or chopping. Young, rapidly growing plants will have the highest levels of prussic acid. The cyanide-producing compounds are more concentrated in young leaves. Minimum plant heights of 18 inches are recommended, to avoid using risky, young leaf tissue. Plants growing under high nitrogen levels are more likely to have even higher cyanide potential.
Frost and freezing can cause a rapid change in prussic acid risk in plants of any age or size. With frost, forage tissues rupture, and cyanide gasses form. The cyanide gas can be present in dangerously high concentrations within a short time, and remain in the frosted leaves for several days. Because cyanide is a gas, it gradually dissipates as the frosted/frozen tissues dry. Thus, risks are highest when grazing frosted sorghums and Sudan grasses that are still green. New growth of sorghum species following frost can be dangerously high in cyanide due to its young stage of growth. Prussic acid content decreases dramatically during the hay drying process and during ensiling. Frosted foliage contains very little prussic acid after it is completely dry. Sorghum and Sudan grass forage that has undergone silage fermentation is generally safe to feed.
Precautions to take to limit risk
When grazing or green-chopping species with prussic acid potential this fall, follow these guidelines:
Do not graze on nights when frost is likely. High levels of the toxic compounds are produced within hours after a frost. Immediately after frost, remove the animals until the grass has dried thoroughly. Generally, the forage will be safe to feed after drying five to six days.
Do not graze wilted plants or plants with young tillers or new regrowth. If new shoots develop after a frost they will have high poisoning potential, Sudan grass should not be grazed until the new growth is at least 18 to 20 inches (24 to 30 inches for sorghum-Sudan grass).
Best management is to allow the final, killing freeze to kill the crop, and then wait five to six days before grazing. Other practical managements may be to harvest as hay or silage since. In most cases, adequate growth foGreen-chopping the frost-damaged plants will lower the risk compared with grazing directly, because animals have less ability to selectively graze damaged tissue; however, the forage can still be toxic, so feed with great caution. Feed green-chopped forage within a few hours, and don´t leave green-chopped forage in wagons or feed bunks overnight.
When making hay or silage from sorghum species this fall, consider the following: Frosted/frozen forage should be safe once baled as dry hay. It is very rare for dry hay to contain toxic levels of prussic acid. If the hay was not properly cured, it should be tested for prussic acid content before feeding. Waiting five to seven days after afrost to chop frosted forage for silage will limit prussic acid risks greatlyr safe grazing cannot be obtained after a later, killing freeze occurs. Don´t allow hungry or stressed animals to graze young growth of species with prussic acid potential.
.
By Jody G. Holthaus
Meadowlark Extension District Agent
The first few frosts of the fall bring the potential for prussic acid poisoning when feeding forages. Some forage species, primarily sorghums and closely related species, contain cyanogenic glucosides, which are converted quickly to prussic acid in freeze-damaged plant tissue. Historically in Iowa there are very few documented cases of prussic acid poisoning. However, the risk is present, and good management practices are necessary to minimize the risks.
Prussic acid, or more precisely, hydrocyanic acid, is a cyanide compound that can kill animals within minutes of ingestion under the right circumstances. Cyanide interferes with the oxygen-carrying function in the blood, causing animals to die of asphyxiation. Symptoms include difficult breathing, excess salivation, staggering, convulsions and collapse. Affected animals will have bright cherry red mucous membranes from the cyanide. Ruminants are more susceptible than horses or swine because they consume large amounts of forage quickly and the rumen bacteria contribute to the release of the cyanide from consumed plant tissue.
Sudan grass varieties are low to intermediate in cyanide poisoning potential, sorghum-Sudan grass hybrids and forage sorghums are intermediate to high, and grain sorghum has high to very high poisoning potential. Pearl millet and foxtail millet have very low levels of cyanogenic glucosides. A few other plants also can produce prussic acid, including cherry trees.
Prussic acid does not form in sorghum and Sudan grass plants until the leaf tissue is ruptured, as with grazing or chopping. Young, rapidly growing plants will have the highest levels of prussic acid. The cyanide-producing compounds are more concentrated in young leaves. Minimum plant heights of 18 inches are recommended, to avoid using risky, young leaf tissue. Plants growing under high nitrogen levels are more likely to have even higher cyanide potential.
Frost and freezing can cause a rapid change in prussic acid risk in plants of any age or size. With frost, forage tissues rupture, and cyanide gasses form. The cyanide gas can be present in dangerously high concentrations within a short time, and remain in the frosted leaves for several days. Because cyanide is a gas, it gradually dissipates as the frosted/frozen tissues dry. Thus, risks are highest when grazing frosted sorghums and Sudan grasses that are still green. New growth of sorghum species following frost can be dangerously high in cyanide due to its young stage of growth. Prussic acid content decreases dramatically during the hay drying process and during ensiling. Frosted foliage contains very little prussic acid after it is completely dry. Sorghum and Sudan grass forage that has undergone silage fermentation is generally safe to feed.
Precautions to take to limit risk
When grazing or green-chopping species with prussic acid potential this fall, follow these guidelines:
Do not graze on nights when frost is likely. High levels of the toxic compounds are produced within hours after a frost. Immediately after frost, remove the animals until the grass has dried thoroughly. Generally, the forage will be safe to feed after drying five to six days.
Do not graze wilted plants or plants with young tillers or new regrowth. If new shoots develop after a frost they will have high poisoning potential, Sudan grass should not be grazed until the new growth is at least 18 to 20 inches (24 to 30 inches for sorghum-Sudan grass).
Best management is to allow the final, killing freeze to kill the crop, and then wait five to six days before grazing. Other practical managements may be to harvest as hay or silage since. In most cases, adequate growth foGreen-chopping the frost-damaged plants will lower the risk compared with grazing directly, because animals have less ability to selectively graze damaged tissue; however, the forage can still be toxic, so feed with great caution. Feed green-chopped forage within a few hours, and don´t leave green-chopped forage in wagons or feed bunks overnight.
When making hay or silage from sorghum species this fall, consider the following: Frosted/frozen forage should be safe once baled as dry hay. It is very rare for dry hay to contain toxic levels of prussic acid. If the hay was not properly cured, it should be tested for prussic acid content before feeding. Waiting five to seven days after afrost to chop frosted forage for silage will limit prussic acid risks greatlyr safe grazing cannot be obtained after a later, killing freeze occurs. Don´t allow hungry or stressed animals to graze young growth of species with prussic acid potential.
.
I don't fertilize the jgrass either and have no problem with it during the summer. It seems most articles tend to think its the young immature plants that get frosted on that is the most dangerous rather than the plants that are already headed out.lavacarancher":15il6bk9 said:
I have a neighbor who has a 50 ac field that jgrass takes over almost solid in the summer and he usually turns a bunch of cows in there right around frost time every year and has no problems, but the jgrass has been standing there maturing for a couple of months....so I guess it is too mature for prussic acid to be a problem.
A couple of years ago I thought I would be helpful and warn him about the prussic acid/danger with his jgrass and he had never heard of prussic acid poisoning!
bigbull338
Well-known member
you can graze them on johnson grass as long as it doesnt rain on it.because once it rains on it cows will get grass tetney for 2 or 3 days till it drys out.grass tetney will kill them fast.been there done that,had 2 cows get grass tetney.and we hadnt been watching them we wouldve lost them.it only takes 2 or 3 bites of johnson grass to kill a cow.if you dont know theres johmson grass in a pasture you may never know why a cow died.
cross_7
Well-known member
I'd suspect prussic acid
As its more likely to occur on new growth after a rain
I saw my grandad lose 9 head onetime and have been leery of it since
As its more likely to occur on new growth after a rain
I saw my grandad lose 9 head onetime and have been leery of it since
cross_7":2qac0i2a said:
Are you talking about it
being rained on after an extended dry spell?
Like I said before, I've been grazing jgrass all summer that has had plenty of moisture.....no stress. With no issues.
greybeard
Well-known member
Banjo":3035eiei said:
As I understand it, the JG has to have been stressed first--either by drought or frost, and then the new growth is the toxic stage.
But with drought stress, I don't think it's that cut and dried or that simple. If it were, 1/2 the cattle in E Texas would be dead right now. Aug was very dry, then we got some rain the very last days of Aug and last couple of days. Most people, myself included, have at least a little jg in their pastures, even tho I try to keep it killed off.
Look at how cattle move across a pasture, whether it's a big pasture or small. They'll come across a clump of jg, eat it down almost to the ground then move on. Might be 2 days before they get back to that spot again and likely as not, it has new growth, and if any rain fell on it, it's sure to have new growth, but I haven't had any tetany/prussic acid problems (knock on wood).
There has got to be more to it than just drought stress and new growth.
When I was a kid, a neighbor turned his cows in a bean field after a frost. A little Johnson grass around one light pole killed 16 head. It made a big impression on me. I'm probably too cautious, UK gave me some of those strips that detects it. I'm out, and need some more. Anybody know where to order them?
cross_7
Well-known member
Banjo":1z77rknv said:
I sure ain't an expert but it's said new growth from frost, drought, hayed or grazed
I'd suspect there has to be enough new growth and a cow would have to consume enough new growth to be toxic
Being its new growth it's in the lower part of the plant
Most cattle walk and graze along so they may not be eating enough to be toxic
A couple years ago they said some cattle were poisoned on tifton 85 but they had been hungry when turned in on it
I'd guess that'd have to be several factors to make it work or fail
