A recent news story has linked the mass deaths of almost an entire herd of cattle in Texas to a normally harmless grass which apparently began producing cyanide grass. The exact cause of the incident is still being investigated but similar elevations in cyanide production have been found in other pastures in the area as well. Thankfully, no other cattle have died to date.
Normally Harmless Grasses May Produce Cyanide and Poison Cattle During Drought Conditions
Though the grass involved in the incident in Texas was a Bermuda grass hybrid known as Tifton 85 which has been safe for the past 15 years, there are a number of different types of grasses which are known to cause cyanide (also known as prussic acid) toxicity under the right conditions. According to Agricultural Extension Center at the University of Tennessee, Johnson grass (Sorghum halepense) is the most toxic of the grasses that may cause cyanide poisoning in cattle. Other grasses that may become toxic include arrow grass (Triglochin supp.), Sudan grass (S. Vulgare var sudanensis) and common sorghum (S. Vulgare).
Signs of Cyanide Poisoning in Cattle
Cyanide poisoning in cattle interferes with the normal transport of oxygen from the blood to the tissues. Symptoms of cyanide poisoning occur very quickly. Depending on the amount of cyanide ingested, death can happen in a matter of minutes.
According to the University of Tennessee Agricultural Extension Center:
“Distressed breathing, muscle tremors and an increased heart rate are common signs. Most animals stagger and struggle before becoming unable to stand. Generalized muscle spasms precede death. Mucous membranes are bright red while the animal is breathing. Acute death usually occurs within 30 minutes of beginning of signs. Animals living 1½ to 2 hours following the beginning of signs usually recover.”
Treatment of Cattle Poisoned with Cyanide Producing Grasses
Unfortunately, treatment is often not successful. In the case of the cattle in Texas, many of the cattle were already dead before the situation was even discovered and others were dying.
When attempted, “a commercial mixture of 3% sodium nitrite and 30% sodium thiosulfate can be given intravenously,” according to the University of Tennessee Agricultural Extension Center and may be useful for treatment. However, treatment must be instituted quickly to stand a chance of being effective.
In the case of the mass cattle deaths in Texas, experts are still trying to understand why grass which had been previously been safely grazed for the previous 15 years suddenly became toxic. However, it is believed that a combination of events including a drought spanning the past 2 years possibly played a part. According to CBS News, “scientists at the U.S. Department of Agriculture are dissecting the grass to determine if there might have been some strange, unexpected mutation.”