Such events require producers to monitor pastures for good stands of desirable plant species prior to grazing events and proper management of poisonous weeds at the same time. Other factors, such as high amounts of certain toxic metabolites like tryptophan/3-methylindole present in lush forages, nitrous oxides present especially around silos and allergens from moldy feed, also can cause varying levels of toxicity to animals.
In 2018, excess moisture in the region caused in suboptimal growing conditions, which resulted in poor forage stand. Whereas in 2019, drought-like conditions in late summer and early fall resulted in similar conditions. Producers involved did not realize that until it was too late.
First published: Wednesday, July 11, 2018
Information by Rakesh Chandran, Ph.D., WVU Extension Service Weed Science Specialist
Abnormal breathing is manifested in affected animals referred to as atypical interstitial pneumonia syndrome (AIP).
The volatile oils present in perilla mint contain several compounds in varying amounts. Among these, the perilla ketones are considered to me most toxic to animals and are present in high quantities during later stages (August to October) of the growing season, especially in seeds.
Perilla mint is most susceptible to control during the spring months when the plants are young and actively growing. Once they come to bloom, the plants become hardy and more difficult to control. As an annual, it can be removed mechanically by taking advantage of its shallow root system. Herbicides, such as 2,4-D (low-volatile ester formulations) or tank-mixtures containing both 2,4-D and dicamba (several formulations) along with a surfactant, provide good control when applied in early spring. Herbicides containing aminopyrlid (Milestone, Grazon Next) also provide effective control, but may persist in treated hay and in manure derived from animals that were fed with treated forage or hay.
Can you think of a plant with medicinal and culinary attributes, yet it’s often toxic to livestock? The weed in question is perilla mint ( Perilla frutescens). Perilla mint is becoming more and more common in pastures across West Virginia, causing concern for some.
Perilla mint is an annual weed prevalent in pastures, periphery of woodlots and occasionally, in gardens and other disturbed fields. It can be easily identified by its ribbed, square stems and broad leaves, arranged oppositely with a toothed margin. The leaves vary in color from green to purple, especially when found growing in the shade, and boast a minty aroma when crushed.
Perilla Mint – Weed of the Week Share this Did You Know? A few facts: Can be toxic to livestock Can be used for medicinal and culinary purposes How to
Back to livestock, mint is a persistent, very seed-productive weed that emerges each April. Its presence offers opportunities for livestock to come in contact with mint throughout the grazing season, but fortunately, they simply don’t like the stuff! So why is mint a routine summer drought problem?
Obviously drought tolerant, plant selections from the mint family were introduced into this country as ornamentals because of the deep purple foliage, fragrance and traits soothing to the eye. There seems to be a pattern of ornamental plant introductions that prove to toxic or otherwise problematic to livestock producers.
It surprises some producers to learn that mint isn’t hard to kill with herbicides. The ideal growth habitat is along creek beds, in wooded pastures and around barns, corrals and holding pens. These out-of-the-way areas see very little, if any early season activity from a spray rig, which helps mint to escape control, even on the best managed farms.
After observing mature cattle die from mint induced respiratory failure, it’s difficult to imagine this plant as an ancient and present culinary favorite in Asian countries. In addition mint plants are reported to have medicinal uses. As a bare-foot youngster many decades ago, my Appalachian, home-remedy trained grandmother treated my thorn-punctured foot with mint leaves, which brought welcome relief.
Also referred to as perilla mint, or beefsteak plant, most livestock producers know it as purple mint or simply mint weed. A member of the square-stemmed mint family, that trait, in addition to its strong mint fragrance, makes it easy to identify even when growing in the thick of other assorted weeds. In the Ozarks, mint weeds are like rocks, meaning they are easily found on most farms. Its rattlesnake name comes from the sound the seeds make when rattling around the dry seed head.
Droughts, as currently being experienced, create a loss of forage availability, which initiates the problem. An abundance of ungrazed mint foliage and the development of its flower, considered to pack the highest risk of toxin, two pieces of the puzzle are present. Animals have a daily dry matter requirement, which they try to satisfy from available forage. Although they dislike mint, when preferred forages aren’t available, grazing animals will eat it, completing the puzzle.
The perilla mint has a broad, tooth-edged leaf.
It was August of the 2010 summer drought in Benton County when the year’s first cattle losses occurred as a result of rattlesnake weed. A few more deaths soon followed, prompting numerous conversations about this seemingly annual event. In Tennessee, this plant has been reported as the cause of more cattle deaths than any other toxic plant.
Even if forage is considered to be plentiful, to reduce this risk check pastures for the presence of mint and try to get it clipped. Herbicide applications at this time may not be a good option since treated weeds often become more palatable to animals.
It was August of the 2010 summer drought in Benton County when the year’s first cattle losses occurred as a result of rattlesnake weed. A few more deaths soon followed,