Poisonous Plants and Farming: Stay Safe, Don't Scratch!

By Carolyn Ross Tomlin, Reprinted from Farming, April 2008, Vol. II, No. 4

Cases of moderate to severe reaction to poison ivy, poison oak and poison sumac are on the rise. Lewis Ziska, Ph.D., a weed ecologist at the U.S. Department of Agriculture in Beltsville, Md., says, "In the last 50 years, the growth rate of the poison ivy plant has doubled. About 80 percent of people are sensitive to poison ivy, meaning they will develop a rash if they come into contact with the plant."

According to another study by the U.S. Department of Agriculture, climate change isn't just upping outdoor temperature and warming the oceans. It also may greatly increase a farmer's chance of getting a really bad case of poison ivy. Due to a rise in carbon dioxide in the atmosphere, the growth rate of poison ivy has increased. These elevated carbon dioxide levels are creating bigger, stronger plants that produce more urushiol (pronounced oo-roo-shee-ohl), the oil that causes the allergic reaction and miserable rash. The urushiol isn't just more plentiful; it might also be more potent and powerful. Because this sap is inside the plant, brushing against an intact plant will not cause a reaction. But, it's rare to find a plant that is undamaged.

"All three plants are very fragile," says William L. Epstein, professor of dermatology, University of California, San Francisco. Stems or leaves broken by the wind or animals, and even the tiny holes made by chewing insects, can release urushiol.

Farmers who work the land or raise livestock where this noxious plant thrives should be aware of the effects of poison ivy and its cousins. Clearing fencerows, removing underbrush from surrounding pastures or cutting trees where vines erode all create problems for those allergic to the plant. Farmers who raise livestock face another problem: cows that wander into thickets and undergrowth and must be herded out.

Identification of the plant

You've heard the age-old advice, "Leaves of three, let them be." However, some of these plants have leaves in groups of five to nine. Learning to identify these plants may mean the difference in being able to perform work-related farm chores or having to stay indoors with an itchy rash.

Poison ivy (Toxicodendron radicans) usually grows as a trailing or climbing vine. The stems grow from branched, creeping horizontal rootstocks, which can spread several yards from the parent plant, sending up new shoots. Alternating on the stem, the leaves are compound and borne at the end of a stalk. Each leaf is composed of three shiny, oval, pointed leaflets, which are often reddish when young, becoming glossy dark green in summer. The edges may be smooth, toothed or lobed. Clusters of small greenish flowers appear in summer, flowed by round, ridged, cream to yellow fruits that are .25-inch wide. The foliage turns bright orange to scarlet in the fall. It grows in woods, lakes and streams in the South. Midwest and East.

Poison oak (T. diversilobum) differs in that it grows as a dense, leafy shrub in open or partially shaded areas: in deeper shade it becomes a vine, climbing with aerial roots. Like poison ivy, it has extensive creeping horizontal rootstocks. Its leaves are also compound, made up of three leaflets, although at first glance the leaflets look like individual leaves. The margins of the leaves are scalloped, toothed or lobed. The new growth is tinged red, usually becoming shiny green in summer, then turning scarlet in fall. In spring, the plant develops clusters of small, white flowers, which develop into waxy, white berries. It grows from New Jersey to Texas and along the Pacific coast.

Poison sumac (T. vernix) grows in boggy areas, especially in the Southeast. It appears as a rangy shrub up to 15 feet tall with 7 to 13 smooth-edged leaflets. Poison sumac has glossy pale yellow or cream-colored berries.

Wiping out poison ivy plants

Farmers who have poison ivy on their land have resorted to a variety of ways to eradicate this vine. One is to turn a herd of goats loose on the plants. With their ability to climb, they'll also clean ditch banks and gullies where it would be difficult to use machinery. Animals are not allergic to the plant, only people. Plus, the goats work for food, not cash.

Two herbicides most commonly used for these noxious plants are Roundup and Ortho Poison Ivy Killer, but the products will get rid of surrounding plants as well. Spraying Roundup (active ingredient glyphosate) on the foliage of young plants will eliminate the poison ivy, but if the vine is growing up a tree of shrub, the Roundup will kill it. According to Joseph Neal, Ph.D., associate professor of weed science, Cornell University, says, "If used sparingly, Ortho Poison Ivy Killer (active ingredient triciopyr) will kill the poison ivy, but not harm trees around which the plant climbs. Keep away from shrubs, broadleaf ground cover or herbaceous garden plants." Neal explains it is possible to spray the poison ivy without killing other plants if you pull the vines away from the desirable plants and wipe the ivy foliage with the herbicide, or use a shield on the sprayer to direct the chemical. Another approach is to pull the vines away from the tree (using gloves) and insert the vines into a bucket filled with Brush-B-Con Brush Killer. The vine will carry the chemical down to the roots and die.

"Another removal strategy is to pull the vines away manually (with gloves)," says Neal. "However, you must get rid of every bit of the plant--leaves, vines and roots--or it will sprout again."

During the summer months when the urushiol content is high and the plants are easily bruised, the vines are most noticeable. However, the danger doesn't disappear when the leaves are gone. Reactions still occur for several years after the vine is dead. This is especially true for those burning firewood or cutting vines for wreaths. Even smoke from clearing land where the plants are located can cause those sensitive to poison ivy, oak or sumac to develop a rash. Inhaling the fumes or smoke can cause severe injury.

Protection from the noxious vines

The best protection from poison ivy is to avoid it. However, for farmers and others involved in agricultural careers and work in areas where the plant grows, avoidance isn't always possible. What can you do? Consider the following.

Act fast. Within minutes, the urushiol can penetrate the skin. Even in 10 minutes, the chemical starts to work. The sooner you remove the sap, the better your chance of avoiding the rash. Cleanse the skin as soon as possible with isopropyl (rubbing) alcohol. As alcohol removes your skin's protection, stay away from the plants for 24 hours or more so you will not be exposed again.

Next, wash the skin with running water (without soap). By avoiding soap, the urushiol is not spread around to other areas of the skin. Remove all clothing exposed to the sap and wash immediately. Wipe off shoes with rubbing alcohol. Use rubber gloves to remove clothing and discard the hand coverings. After this step, take a regular shower with soap.

Any tools that come in contact with the plant should be wiped with alcohol, then dried and oiled to prevent rust.

If farm work requires you to come in contact with the poisonous plants, always wear long pants and long sleeves, and if possible, gloves and boots. When pulling vines, wear cotton gloves under plastic gloves. Plastic may rip, and cotton alone will soon become soaked with the sap from the plant.

Depending on your reaction to the plant, the rash can last from a few days up to two to three weeks. Although the rash is not potentially serious, getting poison ivy can cause a week or more of intense itching. Plus, the rash can raise your risk of potentially serious skin infection or secondary infection from scratching the skin.

If a rash develops, outdoor work during the summer months causes increased itching. Staying indoors in an air-conditioned area allows the rash to subside.

Dealing with the rash

The American Academy of Dermatology recommends that people who have had severe reactions in the past should contact a dermatologist as soon as possible after a new exposure. The FDA considers over-the-counter topical corticosteroids (commonly called hydrocortisones under brand names such as Cortaid and Lanacort) safe and effective temporary relief of itching associated with poison ivy.

One home remedy is to use Tide washing detergent on the rash. Mix 1 tablespoon detergent and enough hot water to make a thick paste. Apply to the rash when it first appears and begins to itch. Avoid the face area due to sensitive skin. Leave on for 10 to 20 minutes. Usually, this relieves the itching and the skin can heal quickly.

For farmers out in the field who have been exposed to poison ivy, use a jewelweed plant to prevent and lessen the exposure. Slice the stem, then nib the juice inside on exposed parts, which will promptly ease the irritation. Jewelweed soap can be found at health food stores.

Conclusion

While farming and working around livestock, you have many opportunities to come in contact with poison ivy, poison oak and poison sumac. Each person reacts in a different way and the reaction can vary throughout life as your immune system changes. There are many products on the market to help relieve the rash and blisters, but avoidance is still the best policy.

Steps To Prevent Plant Poisoning

By Shirley A. Weathers, reprinted from RMLA Journal, Spring, 2007

Every year, poisonous plants cause death, temporary and chronic pain and illness, abortions, decreased productivity, and birth defects involving hundreds of thousands of grazing and browsing livestock. The annual economic loss amounts to hundreds of millions of dollars. Although less is known about llama and alpaca susceptibility to plant toxins than other livestock, here are documented cases of poisoning of llamas by at least Oleander; Mountain Black or Sierra laurel (Leticothoe davisiae); Rhododendron; Water hemlock (Cicuta spp.); Ponderosa, Western or Yellow pine (Pinus ponderosa); Yew (Taxus spp.) and Death camas (Zigadenus spp). Camels reportedly have been poisoned by African plant species identical or related to western U.S. plants: Thornapple (Datura stramonium), Milk of Pencil bush (Euphorbia tirucalli), Lantana, Castorbean or Castor-oil plant (Ricinus communis) and Sorghum. * Time will tell more about how llamas react to other plants that have harmed horses, sheep, cattle, goats or pigs, but using caution in allowing them access is the best policy in the meantime.

For complicated reasons of plant and animal evolution, well-nourished herbivores will generally avoid eating most toxic plants. The toxins in some plants make them unpalatable to animals -- they either smell bad or taste bad. Animals learn from other animals, particularly their mothers, to avoid some of the poisonous plants. Still, other poisonous plants produce a disagreeable physiological sensation soon enough after ingestion that animals learn not to eat them at all or they stop before consuming toxic quantities. But these mechanisms of safe eating are not foolproof. As noted above, poisoning does occur and when it does, it can be devastating to both animal and owner.

There are a variety of reasons why livestock eat poisonous plants. There are some to which livestock have been found to be attracted. Some unpalatable plants appear to lose their disagreeable odors or tastes when dried (as in hay); a significant cause of poisoning is consumption of toxic plant parts mixed in hay, silage, grain, or processed feed. Some typically safe plants become toxic when fertilized or treated with certain herbicides. They may simultaneously become more palatable. Weather stresses and other natural conditions may convert the non-toxic to toxic. Probably most importantly, if put into a situation where only poisonous plants are available or where they make up a large percentage of available forage, livestock will eat them.

Whether or not ingesting particular toxic plants will sicken animals is also a complex matter. Not all species of livestock are equally affected by or susceptible to various plant toxins. For example, it is thought at this time that only equines contract "chewing disease," a devastating illness caused by consumption of toxic amounts of Centaurea solstitialis or Centaurea repens (commonly known as Yellow starthistle and Russian knapweed, respectively). The relative health of the individual animal (or, if a ruminant, of the microflora in its rumen) can figure into how well it can handle some toxic substances in the plants it consumes. The digestive systems of some animal species can adapt to be able to detoxify higher levels of toxins with exposure. A substantial quantity of some plants must be ingested to trigger illness or death. A couple of leaves of other plants can kill.

Despite all of these variables (and more), experts agree that plant poisoning can be minimized. The best means is a combination of effective use of good information about toxic plants and provision of adequate amounts of safe alternative food. In the unhappy event that poisoning occurs, being informed may facilitate effective response.

Here are some suggestions that may help owners of livestock of all types protect their animals from poisoning.

Pasture management is critical. Learn about plants in pastures and the animals that will graze there. Seek help from Extension agents and others, if necessary. Some options:

1. Eliminate or fence securely around toxic plants, especially if animals may find them palatable or if they are highly toxic or abundant. NOTE: if you grub out highly poisonous plants such as the various Water hemlock species (Cicuta spp.), take appropriate precautions to protect yourself and others, especially children.
2. If animals will have access to less palatable toxic plants, ensure that they always have adequate safe forage available. Check plant levels and types periodically. Do not overgraze.
3. Watch carefully in early spring or late fall when toxic plants may be more prevalent than others.
4. Know which plants are drought resistant. They may be the only food available under some circumstances.
5. Watch out for toxic plants that are evergreen from fall to spring.
6. Ensure that animals have adequate water, as well as salt and mineral supplementation, if needed.
7. Avoid giving access to plants during their toxic season(s).
8. Check on your pastured animals regularly and know the signs of poisoning to allow prompt action in case poisoning occurs.
9. Be careful with herbicides (including those that may be applied by others, e.g.. local government entities). Learn about their direct effect on animals, whether animals have been found to be attracted by application of the product and, if palatability is likely to increase, know about the inherent toxicity of those plants.
10. Be prepared to identify and respond appropriately to toxic plants when animals will be taken into unfamiliar areas. New poisonous plants may be eaten simply because the animal has no experience with them.
11. Avoid driving animals through areas with high concentrations of toxic plants, particularly if they are hungry.
12. When tying, picketing, or staking animals, identify and avoid areas where they are likely to consume toxic plants. If at all possible, find a place that is grassy, rather than leafy. Most, although not all, wild grasses are safe forage (Be able to identify and avoid Triglochin miritma -- known in most areas as Seaside arrowgrass -- and Zigadenus spp. -- commonly known as Death camases, but there are several other common names).
13. Do not assume that others know about poisonous plants. Feeding animals "treats" seems to be an almost irresistible urge of humans. Educate both adults and children who may come in contact with them about leaves, fruits, etc. This exercise will also alert children to the whole issue of poisonous plants. Many plants are at least as dangerous for children to eat as livestock. Consider providing visitors with "official treats" that animals like and can safely eat.
14. If animals are rented or lent to others, orient the temporary caretakers to toxic plants along with other instructions on care and handling. Provide plant identification resources to be taken along with the animals.
15. When selling animals, ensure that buyers are aware of toxic plants. Consider providing pertinent materials to the new owners.
16. Do not feed yard or garden vegetation (clippings or trimmings) to livestock.
17. Try to arrange to walk uncut hay fields before buying and check hay when feeding. Buy grain and processed feeds from reputable sources.
18. Consider removing toxic trees and shrubs in corrals, pastures, and yard that could be accessible to livestock. Of course, the urgency of this measure depends on the toxicity of the plants.
19. Anticipate accidental circumstances such as leaves blown by wind or the fact that animals sometimes get out.
20. The safest course during Christmas and other holidays is to avoid feeding trees or other greenery to livestock. Although Pinus ponderosa (Ponderosa pine, among other common names) is the most commonly referenced harmful member of the Pinus genus, other species and other conifers also may be toxic, especially if consumed in large quantities over a short period. Many common types of holiday greenery can be deadly.
21. Check branches and tree limbs brought down, in pastures by storms to ensure that they are not from toxic trees.

Plant poisoning is generally a complex medical situation and will probably require a veterinarian's evaluation and care. The following may be helpful for livestock owners to keep in mind:

1. Establish a connection with a veterinarian before an emergency arises. Locate a practitioner familiar with your species of animal(s) and involve him or her in routine care.
2. Ask for information about any plants in the area that may already have caused problems. If other animals have been poisoned by local plants, there is a good chance that local veterinarians at feast will be aware of that. They also may have some good advice to give you about prevention or response or both.
3. If you will be taking animals into a situation where veterinarian assistance will be difficult to obtain, ask your veterinarian to discuss some prudent actions to take in the event of poisoning. Always notify a veterinarian when plant poisoning is suspected. Be prepared to provide him or her with as much information as possible about the situation.
4. Discuss appropriate supportive/ symptomatic care you may be able to provide to sick animals and be prepared to provide it until assistance arrives.
5. Try to identify any suspect plants.
6. Get a sample.
7. Inspect the area where the animal was grazing. Try to determine the amount and duration of consumption.
8. Observe and make careful note of any physiological or behavioral signs the affected animal may exhibit.
9. Keep an open mind and investigate other possible toxic agents to which a sickened animal may have been exposed, as well as the possibility that another type of illness may be involved.

On a personal note, when I began this book, I understood the grave potential of plant poisoning, but had not had any direct experience with it Then in the midst of writing it, our neighbors had to put down five horses due to Russian knapweed poisoning. Just after the book was published, one of our pack llamas plucked a large mouthful of a young Water hemlock plant as we prepared to cross a stream. Although almost certainly not a lethal dose for a 300-pound animal, I'm convinced that I prevented him from being sickened by recognizing and forcibly removing the plant matter from his mouth.

Copyright 1998 by Shirley A. Weathers

Shirley Weathers, RAMA member and co-owner of Walsh & Weathers Research and Policy Studies and Rosebud Llamas Utah, excerpted this article from her book, Field Guide to Plants Poisonous to Livestock-- Western US. The book is designed to help livestock owners recognize over 100 toxic western plants and provide adequate basic knowledge to consider effective animal or pasture management responses when those plants are present. Possibly physiological and behavioral signs of poisoning are also provided, as well as types of care or treatment that may be helpful. The field guide is $14.95 (Utah residents please add 6.00% sales tax.), plus $3.00 shipping for one book and $1.00 for each additional book. Mail orders to Rosebud Press, PO Box 270090, Fruitland, UT 84027-0090. For questions or comments, phone: (435) 548-2630, FAX: (435) 548-2438, email: www@ubtanet.com. Visit http://users.ubtanet.com/wtw/ to see sample plant entries from the book.

(Cornell University Poisonous Plants Informational Database is full of wonderful descriptions and pictures of toxic plants that fill our everyday world: http://www.ansci_cornell.edu/plants/comlist.html)

* Murray E. Fowler, "Plant Poisoning in Camelids," Poisonous Plants-- Proceedings of the Third International Symposium, Ames: Iowa State University Press, 1992, pp. 33

Plant Poisoning in Llamas and Alpacas

By Murray E. Fowler, DVM University of California, Davis

Llamas and alpacas are fastidious eaters and generally don't ingest a lot of any strange feed item. Nonetheless, accidents do happen both on the trail, and in the farmstead. Following are two examples of plant poisoning that illustrate some of the hazards. More details and information on other plants may be found in the references listed.

Oleander Poisoning

Oleander Nerium oleander is a beautiful ornamental, evergreen shrub or a small tree, native to the Mediterranean region. It was introduced into the United States many years ago and is now commonly planted in freeway mediums. As a potted shrub that can be moved inside during the winter, it may be found almost anywhere. Oleander's popularity is enhanced by it prolific sprays of white, pink, rose or red flowers, which bloom for many months of the year.

Oleander is one of the most poisonous plants likely to be encountered by animals. A fatal does may be as little as 1/3 of an ounce (7.5 gm) of green or dried leaves for a 30O pound llama. For most poisonous plants, an animal usually must ingest an amount equal to 0.5 to 1.0% of its body weight before developing signs of poisoning. In the case of oleander, fatal poisoning results from ingestion of only .005% of body weight. The ingestion of three medium to large leaves may be lethal to a llama, see table 1.

The poisonous principle is oleandrin, similar in action to an overdose of digitalis, or its more common commercial form, digoxin. Llamas and alpacas may also be at risk if they eat purple foxglove, a garden flower that flourishes in the cooler weather of the northwest and northeastern United States.

Llamas and alpacas may also obtain oleander leaves in a variety of ways. Rarely will they ingest leaves directly from the living shrub, because the green plant is bitter. Oleander grows rapidly, necessitating frequent pruning, and if cuttings or lawn clippings containing leaves are placed where llamas can eat them, the risk of poisoning is great. Dried leaves are more palatable than green leaves, but equally toxic. Poisoning once occurred when oleander branches and leaves were run through a shredder, and the resulting mulch placed in a flowerbed. The dried leaf parts blew into a pasture containing llamas.

Two recent episodes of oleander poisoning prompt me to remind owners of the hazard of having oleander shrubs, or any part thereof, anywhere near llamas or alpacas. In the first case, a llama was newly introduced (2 weeks previously) to a herd and a new pasture. The llama was noticed lying down and reluctant to get up. It also refused to eat. A couple of days passed before help was requested. The possibility of oleander poisoning was raised and became a factor when it was reported that oleander grew at the border of the pasture and, furthermore, a gardener had pruned oleander and burned a pile of the clippings in the pasture. Some of the branches did not burn, leaving dried leaves available to the llama. Other animals at the farm had avoided consumption of oleander, but the new animal was inquisitive.

A veterinary practitioner examined the llama and found an extremely rapid heartbeat and no stomach mobility in addition to the depression and anorexia. Supportive treatment was administered, but intensive care and surgery were not options. For the next four or five days, the llama vacillated from being bright and alert or depressed but finally rallied and began eating and moving about.

The second episode involved a herd of alpacas. A three-year-old female died suddenly. No necropsy was performed. A month later, another female, 2.5 years old, became depressed and anorexic. The animal was examined without conclusive results. It was treated according to signs and although seemingly improving, was found dead two days later. No necropsy was performed. A third weanling (18 months old) in the herd became depressed and anorexic. Because of the way it stood, as if it were lame on all four limbs, the examining veterinarian thought it had vitamin D deficiency (rickets) and treated it accordingly. The practitioner asked the owner if any oleander was on the property, and the reply was yes, but only at a great distance from the alpacas, and that there was no way the alpacas could have had access to it. Within 24 hours that alpaca died. A necropsy was performed on this animal, and samples were submitted to a diagnostic laboratory. The pathologist noticed degenerative lesions in the heart muscle, suggestive of selenium deficiency or oleander poisoning. A second weanling with depression and anorexia was referred to the Veterinary Medical Teaching Hospital at the University of California, Davis.

With a suggestion that oleander poisoning was a possibility, a newly developed blood test for the presence of oleandrin was performed and was positive. Fortunately for this alpaca, the ingested dose of oleander was not lethal.

Generally, oleander poisoning is an acute episode leading to the death of the animal. In these two episodes, at least one animal lived. The question as to what residual effects in the heart muscle could cause problems later on? The pathologist indicated that, had the animal lived, the degenerative lesions found in the heart would lead to scar tissue formation in two to three weeks, and if the effect on the heart was extensive enough, it could lead to poor cardiac function at a later time.

Except for depression and anorexia, the clinical signs noted in the alpacas were not the usual signs observed in other animals suffering from oleander poisoning. Typically, animals develop diarrhea, which may become bloody. Neither the alpacas nor the llama had diarrhea. If one listens to the heart carefully, over a long time period, various types of arrhythmia (including rapid heart beat) may be heard, but there may be periods of normal heart beat too. Ultimately, when the heart is no longer able to circulate blood satisfactorily, mucous membranes of the nose and mouth may become cyanotic (bluish). Muscle trembling may be seen and breathing becomes difficult. Death may occur within ten hours of ingesting oleander leaves or, as noted above, the animal may survive.

Sudden death is an uncommon occurrence, and obviously causes alarm in the owner. Any animal that dies under such circumstances should be necropsied. In geographical areas where oleander is normally found, possible access to the plant material should be explored and such information passed on to the pathologist conducting the necropsy. It is possible to identify even small pieces of oleander leaf in the stomach, which would be a definitive diagnosis. The only effective treatment for oleander poisoning is to remove the plant material from the stomach by surgery. Animals already showing signs of oleander poisoning are a poor surgical risk at best, so prevention of poisoning by eliminating oleander plantings in and around llama or alpaca facilities is a must. Lawn clippings and pruning clippings of any kind should never be placed where animals have access to them. In the case of the alpacas, further communication with the owner indicated that gardeners may have been responsible for leaves getting to the animals.

Rhododendron-like shrubs

A llama packer shared a sad tale. Eight llamas were used for a trek into the Huntington Lake area in southern California. The animals were tethered in a meadow. One of the llamas became ill and in 48 hours was dead. The owners searched the meadow and found a short shrub that was later identified as alpine laurel Kalmia latifolia. It was evident that the llamas had eaten some of the shrub. All eight llamas had access to the shrub, but only one sickened and died.

Unfortunately, no list of poisonous plants is ever going to mention all plants that may possibly cause problems. If every plant that has been incriminated as being poisonous were to be included, the list would be unmanageable and not be helpful. The plant, in this case, is a member of the heather family (Ericaceae). Alpine laurel KaImia latifolia is also called mountain laurel, calico bush, or ivybush. Its cousins, the rhododendrons and azaleas, are known to be poisonous to livestock. Rhododendrons have been responsible for the deaths of a number of llamas.

The heather family is a large family and in California alone, there are hundreds of species. Most of the heathers are non-poisonous and many are edible (blueberries, huckleberry, cranberry). Manzanitas, along with other shrubs make up the chaparral plant community that forms a dense shrub covering of the foothills of both the coastal range and the Sierras_

Poisonous genera of this plant family include Rhododendron (rhododendrons, western azalea, California rosebay), Kalmia (alpine laurel, mountain laurel, lambkill, sheepkill. dwarf laurel, bog laurel), Ledum (Labrador tea), Menziesia (mock azalea, rustyleaf), Pieris (Japanese pieris) and Leucothoe (Sierra laurel, black laurel).

The poison found in these shrubs is the same in all the species. It is a complex glycoside, andromedotoxin or grayanotoxin. The clinical signs exhibited are essentially the same for all the plants and all the animal species that are affected. Signs include anorexia, coughing, choking, retching, foaming at the mouth, vomiting, colic, paralysis, depression, groaning, and muscle twitching.

How then can owners hope to prevent plant poisoning on the trail? Generally, grasses are not a problem. Most of the cases of poisoning have been caused by consuming shrubs. They should avoid tying llamas to trees or shrubs that are unknown to them. They should walk the area to be grazed or browsed to see if any unknown shrubs are present.

The next question should be, “But how can they hope to learn all the plants where they go trekking?” It may not be possible to learn all about them on a single trip, but a knowledge of the shrubs, trees and other plants of the area will enhance the wilderness experience. They should purchase some booklets on the plants and the wildlife of their trekking area. Most large bookstores carry such items. The gift shops of National Parks and National Monuments abound in nature books.

Selected references

A book that ought to be in the library of every llama or alpaca owner should be Field Guide to Plants Poisonous to Livestock, Western US by Shirley A. Weathers, a llama owner, a book published by Rosebud Press, PO Box 270090, Fruitland, UT 84027-0090. The ISBN number is 0-9660397-3-4 (Owners).

Another book with excellent black and white drawings is Livestock Poisoning Plants of Arizona by Ervin M. Schmitz, et al. This book is published by the University of Arizona Press in Tucson, Arizona.

Other references include:

Burrows, G.E. and Tytle, RI., 2001. Toxic Plants of North America. Ames, Iowa State University Press. This is the most comprehensive book available in the United States. It covers the botany, identification and medical aspects of all the poisonous plants in all species of animals. It is expensive ($175.00), but it is a large book (1342 pages, 8.5" by 11” format).

Fowler. M.E., 1998. Plant Poisoning. In Fowler, M.E., 1998. Medicine and Surgery of South American Camelids, 2nd ed. Ames, Iowa State University Press, pp. 501-509 (technical).

Hoyt, Linda. A Reference Guide to Poisonous Plants. Greater Appalachian Llama and Alpaca Association. Obtain from the Author, RR 3 Box 2900, Skowhegen, ME 04976. For the Northeastern USA (Owners).