By Rona Sullivan – There are a multitude of plants containing materials toxic to dairy goats if eaten in sufficient quantity. Some of those plants are well-known, some quite rare, some useful, and still others are valued as ornamentals. Poisonous plants for goats are best grouped by the type of poison they contain, or the effects of their toxins, or by their parts that contain the poison. Some plants may contain more than one poisonous principle.
POISONOUS PLANTS FOR GOATS BY CATEGORY
• Volatile or essential oils as poisonous principle: Baneberry, buttercups, crowfoot, ground ivy, lobelia, snakeberry, spurge, white cohosh.
• Saponin containing plants: Bagpod, coffee weed, purple sesban, rattlebox, soapwort.
• Photosensitizing plants: Buckwheat, goat weed, klamath weed, lantana, rape, St. John’s Wort.
• Plants that cause mechanical injury: Clover, cocklebur, downy brome grass, sand bur, squirrel tail grass.
• Tannic acid as a poisonous principle: Oaks
• Poisonous principle not fully known: Inkberry (poke weed)
• Resins as poisonous principle: Some discarded Christmas trees, namely Ponderosa pine needles.
These poisonous plants for goats contain, under certain conditions, prussic acid (hydrocyanic acid), which is a deadly poison known to interfere with the blood’s ability to carry oxygen. Death in these cases is usually rapid and absent of outward symptoms. Members of the Prunus family of plants, especially wild cherries, are dangerous.
PEACHES, PLUMS AND OTHER STONEFRUITS
Wilting of the green leaves caused by frost, storm damage, or cutting precipitates changes to glucoside found in the leaves, changing it to hydrocyanic acid (HCN) and sugar. Those sweet, wilted leaves are more attractive to goats than fresh foliage. HCN content varies widely; but under some conditions, a few handfuls of leaves are enough to kill much larger animals such as horses or cows.
So, a cyanide poisoning should be suspected when sudden death of animals follows windstorms or an early, sharp frost. These leaves apparently lose their poison after they have become dry; it’s the limp, green or partially yellowed leaves that hold the greatest danger. Stone-fruits also belong to this group.
COMMON CYANOGENETIC PLANTS
Sudan grass and sorghums are also cyanogenetic plants. These plants are also deadly when damaged or frozen. Sprouts following an early frost are particularly dangerous. However, very little Sudan grass poisoning occurs from animals trampling down the plants and later eating them, although this is often listed as dangerous. In dry weather, Sudan grass is often pastured to the ground with no ill effects. After Sudan grass has been repeatedly frozen and the plants are completely dead they are safe, though not very valuable in the goat pasture.
Once frozen, sorghum, sorghum/Sudan hybrids, or their aftermath, should not be pastured. As long as the plants show any green color they may be poisonous. Both frosted sorghum and Sudan grass can be best and most safely utilized by ensiling them for at least two weeks before offering as goat feed. Normal ensilage fermentation safely eliminates the poisonous principle.
Common milkweed plant, a perennial that grows three to four feet high, has a heavy stem and leaves, and is frequently found in pastures. The milky white sap is sticky and has a bitter taste, but goats may be tempted to browse on the uppermost, tender leaves when better forage isn’t abundant. Remove plants by spading, pulling, cutting or plowing extensive areas, instead planting cultivated crops for a year or two.
Horse nettle is a perennial plant, two-feet-high, with spiny stems and leaves, and smooth orange-yellow berries. The fruits are more toxic than the foliage. It’s a common plant in grasslands and fields and is a member of the nightshade family.
Black nightshade is an annual plant, two feet high, with many branches. The leaves may present as either smooth or hairy. The stems angled in the cross-section are sometimes spiny. Clusters of white flowers, one-quarter inch across, bloom in midsummer and are followed by small, black fruits. Both the foliage and green berries are toxic. The ripe berries are not poisonous. Black nightshade is widely distributed.
Mountain laurel is a natural evergreen shrub that grows upwards of five-feet tall and has glossy green magnolia-looking leaves. Flowers appear in clusters at the ends of branches. Goats have been known to eat the leaves in early spring when little foliage is available. Weakness, nausea, salivation and vomiting are symptoms of poisoning. The preventative is to keep livestock out of areas where mountain laurel is abundant.
Additional cyanogenetic plants, (Glucosides—Glycosides): Arrow grass, black locust, blue cohosh, broomcarn, buckeye (horse chestnut), cherry, choke-cherry, corn cockle, dogbane, elderberry, hemp, horse nettle, Indian hemp, ivy, Johnson grass, kafir, laurel, leucothoe, lily of the valley, maleberry, marijuana, milkweeds, milo, nightshade, oleander, rhododendron, sevenbark, silver sneezewood, sorghum, stagger brush, Sudan grass, velvet grass, white snakeroot, wild hydrangea.
Photodynamic means that photo-sensitive animals can get reactions. Conditions that are conducive to a reaction occurring are:
1. Pink areas of un-pigmented skin.
2. Ingestion of sufficient quantities of the offending plant.
3. Exposure to bright sunlight.
In typical cases, a goat may suddenly become sore on the white areas of their body. Whole areas of white skin may rise up and peel off. White goats may become severely affected and die from this condition.
Additional plants which can cause this type of photo-sensitization include: Rape, alsike clover, buckwheat, lantana, St. John’s Wort, and ornamental hypericus. St. John’s Wort and ornamental hypericum both have showy, golden-yellow flowers that are not readily ingested. White goats do frequently become badly ‘‘sunburned’’ when they are on rape pasture in bright sunny weather, if they have little or no shade. Alsike clover or other legumes may produce these symptoms in dairy goats under the aforementioned conditions.
PLANTS THAT PRODUCE MECHANICAL INJURY
A number of plants may have spiny coverings, long beards, or fine hairs, which upon ingestion, may cause mechanical injuries or form hairballs in the stomach and intestines. Sandbur, downy brome grass, squirrel-tail grass, poverty grass, mesquite, cocklebur and clover are some of those offending plants.
The following alkaloid-containing plants are rarely eaten, except to stave off starvation. Deaths from alkaloid-containing plants usually result from severe digestive disturbances, pain, and nervous symptoms. Goats, and other animals usually die in convulsions.
Poison hemlock needs dry land to grow and is often found in gardens as an ornamental plant. It is a hollow-stemmed biennial, about four-feet high, with double compound leaves resembling parsley, and a large white taproot like parsnip. Flowers are often incorporated into large mixed flower sprays in rural churches and at social events. Flowers are showy, umbrella-like clusters, and appear in late summer. The poison is a volatile alkaloid coniine.
Buttercups contain an acrid, volatile alkaloid amenenol, strong enough to blister the skin, causing inflammation of the intestinal tract. Cattle and goats poisoned by buttercups produce bitter milk of a reddish tint. The toxic material volatilizes and is lost when buttercups are dried, such as in hay. A heavy growth of buttercups is an indication of low soil fertility. Have the soil analyzed, applying ground lime and fertilizers accordingly. The increased grass growth will soon crowd out buttercups.
Other alkaloid-containing plants: Aconite, allspice, black snake root, bloodroot, boxwood, celandine, common poppy, crotalaria, crow poison, death camas, dicentra, false hellebore, false jessamine, fume wort, hellebore, hemp, horse nettle, Indian hemp, Indian poke weed, jimson weed, larkspur, lobelia, lupines, marijuana, mayapple, monkshood, moonseed, pink death camas, poison darnel, poison pokeweed, rye grass, rattleweed, rock poppy, spider lily, spotted cowbane, stagger grass, stagger weed, sweet shrub, thorn apple, varebells, wild parsnip, wolf’s-bane, yellow jessamine.
POISONOUS PLANTS FOR GOATS
Outside pastures, they are found in wooded areas and/or yards. Comparatively few plants containing poisons grow in areas usually used as pastures. Bracken fern is very common in wooded areas or unimproved pasture. Most animals will not eat bracken fern if there is adequate pasture or other feed. In ruminants such as goats, bracken fern must be consumed over a period of several weeks before toxicity signs develop.
Clippings that should not be fed to dairy goats are: Yew, delphinium, oleander, larkspur, lily-of-the-valley, laurels and rhododendrons (includes mountain laurel and azaleas), and poison hemlock, which falls in among the toxic alkaloid offenders, as well as into this ornamental category
AN OUNCE OF PREVENTION
Last, but not least, make sure to fence out goats from ornamental plants. That means making any livestock and homestead fencing strong enough to keep them from coming into the yard. I use cattle panels anywhere that the goats can see me. If the goats deem their owner or other members of the family as a part of their flock, and there is a point at the fence where they can see people, that is the place to strengthen. Some outdoor or indoor ornamental plants are highly toxic, so it is best not to feed clippings from ornamental plants.
Symptoms of the affected goats are listlessness, weight loss and possible small hemorrhages on the mucous membranes. Goats have been known to die from internal hemorrhages.
The USDA and the State Departments of Agriculture, through local extension offices and internet, offer informational bulletins for recognizing those poisonous plants in any local area. I sometimes peruse them, but mostly depend on my Merck Veterinary Manual and my Audubon field texts with photos. I especially recommend North American Trees and North American Wildflowers.
Good health to you and your goats, and watch out for these poisonous plants for goats.
Originally published in the March/April 2009 issue of Dairy Goat Journal and regularly vetted for accuracy.