24. GROUNDSEL, RAGWORT

Senecio spp.

(daisy family)

TOXICITY RATING: High. Senecio is very toxic both fresh and in hay, affected animals often die.

ANIMALS AFFECTED: All grazing animals may be affected, but horses and cattle are particularly susceptible. Young, growing animals are more susceptible than mature animals, and fetuses may be affected in utero.

DANGEROUS PARTS OF PLANT: All above ground parts, with higher concentrations in the seeds.

CLASS OF SIGNS: "Poor doer", weight loss, unthriftiness, poor hair coat, anorexia, behavioral changes, sunscald, liver failure, jaundice, death.

PLANT DESCRIPTION: There are several species of ragworts. In Indiana they are perennial herbs about 1 foot tall (rarely to 3 feet tall). Basal leaves are spoon-shaped and stem leaves are alternate and pinnately cut into narrow segments. At the top of the plant are clusters of yellow composite (daisy-like) flowers with yellow ray petals. Most ragworts grow along roadsides, in pastures, and in wet or waste areas. Senecio aureus (golden ragwort) blooms in early spring in woodlands or meadows statewide (fig. 24).

SIGNS: Poisoning from ragwort may be chronic or acute, with the chronic form more commonly encountered. The disease is also called "seneciosis" or "pictou" disease. The toxic principle is a mixture of pyrrolizidine alkaloids which adversely affect the liver. The plant grows in late winter through the spring and tends to be incorporated in first cutting hays. Animals may not show signs until the fall or winter after eating this hay for some time. In horses especially, the clinical signs may develop months after ragwort hay is no longer being fed, making an accurate diagnosis difficult.

In the rare acute toxic case (20 or more pounds consumed in a short period of time for a horse), the animals may become very excited and violent, with gastrointestinal signs (colic, diarrhea), dilated pupils and increased heart rate, and sudden death. Chronic toxicity is far more likely to be encountered. The animals must consume the plants fresh or in hay for weeks to months before clinical signs appear. The toxin is cumulative, and continues to damage the liver until enough of the liver is affected to cause clinical signs. Approximately 50 to 150 pounds of ragwort needs to be consumed by a horse before signs appear. Cattle are more resistant to the toxic effects than horses and reports have indicated that cattle may be fed small amounts of ragwort hay without ill effects. There are reports that sheep are relatively resistant to this toxin.

In chronic cases, the first clinical signs are weight loss, "poor doer", unthriftiness, and a decreasing appetite. These and all clinical signs are reflective of the gradual loss of liver function. Later, nearly total anorexia, jaundice, behavioral changes (depression, drowsiness, confusion, aimless wandering, "sleepy staggers") and an uncoordinated gait may manifest. Some animals will head press, where the animals lower their head and press it and/or their neck against a sturdy object. Some animals have been noted to stumble over objects and to appear blind. Since the liver is responsible for degrading diet-derived plant pigments, these pigments are not destroyed, and enter into the circulation. The pigments react with light and can cause photosensitization and sunscald, especially to the more lightly pigmented areas. Near the end of the course of the disease, abdominal fluid may build up ("ascites"), and fluid may build up under the skin in the "lower" parts of the body (throat latch, under the abdomen, legs), and the animal may develop diarrhea. Loss of blood's ability to clot (another important liver function) may be present as well, with bruising and hemorrhaging noted (which may occur in the urinary tract and present as red to black colored urine). Just prior to death, the animal may collapse and go into convulsions. Once clinical signs become apparent, the chances that the animal will recover are very unlikely.

In cattle, other signs can be noted in addition to those listed above. The muzzle may become dry and scaly, and animals may strain to defecate, causing the rectum to prolapse. Affected animals will produce milk with an unusual odor. It is not known, but it is suspected, that this milk may be toxic.

FIRST AID: Once clinical signs are present, recovery is less likely. Newer and experimental treatments exist, but the prognosis is poor for survival. Remove all ragwort hay from animals and provide proper feed. A veterinarian may be able to provide some treatment or referral to an animal hospital for care of valuable animals, but even this treatment option has a low rate of success, especially for severely affected animals.

SAFETY IN PREPARED FEEDS: All plants that contain pyrrolizidine alkaloids remain toxic in hay, silage and other feeds. Horses should never be allowed to consume any feed containing ragwort. Ruminant (cattle primarily) may be able to tolerate small amounts of ragwort hay if it is fed intermittently and enough good forage is made available. The recommendation for cattle is that ragwort hay be fed at 10% or less of the body weight over the course of a year. This would amount to 50 pounds per year for a 500 pound animal. If at all possible, the ragwort hay should never be fed, even to cattle.

PREVENTION: Learn to recognize ragwort both fresh and in hay, and only deal with reputable feed dealers. Never feed ragwort to horses, and it is advisable not to feed it to cattle. If ragwort hay must be fed to cattle, follow the guidelines listed above.

NOTE: Plants that also may cause similar signs due to the presence of pyrrolizidine alkaloids: Stinking willie (Senecio jacobea), common groundsel (S. vulgaris), fiddleneck and tarweed (Amsinckia spp), rattlebox (Crotalaria), Hound's tongue (Cynoglossum officinale), heliotropum (Heliotropium spp) and salivation Jane (Echium lycopsis). Ragwort poisoning is a major problem in the western United States and may be increasing in the East. The greatest risk in Indiana seems to be in the southwestern counties where cressleaf groundsel (Senecio glabellus) grows. Another species, prairie ragwort (Senecio plattensis), occurs in the northern half of the state. Ragwort growing in alfalfa fields has been reported.