Synonyms

No known synonym

Name of the disease in English

Poisoning by a photosensitizing plant

The disease in brief

Photosensitization which makes the skin very sensitive to light can come from plant poisoning:

-Plants containing a photosensitizing substance cause primary photosensitization: Lady's thumb (Plygonum persicaria), buckwheat (Fagopyrum sp.), St. John's wort (Hypericum sp.),forage legumes: White clover (Trifolium repens), hybrid clover (Trifolium hybridum), alfalfa (Medicago sativa), vetch (Vicia sp.)

-Plants hepatotoxic  such as lupin (Lupinus sp.), sorghum (Sorghum sp.) and sporidesmin (a mycotoxin that develops on dried grass when the rain returns): They cause secondary photosensitization.

-There phylloerythrin, photosensitizing, is a derivative of chlorophyll which is formed in the digestive tract of ruminants and evacuated partly in the feces, partly by the liver via the bile if all goes well; if liver function is impaired or the evacuation of bile is prevented, phyloerythrin is found in the blood and in the skin. It causes secondary photosensitization.

Clinic & diagnosis

Photosensitization is suspected when specific lesions are seen in specific locations or with particular behavior:

-The hair is bristling, or the skin is red and painful to the touch, then the skin loses its hair, takes on a burnt or cardboard appearance (sometimes peeling off in shreds), finally becomes crusty, thickened and grayish.

-These lesions are limited to white or light skin, or hairless areas, or the udder or teats or muzzle or lips; or the bovine may fear light, be restless or exhibit colic-like symptoms by tapping its belly.

The animal may present hyperthermia

Typical sign of the disease

No description

Pictures

See below

Diagnostic formulas

No description

Differential diagnosis

-Leptospirosis UR15

– Intoxication/Senecio-N27 

– Congenital calf porphyria OR “pink tooth disease” – DR42 

Confirm a suspicion?

The toxic plant can be found by a field survey. It is also possible to confirm secondary photosensitization by taking blood on EDTA to measure gamma GT, which is a marker of cholestasis.

Prognosis and treatment

Put the cattle in the shade and protect them from the toxin, but also put in place:

-Anti-inflammatory treatment is useful in non-pregnant patients:

- Local treatment of skin lesions (disinfection, protective creams)

The prognosis is reserved in all cases; photosensitization secondary to liver damage may remain of no economic value after recovery.

Prevention

Identify risky plants in cattle feed or their environment; remove them from the ration or reduce their quantity; deprive cattle of access to risky wild plants.

References

Jouve C. (2009) Contribution to the development of a website on plant toxicology in ruminants: Monographs of the main plants incriminated according to data from the CNITV-Th. Med .Vet. Université Claude Bernard-Lyon1 271p