Dangerous Pasture and Hay Crops, Poisionous Plants, Toxic Plants

Sudan Grass - (sorghum)
including Improved Varieties

Members of the Sorghum family contain dhurrin, a glucoside that breaks down to release hydrocyanic acid also known as prussic acid. A sudden disruption
of growth such as frost, drought or cutting, causes prussic acid to be released inside the plant at a more rapid rate. High prussic acid levels may be lethal to cattle and horses. Prussic acid will breakdown in one to two weeks, so material made into hay or silage is safe to use after curing.

Nutritional Concerns and Animal Health Hazards

Prussic acid poisoning is a concern in feeding Sorghum, Sudan grass, or Sorghum-Sudan grass hybrids. In the stomach, these compounds are converted into prussic acid, which is easily absorbed into the blood. High blood levels of prussic acid interfere with respiration and cattle can soon die from respiratory paralysis. Horses should not be allowed to graze these plants as they may develop cystitis syndrome. This condition looks like colic with accompanying bloody urine and can be fatal to horses. Affected animals may show a staggering gait and urine dribbling. Pregnant mares may abort. There is no treatment for this poisoning and poor prognosis of recovery.

Nitrate poisoning and formation of toxic silo gas can be a problem with Sorghum-Sudan grass. High nitrate levels are only a problem under abnormal growing conditions such as:

* High nitrogen fertilization caused by heavy fertilizer or manure applications or following legume plow down.
*   Prolonged drought followed by rain.
* Any condition which kills the leaves while the roots and stems remain active will initiate accumulation of nitrates (frost, hail, grazing and trampling, or sometimes drought and overcast weather).

If you suspect high nitrates in the forage, have it tested .

This Factsheet was authored by:
Beth Wheeler, Dairy Nutrition Specialist, OMAFRA, Kemptville.
Joan McKinlay, Soil and Crop Specialist, OMAFRA, Markdale.
For more information...Joan McKinlay at jmckinla@omafra.gov.on.ca
http://www.gov.on.ca/OMAFRA/english/crops/facts/98-043.htm

BLISTER BEETLES IN ALFALFA HAY
Blister Beetles Epicautaspp., Meloidae, COLEOPTERA

DESCRIPTION (several species)
Adult - Blister beetles are slender insects 12 to 19 mm long. They have prominent heads and may be black with yellow margins or black and yellow striped.
Egg - The yellow cylindrical eggs are 1.3 to 1.8 mm long.
Larva - Each of the seven larval instars differ in size, shape and color. They can be 2.5 to 13 mm long, slender to plump, and white to yellow or brown. All instars have three pairs of short ventral legs and 12 body segments, excluding the head.
Pupa - The white, 10-mm-long pupae darken gradually beginning with the eyes.

BIOLOGY              Learn about storing your hay.
Distribution - Blister beetles are found throughout the continental U.S. and agricultural areas of Canada. Although fairly common in North Carolina, they are infrequently pests of importance.
Host Plants - Blister beetles have a wide host range. Important vegetable hosts include potato, tomato, melon, eggplant, sweet potato, bean, pea, cowpea, pumpkin, onion, spinach, beet, carrot, pepper, radish, corn, and cabbage. The beetles feed on alfalfa and soybean foliage. The real problem with blister beetles is their toxicity to livestock, especially horses, when accidentally eaten in feed. The beetles produce cantharidin, an irritant that causes painful blistering when the insects are handled. The cantharidin remains in the beetle's body even after it dies. That becomes a problem when alfalfa is swathed, during which dead blister beetles can be incorporated into the hay as it is made. Thus, livestock can accidentally consume whole beetles or their squashed remains when the hay is fed.

Horses are especially susceptible to blister beetle poisoning. Consumption of 25 to 300 beetles can kill a mature horse. Cattle and sheep are much less susceptible, but blister beetles will reduce digestibility of hay and may throw cattle off feed. Also, cantharidin is a stable compound that withstands decomposition even when it is dried or heated; the hay will keep its toxicity in storage.

Symptoms that include:
*   colic
*   blisters on the tongue and in the mouth
*   blood or intestinal lining discharge in stools
*   problems with urination
*   bloody discharge in urine
*   straining
*   elevated temperature
*   depression
*   increased heart and respiratory rates
*   dehydration
*   sweating
*   diarrhea

Because the toxin is absorbed and then excreted with the urine, severe inflammation of the urinary tract is a common sign of poisoning. Death may occur within 24 hours, and treatment with mineral oil by stomach tube is recommended but not always very effective. If blister beetle poisoning is suspected, contact a veterinarian immediately.

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