Guajillo

Acacia berlandieri Benth.

Fabaceae (Legume family)


Description

Guajillo is a nearly thornless shrub to small tree in the Legume family. The plant height varies greatly, but it can grow up to 15 feet tall.

Guajillo leaves are arranged like those of mesquite but are smaller. The sweet-scented, white to yellow flowers are clustered in dense groups. The plant produces a flattened, bean-type legume fruit that is four to six times longer than it is wide.

The forage value of guajillo is poor for livestock and wildlife except under under drought conditions. However, it may be toxic when consumed as a major part of the diet.


Habitat

Guajillo grows on a variety of soil types but is most prolific on ridges and shallow soils. Found mainly in the South Texas Plains and southwest Texas, it is less common in the southern Edwards Plateau and Trans-Pecos regions. It also grows extensively in northern Mexico.


Toxic Agent

Guajillo poisons sheep, goats and possibly cattle. The leaves contain excitatory amines, principally N-methyl-β-phenethylamine and tyramine. Overconsumption may cause a condition in sheep and goats known as guajillo wobbles, which may be followed by death. The lethal dose of plant material for sheep and goats has not been determined. The toxic dosage is 15 times the animal's weight in leaves and fruit consumed over several months.


Signs of Livestock Ingestion

Signs of guajillo poisoning include: Guajillo wobbles or limber leg in sheep and goats, an uncoordinated, rubbery action, usually in the rear legs; Downed animals remain alert with normal appetite; Death.

At first, leg dysfunction appears only when animals are forced to move, but after several days the animal becomes unable to rise and may die. These signs are generally not apparent unless the animal has eaten guajillo almost exclusively for at least 9 months. Research in sheep, goats and cattle has shown that the amine compounds can cause excessive release of stress hormones. As a result, certain reproductive functions (such as normal release of reproductive hormones, estrus, ovulation and testicular development) can be suppressed. Reduced pregnancy rates have been reported in nannies.


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