LOCOWEED, ASTRAGALUS, OXYTROPIS POISONING IN RUMINANTS AND HORSES
 
Description    ASTRAGALUS and OXYTROPIS species (locoweeds) can contain swainsonine, an alkaloid that inhibits lysosomal {alpha}-mannosidase and mannosidase II resulting in oligosaccharide accumulation in lysosomes with characteristic vacuolated cells. Locoweeds are among the most destructive and costly poisonous plants to livestock production in the Western United States. The toxin is cumulative; mild cases generally resolve within 1-2 weeks of stopping consumption of the plants but patients with chronic locoism do not recover. A high level of locoweed in the diet is required for a few months before signs begin. In addition to direct affects, a syndrome of abortion and congenital angular or flexion-extension type of limb deformities has been reported in the offspring of horses and ruminants consuming locoweed.
 
Species   Bovine, Equine, Caprine, Ovine
 
Signs   Abnormal behavior, aggression, changing habits, Abnormal forelimb curvature, Abnormal hindlimb curvature, Abnormal lung or pleural sounds, Abnormal proprioceptive positioning, Abortion or weak newborns, Ataxia, Blindness, Bunny hopping, Contracture fore limb, leg, Contracture hind limb, leg, Deafness, Decreased amount of stools, absent feces, constipation, Decreased mobility of forelimb joint, Decreased mobility of hindlimb joint, Decreased tearing, lacrimation, Difficulty in prehending or chewing food, Disoriented, Dryness of skin or hair, Dullness, Dysmetria, Dysphagia, Dyspnea, Excessive salivation, Excitement, Exercise intolerance, Female infertility, Generalized lameness or stiffness, Generalized weakness, Head, face, ears, jaw weakness, droop, Hyperesthesia, Icterus, Inability to stand, Increased frequency of urination, Increased respiratory rate, Opisthotonus, Paraparesis, Pica, Rough hair coat, Seizures or syncope, Sudden death, Tetraparesis, Tongue weakness, Torticollis, Trembling, Tremor, Underweight, poor condition, thin, emaciated, unthriftiness, ill thrift, Weight loss
 
References   Niles GA. Toxicoses of the Ruminant Nervous System. Vet Clin North Am Food Anim Pract 2017;33:111 [Web Reference]
Gibbons P. Cerebellar Disease of Ruminants. Vet Clin North Am Food Anim Pract 2017;33:59 [Web Reference]
Caloni F. Plants poisonous to horses in Europe. Eq Vet Educ 2015;27:269 [Web Reference]
Copyright © 2017 Cornell University College of Veterinary Medicine