Description    Urea is an inexpensive non-protein-nitrogen source in ruminant feeds but can be hazardous, especially in an animal unaccustomed to urea in the diet. The addition of anhydrous ammonia to molasses, hay, and silage has led to excitability ('bovine bonkers', 'bovine hysteria') in cattle eating those feeds and in calves nursing those cows; this syndrome has also been reported to occur in sheep and goats. Accidental exposure or contamination of water by liquid nitrogenous fertilizer has also caused toxicity; direct chemical irritation of the cornea can be caused by exposure to fertilizer containing anhydrous ammonia. Excessive consumption of raw soybeans or soybean derivatives can cause rapid ammonia release.
Species   Bovine, Caprine, Ovine
Signs   Abdominal distention, Abnormal behavior, aggression, changing habits, Abnormal proprioceptive positioning, Abnormal tooth color, Anorexia, Arrhythmia, Ataxia, Blepharospasm, Blindness, Bloat in ruminants, Bloody stools, feces, hematochezia, Bradycardia, Circling, Colic, Coma, Constant or increased vocalization, Corneal edema, opacity, Corneal neovascularization, Corneal ulcer, Cyanosis, Dehydration, Diarrhea, Dullness, Dysmetria, Dyspnea, Excessive salivation, Excitement, Fever, Generalized weakness, Head pressing, Head shaking, Hyperesthesia, Hypothermia, Inability to stand, Increased frequency of urination, Increased respiratory rate, Jugular pulse, Lacrimation, Miosis, Mucoid nasal discharge, Mydriasis, Neck weakness, Nystagmus, Ocular pain, Opisthotonus, Photophobia, Polydipsia, Polyuria, Propulsion, Reluctant to move, Rumen hypomotility or atony, Seizures or syncope, Sudden death, Sweating, Tachycardia, Tetany, Trembling, Tremor, Underweight, poor condition, thin, emaciated, unthriftiness, ill thrift, Vomiting or regurgitation, Weight loss
References   Niles GA. Toxicoses of the Ruminant Nervous System. Vet Clin North Am Food Anim Pract 2017;33:111 [Web Reference]
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