VLD 421: Veterinary Clinical Biochemistry and Laboratory Diagnosis-II (0+1)

HERBICIDES

Appreciation and Differentiation of Symptoms caused by Herbicides

1.	Chlorophenoxy compounds/ Phenoxy acid derivatives/ Phenoxy herbicides	Gastrointestinal signs includes rumen stasis in cattle, and vomition, diarrhoea, salivation etc. in dogs and pigs Neuromuscular signs include depression and muscular weakness in cattle, and ataxia, posterior weakness (particularly pelvic limbs) and periodic clonic spasms (at high doses) in dogs. Sublethal doses, singly or repeatedly produce tenseness and muscular weakness.
2.	Dinitro compounds/Dinitrophenols	Signs include restlessness, loss of appetite, rapid respiration, thirst, muscular weakness, prostration, cyanosis, convulsions, coma and death. The illness runs a rapid course i. e. there is death or recovery within 24 to 48 hours. If production of heat exceeds the capacity for its dissipation, fatal hyperthermia may result. Chronic exposure to dinitro orthocresol may produce fatigue, restlessness, unusual thirst,loss of weight and cataract.
3	Bipyridyls compounds	Diquat toxicosis: Anorexia, gastritis, and severe loss of water into the lumen of the GI tract. Signs of renal impairment and CNS excitement occur in severely affected animals. The animals die during convulsions. Paraquat poisoning : Gastroenteritis (early action) and finally (2-7 days) difficult respiration due to pulmonary oedema and alveolar fibrosis. Animals that survive first few days develop dehydration, pallor or cyanosis, tachycardia, tachypnoea, harsh respiratory sounds, and emphysema or pneumomediastinum.