Experimental intoxication by Myoporum laetum in cattle

Area of Science:

• Veterinary Toxicology
• Plant Poisoning in Livestock

Background:

• Myoporum laetum is a plant known to cause toxicity in animals.
• Understanding regional variations in plant toxicity is crucial for livestock management.

Purpose of the Study:

• To investigate the toxicity of Myoporum laetum in cattle.
• To evaluate clinical signs, pathological findings, and biochemical changes associated with Myoporum laetum ingestion.
• To assess potential regional differences in the toxicity of Myoporum laetum.

Main Methods:

• Administration of fresh Myoporum laetum leaves to 16 calves at varying doses.
• Collection of plant material from different geographical locations (Rio Grande do Sul, Brazil, and Rocha, Uruguay).
• Clinical observation, post-mortem examination, liver biopsies, and serum biochemistry analysis (AST, GGT, bilirubin).

Main Results:

• Ingestion of Myoporum laetum caused clinical signs including depression, abdominal pain, ruminal atony, ocular/nasal discharge, bloody feces, and icterus in 14 out of 16 calves.
• Histopathological examination revealed centrilobular hepatic necrosis.
• Serum liver enzymes and bilirubin levels were elevated.
• The plant collected from Santa Vitoria, Brazil, exhibited the highest toxicity, while the plant from Uruguay showed the least toxicity.

Conclusions:

• Myoporum laetum is toxic to cattle, inducing significant liver damage.
• Toxicity levels of Myoporum laetum can vary depending on the geographical origin of the plant.
• Prompt identification and management are essential for cases of Myoporum laetum poisoning in cattle.