Oak (Quercus incana) leaf poisoning in cattle

Area of Science:

• Veterinary Toxicology
• Ruminant Health
• Plant-Animal Interactions

Background:

• Oak (Quercus spp.) poisoning is a significant concern in livestock.
• Immature leaves of Quercus incana contain high levels of tannins and phenols.
• Cattle are susceptible to toxicosis from ingesting certain plant species.

Purpose of the Study:

• To investigate the clinical signs, clinicopathological findings, and pathological basis of oak poisoning in cattle.
• To determine the toxic components in Quercus incana leaves responsible for the observed effects.
• To document the high mortality rate associated with this poisoning event.

Main Methods:

• Clinical observation of affected crossbred cattle.
• Necropsy and histopathological examination of affected animals.
• Biochemical analysis of blood and urine samples.
• Quantification of tannins and phenols in ingested oak leaves.

Main Results:

• Mortality rate reached 70% in affected cattle.
• Clinical signs included anorexia, severe constipation, brisket edema, and bloody, mucous-coated feces.
• Significant clinicopathological changes included anemia, elevated liver enzymes (AST, ALP), elevated kidney markers (urea nitrogen, creatinine), hyperbilirubinemia, proteinuria, hypoproteinemia, and hypocalcemia.
• Oak leaves contained 97.7 mg tannic acid equivalent and 5.8 mg catechin equivalent/g of dry matter.

Conclusions:

• Ingestion of immature Quercus incana leaves caused severe nephrotoxicity and hepatotoxicity in cattle.
• Hydrolyzable tannins and simple phenols in oak leaves are the likely causative agents.
• Prompt identification and removal of the toxic forage are crucial for mitigating losses in cattle herds.