Copper poisoning in four llamas

Area of Science:

• Veterinary Medicine
• Toxicology
• Animal Nutrition

Background:

• Copper is an essential trace element for livestock, but excessive intake can lead to toxicosis.
• An imbalanced copper:molybdenum ratio in feed can exacerbate copper accumulation and toxicity.
• Llamas are susceptible to copper poisoning, particularly when dietary management is suboptimal.

Purpose of the Study:

• To investigate a case of copper poisoning in llamas.
• To determine the dietary copper levels and copper:molybdenum ratio associated with the toxicosis.
• To characterize the clinical and pathological findings, and compare susceptibility between adult and juvenile llamas.

Main Methods:

• Analysis of total dietary copper and copper:molybdenum ratio in feed.
• Monitoring of clinical signs including anorexia and lethargy.
• Measurement of liver enzyme activities (aspartate amino transaminase, lactate dehydrogenase, gamma-glutamyl transferase) and serum copper concentration.
• Gross necropsy and histological examination of liver tissues.
• Analysis of hepatic copper concentrations.

Main Results:

• Copper poisoning occurred in 1 adult and 3 juvenile llamas due to excessive dietary copper (36 mg/kg) and an unfavorable copper:molybdenum ratio (16.6:1).
• Clinical signs included acute anorexia and lethargy, with elevated liver enzymes and serum copper preceding death.
• Histological findings revealed acute massive hepatic necrosis, bile duct proliferation, and altered hepatic architecture.
• Juvenile llamas exhibited signs of poisoning at lower hepatic copper concentrations compared to adults.

Conclusions:

• Dietary management of copper and molybdenum is critical in llamas to prevent toxicosis.
• Acute copper poisoning in llamas presents with specific clinical and pathological findings.
• Age influences the threshold for copper toxicity, with juveniles being more susceptible at lower copper loads.