Monensin concentrations measured in feeder cattle using enzyme immunoassay

Area of Science:

• Animal Science
• Veterinary Medicine
• Analytical Chemistry

Background:

• Monensin is a widely used ionophore feed additive in cattle production.
• Monitoring monensin levels in biological samples is crucial for assessing exposure and efficacy.
• Accurate analytical methods are needed to quantify monensin in various matrices.

Purpose of the Study:

• To determine the presence and concentration of monensin in fecal, urinary, and serum samples from heifers.
• To evaluate the relationship between monensin feed concentration and its detection in biological samples.
• To validate the use of a modified indirect enzyme immunoassay for monensin quantification.

Main Methods:

• Heifers were fed rations containing different concentrations of monensin (30, 60, and 90 g/ton).
• Fecal, urinary, and serum samples were collected at various time points.
• Monensin concentrations were measured using a modified indirect enzyme immunoassay.

Main Results:

• Monensin was detected in most fecal samples at measurable concentrations (micrograms/g; ppm).
• Monensin was present in the majority of serum and urine samples at low concentrations (ng/ml; ppb).
• Higher monensin feed concentrations resulted in increased detection levels across all sample types.

Conclusions:

• The modified indirect enzyme immunoassay is effective for detecting monensin in biological samples.
• Monensin is absorbed and excreted, with detectable levels found in feces, urine, and serum of treated heifers.
• Feed intake and monensin concentration directly influence the levels found in biological matrices.