Effects of PCR-confirmed subclinical paratuberculosis on retinol and β-carotene levels in dairy cattle

Abstract

In the present study, the effects of IS900 PCR-confirmed subclinical paratuberculosis on serum beta-carotene and retinol concentrations in dairy cattle were investigated. A total of 30 multiparous, clinically normal, paratuberculosis non-vaccinated Holstein dairy cows, ages 3 to 9 years old were tested. Fifteen of the 30 cows were diagnosed as having subclinical paratuberculosis by IS900 PCR on faecal samples (Group 1). The remaining 15 cows, negative to three independent tests for paratuberculosis, were classified as the healthy control group (Group 2). Serum retinol and beta-carotene levels were analyzed by colorimetric assays on serum samples from all 30 cows. There were no differences regarding the serum retinol and beta-carotene concentrations between cows with and without paratuberculosis.