2.2. Plasma sampling and analyses
Cattle were bled monthly during the winter feeding period and fortnightly during the grazing and finishing periods.Samples were collected at 0800 h into test tubes containing EDTA by puncturing the coccygeal vein. The test tubes were immediately wrapped with aluminum foil to protect them from natural light. Subsequently, the samples were centrifuged at 2122 × g for 5 min at 4 ◦C, and the plasma was extracted and frozen at −80 ◦C until the analyses were performed.