Abstract
The aim of this study was to determine the effect of the weaning calves at 2 ages (early vs. late) and 2 weaning paces (abrupt over 3 d vs. gradual over 14 d) on plasma oxylipids. Seventy-one dairy calves (38.8 ± 4.4 kg, body weight ± standard deviation), blocked by sex and body weight at birth, were randomly assigned in a 2 × 2 factorial arrangement of treatments. The factors were weaning age (early (6–7 weeks) vs. late (8–9 weeks)), and weaning pace (abrupt (3 weaning steps over 2 d) vs. gradual (7 weaning steps over 14 d)), generating 4 treatment groups: early-abrupt, early-gradual, late-abrupt, and late-gradual. Blood samples were collected from the jugular vein one day pre-weaning, and one day post-weaning. Oxylipids concentration was measured by liquid chromatography-tandem mass spectrometry. Fatty acid profile (including nonesterified fatty acids) was also assessed. Weaning pace, age, pace × age, body weight at birth, and sex were included as fixed effect and cohort was included as random effect in the model. Linoleic acid derivatives 13- oxooctadecadienoic (OxoODE) and 9-OxoODE had a greater concentration in calves abruptly weaned when compared with that for gradually weaned calves. Calves weaned gradually showed a greater concentration of 9- hydroxyoctadecadienoic (HODE), 13-HODE, 12,13- dihydroxyoctadecenoic (DiHOME), 9,10-DiHOME, all linoleic acid-derived compared with that for abruptly weaned calves. Anti-inflammatory oxylipid 17,18- dihydroxyeicosatrienoic (DiHETE), an eicosapentaenoic acid (EPA) derivative, was greater in calves abruptly weaned compared with gradual. Overall, pace of weaning affected the plasma concentration of oxylipids, demonstrating that weaning pace affects the oxylipids status involved in inflammation in dairy calves.