Production performance and oxidative stability of milk enriched with n-3 fatty acids in Holstein cows fed flaxseed meal

Abstract

Six Holstein cows were used in a replicated 3 × 3 Latin Square design to investigate the effect of flaxseed meal on production performance and oxidative stability of milk enriched with n-3 fatty acids. Flaxseed oil was abomasally infused to all cows at 243 g·d−1 which increased milk concentration of α-linolenic acid from 3.08 (pretrial) up to 53.0 mg·g−1 fat. On a dry matter basis, dietary treatments were canola meal (CM; 165 g·kg−1), flaxseed meal (FM; 165 g·kg−1), and CM (165 g·kg−1) + vitamin E (VE; 300 IU·kg−1). Pre-planned contrasts were CM vs. FM and VE vs. FM. No difference was observed on dry matter intake, milk production, and yield of milk protein, and lactose for any of the contrasts evaluated. However, fat yield tended to be lower with FM relative to CM but was not different from VE. Milk enterolactone concentration was 6.8-fold greater with FM than with CM, whereas milk tocopherol was increased by 3.4-fold with VE relative to FM. Increased concentrations of enterolactone or tocopherol were not efficient to significantly modify the time course of appearance of propanal, hexanal, hept-cis-4-enal, and 1-octen-3-one in milk during storage evaluated for 10 d at 4 °C.