Effects of dietary energy allowance in grass silage-based diets during the dry period on production responses and utilization of body reserves in dairy cows

The aim was to study if overconsumption of grass silage during the far-off dry period (FODP) and decreasing feed allowance in close-up dry period (CUDP) affect body condition score (BCS) and body weight (BW) changes, as well as lactation performance and body tissue mobilization after calving in dairy cows. Control diet (CON) was fed to meet the metabolizable energy (ME) requirements, the test diet (HEI) averaged 144% and 119% of ME requirements in the FODP and CUDP, respectively. All cows were fed concentrates in the CUDP (30% of ME d(-1)). Plasma non-esterified fatty acids (NEFA) were lower and insulin tended to be higher in HEI vs. CON prepartum. No dietary effects in accretion or mobilization of body reserves were observed, and accordingly no differences in silage DMI, ME balance and plasma parameters postpartum were detected. Concentrate DMI and milk yield tended to be lower in HEI vs. CON during early lactation.