The effects of energy concentration in roughage and allowance of concentrates on performance, health and energy efficiency of pluriparous dairy cows during early lactation.

The aim of this study was to investigate the effects of different energy supplies from roughage and concentrates on performance, health and energy efficiency during early lactation. For this purpose an experiment was conducted containing 64 pluriparous German Holstein cows from 3 weeks prepartum until 16 weeks postpartum. During dry period all cows received an equal dry cow ration. After calving, cows were assigned in a 2 × 2 factorial arrangement to one of four groups, receiving either a moderate (MR, 6.0 MJ NEL) or a high (HR, 6.4 MJ NEL) energy concentration in roughage and furthermore moderate (MC, 150 g/kg energy-corrected milk (ECM)) or high amounts of concentrates (HC, 250 g/kg ECM) on dry matter (DM) basis, which were allocated from an automatic feeding system. Higher allocation of concentrates resulted in an increase of DM intake at expense of roughage intake. HC cows had a higher milk yield than MC cows, whereas ECM was higher in HR cows due to a decrease of milk fat yield in MR groups. Energy balance and body condition score were elevated in HC cows, but no differences occurred in development of subclinical ketosis. Furthermore, energy efficiency variables were lower in HC groups because the greater energy intake was not associated with a considerable elevation of milk yield. Consistency of faeces did not indicate digestive disorders in any of the treatment groups although the faecal manure score was significantly lower in HR groups. Our results underline the importance of a high energy uptake from roughage, which can contribute to an adequate performance and beneficial efficiency, especially at lower amounts of concentrates in ration. Feeding concentrates on an average amount of 9.4 kg/d compared to 6.4 kg/d on DM basis improved the energy balance in our trial, but without consequences for metabolic blood variables and general health of the cows.