Roughage intake of simmental, brown Swiss and Holstein Friesian cows fed rations with 0, 25 and 50% concentrates

Abstract

Two short-term feeding trials (3 weeks on each treatment) using a total of 54 lactating cows in a 3 × 3 Latin square design were carried out to determine the ad libitum roughage intake of Simmental (SI), Brown Swiss (BS) and Holstein Friesian (HF) cows, respectively. The cows were fed rations with 0. 25 and 50% of dry matter (DM) as concentrates, the rest as roughage. The roughage consisted of 31.5% hay, 38.1% grass silage and 30.4% maize silage. SI, BS and HF cows consumed 10.7, 11.0 and 12.2 kg DM day −1 roughage, equivalent to 87, 93 and 105 g kg −0.75 bodyweight. For concentrate groups 0, 25 and 50%, roughage intake decreased from 12.8 to 11.7 and 9.4 kg DM day −1. The substitution rate derived from linear regression was 0.36 kg DM kg −1 DM. The milk yield was increased from 14.1 to 16.7 and 19.7 kg by feeding concentrates, while milk protein concentration increased from 3.0 to 3.2 and 3.4% and milk fat concentration decreased from 4.3 to 4.2 and 4.1%. The regressions of forage intake (kg DM) on milk yield (kg energy-standardized milk (ESM)) showed big differences between breeds, but also between concentrate levels. The regression slopes were 0.04, 0.23 and 0.28 for SI, BS and HF cows.