The effect of pasture allowance and concentrate supplementation type on milk production performance and dry matter intake of autumn-calving dairy cows in early lactation

Abstract

This study was undertaken to evaluate the influence of daily pasture allowance and concentrate type on milk production performance, dry matter intake, grazing behavior and blood and urinary metabolites of autumn-calving dairy cows in early lactation. The study lasted 61 days using 28 Holstein Friesian cows. Prior to experimental treatment, milk production averaged 23.1 kg/day (± 3.64 kg/day) and mean live weight was 595 kg (± 48.1 kg). The four dietary treatments were a combination of two pasture allowances above ground level (low, 25.5 vs. high, 38.5 kg of dry matter/cow/day) and two concentrate types offered at the level of 5 kg/cow/day (corn-based concentrate vs. sugar beet pulp-based concentrate). Total dry matter intake of individual cows was estimated using the n-alkenes method and milk composition was analyzed weekly using infrared spectroscopy (Foss 4300 Milko-scan). Pasture allowance significantly ( P < 0.01) increased milk production 22.0 kg/day for low and 24.7 for high, respectively. The concentrate energy source had no effect ( P > 0.05) on milk production, milk fat (3.73%) or protein (3.09%). Pasture dry matter (DM) intake and total DM intake (kg/day) increased from 9.6 to 11.1 and from 13.9 to 15.4 with increased in pasture allowance ( P < 0.05). Live weight and body condition score were unaffected by either pasture allowance or concentrate type. Plasma NEFA and plasma urea nitrogen (PUN) did not differ with pasture allowance averaging 0.298 mmol/l and 8.23 mmol/l, respectively ( P > 0.05). High pasture allowance increased ( P < 0.05) urinary purine derivatives (allantoin + uric acid/Creatinine (PD/C)) ratio. Concentrate type had no effect on any milk production parameter and the effect of daily pasture allowance was the most significant influencing factor.