Effects of different forage-containing rations on metabolic parameters and milk yield in the peripartum of Holstein cows

To evaluate the forage effects on performance and metabolic parameters, 24 Holsteins were randomly fed one of the diets containing a forage mixture with majority of alfalfa hay (AH), alfalfa silage (AS), or corn silage (CS) during the peripartum period. Milk production and dry matter intake (DMI) were recorded daily; body weight (BW) was measured and blood/urine samples were collected on day -21, 1, and 15 relative to parturition. The diets did not affect prepartum and postpartum BW changes and milk production. During the prepartum, DMI for cows fed hay was higher than for cows fed silages. During the postpartum, DMI was the highest for cows fed diet AH, followed by cows fed diets CS and AS. The diets did not affect serum glucose, Ca, P, and K concentrations. Serum blood urea nitrogen (BUN) concentration for cows fed diet CS was lower than for cows fed diet AS. Cows fed diet AH had the highest alkaline phosphatase (ALP) activity. Serum cation-anion difference (SCAD) for cows fed AS was lower than for cows fed CS. Serum Ca concentration was not correlated with SCAD and ALP values, but Ca : P ratio was negatively correlated with serum K concentration. The diets did not influence urine pH and urine cation-anion difference (UCAD) value. Urine Ca concentration and Ca : P ratio for cows fed CS were higher than those for cows fed AS. Urine pH was positively correlated with urine K concentration and UCAD value. In conclusion, the forage type did not affect prepartum performance. Silage, regardless of the kind, was advantageous over hay during the postpartum.