Abstract
The objective of this study was to evaluate the effect of low-DCAD corn silage with elevated chloride content on the mineral balance in dry cows. Corn grown at 2 locations was fertilized with either KCl or NH4Cl (Cl fertilization) or K2SO4 and (NH4)2SO4 (SO4 fertilization). The Cl content of corn silage with Cl fertilizer (low-DCAD corn silage) was 5.3g/kg and that of corn silage with SO4 fertilizer (high-DCAD corn silage) was 3.5g/kg. In a 2×2 crossover design, four non-pregnant dry Holstein cows were kept in individual tie stalls and fed either a high-DCAD corn silage diet (High-DCAD Group) or a low-DCAD corn silage diet (Low-DCAD Group). The intake and apparent absorption of Cl in the Low-DCAD Group were significantly (P<0.01) higher than those in the High-DCAD Group. The intakes of K, Na and S in the Low-DCAD Group were significantly lower than those in the High-DCAD Group. There were no significant differences in apparent absorption of K, Na or S between the Low-DCAD Group and the High-DCAD Group. Urinary pH in the Low-DCAD Group was significantly lower than that in High-DCAD cows (8.06 vs. 8.22). Urinary Ca excretion in the Low-DCAD Group was significantly (P<0.01) higher than that in the High-DCAD Group.
