Effect of Ryegrass Silage Dry Matter Content on the Performance of Lactating Holstein Cows (original) (raw)

Twenty-four lactating Holstein cows were used in a 6 wk randomized block design trial to determine the effect of DM content of annual ryegrass silage on intake and performance. The first 2-wk of the trial was used for standardization and all cows were fed a basal diet. At the end of the preliminary period, cows were blocked by parity and randomly assigned within block to one of two treatments for the following 4 wk. Treatments included annual ryegrass silage wilted to approximately 39 or 53% DM. Diets were fed once daily behind Calan doors and cows were milked twice daily. The chemical composition of the ryegrass silages was similar and fermentation measures were within normal ranges indicating that both silages were well fermented. There were no differences in DMI, yield of milk or components, or concentration of components among treatments. Dairy efficiency (kg energy corrected milk/kg DMI) tended to be higher for cows fed the low DM ryegrass silage (1.46) compared with that observed for cows fed the high DM ryegrass silage (1.35). The improved efficiency is a result of numerically higher DMI and similar milk yield. These results indicate that wilting annual ryegrass beyond 39% DM does not improve milk yield or composition.