Comparison of Low Moisture and Unwilted Coastal Bermudagrass Silages for Lactating Dairy Cows

Abstract

In successive years two conventional tower silos were filled with unwilted Coastal Bermudagrass forage plus 5% feed grain additive, and two with comparable forage wilted to a low moisture level prior to filling. When fed, the unwilted silages ranged from 32.7 to 40.2% dry matter and the low moisture silages varied from 58.4 to 76.4% dry matter.Each year the four silages were fed to 24 lactating cows. In the first years, cows fed the wilted silage consumed 1.2kg per day more forage dry matter (P = 0.05), but produced 1.2kg per day less fat-corrected-milk (FCM) (P = 0.05) than those fed unwilted material plus 5% ground barley. Also, those fed the unwilted silage produced milk containing 0.12% more solids-not-fat (P = 0.01). There were no significant differences in milk, solids-corrected-milk (SCM) production, weight gains, or level of fat or protein in milk the first year. In the second year none of the treatment differences was significant and the two-year combined averages were quite close for all measures of cow performance.The only carry-over effect in the period immediately after the experimental silages were fed was in the SNP content of the milk for the first year.Invisible or gaseous dry matter losses were somewhat lower for the low moisture silage, but there was also considerably more moldy material in this silage. The low moisture silage had a higher pH, but less ammoniacal N.Although these studies indicate that it is possible to make low-moisture silage successfully from Coastal Bermudagrass in conventional tower silos by wilting without additives, this procedure does not offer obviously important advantages over ensiling the forage unwilted under many conditions. Hazards in ensiling Coastal Bermudagrass as low-moisture silage include increased mold and difficulty in controlling the moisture level with changing weather conditions.