Effect of substituting dry corn with rehydrated ensiled corn on dairy cow milk yield and nutrient digestibility

Abstract

The purpose of the present study was to evaluate the effect of substituting dry corn with rehydrated ensiled (90days) corn (REC) in dairy cow diets on the nutrient intake, total tract apparent digestibility, and milk yield and composition. Twelve Holstein cows, with an average of 550 (±30 SD)kg of body weight and 220 (±40 SD) days in milk (DIM), were allocated in three 4×4 contemporary Latin squares, organized in 4 periods composed of 14days for dietary adaptation and 7days for sample and data collection. Cows were fed diets formulated to be isoenergetic (6.489MJNEL/kg DM; dry matter) and isoproteic (150g CP/kg DM). Ensiled sugar cane (460g of DM/kg) was used as forage, and concentrated feed had four substitution levels (0, 33, 66 and 100%) of dry corn by REC. Increased inclusion of REC in substitution of dry corn caused increase of intake of DM, crude protein (CP) and non-fiber carbohydrates (NFC). On the other hand, intake of NDF decreased quadratically with increasing inclusion of REC. The total tract apparent digestibility of DM, OM, CP, ether extract, starch and NFC were linearly increased by 5.4–8% in diets with total substitution of dry corn with REC. Increased inclusion of REC in the diet also increased linearly milk and 3.5% fat-corrected milk yield, and fat, protein, lactose and total solids yield. In conclusion, the substitution of dry corn with REC increases milk production (by 2.1L/cow/day) and apparent total digestibility of starch (by 8 percentage points) in late-lactation dairy cows.