Lactational performance, rumen fermentation, and enteric methane emission of dairy cows fed an amylase-enabled corn silage

This study investigated the effects of an amylase-enabled corn silage on lactational performance, enteric CH4 emission, and rumen fermentation lactating dairy cows. Following a 2-wk covariate period, 48 Holstein cows were blocked based parity, days in milk, milk yield (MY), emission. Cows randomly assigned to 1 2 treatments 8-wk randomized complete block design experiment: (1) control (CON) from isogenic without ?-amylase trait (2) Enogen hybrid (Syngenta Seeds LLC) harvested as (ECS) containing bacterial transgene expressing (i.e., amylase-enabled) endosperm grain. The ECS CON silages included at 40% dietary dry matter (DM) contained, average, 43.3 41.8% DM (% DM) 36.7 37.5% neutral detergent fiber, 36.1 33.1% starch, respectively. Rumen samples collected subset 10 using ororuminal sampling technique wk 3 experimental period. Enteric emission was measured GreenFeed system (C-Lock Inc.). Dry intake (DMI) similar between treatments. Compared with CON, MY (38.8 vs. 40.8 kg/d), feed efficiency (1.47 1.55 kg MY/kg DMI), true protein (1.20 1.25 kg/d) lactose yields (1.89 2.00 increased, whereas urea nitrogen (14.0 12.7 mg/dL) decreased, diet. No effect treatment energy-corrected (ECM) observed, but trend detected for increased ECM (1.45 1.50 ECM/kg DMI) fed compared CON-fed Daily not affected by treatment, intensity decreased diet (11.1 10.3 g/kg ECS, respectively); basis different fermentation, apart reduced molar proportion butyrate ECS-fed cows, treatment. Apparent total-tract digestibility nutrients urinary fecal excretions, Overall, inclusion protein, efficiency, tended increase had no led decrease intensity, silage.