5.1. Experimental Design, Treatments, and Diet
A. H. Thomas
Eight dual-flow continuous culture fermenters were used in a replicated 4 × 4 Latin square design. Each fermenter vessel was treated as an experimental unit. Four fermentation periods of 10 d each, consisting of 7 d of adaptation and 3 d of sampling were carried out. Fermenters were randomly assigned to 1 of 4 AFBThe basal diet was formulated to meet the nutrient requirements of a lactating Holstein dairy cow (680 kg of body weight) producing 42 kg of milk/d, 3.5% milk fat, 3% milk protein, and 4.8% lactose based on the NRC (2001) model. Corn silage was dried in a forced-air oven at 60 °C until the DM was 90% to allow for proper grinding of the feed. Dried corn silage, corn grain, soybean meal, and the mineral premix were ground through a 2 mm screen in a Wiley mill (A. H. Thomas Co., Philadelphia, PA, USA). Alfalfa hay and citrus pulp pellets were included as purchased in the diets. Each fermenter was fed 107 g of DM per day. The diet was fed in two equal allowances at 0800 (8 AM) and 1800 h (6 PM) daily. We chose two timings to mimic twice a day feeding of dairy cows.