Effects of Restricted Periods of Diet Access on Feed Intake, Behavior, and Performance of Alpine Goats in Early Lactation

Restricting periods of diet access to lactating dairy goats could influence level or efficiency of production and offer different management options. Therefore, 40 Alpine goats (12 and 28 of parity 1 and ≥ 2, respectively) with initial BW of 58.0 kg (SEM = 1.50) and 14.2 days in milk (SEM = 0.72) were offered a 40% forage diet (16.6% CP and 37.5% NDF; 20% alfalfa pellets, 10% cottonseed hulls, 10% coarsely ground grass hay, 12.9% wheat middlings, 12.9% rolled oats, 12.9% rolled corn, 11.0% soybean meal, 3.0% soybean oil, 5.0% molasses, and 2.3% other ingredients) free-choice in Calan gate feeders for 12 wk. Feed access was continuous other than during morning and afternoon milking (Control), during the day for 8 h (Day) or night for 16 h (Night), or for 1 or 2 h after morning and afternoon milking (2Hour and 4Hour, respectively). Digestibilities were not influenced by treatment (e.g., OM: 73.1, 76.9, 77.1, 76.3, and 77.3%; SEM = 1.81), DMI was greater (P < 0.05) for Control than for most treatments (2.07, 2.23, 2.70, 2.33, and 2.01 kg/d; SEM = 0.157), and ADG was greater (P = 0.019) for Control than for the mean of restricted feeder access treatments (39, 11, 73, 24, and 21 g for 2Hour, 4Hour, Control, Day, and Night, respectively; SEM = 17.7). Milk yield was similar among treatments (2.60, 3.24, 3.05, 3.07, and 2.58 kg/d; SEM = 0.375), fat concentration tended (P = 0.089) to be lower for Control than for other treatments (3.88, 4.21, 3.41, 3.70, and 3.49%; SEM = 0.208), and milk energy yield was not affected by treatment (7.36, 9.53, 8.20, 8.56, and 6.91 MJ/d for 2Hour, 4Hour, Control, Day, and Night, respectively; SEM = 1.071). Intake of ME (22.69, 25.92, 31.25, 26.69, and 23.46 MJ/d; SEM = 2.184) and heat energy (13.34, 14.09, 17.51, 15.54, and 15.25 MJ/d; SEM = 0.921) were greater (P ≤ 0.011) for Control than for other treatments, resulting in milk energy that was 31.9, 37.6, 26.0, 31.4, and 30.0% of ME intake for 2Hour, 4Hour, Control, Day, and Night, respectively (SEM = 3.08). In conclusion, continuous diet access may affect partitioning of nutrients between milk synthesis and tissue accretion differently than some restricted feeder access treatments, particularly 4Hour.