Abstract #T499

# T499
Effects of restricted diet access on intake and performance by dairy goats in mid- to late lactation.
Nhayandra C. D. Silva*1,2, Ryszard Puchala1, Terry A. Gipson1, Yoko Tsukahara1, Tilahun Sahlu1, Arthur L. Goetsch1, 1American Institute for Goat Research, Langston University, Langston, OK, 2UNESP, Universidade Estadual Paulista, Department of Animal Science, Jaboticabal, SP, Brazil.

Restricting periods of dietary access of lactating dairy goats could influence level or efficiency of production and offer different management options. Therefore, objectives of the experiment were to determine effects of offering feed at different times of the day and for various lengths on intake and milk yield and composition of 50 Alpines (15, 25, and 10 of parity 1, 2, and ≥3, respectively) with initial BW of 55.2 kg (SE = 0.95) and 125 d-in-milk (SE = 3.0). A 40% forage diet (20% alfalfa pellets, 10% cottonseed hulls, and 10% coarsely ground grass hay) was given free-choice in Calan gate feeders during a 2-wk covariate period and subsequent 12-wk experiment. Treatments were feed access continuously (C), during the day for 8 h (D) or night for 16 h (N), and for 2 or 4 h/d with equal lengths after milking in the morning and afternoon (2H and 4H, respectively) (10 animals/treatment). Neither DMI (2.05, 1.87, 2.08, 1.91, and 1.87 kg/d; SE = 0.107) nor milk yield (1.77, 1.75, 1.67, 1.64, and 1.68 kg/d for C, D, N, 2H, and 4H, respectively; SE = 0.098) were influenced by treatment (P > 0.05), with milk yield (1.83, 1.84, 1.60, and 1.54 kg/d in periods 1, 2, 3, and 4, respectively; SE = 0.051) but not DMI differing among periods. Treatment also did not influence ADG (32, 22, 49, 9, and 20 g; SE = 13.0) or body condition score during the study (2.35, 2.32, 2.24, 2.26, and 2.34; SE = 0.052) and at the end (2.49, 2.39, 2.32, 2.33, and 2.42; SE = 0.054). However, there were treatment effects on milk concentrations of fat (3.78, 3.64, 3.54, 3.75, and 3.21%; SE = 0.126) and protein (2.91, 2.88, 2.88, 2.84, and 2.58% for C, D, N, 2H, and 4H, respectively; SE = 0.049). Energy-corrected milk (3.5% fat, 3.2% protein) in kg/d (1.70, 1.66, 1.58, 1.53, and 1.52 kg/d; SE = 0.101) and relative to DMI (0.79, 0.84, 0.78, 0.81, and 0.81 kg/kg for C, D, N, 2H, and 4H, respectively; SE = 0.073) were similar among treatments. In conclusion, dairy goats in mid- and late lactation possess considerable flexibility in eating behavior that may allow for incorporation of limited feed access regimens in management systems for most efficient facility utilization.

Key Words: dairy goat, feed access, milk production