Effects of ad libitum consumption of concentrate and forage offered separately or mixed on growth of Alpine doelings

A. L. Goetsch, G. Detweiler, J. Hayes, R. Puchala, and T. Sahlu

E (Kika) de la Garza Institute for Goat Research, Langston University, Langston, OK

Forty-four weaned Alpine doelings (16 ± 0.19 kg initial BW) were used in a 16-wk experiment to determine how separate free-choice offering of concentrate (C) and forage (F; wheat hay, 14.2% CP and 34.1% ADF) affect performance compared with consumption of mixed diets of different proportions of C and F. Treatments (two groups/treatment) were A-25C: 25% C mixed diet consumed ad libitum; A-50C: 50% C mixed diet consumed ad libitum; A-75C: 75% C mixed diet consumed ad libitum; A-C:A-F: ad libitum consumption of C and F, offered separately; and L-C:A-F: restricted intake of C (approximately 1.5% BW) and ad libitum intake of F. Orts averaged 6.7 ± 0.58% of diet offered. Intake of DM was similar among treatments (625, 641, 623, 704, and 653 g/d; SE = 38.6); dietary concentrate was 26, 53, 80, 84, and 61% of DM intake for A-25C, A-50C, A-75C, A-C:A-F, and L-C:A-F, respectively; SE = 1.51). Average daily gain was greatest (P < 0.05) for A-C:A-F and lowest (P < 0.05) for A-25C (53, 71, 81, 105, and 73 g; SE = 5.2), and ADG:DM intake ranked (P < 0.05) A-25C < A-50C and L-C:A-F < A-75C < A-C:A-F (85, 110, 130, 149, and 111 g/kg for A-25C, A-50C, A-75C, A-C:A-F, and L-C:A-F, respectively; SE = 5.2). In conclusion, separate free-choice offering of C and F for Alpine doelings appears promising as a simple means of achieving high ADG and efficient feed utilization, and restricted offering of C with separate free access to F can yield ADG and ADG:DM intake similar to ad libitum consumption of a mixed diet providing a comparable dietary concentrate level.