Effects of separate offering of forage and concentrate on feed intake and growth of Alpine doelings

Forty-four weaned Alpine doelings (16+/-0.19 kg initial BW) were used in a 16 week experiment to determine how separate free-choice offering of concentrate and forage (wheat hay, 14.2 CP and 62% NDF) affects performance compared with consumption of mixed diets of different proportions of concentrate and forage. Treatments were A-25C: 25% concentrate mixed diet consumed ad libitum; A-500 50% concentrate mixed diet consumed ad libitum; A-75C: 75% concentrate mixed diet consumed ad libitum; AC-AF: ad libitum consumption of concentrate and forage, offered separately; and LC-AF: restricted intake of concentrate (approximately 2% BW) and ad libitum intake of forage. Concentrate was 72.8% ground corn, 15.2% soybean meal, 6% fish meal and 6% dried molasses product. Orts averaged 6.7+/-0.58% of diet offered. Intake of DM was similar among treatments (625, 641, 623, 704 and 653 gram per day; S.E. = 38.6), and dietary concentrate was 26, 53, 80, 84 and 61% of DM intake for A-25C, A-50C, A-75C, AC:AF and LOAF, respectively; S.E. = 1.51). ADG was greatest (P < 0.05) for AC:AF and lowest (P < 0.05) for A-25C (53, 71, 81, 105 and 73 g; S.E. = 5.2), and ADG:DM intake ranked (P < 0.05) A-25C < A-50C and LC:AF < A-75C < AC:AF (85, 110, 130, 149 and 111 g/kg for A-25C, A-50C, A-75C, AC:AF and LC:AF, respectively; S.E. = 5.2). In conclusion, separate free-choice offering of concentrate and forage for Alpine doelings appears promising as a simple means of achieving high ADG and efficient feed utilization, and restricted offering of concentrate with separate free access to forage can yield ADG and ADG:DM intake similar to ad libitum consumption of a mixed diet providing a comparable dietary concentrate level. (C) 2003 Elsevier Science B.V. All rights reserved.