Abstract :
Yearling meat goat doelings, 25 Boer×Spanish (BS) and 25 Spanish (S) (27 and 21 kg initialBW, respectively; S.E. = 0.6),
were used in a 16-week experiment (four 28-day periods) to determine effects on growth of length of nutrient restriction and
level of concentrate supplementation during realimentation. Doelings consumed prairie hay (6.2% CP, 70% NDF and 9.1%
ADL) ad libitum and received daily supplementation with 0.75%BWof concentrate (30% CP; C treatment), sequential 28-day
periods of no supplementation and daily supplementation with 1.50 or 0.75% of concentrate (H-28 and L-28, respectively) or
56 days without supplementation followed by supplementation for 56 days with 1.50 or 0.75% of concentrate (H-56 and L-56,
respectively). Ruminal ammonia N concentration was below 6 mg/dl when concentrate was not supplemented. ADG was
similar among dietary treatments and between genotypes in period 1. Dietary treatment and genotype interacted (P < 0.05)
in ADG during periods 2 and 3. In period 2, ADG was generally lowest among treatments for 56-day restriction treatments,
with the difference being greater for BS vs. S (24, 34, 41, −63 and −96 g for BS, and 6, 13, −5, −40 and −36 g for S, with
C, H-28, L-28, H-56 and L-56, respectively; S.E. = 16.0). In period 3, ADG was similar among dietary treatments for S
but was lower with 28- vs. 56-day restriction treatments for BS (85, −9, 0, 123 and 112 g for BS, and 26, 32, 34, 64 and
68 g for S, with C, H-28, L-28, H-56 and L-56, respectively; S.E. = 17.3). In period 4, ADG was lower (P < 0.05) for C
vs. H-56 and L-56 (39, 53, 71, 87 and 85 g with C, H-28, L-28, H-56 and L-56, respectively). Overall ADG in periods 1–4
(dietary treatment × genotype interaction; P < 0.05) was similar among dietary treatments for S but was greater (P < 0.05)
for C than for H-28, L-28 and L-56 (57, 28, 26, 46 and 22 g for BS, and 18, 24, 29, 35 and 29 g for S, with C, H-28, L-28,
H-56 and L-56, respectively; S.E. = 7.3). In conclusion, maintaining an adequate plane of nutrition for steady growth and
development appears more important for BS than for S yearling doelings, with the former possibly requiring longer periods
of realimentation than previous nutrient restriction.
© 2003 Elsevier B.V. All rights reserved
