Abstract
The intake and growth responses of lambs fed barley straw to a range of
supplements provided on a 3- or 4-day cycle were examined. Supplements were
urea and sulfur (N/S) added to the straw, or 3 increments of each of 3
approximately isonitrogenous supplements consisting of barley grain mixed with
urea and sulfur (Bar/N), cottonseed meal (CSM), and a 0.4 : 0.6 mixture of
fishmeal and lucerne hay (FM/L). Lambs fed straw alone consumed 38.3 g dry
matter (DM)/kg W0.75 day of straw and an estimated
2.54 MJ metabolisable energy (ME)/day, and lost 20 g liveweight
(LW)/day. Supplementation with N/S increased estimated ME intake by
32%. Substitution rates of Bar/N, FM/L, and CSM supplements for
straw were 0.50, 0.36, and 0.25 g/g, respectively, but these rates did not
differ (P > 0.05) between supplements.
Digestibilities of organic matter (OM) and neutral detergent fibre (NDF) were
affected differently depending on both the type and amount of supplement.
Estimated ME intake was increased 7.1, 7.9, and 8.6 kJ/g supplement DM by
Bar/N, FM/L, and CSM, respectively. LW gain and wool growth were
increased (P < 0.01) by consecutive increments of
each of the supplements, and were increased more (P <
0.01) by the FM/L and CSM than by the Bar/N supplement. The slopes of
the linear relationships between LWgain and estimated ME intake were greater
(P < 0.05) for CSM and FM/L than for Bar/N
supplement, ingested ME being used with about twice the efficiency for LW gain
when the protein meal supplements rather than the cereal grain–urea
supplement was fed. However, across all supplement treatments, LW gain was
correlated (r = 0 .9 1 ; P
< 0.001) with the absorbed amino acid supply as estimated from feeding
standards. In conclusion, although supplements based on either cereal grain or
protein meals increased LW gain in these young lambs, there were much greater
responses to the protein meals due principally to more efficient utilisation
of ingested ME for LW gain.
Subject
General Agricultural and Biological Sciences
Cited by
21 articles.
订阅此论文施引文献
订阅此论文施引文献,注册后可以免费订阅5篇论文的施引文献,订阅后可以查看论文全部施引文献