EVALUATION OF BRASSICAS IN GRAZING SYSTEMS FOR SHEEP .1. QUALITY OF FORAGE AND ANIMAL PERFORMANCE

Citation
Rl. Reid et al., EVALUATION OF BRASSICAS IN GRAZING SYSTEMS FOR SHEEP .1. QUALITY OF FORAGE AND ANIMAL PERFORMANCE, Journal of animal science, 72(7), 1994, pp. 1823-1831
Citations number
23
Categorie Soggetti
Agriculture Dairy & AnumalScience
Journal title
ISSN journal
00218812
Volume
72
Issue
7
Year of publication
1994
Pages
1823 - 1831
Database
ISI
SICI code
0021-8812(1994)72:7<1823:EOBIGS>2.0.ZU;2-2
Abstract
Four years of grazing trials were conducted with Brassica forages to e valuate their chemical composition and effect on ADG of fattening lamb s and breeding ewes in late fall. Brassicas tested included kales (Bra ssica oleracea L. var. acephala DC), turnips (B. rapa L.), and a chine se cabbage hybrid (B. rapa L. x B. pekinensis [Lour.] Rupr.). Daily ga ins of lambs varied widely among years (19 to 330 g/d); ADG on Brassic as were, however, generally higher than on stockpiled Kentucky 31 tall fescue (Festuca arundinacea Schreb.) or orchardgrass (Dactylis glomer ata L.)-red clover (Trifolium pratense L.) pastures grazed at the same time. In 1 yr, dietary supplementation of lambs grazing a hybrid turn ip (Forage Star) with iodine and copper oxide needles improved (P < .0 5) ADG; however, there was no effect on gains in two later years. In 2 yr, lambs showed higher ADG on Tyfon chinese cabbage hybrid (241 and 330 g/d) than on Forage Star turnip (197 and 275 g/d) or stockpiled gr ass-clover (135 and 233 g/d), but yield of Tyfon was lower. Indication s that supplementary hay improved ADG of lambs and ewes were not confi rmed in the final year, in which hay increased (P < .05) ADG of lambs in the first 3 wk of grazing Brassicas but decreased gains later. Thyr oid weights were increased (P < .01) consistently in all trials on Bra ssicas, but enlargement was modest and not related to ADG. Brassica fo rages provided high yields (5.6 to 10.5 t/ha) of DM in the late fall t o early winter period, with high carrying capacity for sheep but large variability in ADG.