Intake, digestibility, and nitrogen retention by sheep supplemented with warm-season legume hays or soybean meal

被引:31
作者
Foster, J. L. [1 ]
Adesogan, A. T. [1 ]
Carter, J. N. [3 ]
Blount, A. R. [3 ]
Myer, R. O. [3 ]
Phatak, S. C. [2 ]
机构
[1] Univ Florida, Inst Food & Agr Sci, Dept Anim Sci, Gainesville, FL 32611 USA
[2] Univ Georgia, Dept Hort, Athens, GA 30602 USA
[3] Univ Florida, Inst Food & Agr Sci, N Florida Res & Educ Ctr, Marianna, FL 32446 USA
关键词
bahiagrass; digestibility; intake; nitrogen retention; supplementation; tropical/subtropical legume; CONDENSED TANNINS; BODY-WEIGHT; MACROPTILIUM-ATROPURPUREUM; STYLOSANTHES-GUIANENSIS; DESMODIUM-UNCINATUM; ANIMAL PERFORMANCE; RUMEN FERMENTATION; FEED-INTAKE; BASAL DIET; PROTEIN;
D O I
10.2527/jas.2008-1637
中图分类号
S8 [畜牧、 动物医学、狩猎、蚕、蜂];
学科分类号
0905 ;
摘要
The increasing cost of feed supplements necessitates evaluation of alternatives for ruminant livestock grazing poor quality warm-season grasses. This study determined how supplementing bahiagrass hay (Paspalum notatum Flugge cv. Pensacola) with soybean [Glycine max (L.) Merr.] meal or warm-season legume hays affected intake, digestibility, and N utilization by lambs. Dorper x Katadhin crossbred lambs (30.6 +/- 5.5 kg; n = 42) were fed bahiagrass hay (73.8% NDF, 8.1% CP) for ad libitum intake and supplemented with nothing (control), soybean meal, or hays of annual peanut [Arachis hypogaea (L.) cv. Florida MDR98; 46.2% NDF, 14.7% CP], cowpea [Vigna unguiculata (L.) Walp. cv. Iron clay; 62.2% NDF, 11.7% CP], perennial peanut (Arachis glabrata Benth. cv. Florigraze; 43.3% NDF, 15.2% CP), pigeonpea [Cajanus cajan (L.) Millsp. cv. GA-2; 78.6% NDF, 12.2% CP], or soybean (cv. Pioneer 97B52; 59.0% NDF, 13.5% CP). Legume hays were supplemented at 50% of total diet DM, and soybean meal was supplemented at a level (4.25% of diet DM) that matched the average dietary CP content (10.8%) of the legume hay-supplemented diets. The cowpea, pigeonpea, and soybean were harvested at respective maturities that maximized DM yield and nutritive value, and the peanuts were first cuttings. Diets were fed to 6 lambs per treatment for 2 consecutive 21-d periods. Supplementation with hays of annual and perennial peanut, cowpea, and soybean increased (P < 0.01) DMI vs. control, but apparent DM digestibility was only increased (P = 0.03) by supplementation with annual or perennial peanut hay. Compared with the control, N intake, digestibility, and retention were increased (P < 0.01) by supplementation with legume hay or soybean meal. Responses were greatest when annual or perennial peanut hays were fed. Ruminal ammonia concentration was increased (P < 0.01) by all legume hay supplements vs. the control. Microbial N synthesis and ruminally degraded OM were increased (P = 0.03) by perennial and annual peanut hay supplementation, but efficiency of microbial synthesis was not different (P = 0.52) among diets. Unlike other supplements, annual and perennial peanut hays increased DM and N intake and digestibility and improved microbial N synthesis; therefore, they were the best supplements for the bahiagrass hay under the conditions of this study.
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页码:2891 / 2898
页数:8
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