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ARS Home » Southeast Area » Booneville, Arkansas » Dale Bumpers Small Farms Research Center » Research » Publications at this Location » Publication #66039
Title: INFLUENCES OF GRASS SOURCE AND LEGUME LEVEL ON NET FLUX OF NUTRIENTS ACROSSSPLANCHNIC TISSUES IN SHEEP

Author
item PATIL, A - UNIV OF ARKANSAS
item Goetsch, Arthur
item PARK, K - UNIV OF ARKANSAS
item KOUAKOU, B - UNIV OF ARKANSAS
item GALLOWAY SR, D - UNIV OF ARKANSAS
item JOHNSON, Z - UNIV OF ARKANSAS
item WEST, C - UNIV OF ARKANSAS

Submitted to: Small Ruminant Research
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 2/10/1996
Publication Date: N/A
Citation: N/A

Interpretive Summary: Tropical and temperate grasses provide most nutrients for ruminants throughout the world. Level of animal productivity or efficiency of nutrient use for maintenance, growth or lactation may be at times less than desired. Hence, legumes are often included in grass-based diets ingested as pasture herbage or harvested forage. However, factors responsible for change in animal performance or efficiency of production with dietary legume inclusion are unclear, and effects of grass source and legume level are unknown. Therefore, objectives of this study were to determine influences of level of legume (0, 20 and 40%) in tropical or temperate grass diets consumed ad libitum by mature sheep on net flux of oxygen and nutrients across the portal-drained viscera and liver. Results of this study indicate that dietary legume inclusion in grass diets consumed ad libitum by mature ruminants should not markedly alter performance via increased extra-splanchnic tissue energy, amino acid or glucose availability; effects of legume inclusion on splanchnic tissue net flux of oxygen and nutrients may not be greatly affected by grass source (i.e., tropical vs temperate grasses) with similar digestible energy intake; and little difference may occur between high and low dietary legume levels (e.g., 40 and 20%, respectively). However, these results may not be directly applicable to growing animals or different quality forages.

Technical Abstract: Crossbred wethers (20 months old; 45 +/- 0.7 kg body weight), with catheters in a hepatic vein, the portal vein and a mesenteric vein and artery, consumed ad libitum warm (W) or cool (C) season grass hay diets with 0, 20 or 40% legume (L). Legume, W and C were 54, 80 and 68% neutral detergent fiber and 17, 14 and 10% crude protein, respectively. Digestible energy intake was 3.22, 3.42, 3.66, 3.23, 3.57 and 3.67 (SE 0.208) Mcal d-1, and digestible nitrogen intake was 17.6 20.2, 23.4, 10.1, 14.0 and 17.3 (SE 1.09) g d-1 for W:0% L, W:20% L, W:40% L, C:0% L, C:20% L and C:40% L, respectively. Splanchnic bed oxygen consumption (306, 364, 380, 261, 316 and 383 mM h-1; P<0.05), portal-drained viscera (PDV) release of alpha-amino nitrogen (24.8, 37.6, 38.6, 24.4, 38.4 and 41.7 mM h-1; P<0.05), PDV uptake of urea nitrogen (26.4, 41.0 41.9, 23.0, 41.3 and 36.8 mM h-1; P<0.05) and PDV release of propionate (14.4, 19.4, 20.5, 14.3, 23.6 and 21.1 mM h-1 for W:0% L, W:20% L, W:40% L, C:0% L, C:20% L and C:40% L, respectively; P=0.08) were greater with L than without. Splanchnic releases of alpho-amino nitrogen and glucose were similar among treatments. In conclusion, dietary inclusion of 20 or 40% legume in warm or cool season grass diets consumed ad libitum by mature ruminants may not markedly alter performance via increased extra-splanchnic tissue availability of energy, amino acids, or glucose.