B. Kouakou

Net flux of nutrients across splanchnic tissues in wethers consuming grasses of different sources and physical forms ad libitum.

Crossbred sheep (n 16, 8.5 months of age and 33 (SE 0.9) kg) were used in a 21 d experiment (2 x 2 factorial) to determine effects on net flux of nutrients across the portal-drained viscera (PDV) and liver of ad libitum consumption of bermudagrass (Cynodon dactylon; B) v. ryegrass (Lolium multiflorum)-wheat (Triticum aestivum; RW) hay, coarsely chopped (CC) or finely ground and pelleted (GP). Crude protein concentrations were 86, 81, 113 and 119 g/kg and neutral-detergent fibre concentrations were 710, 688, 654 and 672 g/kg (dry matter basis) for B-CC, B-GP, RW-CC and RW-GP respectively. Digestible energy intake (6.0, 9.6, 10.2 and 13.8 MJ/d) differed (P < 0.01) with grass source and form, and digestible N intake values were 4.4, 7.0, 8.4 and 14.1 (SEM 0.82) g/d for B-CC, B-GP, RW-CC and RW-GP diets respectively. Consumption of O2 by the PDV (118, 165, 144 and 155 mmol/h) and splanchnic bed (196, 273, 247 and 266 mmol/h for B-CC, B-GP, RW-CC and RW-GP respectively) was greater (P = 0.07) for GP than for CC. The ratio splanchnic heat energy production: digestible energy intake was greater (P = 0.06) for B than for RW (0.374, 0.300, 0.278 and 0.219 for B-CC, B-GP, RW-CC and RW-GP respectively). alpha-Amino-N release by the PDV (P < 0.01; 11.6, 12.8, 23.0 and 18.7 mmol/h) and uptake by the liver (P = 0.07; 15.2, 6.1, 17.0 and 19.3 mmol/h for B-CC, B-GP, RW-CC and RW-GP respectively) were greater for RW than for B. Release of NH3-N by the PDV was greater (P = 0.02) for CC than for GP (12.5, 6.2, 15.7 and 8.9 mmol/h), and hepatic urea-N release differed between grass sources (P = 0.03) and physical forms (P = 0.07; 22.6, 12.7, 31.4 and 24.8 mmol/h for B-CC, B-GP, RW-CC and RW-GP respectively). In conclusion, decrease in forage particle size elicited by grinding and pelleting did not affect the difference between grass sources in splanchnic tissue heat energy production relative to digestible energy intake.

Visceral organ mass in wethers consuming diets with different forages and grain levels

Crossbred wethers (72; 33 ± 0.6 kg live weight) were used to investigate interactions among forage source, cereal grain inclusion and level, and length of feeding on visceral tissue mass. Wethers consumed long-stemmed alfalfa ((A) Medicago sativa; early bloom), bermudagrass ((B) Cynodon dactylon; 6 to 8 weeks of regrowth) or ryegrass (Lolium multiflorum; early head emergence)-wheat (Triticum aestivum; anthesis (RW)) hay and approximately 0, 20 or 40% ground corn (0, 20 and 40, respectively) for 49 or 98 d. Digestible organic matter intake ranked (P < 0.05) B < RW < A and was increased (P < 0.05) by grain inclusion (period 1: 0.62, 0.75, 0.73, 0.28, 0.45, 0.49, 0.57, 0.57 and 0.69 kg/d; period 2: 0.73, 0.91, 0.96, 0.30, 0.49, 0.56, 0.55, 0.73 and 0.91 kg/d); mean empty body weight was 37, 40, 40, 34, 35, 36, 36, 38 and 39 kg (SE 1.2) for A-0, A-20, A-40, B-0, B-20, B-40, RW-0, RW-20 and RW-40, respectively. Total gastrointestinal tract tissue mass was lower (P < 0.06) for B than for A or RW (1.98, 2.11, 1.97, 1.69, 1.78, 1.78, 1.84, 1.93 and 1.95 kg), and epithelium comprised a greater (P < 0.05) proportion of ventral ruminal tissue for A versus RW or B (25, 27, 27, 19, 22, 21, 20, 25 and 21% for A-0, A-20, A-40, B-0, B-20, B-40, RW-0, RW-20 and RW-40, respectively). Liver mass was 0.48, 0.51, 0.57, 0.34, 0.40, 0.40, 0.41, 0.49 and 0.44 kg in period 1 (SE 0.037), and 0.53, 0.56, 0.49, 0.38, 0.41, 0.41, 0.42, 0.43 and 0.51 kg in period 2 (SE 0.022) for A-0, A-20, A-40, B-0, B-20, B-40, RW-0, RW-20 and RW-40, respectively. In conclusion, cereal grain inclusion increased digestible organic matter intake and decreased gastrointestinal tract and liver mass relative to digestible organic matter intake similarly regardless of forage source, grain level or feeding period length. Thus, effects of cereal grain inclusion on peripheral tissue energy availability should be greater than expected based on digestible organic matter intake and, relative to conditions without supplemental grain, such differences should decrease with increasing forage quality and feeding period length as digestible organic matter intake increases.

Net flux of nutrients across splanchnic tissues in sheep fed tropical vs. temperate grass hay of moderate or low qualities

Abstract Crossbred wethers (18 months old; 44 ± 0.7 kg body weight), with catheters in a hepatic vein, the portal vein and a mesenteric vein and artery, consumed ad libitum tropical or temperate grass hay each of three different qualities or stages of maturity. Splanchnic tissue energy consumption was similar among tropical grass diets but increased as quality of temperate grass declined. Portal-drained viscera oxygen consumption increased with increasing digestible energy intake and fecal neutral detergent fiber excretion. Energy available to extra-splanchnic tissues with highest quality grass was greater for temperate than for tropical grass because of lower splanchnic tissue energy consumption relative to digestible energy intake. Grass source, quality and nitrogen concentration did not significantly affect portal-drained viscera release of α-amino nitrogen. Hepatic uptake of α-amino nitrogen was greater for tropical than for temperate grass, presumably because of higher nitrogen concentration with greater hepatic ammonia nitrogen uptake. Glucose uptake by the portal-drained viscera was greater for tropical than for temperate grass, and the potential contribution of propionate to hepatic glucose release tended to be greatest for grass highest in quality. Grass quality appears more important to achieve maximal energy availability to extra-splanchnic tissues with temperate than tropical grass.

Influence of grass source and legume level on net flux of nutrients across splanchnic tissues in sheep

Abstract Crossbred catheterized wethers (20 months old; 45 kg BW, SE 0.7) consumed ad libitum warm ((W) bermudagrass; Cynodon dactylon ) or cool ((C) ryegrass-wheat mixture; Lolium multiflorum and Triticum aestivum , respectively) season grass hay with 0%, 20% or 40% legume hay ((L) alfalfa; Medicago sativa ). Legume, W and C had 54%, 80% and 68% NDF and 17%, 14% and 10% CP, respectively (DM basis). Apparent digestible energy intake was 3.22, 3.42, 3.66, 3.23, 3.57 and 3.67 (SE 0.208) Mcal day −1 , and apparent digestible N intake was 17.6, 20.2, 23.4, 10.1, 14.0 and 17.3 (SE 1.09) g day −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 mmol h −1 ; P = 0.02) and portal-drained viscera (PDV) releases of alpha-amino N (24.8, 37.6, 38.6, 24.4, 38.4 and 41.7 mmol h −1 ; P = 0.04) and propionate (14.4, 19.4, 20.5, 14.3, 23.6 and 21.1 mmol 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. However, splanchnic bed net releases of alpha-amino N and glucose were similar among treatments. In conclusion, dietary L inclusion had similar effects on splanchnic tissue oxygen consumption and net fluxes of nutrients regardless of grass source, which differed in concentrations of NDF and CP but not in apparent digestible energy intake. These results suggest that potential improvement of animal performance by substituting 20% or 40% legume for warm or cool season grass, consumed ad libitum by mature ruminants, would not be attributable to change in extra-splanchnic tissue availabilities of energy (based on the difference between apparent digestible energy intake and splanchnic tissue energy consumption), amino acids or glucose.

Effects of forage level in broiler litter-based diets on feed intake, digestibility and particulate passage rate in Holstein steers at different live weights☆☆☆

Abstract Sixteen Holstein steers were used in a split-plot experiment to determine influences of dietary inclusion of broiler litter and level of forage in litter-based diets on feed intake, digestibility and particulate passage rate at different body weights. Body weight (BW) at the end of four 3 week periods, separated by periods of 3 weeks or more, was 151 ± 2.3, 190 ± 3.1, 252 ± 3.7 and 298 ± 3.8 kg in Period 1, 2, 3 and 4, respectively. All steers consumed approximately 1% BW (dry matter) of ground corn; bermudagrass ( Cynodon dactylon ) hay (76% neutral detergent fiber) was consumed ad libitum (Control) or at 0.3 (L), 0.6 (M) or 0.9% BW (H; dry matter); and L, M and H steers consumed ad libitum deep-stacked broiler litter (29% crude protein, 19% ash and 43% neutral detergent fiber). Intake of organic matter (OM) was increased ( P −1 for Control, L, M and H, respectively). Digestible OM intake did not differ between Control and litter diets but increased linearly ( P −1 for Control, L, M and H, respectively; SE 0.067). Particulate passage rate for Yb-labeled hay was greater ( P P = 0.05) as hay level in litter diets increased (3.45, 5.42, 4.31 and 4.85% h −1 for Control, L, M and H, respectively). In conclusion, optimal forage level in broiler litter-based diets for high digestible OM intake by growing Holstein steers appeared to be at least 0.6% BW (i.e. 15% of dry matter intake).

Effects of corn vs. corn plus wheat in forage-based diets containing broiler litter on feed intake, ruminal digesta characteristics and digestion in cattle

Cattle consuming low-to moderate-quality forage were supplemented with corn or a 1:1 corn:wheat mixture with or without broiler litter to determine effects on feed intake, ruminal digesta characteristics and digestion. In the first experiment, mature beef steers (529 ± 33 kg initial body weight) with cannulas in the rumen and duodenum were fed prairie hay and soybean meal alone (control) or with (dry matter basis) 0.3% body weight (BW) of ground corn (C), 0.15% BW of corn plus 0.15% BW of ground wheat (CW), corn plus 0.3% BW of broiler litter (C-L) or the corn-wheat mixture plus 0.3% BW of broiler litter (CW-L). Ruminal fluid ammonia nitrogen (N) concentration 2 h after feeding was increased (P < 0.05) by supplementation and was greater (P < 0.05) for C-L than for CW-L (8.9, 9.3, 11.4, 27.6 and 21.4 mg dl−1 for control, C, CW, C-L and CW-L, respectively). Neither duodenal microbial N flow nor efficiency of microbial growth was affected by treatment. In the second experiment, Holstein steers (129 ± 11 and 219 ± 17 kg initial and final BW, respectively) consumed ad libitum bermudagrass hay alone (control) or with (dry matter basis) 0.6% BW of corn (C), 0.3% BW of corn plus 0.3% BW of wheat (CW), corn plus 0.6% BW of broiler litter (C-L) or the corn-wheat mixture plus 0.6% BW of broiler litter (CW-L). Total organic matter (OM) intake was increased (P < 0.05) by supplementation and inclusion of broiler litter in supplements (4.34, 4.91, 5.14, 5.27 and 5.32 kg day−1); total tract OM digestion was increased (P < 0.05) by supplementation and was lower (P < 0.05) for supplement treatments with than without broiler litter (57.2, 61.8, 63.0, 59.5 and 59.9%); and digestible OM intake was increased (P < 0.05) by supplementation and was not altered by broiler litter inclusion in supplements (2.51, 3.05, 3.25, 3.14 and 3.20 kg day−1 for control, C, CW, C-L and CW-L, respectively). In summary, supplementation of a diet containing broiler litter with a corn-wheat mixture compared with corn alone decreased ruminal ammonia N concentration early after feeding but did not change duodenal microbial N flow or efficiency of microbial growth. Grain source did not alter total feed intake by growing Holstein steers consuming diets with broiler litter, and an increase in total feed intake when broiler litter was included in diets compensated for low digestibility of broiler litter.

Effects of Xylose and Soybean Meal Additions to Deep-Stacked Broiler Litter on Nutritive Characteristics for Ruminants

Abstract Park, K.K., Goetsch, A.L., Patil, A.R., Kouakou, B., Forster, L. A., Jr., Galloway, D.L., Sr. and Johnson, Z.B. 1995. Effects of xylose and soybean meal additions to deep-stacked broiler litter on nutritive characteristics for ruminants. J. Appl. Anim. Res., 7: 1–26. Broiler litter was mixed with xylose (X;l. 7% dry matter) and (or) soybean (S; 20% dry matter) and deep-stacked at 21, 26 or 31% moisture for 7, 21 or 63 d, with a 2x2x3x3 factorial arrangement of treatments, to determine changes in composition and ruminal degradability of organic matter and nitrogen (N). Nitrogen concentration was increased (P<0.05) by S (5.04 vs 4.18%) and decreased (P<0.05) by X (4.57 vs 4.65%). Xylose decreased (P<0.05) NH3-N concentration without but not with S (43.6, 37.5, 28.3 and 28.3% total N for Control, X, S and XS, respectively). At 7 d of incubation, soluble N (0.15 M NaCl) was not affected by X without S, although with S, X decreased (P<0.05) soluble N (68.5, 66.4, 60.2 and 53.8% total N for Control, X ...

OXYGEN CONSUMPTION BY SPLANCHNIC TISSUES IN WETHERS CONSUMING AD LIBITUM DIFFERENT PROPORTIONS OF BERMUDAGRASS AND RYEGRASS-WHEAT

Crossbred wethers (n = 18, 7.5 month of age and 31 +/- 0.8 kg) were used in a 23-day experiment to determine effects of ad libitum consumption of diets differing in proportions of coarsely chopped bermudagrass and ryegrass-wheat hay (0, 33, 67 and 100%) on oxygen consumption by splanchnic tissues. Bermudagrass and ryegrass-wheat were 9 and 13% CP and 78 and 71% NDF, respectively. Intake of dry matter (1.03, 0.92, 0.92 and 0.76 kg/d) and digestible energy (13.5, 10.7, 10.6 and 8.2 MJ/d for 0, 33, 67 and 100% bermudagrass, respectively) changed linearly and cubically (P < 0.05) as bermudagrass level increased. Consumption of oxygen by the portal-drained viscera tended to decrease linearly (P = 0.14) with increasing bermudagrass (182, 154, 156 and 137 mM/h), and hepatic oxygen consumption decreased linearly (P < 0.05) and changed cubically (P = 0.07; 150, 113, 116 and 103 mM/h for 0, 33, 67 and 100% bermudagrass, respectively). Splanchnic tissue energy consumption expressed as a percentage of digestible energy intake increased linearly (P = 0.08) with increasing bermudagrass (24.0, 27.6, 28.6 and 33.2% for 0, 33, 67 and 100% bermudagrass, respectively). In conclusion, the level rather than presence alone of different grass sources consumed ad libitum affected energy use by the splanchnic bed, and as a percentage of digestible energy intake splanchnic bed energy consumption increased with increasing dietary bermudagrass level and decreasing digestible energy intake.

Influence of grass source on net flux of nutrients across splanchnic tissues in sheep with restricted intake

Crossbred wethers (22 months old; 46 +/- 1.3 kg body weight), with catheters in a hepatic vein, the portal vein and a mesenteric vein and artery, consumed warm (W; bermudagrass hay) or cool season grass hay (C; ryegrass-wheat) at 1.6% body weight (dry matter basis) in a crossover design experiment. Warm and cool season grasses were 13.6 and 9.9% crude protein, 77 and 66% neutral detergent fibre and 4.6 and 4.0% acid detergent lignin, respectively. Neutral detergent fibre digestibility (70.3 and 77.4%) and digestible energy intake (8.5 and 9.3 mJ/d) were greater (P < 0.02) for C than for W, and digestible nitrogen intake (11.5 and 8.0 g/d for W and C, respectively) was greater (P < 0.01) for W. Ruminal fluid concentrations of ammonia nitrogen and total volatile fatty acids were not altered by grass source, and acetate: propionate was greater (P < 0.02) for W (3.80) than for the C (3.54). Portal-drained viscera blood flow (118 and 119 l/h; SE 8.0), oxygen consumption (141 and 142 mM/h; SE 3.7), alpha-amino nitrogen release (13.4 and 13.1 mM/h; SE 3.42), urea nitrogen uptake (22.8 and 22.5 mM/h; SE 4.97), ammonia nitrogen release (14.9 and 15.7 mM/h; SE 3.36), glucose uptake (10.0 and 6.5 mM/h; SE 1.30), propionate release (14.5 and 16.4 mM/h; SE 1.88), lactate release (4.64 and 5.03 mM/h; SE 1.908) and acetate release (54.8 and 55.4 mM/h for W and C, respectively; SE 8.82) were similar between grasses. Energy consumption by the portal-drained viscera accounted for a slightly greater (P < 0.01) percentage of digestible energy intake with W vs C (18.8 vs 17.0%; SE 0.10). In conclusion, with restricted consumption of W or C by mature sheep, grass source had little impact on net flux of oxygen and nutrients across the portal-drained viscera and splanchnic bed.

Composition and in vitro digestibility of fibrous substrates placed in deep-stacked broiler litter

Effects of mixing urea (0 or 5.4% of broiler litter dry matter) with broiler litter (1.1 m high) on composition and digestibility of various fibrous substrates in dacron bags placed for 3 or 9 weeks at 36 or 72 cm from the surface of deep-stacks open or covered with plastic were determined with a 5 × 2 × 2 × 2 × 2 factorial arrangement of treatments. Urea increased ammonia concentration in broiler litter, but markedly so only when the deep-stack was covered. Overall, urea decreased neutral detergent fiber (NDF) concentration in bermudagrass, wheat straw and rice straw, with small or nonsignificant changes noted for rice hulls and pine shavings. In vitro NDF digestibility at 48 h was increased (P < 0.05) by urea for bermudagrass (58.9% vs. 46.4%) and wheat straw (42.1% vs. 33.3%); greater (P < 0.05) at 9 than at 3 weeks (43.0% vs. 24.2%) for rice straw; and greater (P < 0.05) at 9 than at 3 weeks (10.4% vs. 6.9%) for pine shavings. In summary, covering broiler litter deep-stacked without added urea did not appreciably affect nutritive value of fibrous substrates. Urea increased 48-h in vitro NDF digestibility for bermudagrass and wheat straw regardless of other deep-stack conditions. In conclusion, these results suggest potential to improve nutritive value for ruminants of some fibrous substrates added to broiler litter with urea before deep-stacking.