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Growth of alfalfa in sludge-amended soils and inoculated with rhizobia produced in sludge.

The efficiency of rhizobial inoculants produced in wastewater sludge used as a growth medium and as a carrier was compared with that of inoculants produced in yeast mannitol broth (YMB) medium and by using peat as a carrier. Alfalfa (Medicago sativa L.) plants were inoculated with solid and liquid Sinorhizobium meliloti inoculants and grown in pots containing two soil types (Kamouraska clay soil and Saint-André sandy soil). The effect of various levels of sludge amendment (60 and 120 kg N/ha) and nitrogen fertilizer (60 kg N/ ha) was also studied. The sludge-based inoculants showed the same symbiotic efficiency (nodulation and plant yield) as YMB-based inoculants. The inoculation increased the nodulation indexes from 4-6 to 8-12, and the rhizobial number from 10(3) (uninoculated soils) to 10(6)-10(7) cells/g in inoculated soils. However, the shoot dry weights and the nitrogen contents were not increased significantly by the inoculation. Applying sludge as an amendment enhanced the rhizobial number in soils from 10(3) to 10(4) cells/g and improved significantly the plant growth (shoot dry weights and nitrogen contents). This improvement increased with sludge rate and with the cut (three cuts). Compared with sludge, N fertilizer gave lower plant yields. The nodulation was not affected by sludge and N-fertilizer application. The texture and physico-chemical properties of soil were found to affect the yield and nitrogen content of the plants. In this study, macroelements and heavy metals were at acceptable levels and were not considered to be negative factors.

Conservation of Natural Resources↗

Digesta kinetics, ruminal fermentation characteristics and serum metabolites of pregnant and lactating ewes fed chopped alfalfa hay.

Eight ruminally cannulated ewes (four control and four bred; average BW = 85.7 kg), limit-fed alfalfa hay (1.86% BW), were used in two experiments to determine the effects of pregnancy and lactation on digestive function and serum metabolites. Seven-day sampling periods were used starting on d 102, 118 and 132 of gestation (Exp. 1) and d 14 and 32 of lactation (Exp. 2). Particulate (6.8 vs 4.9%/h; PPR) and fluid passage rates (13.9 vs 10.9%/h) were greater (P less than .05) and gastrointestinal mean retention time (28.9 vs 35.7 h) and fluid turnover time (FTT, 7.5 vs 9.5 h) were lesser (P less than .05) in pregnant than in nonpregnant ewes, respectively. Isobutyrate concentration was lower (P less than .05) in pregnant (1.7 mol/100 mol) than in nonpregnant (1.9 mol/100 mol) ewes. No differences (P greater than .10) were noted for any other ruminal fermentation measures between pregnant and nonpregnant ewes. In Exp. 2, no differences (P greater than .10) were noted in digesta kinetics or ruminal fermentation measures except for isobutyrate and isovalerate molar proportions and serum urea N (SUN) concentration. Isobutyrate, isovalerate and SUN concentrations (21.8 vs 26.1 mg/dl) were lower (P less than .05) in lactating ewes than in nonlactating ewes. Gastrointestinal fill (5.7 vs 7.7 g/kg BW) and FTT (9.3 vs 12.7 h) were lesser and DM digestion (66.7 vs 57.4%) was greater (P less than .05) in lactating than in nonlactating ewes. Data suggest that, during pregnancy, passage rate increases occur without affecting DM digestion and that, during lactation, PPR is not affected when ewes are limit-fed.

Animals↗

Effects of protein and energy supplementation of Guernsey cows on the kinetics of digestion and passage of orchardgrass versus alfalfa.

Four mature, nonlactating Guernsey cows were used in a 4 x 4 latin square experiment to determine nutrient digestibility, rate of particulate passage, ruminal volume and composition of ruminal contents in cows fed diets at 80% of ad libitum intake. Diets consisted of 100% alfalfa (AL), 100% orchardgrass (OG), 85% OG plus 15% soybean meal (OG + SBM) and 70% OG plus 20% SBM plus 10% starch (OG + SBM + S) on an as-fed basis. Particulate passage rates were measured by either meal marking (Ce) or ruminal marking (La). Intake (1.6 vs 1.4% of BW) and digestibility of DM (63 vs 56%) and NDF (66 vs 39%) were greater (P less than .05) for OG than for AL. Dry matter and CP digestibility were improved 6 and 16 percentage units, respectively, when OG was supplemented with SBM + S. Nitrogen retention, higher (19 vs 3 g/d; P less than .02) in animals fed OG than in those fed AL, was reduced (P less than .05) when OG was supplemented with SBM (5 g/d), but it was improved (P less than .05) when OG + SBM was supplemented with S (39 g/d). Particulate passage (-k) measured with Ce (3.8 vs 4.6%/h) and La (4.2 vs 4.9%/h) was slower (P less than .01 and P less than .10) for AL vs OG, respectively. Supplementation of OG with SBM increased (P less than .01) -k and reduced (P less than .01) ruminal t1/2 and total t1/2. Averaged across diets, total (32.3 vs 31.1 h) and ruminal t1/2 (15.1 vs 14.0 h) of Ce were slower (P less than .10) than La. Marking techniques were not different (P greater than .05) in sensitivity for passage characteristics. Total ruminal NDF content was not different (P greater than .05) for AL vs OG (10 vs 9 g/kg BW), but it was lower for OG + SBM and OG + SBM + S (7.8 and 7.9 g/kg BW; P less than .05). Supplementation of OG with protein and starch increased total diet intake but did not decrease extent of NDF and ADF digestion.

Animal Feed↗

Effects of supplemental alfalfa hay on feed intake and digestion by Holstein steers consuming high-quality bermudagrass or orchardgrass hay.

Effects of level and frequency of supplementation with alfalfa (A) on feed intake and digestion by steers fed bermudagrass (B) or orchardgrass (O) were determined in two Latin square experiments. In Exp. 1, six Holstein steers (224 kg) were fed B (2.25% N; 71.4% NDF) or O (2.52% N; 64.3% NDF) with 0, 15 or 30% (DM) A (2.70% N; 44.0% NDF). Total DMI was 2.43, 2.72 and 2.85% BW for B and 2.98, 3.00 and 2.87% BW for O with 0, 15 and 30% A, respectively. Total DMI was affected by forage (P less than .05), A level (linear; P less than .06) and a forage x A level (linear) interaction (P less than .05). Digestible OM intake increased .42 (15%) and .67 kg (24%) with feeding of 15 and 30% A, respectively, for B, but for O, only dietary inclusion of 30% A elevated digestible OM intake (.14 kg and 4% increases). In Exp. 2, five Holstein steers (165 kg) were fed B (1.81% N; 78.6% NDF) alone or with A (2.76% N; 52.8% NDF). Morning meals consisted of ad libitum B (OA), .3% BW of A daily (.3A), .6% BW of A every 2nd d (.6A), .9% BW of A every 3rd d (.9A) or 1.2% BW of A every 4th d (1.2A). All steers received B in the afternoon ad libitum, and B was given in the morning when A was not fed. Total DMI was 2.31, 2.12, 2.12, 2.26 and 2.29% BW for OA, .3A, .6A, .9A and 1.2A, respectively (SE .049). Grass characteristics affected response in feed intake to legume supplementation. Frequency of dietary legume addition may alter feed intake.

Animal Feed↗

In vitro ouabain-sensitive respiration and protein synthesis in ruminal epithelial papillae of Hereford steers fed either alfalfa or bromegrass hay once daily.

Seven Hereford steers (457 +/- 8.5 kg BW) with ruminal cannulas were fed either long or short chopped bromegrass (B) or alfalfa (A) hay at 90% of a 3-h ad libitum intake once daily between 0900 and 1200 in a 4 x 4 complete and 3 x 4 incomplete Latin square design. After evacuation of ruminal contents, papillae from the ventral sac of the rumen were excised at 0900, 1200, and 2100 and placed in oxygenated media. Oxygen consumption was determined polarographically, after which either 10(-4) M ouabain or 10(-4) M cycloheximide was added for determination of ouabain-sensitive (OSO2) or cycloheximide-sensitive (CSO2) O2 consumption, respectively. Additionally, protein synthesis was measured by uptake of [3H]phenylalanine. Twenty-four-hour patterns of ruminal fluid pH, osmolality, ammonia N, and VFA were also determined. Steers fed A exhibited a rapid rise in total O2, OSO2, and CSO2 immediately after consumption of a meal; the respiration patterns of ruminal epithelial papillae from animals fed B lagged behind those observed for animals fed A. Patterns of O2 consumption for both diets paralleled those observed for ruminal concentration of products of fermentation; those fed A had a larger magnitude of change in both O2 consumption and fermentation products. Ruminal epithelial O2 consumption seems to be determined by substrate availability and products of fermentation, and Na+,K+ATPase and protein synthetic activity each account for one-fifth of ruminal papillae O2 consumption. Fractional rates of protein synthesis were unaffected by type of forage consumed.

Ammonia↗

Bioavailability of calcium in sun-cured alfalfa meal and effect of dietary calcium concentration on bone and plasma characteristics during two phases of gestation in gilts.

A study was conducted with gravid gilts to determine the bioavailability of Ca in sun-cured alfalfa meal (AM) and the effect of dietary Ca concentration on bone and blood characteristics during two phases of gestation. Two Ca sources (AM and CaCO3), three dietary concentrations of Ca (50, 75, and 100% of the NRC requirement), and two gestation phases (55 and 105 d) were used in a 2 x 3 x 2 factorial arrangement in a randomized design with five replications (60 gravid gilts). Response criteria were as follows: 1) plasma Ca, P, and alkaline phosphatase (AKP) measured at the onset and at 25-d intervals and 2) metacarpal (MC) and metatarsal (MT) bone breaking strength (kilograms), ash content (percentage), density (grams/cubic centimeter), and ash density (grams of ash/cubic centimeter) at the conclusion of the experiment. Plasma Ca, P, and AKP concentrations were similar between Ca sources. Because the response between Ca sources was similar, the data were pooled among sources. There was a linear decline in plasma P and AKP (P < or = .05) as dietary Ca concentration increased. As gestation progressed from 0 to 100 d, there was a decline (P < .05) in plasma Ca and P. There were no differences in bone breaking strength and ash between Ca sources in either the MC or MT. No differences in bone strength between gestation phases occurred. A gestation phase x dietary Ca concentration interaction (P < .05) was observed for bone ash in both bones.(ABSTRACT TRUNCATED AT 250 WORDS)

Alkaline Phosphatase↗

Relationships between reticular contractions and digesta passage in steers consuming alfalfa hay and barley straw combinations ad libitum.

A Latin square design experiment was conducted to determine changes in voluntary feed intake, passage of digesta from the ruminoreticulum, and changes in frequency, duration, and amplitude of reticular contractions in four Hereford crossbred steers (474 +/- 10 kg) fed diets consisting of different combinations of alfalfa hay and barley straw. Diets consisted of 1) 100% straw, 2) 67% straw and 33% hay, 3) 33% straw and 67% hay, and 4) 100% hay. The diets were offered at 110% of ad libitum intake. Intakes of DM, OM, and lignin decreased linearly (P = .009, .011, and .003, respectively) with increased dietary straw, whereas diet did not affect intakes of NDF. Daily flows of DM, cell-wall components, and total contents at the duodenum decreased linearly with increased percentage of straw in the diet. Total digesta and fluid in the rumen increased linearly (P = .03 and .02) with increased straw content in the diet. Diet did not affect mean characteristics of reticular contractions. However, flow of total digesta through the proximal duodenum per contraction, per minute, and per centimeter of Hg amplitude of contraction decreased linearly (P = .01 and .02), whereas flow per centimeter of Hg tended to decrease (P = .08) with increased percentage of straw in the diet. Similarly, the flow of NDF through the proximal duodenum per reticular contraction and per minute of contraction decreased linearly (P = .006 and .03) as the percentage of straw increased in the diet. However, when confounding effects of DMI were removed, the characteristics of reticular contractions were not related to DM and NDF flow at the duodenum.(ABSTRACT TRUNCATED AT 250 WORDS)

Animal Feed↗

Periparturient changes in intake, ruminal capacity, and digestive characteristics in beef cows consuming alfalfa hay.

Four multiparous, ruminally fistulated Angus x Hereford cows (average BW = 568 kg) were bred to the same bull and used to monitor periparturient changes in DMI, ruminal capacity, and digestion and fermentation characteristics. Cows were individually fed alfalfa hay (16.0% CP, 51.3% NDF) at 130% of the average DMI of the previous 5-d period. Ruminal capacity and DM fill were measured once every 2 wk by removing the ruminal contents from each cow and filling the empty rumen with water. Dry matter intake was measured daily. Ruminal VFA, pH, NH3, and total tract DM digestibility (DMD) were measured during three 7-d periods (average of 58 d before calving, 16 d before calving, and 25 d after calving). Ruminal capacity and DM fill varied in a quadratic manner (P < .01); both were least 6 d before calving. Forage DMI (quadratic effect; P = .02) increased moderately during the prepartum period but increased dramatically after parturition. Although postpartum (d 22) ruminal capacity was only 5% greater than at 61 d before calving, postpartum DMI was 69% greater than DMI measured 61 d before calving. Indigestible ADF (IADF) passage rate changed quadratically with period (P = .01); the greatest IADF passage rate was observed 6 d before calving. Ruminal VFA (mM) also tended to change quadratically (P = .08); the highest concentrations occurred 25 d after calving. The acetate:propionate ratio declined linearly with period (P = .01). Ruminal fluid dilution rate, pH, NH3, and DMD did not change significantly over time.(ABSTRACT TRUNCATED AT 250 WORDS)

Animal Feed↗

Corn supplementation of lambs grazing alfalfa.

We investigated the effects of supplementing Rambouillet x Suffolk wether lambs grazing irrigated 'Cimarron' alfalfa (Medicago sativa L.) with three levels (0 [C0], 123 [C123], and 247 [C247] g of DM.lamb-1.d-1) of cracked corn. Each treatment group also received 190 g of a supplement designed to prevent bloat. Replicated pastures (three per treatment) grown on a fine, mixed, thermic Torretic Paleustoll soil were grazed rotationally (forage plus supplement allowance of 6.5% of BW/d) by lambs for 85 d during spring 1992. Supplemental corn levels were analyzed as single degree of freedom contrasts for linear and quadratic effects. At the start of the experiment, lambs weighed 30.7 +/- .32 kg. Average daily gains for C0 C123, and C247 were 141, 154, and 169 g/d, respectively. Lamb production per hectare increased quadratically (P < .01) with increasing corn level (C0 [716 kg of lamb/ha], C123 [816 kg of lamb/ha], and C247 [964 kg of lamb/ha]). Supplementation with C247 vs C0 increased carcass weights (11%), dressing percentage (6%), and backfat thickness (30%). Plasma urea N (PUN) concentrations did not differ (P > .10) between C0 and C123 after 27 d of corn supplementation, but after 75 d PUN concentrations between C0 and C123 had decreased (P < .10) by 11%. For C247, PUN concentrations after 27 and 75 d of corn supplementation had decreased (P < .10) by 17 and 18%, respectively, compared with C0. Plasma urea N concentrations increased (P < .01) linearly (r2 = .93) with an increase in digestible CP:DE ratio (DP:DE).(ABSTRACT TRUNCATED AT 250 WORDS)

Animal Feed↗

Growth and tissue accretion of lambs fed concentrate in drylot, grazed on alfalfa or ryegrass at weaning, or after backgrounding on ryegrass.

Weaned Targhee x Hampshire lambs (average BW 27.6 kg) were used to determine the effects of concentrate feeding, forage grazing, or finishing on concentrate after grazing upon growth and carcass tissue accretion. Lambs were assigned randomly and balanced by weight and sex to five replicated treatments (12 lambs/treatment): all-concentrate in drylot (DL); rotational grazing alfalfa (ALF); rotational grazing ryegrass (RG); RG for 62 d, then DL (RGDL); RG for 62 d, then ALF (RGALF). Lambs were slaughtered when fat thickness over the ribeye was estimated at 3.8 to 5.6 mm. Lamb growth and carcass measurements included ADG, accretion of bone, lean, and fat in the carcass, and final BW. Lambs on DL had the highest (P = .001) ADG, whereas lambs on RG treatments tended to have the lowest ADG and heaviest final BW. Compared with DL lambs, ALF lambs had lower (P < .05) ADG but comparable final BW. Lambs that grazed RG had more (P = .001) carcass lean weight than lambs fed in DL, but carcass lean weight of lambs grazed on ALF did not differ (P > .05) from that of lambs on the DL or RG treatment. Carcass fat was less (P = .001) for ALF lambs than for the DL, RGDL, or RGALF treatment group. Daily accretion of bone, lean, and fat was highest (P = .001) for DL. Daily accretion of lean and fat for the RG group was less (P = .001) than for the ALF group but did not differ (P > .05) from that of RGALF lambs. Lean:fat ratio in weight gain for DL lambs was less (P < .01) than ratios for the ALF and RG groups, which were similar to those for RGDL and RGALF lambs. When slaughtered at the same level of fat over the ribeye, DL-fed lambs had higher ADG and fewer days on test than grazed lambs. However, lambs finished or backgrounded on forage had high lean:fat tissue gain and a higher percentage of lean in their carcasses than DL-fed lambs.

Aging↗

In vitro determination of ruminal protein degradability of alfalfa and prairie hay via a commercial protease in the presence or absence of cellulase or driselase.

Ruminal protein degradation of alfalfa (2.62% N, 49.6% NDF, and in vivo undegradable intake protein [UIP] = 16.4% of CP) and prairie hay (.88% N, 69.4% NDF, and in vivo UIP = 44.5% of CP) was estimated using the Streptomyces griseus protease (SGP) in vitro method with or without pretreatment with two carbohydrases: cellulase from Penicillium funiculosum or driselase from Basidiomycetes. Driselase is a broad-spectrum carbohydrase. Incubating forage samples for 48 h with cellulase or driselase at a concentration of 800 mg/g per g of hay nearly maximized ADF and NDF disappearances. This concentration and incubation time then were used to pretreat hay samples. A 2-h pretreatment was included to evaluate the potential for reducing the analysis time. Other sets of samples were or were not pretreated with acetate buffer alone. Following pretreatment, samples were subjected to SGP for .25, .5, 1, 2, 4, 8, 12, 24, and 48 h. Pretreatment altered the sizes of protein pools and their degradation rates. When the UIP contents of the forages were estimated using SGP and a single-pool, first-order, kinetic model, cellulase (48 h) or driselase pretreatments yielded UIP predictions that were more similar to in vivo values. Some carbohydrase and protease combinations also yielded single time-point estimates of UIP that were similar to in vivo values. Similarly, when sufficient time was permitted for protease incubation, single time-point estimates derived from protease alone were similar to in vivo values.

Animals↗

Wet corn gluten feed and alfalfa hay combinations in steam-flaked corn finishing cattle diets.

One finishing trial and one digestibility trial were used to evaluate wet corn gluten feed (WCGF) and alfalfa hay (AH) combinations in steam-flaked corn (SFC) finishing diets. In Exp. 1, 631 crossbred heifers (initial BW = 284 +/- 7.9 kg) were fed SFC-based diets containing combinations of WCGF (25, 35, or 45% of diet DM) and AH (2 or 6% of dietary DM) in a 2 x 3 factorial arrangement of treatments. No interactions existed between WCGF and AH for heifer performance. Increasing dietary WCGF linearly decreased gain efficiency (P < 0.01), dietary NEg concentration (P < 0.05), and 12th-rib fat thickness (P = 0.10). Cattle fed 35% WCGF had the lowest occurrence of abscessed livers, resulting in a quadratic response (P < 0.05) as dietary WCGF increased. In Exp. 2, 12 ruminally cannulated Jersey steers (585 kg) were fed SFC-based diets containing combinations of WCGF (25 or 45% of diet DM) and AH (0, 2, or 6% of diet DM) in an incomplete Latin square design with a 2 x 3 factorial arrangement of treatments. Starch intake was lower (P < 0.05), but NDF intake was greater (P < 0.05) as AH and WCGF increased in the diet. Ruminal pH was increased by AH (linear, P < 0.05) and tended (P < 0.07) to increase with WCGF. Feeding 2% AH led to the greatest ruminal NH3 but the lowest total VFA and propionate (quadratic, P < 0.05). Addition of AH to diets containing 25% WCGF increased acetate to a greater extent than addition to diets containing 45% WCGF (AH x WCGF interaction, P < 0.05). Feeding 45% WCGF tended to increase passage rate (P = 0.17) and decrease (P < 0.05) total tract OM digestibility but increase (P < 0.05) in situ degradation of DM from AH and WCGF. Interactions between AH and WCGF existed (P < 0.05) for ruminal fluid volume (quadratic effect of AH x WCGF level), in situ SFC degradation (linear effect of AH x WCGF level), and in situ rate of WCGF DM disappearance (quadratic effect of AH x WCGF level). We conclude that AH levels may be decreased when WCGF is added to SFC diets as 25% or more of the dietary DM.

Animal Feed↗

Combinations of alfalfa hay and wet corn gluten feed in limit-fed growing diets for beef cattle.

Two experiments were conducted to evaluate the effects of alfalfa hay (AH) and wet corn gluten feed (WCGF) combinations on ADG and gain efficiency of cattle limit-fed growing diets. In Exp. 1, crossbred beef steers (n = 220; initial BW = 262 kg) were limit-fed diets consisting of steam-flaked corn and 40% WCGF (DM basis) with 0, 10, or 20% ground AH (0AH, 10AH, and 20AH, respectively). A fourth diet containing 20% ground AH and steam-flaked corn served as a control. All diets were fed once daily at 1.8% of BW (DM basis). Growing period ADG, gain efficiency, and dietary NE calculated from performance data decreased linearly (P < 0.01) with addition of AH to diets containing WCGF. Rate of DMI increased linearly (P < 0.05) with AH addition to diets containing WCGF. Following the growing period, steers were finished on a common diet offered ad libitum. Gain efficiencies during the finishing period were higher (P < 0.05) for steers fed the 20AH diet than for steers fed the control diet. In Exp. 2, crossbred beef heifers (n = 339; initial BW = 277 kg) were limit-fed diets containing steam-flaked corn with 10, 20, or 30% ground AH and 0, 40, or 68% WCGF in a 3 x 3 factorial arrangement, fed once daily at 1.6% of BW (DM basis). An AH x WCGF interaction occurred (P < 0.05) for growing period ADG and gain efficiency. Increasing AH or WCGF decreased cattle ADG, gain efficiency, and dietary NE with the exception of heifers fed 30AH/40WCGF, which had ADG that did not differ (P > 0.10) from that of heifers fed 20AH/0WCGF or 30AH/0WCGF, and which had greater gain efficiencies (P < 0.05) than heifers fed 30AH/0WCGF. Rate of DMI increased linearly (P < 0.01) with increasing AH and decreased linearly (P < 0.01) with increasing WCGF. Heifers were finished on diets containing 33% WCGF with 0 or 0.5% added urea (DM basis) offered ad libitum. Increasing WCGF in growing diets tended (linear, P < 0.10) to increase finishing ADG and gain efficiency, whereas increasing AH decreased (linear, P < 0.05) kidney, pelvic, and heart fat, and the percentage of carcasses grading USDA Prime. Urea tended to increase ADG (P < 0.10), but decreased (P < 0.04) the percentage of carcasses grading USDA Choice. Results suggest that the value of WCGF relative to steam-flaked corn in limit-fed growing diets might be improved in diets containing 30% AH relative to diets containing 10 or 20% AH.

Animal Feed↗

Dry matter intake and digestion of alfalfa harvested at sunset and sunrise.

The preference exhibited by animals in selecting one feed over another is important only if the preferred diet is consumed daily in larger quantities, digested to a greater extent, or both. Six alfalfa (Medicago sativa L.) hays were harvested in pairs at sunset (PM) and sunrise (AM) on consecutive days at three harvest dates. A previous study of these hays demonstrated differences in ruminant preference favoring PM harvests. This study evaluated the effects of time of cutting and harvest date on voluntary DMI and nutrient digestibility. The hays were field-cured, baled, and chopped before evaluation for intake and digestibility. Studies were conducted for sheep (Ovis aries), goats (Capra hircus), and cattle (Bos taurus). Goats, but not steers or sheep, demonstrated differences in nutrient digestibility between PM- and AM-cut hays. Goats consumed more PM than AM hay (2.97 vs. 2.83 kg/100 kg of BW; P = 0.07) and digested it to a greater extent (0.710 vs. 0.696; P = 0.03), resulting in greater digestible DMI (2.11 vs. 1.97 kg/100 kg of BW; P = 0.03). Sheep consumed (mean = 2.52 kg/100 kg of BW; P = 0.59) and digested (mean = 0.681; P = 0.25) PM- and AM-cut hays similarly. Steers consumed larger quantities of PM-than AM-cut hay (2.90 vs. 2.62 kg/100 kg of BW; P = 0.11), but digestion did not differ with cutting time (mean = 0.660; P = 0.75). Difference values (composition of fed hay minus composition of orts) indicated that sheep and goats selected from the feed offered similarly, whereas steers selected differently. Difference values for CP averaged 94 and 101 g/kg for goats and sheep and 32 g/kg for steers (P < 0.01), and difference values for NDF averaged 185 and 196 g/kg for goats and sheep and 73 g/kg for steers (P <or= 0.01). Steer DMI and digestible DMI were associated with preference (r = +0.83, P <or= 0.05; and r = +0.89, P <or= 0.05) and with coordinates for preference criteria (dimension 1; r = +0.90, P <or= 0.05; and r = +0.89, P <or= 0.05) from a previous preference trial. Intake and digestion responses for goats and sheep showed no relationship with the previous preference trial measurements. For cattle and goats, the management strategy of mowing in the afternoon seems to take advantage of small, but influential diurnal changes in the soluble carbohydrate fraction and offers the potential to improve forage quality.

Animal Husbandry↗

Splanchnic metabolism of nitrogenous compounds and urinary nitrogen excretion in steers fed alfalfa under conditions of increased absorption of ammonia and L-arginine supply across the portal-drained viscera.

Effects of increased ammonia and/or arginine absorption across the portal-drained viscera (PDV) on net splanchnic (PDV and liver) metabolism of nitrogenous compounds and urinary N excretion were investigated in six catheterized Hereford x Angus steers (501 +/- 1 kg BW) fed a 75% alfalfa:25% (as-fed basis) corn-soybean meal diet (0.523 MJ of ME/[kg BW(0.75).d]) every 2 h without (27.0 g of N/kg of dietary DM) and with 20 g of urea/kg of dietary DM (35.7 g of N/kg of dietary DM) in a split-plot design. Net splanchnic flux measurements were obtained immediately before beginning and ending a 72-h mesenteric vein infusion of L-arginine (15 mmol/h). For 3 d before and during arginine infusion, daily urine voided was measured and analyzed for N composition. Feeding urea increased PDV absorption (P < 0.01) and hepatic removal (P < 0.01) of ammonia N, accounting for 80% of increased hepatic urea N output (P < 0.01). Numerical increases in net hepatic removal of AA N could account for the remaining portion of increased hepatic urea N output. Arginine infusion increased hepatic arginine removal (P < 0.01) and hepatic urea N output (P < 0.03) and switched hepatic ornithine flux from net uptake to net output (P < 0.01), but numerical changes in net hepatic removal of ammonia and AA N could not account fully for the increase in hepatic urea N output. Increases in urine N excretion equaled quantities of N fed as urea or infused as arginine. Estimated salivary urea N excretion was not changed by either treatment. Urea cycle regulation occurs via a complex interaction of mechanisms and requires N sources other than ammonia, but the effect of increased ammonia absorption on hepatic catabolism of individual AA in the present study was not significant.

Amino Acids↗

Splanchnic metabolism of nutrients and hormones in steers fed alfalfa under conditions of increased absorption of ammonia and L-arginine supply across the portal-drained viscera.

Effects of increased ammonia and/or arginine absorption on net splanchnic (portal-drained viscera [PDV] plus liver) metabolism of nonnitrogenous nutrients and hormones in cattle were examined. Six Hereford x Angus steers (501 +/- 1 kg BW) prepared with vascular catheters for measurements of net flux across the splanchnic bed were fed a 75% alfalfa:25% (as-fed basis) corn and soybean meal diet (0.523 MJ of ME/[kg BW(0.75).d]) every 2 h without (27.0 g of N/kg of DM) and with 20 g of urea/kg of DM (35.7 g of N/kg of DM) in a split-plot design. Net flux measurements were made immediately before and after a 72-h mesenteric vein infusion of L-arginine (15 mmol/h). There were no treatment effects on PDV or hepatic O2 consumption. Dietary urea had no effect on splanchnic metabolism of glucose or L-lactate, but arginine infusion decreased net hepatic removal of L-lactate when urea was fed (P < 0.01). Net PDV appearance of n-butyrate was increased by arginine infusion (P < 0.07), and both dietary urea (P < 0.09) and arginine infusion (P < 0.05) increased net hepatic removal of n-butyrate. Dietary urea also increased total splanchnic acetate output (P < 0.06), tended to increase arterial glucagon concentration (P < 0.11), and decreased arterial ST concentration (P < 0.03). Arginine infusion increased arterial concentration (P < 0.07) and net PDV release (P < 0.10) and tended to increase hepatic removal (P < 0.11) of insulin, as well as arterial concentration (P < 0.01) and total splanchnic output (P < 0.01) of glucagon. Despite changes in splanchnic N metabolism, increased ammonia and arginine absorption had little measurable effect on splanchnic metabolism of glucose and other nonnitrogenous components of splanchnic energy metabolism.

3-Hydroxybutyric Acid↗

Wet corn gluten feed and alfalfa hay levels in dry-rolled corn finishing diets: effects on finishing performance and feedlot nitrogen mass balance.

One-hundred ninety-two crossbred steers (initial BW = 351 +/- 11 kg) were used to determine the effects of removing alfalfa hay (AH) from dry-rolled corn-based diets containing wet corn gluten feed (WCGF) on animal performance and nutrient (N and OM) mass balance in open feedlot pens. Steers were stratified by weight and assigned randomly to 24 pens (2 x 3 factorial) and fed for 132 d from June to October 2002. Experimental diets contained either 0 or 35% WCGF and 0, 3.75, or 7.5% AH, and were formulated to be isonitrogenous. For efficiency of gain, an interaction occurred (P = 0.09) between AH and WCGF. Feed efficiencies of cattle fed 35% WCGF were improved 4.4% (P = 0.10) compared with efficiencies of cattle fed no WCGF at 0% AH; there was a marked improvement in ADG for cattle fed WCGF compared with no WCGF in diets with 0% AH. Within 35% WCGF diets, efficiency decreased as AH inclusion increased (P = 0.06). Efficiency was equal across AH levels when 0% WCGF was fed; however, ADG was decreased when AH was removed. Interactions between AH and WCGF were not detected for other performance or carcass criteria; therefore, main effects of AH and WCGF are discussed. Daily intake, ADG, and HCW increased linearly (P < 0.05) as dietary AH level increased. Feeding 35% WCGF also resulted in greater DMI (P < 0.01) and a tendency for greater ADG and HCW (P < or = 0.10) compared with steers fed no WCGF. Interactions between AH and WCGF were not observed for feedlot N mass balance. As level of AH increased across diets, N intake, N retention, and N excretion increased (P < 0.05). Steers fed 35% WCGF consumed and excreted more N (P < 0.01) than those fed no WCGF. More manure DM (P = 0.11), OM, and N (P < 0.01) were removed from pens housing steers fed 35% WCGF as well as greater OM and N recovery in finished compost. More N (kilogram/steer) was also lost to volatilization as a result of greater N excretion when WCGF was fed. Expressed as a percentage of N excretion, loss of N from pens housing steers fed 0 and 35% WCGF was not different, averaging nearly 80%. These data suggest that AH has less value when dry-rolled corn-based diets contain 35% WCGF and can be decreased from conventional levels. Furthermore, loss of N from open feedlot pens is high during the summer months, and feeding WCGF may not reduce N losses during these times of year.

Animal Feed↗

Effects of alfalfa extract, anise, capsicum, and a mixture of cinnamaldehyde and eugenol on ruminal fermentation and protein degradation in beef heifers fed a high-concentrate diet.

Four Holstein heifers (360 +/- 22 and 450 +/- 28 kg of BW in Exp. 1 and 2, respectively) fitted with ruminal trocars were used in 4 x 4 Latin square designs to evaluate the effects on ruminal microbial fermentation of the following: Exp. 1, no additive, alfalfa extract (30 g/d, AEX), a mixture of cinnamaldehyde (0.18 g/d) and eugenol (0.09 g/d; CIE1), and AEX and CIE1 in combination; and Exp. 2, no additive, anise oil (2 g/d), capsicum oil (1 g/d), and a mixture of cinnamaldehyde (0.6 g/d) and eugenol (0.3 g/d). Heifers were fed a 90:10 concentrate:barley straw diet (16% CP; 25% NDF) for ad libitum intake. Each period consisted of 15 d for adaptation and 6 d for sampling. On d 16 to 18, DM and water intakes were measured. On d 19 to 21 ruminal contents were sampled at 0, 3, 6, 9, and 12 h after feeding to determine ruminal pH and the concentrations of VFA, L-lactate, large peptides, small peptides plus AA (SPep+AA), and ammonia N. On d 20 and 21, samples of ruminal fluid were collected at 0 and 3 h after feeding to determine protozoal counts. In Exp. 1, CIE1 and AEX decreased (P < 0.05) total DMI, concentrate DMI, and water intake. The increase (P < 0.05) in SPep+AA and the decrease (P < 0.05) in ammonia N when supplementing CIE1 suggest that deamination was inhibited. Treatment AEX increased (P < 0.05) the acetate to propionate ratio, which is less efficient for beef production. Treatment CIE1 increased (P < 0.05) counts of holotrichs. Effects of AEX and CIE1 were not additive for many of the measured metabolites. In Exp. 2, treatments had no effect on ruminal pH, total VFA concentration, and butyrate proportion. The capsicum oil treatment increased (P < 0.05) DMI, water intake, and SPep+AA N concentration and decreased (P < 0.05) acetate proportion, branched-chain VFA concentration, and large peptide N concentration. The cinnamaldehyde (0.6 g/d) and eugenol (0.3 g/d) treatment decreased (P < 0.05) water intake, acetate proportion, branched-chain VFA, L-lactate, and ammonia N concentrations and increased (P < 0.05) propionate proportion and SPep+AA N concentration. The anise oil treatment decreased (P < 0.05) acetate to propionate ratio, branched-chain VFA and ammonia N concentrations, and protozoal counts. The results indicate that at the doses used a mixture of cinnamaldehyde and eugenol, anise oil, and capsicum oil may be useful as modifiers of rumen fermentation in beef production systems.

Acrolein↗