Ruminal Degradability Of DM Research Articles

Effect of inoculants on whole-crop barley silage fermentation and dry matter disappearance in situ.

Whole-crop barley harvested at the mid-dough stage was ensiled in 3-L laboratory silos either directly (at 30.7% DM) or after wilting (37.8% DM), and with or without application of Inoculant A, B, or D. Each inoculant contained multiple strains of Lactobacillus plantarum and Enterococcus faecium. Two silos per treatment were opened on d 1, 3, 7, 15, and 47 for silage analysis. Wilted silages had higher (P < 0.05) pH than unwilted silages, and Inoculant B (unwilted crop) and Inoculants A, B, and D (wilted crop) decreased (P < 0.05) silage pH compared to the controls. Reducing sugars concentration was 36% lower (P < 0.05), on average, in the wilted than in the unwilted silages. Silages prepared with Inoculants B or D had lower (P < 0.05) concentrations of reducing sugars than the control. Wilting of the barley crop further increased the difference between inoculated and control silages (wilting x inoculation P < 0.05). Neither wilting nor silage inoculants affected concentrations of nonprotein N, ammonia N, or free amino acid N in silage. Wilting did not affect the concentration of lactic acid bacteria (LAB) in the silages. Across DM levels, inoculant-treated silages had larger (P < 0.01) populations of LAB than did the uninoculated controls (7.1 x 10(9) vs 2.3 x 10(9) cfu/g silage DM). Wilting resulted in lesser (P < 0.05) silage lactic acid concentration than the directly ensiled crop. At both DM levels, lactic acid concentration was higher (P < 0.001) in inoculated silages than in controls. The in situ soluble and potentially degradable fractions of silage DM were not affected by wilting or inoculant treatment. The rate of degradation of the potentially degradable silage DM was 35% lower (P < 0.05) in wilted than in unwilted silage. As a result, the calculated effective degradability of silage DM was lower (P < 0.001) in wilted than in unwilted silage. Inoculants did not influence the rate of degradation or effective degradability of silage DM in the rumen. Whole-crop barley ensiled at approximately 30% DM (without wilting) contained higher concentrations of soluble sugars and lactic acid and had higher ruminal degradability of DM than wilted silage (38% DM). Although inoculants did not improve DM degradability of barley silage, lower terminal pH and increased concentrations of lactic acid may improve aerobic stability upon feed-out.

Addition of rice straw or/and wheat bran on composition, ruminal degradability and voluntary intake of bamboo shoot shells silage fed to sheep

This study investigated the quality of bamboo shoot shell silage prepared with or without rice straw (RS) or/and wheat bran (WB), and to evaluate their nutritive value in terms of chemical composition, ruminal degradation characteristics, and voluntary intake by lambs. The bamboo shoot shells silages were prepared in experimental silos to create four treatments: (1) 100% (fresh basis) bamboo shoot shells (control); (2) 90% bamboo shoot shells+10% RS (RS10); (3) 90% bamboo shoot shells+5% RS and 5% WB (RS5WB5), and (4) 90% bamboo shoot shells+10% WB (WB10). Voluntary intakes of the silages were determined in a 4×4 Latin square design with four lambs. The bamboo shoot shell silage alone was of poor quality with moulding and seepage to the bottom of the silo. Addition of RS or/and WB improved silage quality, but addition of WB was superior to that with RS. The DM loss was very high in control silage (>17%), but addition with RS increased DM recovery, with little effect on quality of silage. Recovery of DM further increased in both WB-added groups and was higher than that in the RS-added silage. Adding WB improved the quality of silage, judged by a lower pH value, decreased NH 3-N concentration and increased content of lactic and total acids. While adding RS decreased the ruminal degradation of DM and crude protein of bamboo shoot shells silage, WB addition increased both rapidly and slowly degraded fractions of bamboo shoot shells silage, and ruminal degradability of DM and crude protein at 48 h was increased. Voluntary DM intake of bamboo shoot shells silage was 32, 67 and 120% higher for groups RS10, RS5WB5 and WB10 than for the control. The CP intake was 18, 55, and 232% higher with addition of 10% RS, 10% RS plus 5% WB, and 10% WB, compared to the control. Improved performance of lambs may be expected from bamboo shoot shell silage prepared with RS or/and WB, but improvements are substantively higher for WB.

Effects of calendar date and summer management on the in situ dry matter and fiber degradation of stockpiled forage from bermudagrass pastures.

Limited information is available that describes the disappearance kinetics of bermudagrass (Cynodon dactylon L. Pers.) during fall and early winter. Five ruminally cannulated, crossbred steers (387 +/- 18.3 kg) were used to determine the effects of calendar date and previous summer management on the in situ degradation kinetics of DM and NDF for forage clipped from stockpiled 'Greenfield' bermudagrass pastures. Forage was stockpiled at two sites following summer hay or pasture management, and samples were taken outside (GRAZED) and under caged exclosures (UNGRAZED) at 4-wk intervals beginning October 17, 1997, and ending January 9, 1998. No effort was made to remove or avoid contaminate species. Concentrations of NDF increased (P < 0.001) to a maximum for UNGRAZED forages at the hay site between October 17 and December 12, but sampling date had no effect (P = 0.627) on concentrations of NDF at the pasture site. Concentrations of ADF and lignin increased (P < or = 0.023) during at least one sampling interval in UNGRAZED forages at both sites. At the hay site, degradation rates of DM decreased (P < 0.001) by 0.013/h for UNGRAZED forage between October 17 and January 9, whereas the effective ruminal degradability of DM decreased (P < 0.001) by 33.5% during the same time period. Fractional degradation rates of NDF for UNGRAZED forages at the hay site decreased (P < 0.001) by 0.014/h between October 17 and November 14 but did not change (P > or = 0.077) throughout the remainder of the study. The effective ruminal degradability of NDF decreased (P < 0.001) by 33.8% between the first and last sampling date. At the pasture site, sampling date did not affect (P = 0.458) rates of DM degradation, but the effective degradability of DM for UNGRAZED forages decreased (P = 0.001) by 19.0% from October 17 to December 12. Rates of NDF degradation for UNGRAZED forages did not differ (P > or = 0.113) on the first three sampling dates, but the rate on January 9 was slower than that observed on October 17 (P = 0.025) and November 14 (P = 0.044). The effective degradability of NDF decreased (P < 0.001) by 19.2% between October 17 and December 12. These data indicate that stockpiled bermudagrass should be used during a limited window during the late fall; after this time, the nutritive value becomes very poor.

Grazing methods and stocking rates for direct-seeded alfalfa pastures: II. Pasture quality and diet selection.

A 2-yr study was conducted to determine the effects of two grazing methods (GM) and two stocking rates (SR) on alfalfa (Medicago sativa L. var. WL225) pasture quality and diet selection by Holstein steers. Eight pasture plots (.76 ha) were seeded in 1988 and divided into two blocks of four pastures each. Pastures were managed to allow a 36-d rest period with an average grazing season of 105 d. Before steers entered the next paddock, canopy heights (CH) of alfalfa plants were determined and pasture-forage samples were collected. Forage samples were analyzed for DM, OM, CP, and in vitro OM digestibility (IVOMD). At 12-d intervals beginning with the second grazing cycle, extrusa samples were collected from steers with esophageal fistulas. Extrusa samples were frozen, freeze-dried, and analyzed for OM, CP, IVOMD, in situ ruminal DM degradation, and ruminal undegradable protein. There were no effects of GM on alfalfa CH or pasture DM, OM, CP, and IVOMD. Increasing the SR increased pasture CP content in both years and increased DM, OM, and IVOMD in the 2nd yr. There was no effect of GM or SR on the quality of forage selected by esophageally fistulated steers. Esophageally fistulated steers selected forage that had greater OM, CP, and IVOMD than the average nutrient content of the forage. Although forage quality was greater when stocking rates were increased, the quantity of forage available per animal may have limited gains.

Avaliação do capim-elefante (Pennisetum purpureum Schum.) cultivar taiwan A-148, ensilado com diferentes técnicas de redução de umidade

O objetivo deste trabalho foi avaliar o efeito de diferentes técnicas de redução de umidade sobre a composição química, digestibilidade in vitro da matéria seca (DIVMS) e degradação ruminal da matéria seca da silagem de capim-elefante (Pennisetum purpureum Schum.) cv. Taiwan A-148. Os tratamentos (A, Controle; B, 20,0; C, 30,0; D, 40,0% de sabugo de milho; E, emurchecimento por 12 horas; F, emurchecimento por 24 horas; e G, esmagamento + emurchecimento por 24 horas) foram distribuídos em delineamento inteiramente casualizado com três repetições. Os tratamentos da silagem B e E não foram eficientes em reduzir a umidade excessiva da forragem. O emurchecimento por 24 horas aumentou o teor de MS, sem influir no teor de PB e na DIVMS. Os tratamentos C e D favoreceram o desenvolvimento da população de clostrídeos, aumentaram a concentração de N-NH3 e reduziram a concentração de ácido lático e a DIVMS das silagens. O tratamento G aumentou o teor de MS e reduziu a concentração de N-NH3 e DIVMS. A adiçao de sabugo de milho (tratamentos B, C e D) reduziu a degradação ruminal da MS das silagens. O sabugo de milho reduziu a umidade, mas apresentou efeitos negativos na qualidade da silagem, enquanto o esmagamento e/ou emurchecimento foram procedimentos que mostraram bons resultados em relação à conservação do material ensilado.

Effect of Cultivars on In Vitro and Ruminal Degradation of the Nitrogen Fraction in Birdsfoot Trefoil Silage

Experiments were carried out to determine the effects of tannin content on N fractions and DM digestibility of birds-foot trefoil harvested at 20% bloom stage. Five trefoil cultivars, harvested in both June and August, were used: Upstar, Mirabel, Empire, Leo, and Bt-8861. Forage was ensiled in 1.3-kg laboratory silos for 60 d with 4 silos per cultivar and harvest. Concentrations of DM and tannin in forage were determined prior to ensiling, and N fractions, DM digestibility, and pH in silage were also determined. Tannin concentration and protein N content of silage were lower in Empire than in the other cultivars. Ruminal degradability of DM and CP of Empire (low tannin) and Upstar (high tannin) birdsfoot trefoil were estimated with two fistulated cows using nylon bags that were incubated ≤96h. The DM-soluble fraction of Empire was significantly lower than that of Upstar for the first harvest only. This difference was partly due to the high proportions of dry shoots. The CP-soluble fraction of Empire was higher than that of Upstar, but the percentage of CP that was potentially degradable in the rumen was lower for Empire. This difference could result in different CP availability over time even for similar effective degradability of CP. Tannin had no additional effect on total CP degradability in the rumen.

Intake, Digestibility, and Ruminal Degradability of Shredded Hay

Thirty-two Outaouais intact male lambs averaging 39.1kg were assigned randomly to a 2 × 2 factorial arrangement of treatments consisting of two forages and two methods of harvesting to determine intake and digestibility. The four treatments fed during the experiment consisted of alfalfa and timothy hays harvested with either a prototype mat maker or a conventional mower conditioner. Hays were fed for ad libitum intake for the entire experiment, and data on digestibility and intake were collected for 9 d after a 21-d adaptation. Ruminal degradability of DM, N, and ADF of hays was estimated with two fistulated cows using nylon bags incubated up to 96h. Harvesting with the prototype mat maker compared with the conventional mower generally increased intake and digestibility of alfalfa and timothy hays. Ruminal degradability of DM and the potentially degradable fraction of DM and ADF was higher when hay was harvested with the prototype mat maker than with the conventional mower. The increased digestibility of hay harvested with the prototype mat maker could be explained by the increased digestibility in the rumen because harvesting with the prototype mat maker increased the potentially degradable fraction of DM and ADF. These results suggest that the digestible energy content of hay was increased by shredding.

In Situ Dry Matter, Protein, and Fiber Degradation of Perennial Forages

Eight forages (alfalfa, birdsfoot trefoil, red clover, bromegrass, orchardgrass, perennial ryegrass, quackgrass, and timothy) at three maturities were evaluated for ruminal DM, CP, and NDF degradation kinetics. Duplicate dacron bags were incubated for 0, 3, 6, 10, 13, 25, 48, and 72h in two late lactation Holstein cows fitted with ruminal cannulas over eight experimental periods. Species and maturity effects were observed for soluble, slow, and undegraded fractions; degradation rate; and ruminally degradable DM, CP, and NDF. Significant species by maturity interactions also were evident for fractions and ruminal degradabilities of DM, CP, and NDF. Legumes exhibited more extensive ruminal DM degradation than did grasses. No clear trends were evident in rate of ruminal CP degradation between legumes and grasses. Mature grasses were lowest in ruminally degradable CP. Legumes exhibited a higher undegraded fraction and faster degradation rate of slowly degraded NDF fractions, resulting in similar ruminally degraded NDF for legumes and grasses. Extensive differences in ruminal degradation kinetics existed between perennial legume and grass species and maturities. Species by maturity interactions were diverse, making categorization of degradation characteristics of legumes and grasses difficult.