Degradation Rate Of Crude Protein Research Articles

Evaluation of Molly model predictions of ruminal fermentation, nutrient digestion, and performance by dairy cows consuming ryegrass-based diets

Several studies have been conducted to improve grazing management and supplementation in pasture-based systems. However, it is necessary to develop tools that integrate the available information linking the representation of biological processes with animal performance for use in decision making. The objective of this study was to evaluate the precision and accuracy of the Molly cow model predictions of ruminal fermentation, nutrient digestion, and animal performance by cows consuming pasture-based diets to identify model strengths and weaknesses, and to derive new digestive parameters when relevant. Model modifications for adipose tissue, protein synthesis in lean body mass and viscera representation were included. Data used for model evaluations were collected from 25 publications containing 115 treatment means sourced from studies conducted with lactating dairy cattle. The inclusion criteria were that diets contained ≥45% perennial ryegrass (Lolium perenne L.), and that dry matter intake, dietary ingredient composition, and nutrient digestion observations were reported. Animal performance and N excretion variables were also included if they were reported. Model performance was assessed before and after model reparameterization of selected digestive parameters, global sensitivity analysis was conducted after reparameterization, and a 5-fold cross evaluation was performed. Although rumen fermentation predictions were not significantly improved, rumen volatile fatty acids absorption rates were recalculated, which improved the concordance correlation coefficient (CCC) for rumen propionate and ammonia concentration predictions but decreased CCC for acetate predictions. Similar degradation rates of crude protein were observed for grass and total mixed ration diets, but rumen-undegradable protein predictions seemed to be affected by the solubility of the protein source as was the intestinal digestibility coefficient. Ruminal fiber degradation was greater after reparameterization, driven primarily by hemicellulose degradation. Predictions of ruminal and fecal outflow of neutral detergent fiber and acid detergent fiber, as well as total fecal output predictions, improved significantly after reparameterization. Blood urea N and urinary N excretion predictions resulted in similar accuracy using both sets of model parameters, whereas fecal N excretion predictions were significantly improved after reparameterization. Body weight and body condition score predictions were greatly improved after model modifications and reparameterization. Before reparameterization, yield predictions for daily milk, milk fat, milk protein, and milk lactose were greatly overestimated (mean bias of 61.0, 58.7, 73.7, and 64.6% of mean squared error, respectively). Although this problem was partially addressed by model modifications and reparameterization (mean bias of 3.2, 1.1, 1.7, and 0.4% of mean squared error, respectively), CCC values were still small. The ability of the model to predict grass digestion and animal performance in dairy cows consuming pasture-based diets was improved, demonstrating the applicability of this model to these productive systems. However, the failure to predict grass digestion based on standard model inputs without reparameterization indicates there are still fundamental challenges in characterizing feeds for this model.

Dynamics of degradation of high-quality tropical forage according to levels of nitrogen supplementation.

The present study aimed to evaluate the degradation dynamics of high-quality tropical forage according to the levels of nitrogen supplementation. In this study, 4 rumen-fistulated cows with a body weight of 653 ± 47kg were used. These animals were distributed in a 4 × 4 Latin square experimental design. Cows were kept under a grazing regime in an area formed by Panicum maximum Jacq. cv. Tanzania. These animals received 4 levels of crude protein (CP) in the supplements (122, 142, 162, and 180g/kg of CP in DM). The degradability of dry matter (DM), crude protein (CP), and neutral detergent fiber (NDF) was determined by in situ incubation of forage samples at 0, 6, 12, 24, 48, 72, 96, and 120h. Both the concentration of ammonia nitrogen (NH3-N) and the microbial protein synthesis were affected by CP levels of the supplements (P < 0.05). There was a significant difference (P < 0.05) for fraction b, potential degradability, and effective degradability of DM and NDF, and for the c degradation rate of CP of Tanzania grass which had the highest values at 122g/kg of CP. Overall, the greatest degradation of nutrients from Tanzania grass occurred in the diet with 122g/kg of CP and 604g/kg of NFC in dairy cattle supplements that resulted in the highest rates of nitrogen utilization by rumen microbes.

Comparison of Chemical Composition and Rumen Degradation Kinetics of Three Forages: Whole Plant Barley, Whole Plant Foxtail Millet and Grass-Legume Hay

&lt;p&gt;The objective of this study was to determine the chemical composition and &lt;em&gt;in situ&lt;/em&gt; rumen degradability of whole plant barley (&lt;em&gt;Hordeum vulgare&lt;/em&gt;), whole plant foxtail millet (&lt;em&gt;Setaria italica&lt;/em&gt;) and smooth bromegrass (&lt;em&gt;Bromus inermis&lt;/em&gt; &lt;em&gt;Leyss&lt;/em&gt;)-alfalfa (&lt;em&gt;Medicago sativa &lt;/em&gt;L.) (grass-legume) hay, collected during a companion field grazing study. Relative to grass-legume hay, barley and millet were higher (P = 0.05) in crude protein (CP) and soluble CP, and lower (P = 0.02) in neutral detergent fiber (NDF), acid detergent fiber (ADF), lignin, neutral detergent insoluble CP, and acid detergent insoluble crude protein. The potentially undegradable fraction of CP averaged 32% lower for barley and millet, compared to grass-legume hay, while CP soluble fraction was 36 and 64% higher (P &amp;lt; 0.05) for barley and millet, respectively, than for grass-legume hay. Millet had the highest NDF degradability (P = 0.03) and grass-legume hay the least. Barley and millet had greater (P = 0.02) effective degradability of dry matter (DM), CP, and NDF than grass-legume hay. Millet had the highest (P = 0.01) degradable and lowest undegradable fractions of DM and NDF, and lowest soluble fraction of NDF and rate of CP degradation (P &amp;lt; 0.05). Results indicate that whole plant barley and millet have greater nutritive value than grass-legume hay and may be suitable annual forages for extensive grazing.&lt;/p&gt;

Seasonal changes in the digestion and passage rates of fresh dwarf bamboo ( Pleioblastus argenteostriatus f. glaber) in sheep

The aim of this study was to determine and characterize the ruminal degradability and passage rate of fresh dwarf bamboo ( Pleioblastus argenteostriatus f. glaber) cut in spring and autumn, to study the influence of these variables on intake and digestibility by sheep. The experiment was conducted in late spring (May to early June) and autumn (late September to early October). Eight Suffolk ewes, surgically fitted with ruminal cannulae, were used to measure the ruminal degradability and passage rate. Half of the animals received fresh dwarf bamboo and the other half fresh bahiagrass twice daily to meet maintenance requirements. In spring, the lignin content of dwarf bamboo was similar to that of bahiagrass and approximately twice that of bahiagrass in autumn. The slowly degradable fraction of dry matter (DM) and neutral detergent fiber (NDFom) was lower in dwarf bamboo than in bahiagrass. This fraction decreased in dwarf bamboo in the autumn, in contrast to bahiagrass which maintained similar levels as in the spring (Grass × Season interaction; P=0.005 and 0.016 for DM and NDFom, respectively). However, no difference was observed in degradation rate between grasses and seasons. The degradation rate of crude protein (CP) in dwarf bamboo was lower than that of bahiagrass, particularly in autumn. The ruminal passage rate was unaltered by the type of grass and season. DM intake was similar between the grasses, although a seasonal decrease was observed in both the grasses (P=0.006). The digestibility of DM and NDFom were clearly lower in dwarf bamboo than in bahiagrass (P<0.001) and digestibility decreased in autumn (P<0.05) in both grasses. Seasonal variation in DM intake and digestibility of bahiagrass was independent of ruminal degradation characteristics, but in dwarf bamboo both variables were associated with lower potential degradability in the rumen and higher cell wall lignification. However, besides lignin, other non-identified factors also may have contributed to depress ruminal digestion of dwarf bamboo as suggested by the comparison with bahiagrass in spring at similar levels of lignification.

Degradabilidade in situ da matéria seca e da proteína bruta do farelo de arroz, farelo de trigo, grão de milho e grão de aveia

The objective of this work was to determine the ruminal degradability of dry matter (DM) and crude protein (CP) of maize grain (MG), oat grain (OG), wheat meal (WM) and rice meal (RM). The in situ technique was used with nylon bag, and the 0, 3, 6, 12, 18, 24, 48 and 72 hours intervals of ruminal incubation were evaluated. Four steers were used in a 4 x 4 latin square. The dry matter of the OG presented the highest soluble fraction (36.58%), the highest rate of degradation (12.95% h-1 ) and the highest effective degradation (ED) (79.28%). The RM presented the lowest potential degradable fraction (29.24%) and the lowest ED of DM (49.16%). The MG presented the highest soluble fraction of CP (56.88%). The OG presented the highest degradation rate of CP (11.05%). The WM presented the highest ED of CP (77.38%) and the RM presented the lowest ED of CP (66.65%).

Effects of microwave irradiation on ruminal dry matter, protein and starch degradation characteristics of barley grain

This study evaluated effects of microwave irradiation (800 W) for 3, 5 and 7 min on dry matter (DM), crude protein (CP) and starch degradation characteristics of barley grain and to monitor the fate of its proteins in the rumen. Duplicate in situ bags of untreated or irradiated barley grain were incubated in the rumen of four non-lactating Holstein cows for up to 48 h. Proteins of untreated and irradiated bag residues were fractionated by gel electrophoresis. Irradiation for 3 min had no effect, but for 5 and 7 min decreased (P<0.05) the effective DM degradability. The washout fraction, and the degradation rate of CP, decreased (P<0.05) and the potentially degradable CP fraction increased (P<0.05) as irradiation period increased. Effective CP degradability of barley irradiated for 3, 5 and 7 min decreased (P<0.05) by 6%, 10% and 13%, respectively. Microwave irradiation increased (P<0.05) the washout fraction and decreased (P<0.05) the potentially degradable fraction and degradation rate of starch. Irradiation for 5 min had no effect on effective starch degradability, but for 3 and 7 min increased, and decreased it (P<0.05), respectively. From electrophoretic analyses, three major hordein fractions (B-, C- and D-hordein) occurred. In untreated barley grain, most hordein fractions had disappeared after 6 h of incubation, but in microwave irradiated barley, C- and D-hordein were not degraded until 12 h of incubation in the rumen. Microwave irradiation of barley grain for 3 min increased its starch degradability and, over 5 min, decreased the rate and extent of CP and starch degradation.

Effect of ethanol concentration on the kinetics of ruminal degradation of soybean meal

Effects of ethanol treatment on ruminal in situ degradation kinetics of dry matter (DM) and crude protein (CP) of soybean meal (SBM) were determined. Soybean meal samples were soaked in 500, 600 or 700 ml/l ethanol solutions for 2 h. Duplicate nylon bags of untreated or treated SBM were suspended in the rumen of four non-lactating Holstein cows for up to 48 h, and resulting data were fitted to non-linear degradation model to calculate degradation parameters of DM and CP. Intestinal CP digestibility was measured using the mobile nylon bag technique. Proteins of untreated and treated bag residues were fractionated by gel electrophoresis. There were differences (P<0.05) for DM and CP degradation parameters between untreated and ethanol treated SBM. Regardless of the concentration, ethanol treatments applied to SBM decreased the washout fraction, the estimated rate of CP degradation, and the effective protein degradation (EPD) compared to untreated SBM. The lowest estimated rate of CP degradation and the calculated EPD were observed when SBM was treated with 600 ml/l ethanol solution. Extending the ethanol concentration over 600 ml/l to SBM was considered excessive. Ethanol treatments increased (P<0.05) the intestinal mobile bag digestibility of ruminally undegraded CP. At concentration of 500, 600 and 700 ml/l, digestibility of CP increased by 4, 12 and 13% compared to untreated SBM, respectively. Electrophoretic analyses of untreated, 500, 600 and 700 ml/l ethanol treated SBM revealed that two of the subunits of β-conglycinin (ά and α) had been degraded completely after 2, 6, 8 and 8 h, whereas the β subunit of this protein has been degraded after 4, 8, 12 and 12 h, respectively. In untreated SBM, the acidic and basic subunits of glycinin had been degraded in 8 and 12 h of incubation, but in treated SBM had not been degraded even after 48 h of incubation. Based upon these results, treatment of SBM with 600 ml/l ethanol solution had the greatest potential to increase rumen undegradable protein.

Ruminal biohydrogenation of fatty acids, protein degradability, and dry matter digestibility of flaxseed treated with different sugar and heat combinations

Two experiments were conducted to study the effects of processing techniques on in vitro ruminal undegradable protein (RUP), in vitro ruminal biohydrogenation of fatty acids, and in vitro dry matter digestibility (IVDMD) of rolled flaxseed. In the first experiment, the influence of micronization treatment (130°C for 4 h, 140°C for 2 h, 150°C for 1 h, and 160°C for 0.5 h) was examined. The IVDMD significantly decreased when heating at 150°C for 1 h and 160°C for 0.5 h. Degradation rate of crude protein (CP) decreased and RUP concentration increased in parallel with heating temperature. Micronization had little effect on biohydrogenation of fatty acids. In the second experiment, the influence of sugar addition [none, soaked in a high fructose corn syrup (HFCS) or a lignosulfonate solution] before heating, either in an autoclave or a forced-air oven, at two temperatures (100 or 120°C), and two temperature holding times (30 and 60 min) was examined. Increased temperature and heating time decreased degradation rate of CP and increased the RUP fraction of flaxseeds. There was a decre ase in IVDMD with increased temperature when fructose was added. Moist heating is a better option than dry heating, but it has little advantage over not heating to prevent ruminal biohydrogenation of polyunsaturated fatty acids of flaxseeds. Key words: Biohydrogenation, degradability, in vitro, micronization, lignosulfonate

Effects of summer management and fall harvest date on ruminal in situ degradation of crude protein in stockpiled bermudagrass

Limited information is available describing digestive kinetics of crude protein (CP) in stockpiled bermudagrass ( Cynodon dactylon (L.) Pers.) during late fall and early winter. ‘Greenfield’ bermudagrass was stockpiled at two sites following summer hay or pasture management, and samples were taken at 4-week intervals under caged exclosures (UNGRAZED) and outside exclosures (GRAZED) between 17 October 1997 and 9 January 1998. Forage samples were subsequently incubated in situ in five ruminally cannulated, crossbred steers to determine effects of fall harvest date and previous summer management on in situ degradation kinetics of forage CP. At the hay site, concentrations of total plant CP declined ( P<0.05) for UNGRAZED forages between 17 October (134.4 g kg −1) and 12 December (119.4 g kg −1), but concentrations of CP did not differ ( P>0.05) on the 17 October and 9 January harvest dates. From the pasture site, concentrations of total CP for UNGRAZED forages did not change ( P>0.05) throughout the trial. In situ degradation rates of CP from the hay site were not different ( P>0.05) for UNGRAZED forages on 17 October and 9 January (overall mean=0.056 h −1). The ruminal degradation of CP decreased ( P<0.05) by 63 g kg −1 CP between 14 November and 12 December, but did not change during the first and last sampling intervals. At the pasture site, rates of CP degradation increased ( P<0.05) for UNGRAZED forages between 17 October (0.044 h −1) and 9 January (0.080 h −1) due to the presence of immature, winter annual weeds. Similarly, the ruminal degradation of CP increased ( P<0.05) between 12 December (580 g kg −1) and 9 January (624 g kg −1) in response to winter annual weed presence. Ruminal availability of CP in stockpiled bermudagrass decreases as the dormant forage ages, but may be adequate to meet the minimum CP requirements of dry, pregnant beef cows.

Intake, digestion, and nitrogen balance of sheep fed shrub foliage and medic pods as a supplement to wheat straw

Low animal performance in arid and semi-arid areas of Morocco is mainly due to protein and energy deficiencies of available forages. A metabolism trial was conducted to evaluate the influence of supplementation with shrub foliage and medic (Medicago sp.) pods on nitrogen (N) utilization by sheep fed low-quality roughage. Diets were wheat (Triticum aestivum L.) straw (WS), WS plus alfalfa (Medicago sativa L.) hay (AH), WS plus oldman saltbush (Atriplex nummularia Lindl.) foliage (AN), WS plus blue wattle (Acacia cyanophylla Lindl.) foliage (AC), and WS plus medic pods (MP). Alfalfa feeding level was set to provide a crude protein (CP) concentration of 90 g kg−1 dry matter (DM) in the diet. Shrub foliage and medic pods were offered ad libitum. Average intake levels for AN, AC, and MP were 37.2, 32.4, and 47.2% DM, respectively. Chemical composition and in vitro dry matter disappearance (IVDMD) were measured. Digestible dry matter intake (DDMI) was greatest (P < 0.05) for saltbush diet (36.3 g kg−0.75), followed by the alfalfa diet (30.0 g kg−0.75). Unsupplemented wheat straw and blue wattle diets had the lowest DDMI (21.3 g kg−0.75). The daily N balance for the supplemented diets was greatest (P < 0.001) for alfalfa and saltbush diets with +6.7 g and least for the blue wattle diet (+ 3.0 g). Feeding the unsupplemented wheat straw diet resulted in the lowest N retention (+ 0.6 g day−1). A degradability trial was then conducted to investigate the rate and extent of DM and CP digestion of the same forages in the rumen. Forage samples were incubated for 0, 2, 4, 8, 12, 24, 48, and 72 h. Rate and extent of DM digestion were highest (P < 0.05) for saltbush foliage. Rate of CP degradation was fastest (P < 0.05) for alfalfa hay (0.151 h−1). Extent of CP degradation was greatest (P < 0.05) for saltbush foliage (74.4%), followed by MP (69.0%), AH (63.9%), and BW (6.8%). Inclusion of saltbush foliage, and to some extent medic pods, with low-quality forage diet was comparable to inclusion of alfalfa hay. These results indicated that improving degraded rangelands by planting palatable shrubs, and managing medic pastures to produce enough pods to be grazed in the summer should reduce the need to supply sheep with costly protein-rich supplements during periods of feed shortage.

単独給与した乾草の種類が大豆粕のタンパク質分解率におよぼす影響

Using the in situ technique, the effective degradability of crude protein (CP) of soybean meal was determined in the rumen of sheep given four kinds of hay: alfalfa (AL), bermuda grass, Italian ryegrass (IR) and sudan grass (SG) in order to assess the degradability (dg) values of CP in soybean meal (SBM) determined under different hay feeding regimens. The intake of hay tended to be higher in AL and bermuda grass (BG) feeding than in IR and SG. The rate constants of rumen passage did not differ significantly among the different hay feeding with a tendency to have a higher rate in AL feeding. The degradation rate of CP in SBM tended to be higher in AL and BG feeding than in IR and SG. The effective degradability of CP in SBM determined under feeding of BG was significantly higher than the feeding of other hays. When the range of tabulated dg values of CP was considered, the difference found in the present study was inferred to cause no critical errors in the calculation of the de values of CP in SBM.

Raw or roasted lupin supplementation of grass silage diets for beef steers

Raw or roasted lupins were evaluated as protein supplements in rations for growing and finishing beef steers. Lupins were roasted in a flame roaster with an exit temperature of 105°C. The effect of heating on protein solubility and rumen degradability of lupin was evaluated by chemical and Dacron bag procedures. The solubility of N in buffer was reduced from 69.8% in raw lupin to 35.8% in roasted lupin. Effective degradability of crude protein (CP) and rate of CP degradation predicted by the Dacron bag procedure were lower for roasted lupin (82.3% and 9.2% h −1, respectively) than for raw lupin (86.7% and 11.9% h −1, respectively). Heat damage measured by acid detergent insoluble N did not differ between raw (3.31% of total N) and roasted lupin (3.46% of total N). Twenty-eight Charolais cross steers with an average weight of 235 kg (± 35 kg) were fed grass silage only (SIL) or silage plus supplements, to supply CP at 6.5% of the silage dry matter intake (DMI), with raw lupin (RL), roasted lupin (ROL) or soybean meal (SBM) as the source of supplementary protein. When the steers reached 330 kg liveweight they were placed on a finishing diet of chopped hay, barley and protein supplements at a rate of 4.5% of barley DMI. In the growing phase, steers fed RL, ROL or SBM had significantly higher ( P < 0.05) daily gains than steers fed silage alone. Steers fed the SBM diet had significantly higher daily gains than RL, and steers fed ROL had intermediate gains. Daily gains of steers fed raw and roasted lupin were not significantly ( P > 0.05) different. Silage DMI was significantly lower on diets supplemented with RL and ROL compared with SIL. In the finishing phase, there were no significant differences in daily gain, carcass weight, dressing percentage, loin eye area or DMI among the diets. Heat treatment of lupins decreased solubility and ruminal degradability of CP. Growth performance of beef steers fed roasted lupin was similar to that of steers fed SBM.

Ruminal degradability of crude protein from different treated soybean meals in lactating cows.

Ruminal crude protein (CP) degradability of four commercially available soybean meal (SBM) types--untoasted (U), toasted (T), heat-treated (H) and formaldehyde-treated (F)--was studied by the use of in sacco and in vivo techniques with lactating German Friesian cows cannulated in the rumen, duodenum and ileum. In two in sacco experiments three cows were fed a diet based either on grass hay plus ear-maize silage or on barley whole plant silage. Ruminal degradation rate of CP was estimated as percent nitrogen (N) disappearance from polyester bags incubated in the rumen for 2, 4, 6, 8, 12 and 24 h. Ruminal degradation rate of CP varied among the four SBM types as well as between the two basal diets. N disappearance from the bags after 12 h of incubation averaged 96, 67, 37, and 23% for the U, T, H, and F SBM types, respectively, in the cows fed the hay/ear-maize silage diet vs 99, 86, 58 and 41% for the four SBM types, respectively, in the cows fed the barley whole plant silage diet. In the in vivo experiment, four cows were fed diets based on meadow hay and ear-maize silage in a 4 x 4 Latin square design. The effect of SBM treatment on the flow rate of non-ammonia N (NAN) into the duodenum, and its relationship with the ruminal degradation rate of CP of the four SBM types, was studied. Formaldehyde treatment increased the amount of NAN entering the duodenum (P less than .05): 485 g cow-1 day-1 compared to 383, 418 and 428 g for U, T and H, respectively. Calculated ruminal CP degradabilities were 93, 75, 71 and 38% for SBM types U, T, H and F, respectively.

The in sacco degradation of crude protein and cell wall constituents in grass, alfalfa and maize silages.

Degradation of crude protein (CP) and cell wall constituents (CWC) in grass, lucerne and maize silages were estimated after incubation for 48 h in nylon bags in the rumen of 2 Dutch Friesian cows fed daily on hay 10 kg and concentrates 1 kg. Estimation of fractional rates of degradation was based on a single exponential degradation model. Fractional degradation rates of CP in grass, lucerne and maize silages were 5.2, 5.0 and 6.3% per h respectively. Corresponding values for CWC were 4.3, 4.0 and 2.8% per h. The non-degradable CWC fraction was higher in lucerne silage (52.1%) than in grass and miaze silages (20.4 and 24.6%, respectively). Extent of degradation of lucerne CWC was lower than that of maize and grass silages but voluntary intake of lucerne silage by steers was higher. Voluntary intake of silages cannot be explained by content, composition and degradation of CWC only; the physical structure may also be involved. (Abstract retrieved from CAB Abstracts by CABI’s permission)

Factors affecting in sacco degradation of dry matter and crude protein in grass silage

The degradability of dry matter and crude protein was studied in 96 grass silages, which were collected from practical farms in different parts of Finland. The degradabilities were determined by the nylonbag technique in sheep on a grass silage and hay (50 : 50 on DM basis) -based diet. Among chemical components the N-free extracts increased, and the crude fibre decreased the dry matter degradation in the rumen. The correlation between the end-products from silage fermentation and the dry matter degradability was generally negative. The level of the crude protein degradability was significantly increased when the crude protein content in the silage DM was increased. The amount of NO3 in the silage DM had a similar effect. The rate of crude protein degradation was regulated mainly by the proteolysis in the silage, e.g. the amounts of NH, and especially watersoluble N in the total N of silage. Crude fibre tended to protect crude protein against ruminal digestion.

In Situ Particle Size Reduction and the Effect of Particle Size on Degradation of Crude Protein and Dry Matter in the Rumen of Dairy Steers

The contribution of rumen microbes to particle size reduction was examined and the influence of particle size on in situ degradation rates of crude protein and dry matter in the rumen of dairy steers fed ad libitum was determined. In addition to rumination and mastication, microbial action is of major importance in particle size reduction of some feed-stuffs in ruminants. Rates of crude protein degradation differed among feed-stuffs but were not significantly affected by particle size within feed samples. Primary and secondary rates of dry matter degradation were observed for wheat bran, linseed meal, and cottonseed meal. Soybean meal and formaldehyde-treated soybean meal data displayed only primary degradation rates for dry matter. Differences in primary rates of dry matter degradation among various particle sizes were significant only for linseed meal. Absence of a consistent pattern to the influence of particle size on rates of dry matter and crude protein degradation within a feed indicates the importance of other factors.