Ruminal Degradability Of Crude Protein Research Articles

Ruminal dry matter and crude protein degradation kinetics of five sainfoin (Onobrychis viciifolia Scop) accessions differing in condensed tannin content and obtained from different harvests

Sainfoin is known to vary in content of condensed tannins (CT) among accessions and harvests. In the present study, the hypothesis was tested that this results in significant differences in ruminal degradation kinetics and, with that, suitability to be used for certain purposes like increasing ruminal by pass of protein. The in sacco ruminal degradation kinetics of dry matter (DM) and crude protein (CP) of five Swiss sainfoin accessions comprising of three landraces (Moiry, Sarzens and Premier, all single flowering) and two commercial cultivars (Visnovsky and Perly, both multiple flowering) were determined with three ruminal fistulated cows. In doing so, the first and the second harvest (after 42 d of regrowth) in the second year of establishment of the plots were compared. Cultivation was done in triplicate on each of three different sites in Switzerland. Data was subjected to analysis of variance including all main effects and interactions. Finally, compositional data on CT, CP and fibre was correlated with effective ruminal degradability (ED) of DM and CP to assess how well these could be predicted. Accession hardly influenced either the degradation kinetics and effective degradability of DM and CP despite the varying chemical composition of accessions. Exceptions were the degradable but insoluble fraction, B, in DM (P=0.050) and CP (P=0.041) and the potential degradable fraction, D, in CP (P=0.017) which were influenced by accession. Conversely, harvest influenced (P<0.05) degradation kinetics and effective degradability of DM the most but not the kinetics and effective degradability of CP. The ranking of accessions was not completely consistent in the different degradation variables. However, according to the results of the multiple regression analysis, ED of DM (P=0.001) and CP (P≤0.013) declined with increasing CT content. These relationships were roughly linear. Accordingly, ED was often higher in samples from first compared to the second harvest. Most striking was, however, that only some accessions exhibited consistent and marked changes in both DM and CP degradation kinetics from the first to the second harvest whereas others did not. It appears that the first group particularly included the commercial accessions which were multiple flowering cultivars and the second group comprised the single flowering landraces. This finding could be used to select accessions with predictably stable ruminal degradability.

Ruminal and intestinal amino acid digestion of distiller's grain vary with grain source and milling process

A study was conducted to evaluate the in situ ruminal degradability of crude protein (CP), amino acid (AA) profiles of ruminal undegradable protein (RUP), and in vitro intestinal digestibility of AA for dried distillers grains with solubles (DDGS) as affected by grain source (corn vs. wheat) and milling process (conventional vs. fractional). The feeds tested included wheat, wheat DDGS (WDDGS), corn, corn DDGS (CDDGS) and corn fractional DDGS (FDDGS). The feeds were evaluated in three ruminally cannulated beef heifers fed a diet containing 600g/kg barley silage and 400g/kg barley-based concentrate (dry matter [DM] basis). Polyester bags containing 5g of ground feed (2-mm) were incubated in the rumen of each heifer for 0, 2, 4, 6, 12, 16, 24, and 48h. Ruminal microbes were labeled using 15N to correct the bacterial contamination. The model y=a+b(1−e−c(t−lag)) was fitted to determine degradation kinetics of DM and protein. Effective degradability (ED) was determined as: a+[bc/(c+k)], where k was assumed to be 0.06/h. In vitro intestinal digestibility of the RUP and AA were determined on the residue after 16h of ruminal incubation using a modified 3-step method. The CP, neutral detergent fiber, acid detergent fiber, ether extract, and mineral contents of DDGS varied (P<0.01) with grain and milling process. Amino acid profiles of DDGS were different (P<0.05) from those of the original grain. Ruminal degradation of CP was lower (P<0.01) in DDGS than in the original grain, and lower (P<0.01) in FDDGS than in CDDGS, with no difference between WDDGS and CDDGS. However, ruminal degradation of essential AA (EAA) was higher (P<0.05) for WDDGS than for CDDGS, and it was lowest (P<0.01) for FDDGS. The AA profiles of RUP were different (P<0.05) between DDGS and the original grain as well as between DDGS types. Intestinal digestibility widely varied among individual AA and among feeds. The intestinal digestibility of total AA and EAA was not different between WDDGS and CDDGS, but it was lower (P<0.05) for FDDGS than for CDDGS. Estimated intestinal absorbable total AA and EAA were highest (P<0.05) for FDDGS, intermediate (P<0.05) for CDDGS, and lowest (P<0.05) for WDDGS. The results suggest that the AA availability of DDGS varies with the grain source used to produce ethanol and with the milling process prior to ethanol fermentation. Although FDDGS is a good RUP source, its CP digestibility coefficient in the total digestive tract of cattle is lower (P<0.05) than that of WDDGS and CDDGS.

Short Communication: Effect of forage sources and &lt;i&gt;Saccharomyces cerevisiae&lt;/i&gt; (Sc 47) on ruminal fermentation parameters

Diet composition has been suggested as a factor that influences the variability of responses when Saccharomyces cerevisiae (SC) is fed to ruminant animals. Diets based on lucerne hay (462 g/kg DM) and maize silage (488 g/kg DM) were fed to determine the effects of 0 or 5 g SC 47 (8´109 cfu/g) on ruminal digestion, fermentation and protozoa population. Ruminal pH, acetate, propionate, degradation rate and effective degradability were significantly affected by the forage sources. The addition of SC caused an increase in degradability of forage neutral detergent fibre (NDF), and tended to enhance degradability of total diet organic matter (OM), and the concentration of propionate and result in a decrease in protozoa numbers at 3 h post feeding. Ruminal crude protein degradation, ammonia-N concentration, acetate : propionate ratio and pH were not elicited by the addition of SC. Although the ruminal environment was significantly affected by the forage sources, no interaction between SC and forage sources occurred for ruminal digestion parameters: pH, ammonia-N and protozoa populations. However, compared with the maize silage, the SC increased the initial degradability (3 h after feeding) of forage NDF (4.6% vs. 1.7%), total diet OM (3.1% vs. 1.0%) and crude protein (CP) (5.5% vs. 0.1%) to higher proportions for lucerne hay. Moreover, acetate concentration was increased on the diet based on maize silage and decreased on the diet based on lucerne hay with supplementation of SC. Although ruminal environments were considerably altered by the forage sources, the SC exhibited a transitory effect (3 h post feeding) without overall improvement on ruminal digestion and fermentation; nevertheless, this observation was more pronounced for lucerne-based diet. Keywords: Rumen degradability, fermentation, protozoa, forage sources

Estimating ruminal crude protein degradation of forages using in situ and in vitro techniques

Rumen insoluble feed crude protein (CP) escaping degradation (RUP) was estimated from a variety of forages using two in vitro procedures: the Cornell protein fractionation procedure and the enzymatic degradation procedure by Streptomyces griseus protease. Some recent improvements to both in vitro procedures were applied. The in situ technique served as a reference method and a novel combination of methods was used to correct for microbial colonisation of residues. Twenty-five forages, varying in conservation type (unconserved, ensiled, dried) were analysed. Assumed passage rates (Kp) of 0.02, 0.04 and 0.06/h were applied to estimates of RUP using in situ and chemical fractionation. Results from both in vitro procedures correlated linearly with in situ values (P<0.05). In terms of variation around the regression line, distance of the slope from zero and root mean square error, enzymatic degradation was the more accurate method in estimating in situ RUP (r2=0.71, P<0.0001; Kp4). In both in vitro procedures, silage and dried forage were more accurately estimated than unconserved forage, which may be explained by the higher and more variable concentration of intermediately degraded CP fraction B2 in the latter. Estimation of in situ RUP from CP fractions needs further improvement. Results imply that in vitro procedures may be used to predict in situ estimates of RUP with a higher level of confidence.

Comparison of electron beam and gamma ray irradiations effects on ruminal crude protein and amino acid degradation kinetics, and in vitro digestibility of cottonseed meal

This study was conducted to compare effects of electron beam (EB) and gamma ray (GR) treatments at doses of 25, 50 and 75kGy on ruminal degradation kinetics of crude protein (CP), amino acid (AA), and in vitro digestibility of cottonseed meal (CSM). Ionizing radiations of EB and GR had significant effects (P<0.05) on CP and AA ruminal degradability characteristics of CSM. Effective ruminal degradability (ERD) of CP was lower in EB and GR irradiated CSM (P<0.05) than in unirradiated CSM. GR and EB treatments had the same effects on ERD decreasing of CP (P>0.05). Irradiation processing caused decrement in AA degradation after 16h of ruminal incubation (P<0.05). EB irradiation was more effective than GR irradiation in lessening the ruminal degradability of AA (P<0.05). EB and GR treatments at a dose of 75kGy increased in vitro digestibility of CSM numerically. This study showed that EB could cause CP and AA bypass rumen as well as GR. Therefore, ionizing irradiation processing can be used as an efficient method in improving nutritional value of CSM.

Evaluation of canola meal as a protein supplement for dairy cows: A review and a meta-analysis

Huhtanen, P., Hetta, M. and Swensson, C. 2011. Evaluation of canola meal as a protein supplement for dairy cows: A review and a meta-analysis. Can. J. Anim. Sci. 91: 529–543. A review and a meta-analysis were conducted to compare the feeding value of soybean meal (SBM) and canola meal (CM) in dairy cows and to evaluate the effects of heat-treatment of CM (TCM) on the performance of dairy cows. The dataset included in total 292 treatment means from 122 studies, in which dietary crude protein (CP) concentration was increased by replacing energy supplements with protein supplements. A mixed model regression analysis with random study effect was used to estimate the marginal production responses to different protein sources. The differences between the slopes were compared by t-test. All protein sources increased dry matter intake, but the responses were greater (P&lt;0.01) for CM and TCM compared with SBM. Feeding CM or TCM produced greater (P&lt;0.01) daily milk yield responses than SBM (3.4±0.19 and 3.7±0.25 vs. 2.1±0.25) kg kg−1increase in CP intake. Marginal milk protein yield responses (g kg−1increase in CP intake) were greater (P&lt;0.01) for CM (136±5.4) and TCM (133±8.5) compared with SBM (98±8.0). Smaller response to incremental CP intake can partly be related to the higher average dietary CP concentration in SBM studies. Literature data on rumen ammonia N concentration and omasal protein flow did not support the higher ruminal tabulated ruminal CP degradability of CM compared with SBM. It is concluded that CM can successfully be substituted for SBM on isonitrogenous basis and that most feed evaluation systems overestimate metabolizable protein concentration of SBM relative to CM.

Treating canola meal changes in situ degradation, nutrient apparent digestibility, and protein fractions in sheep

The present study was conducted to evaluate the effects of three different treatment methods of canola meal (CM) on ruminal degradability of crude protein (CP) and dry matter (DM) in situ and apparent digestibility of nutrients in sheep. The fractionation of protein for treated CM was measured as well. Treatments were: T0=CM with no treatment (control); T1=treatment with formaldehyde; T2=treatment with acetic acid; and T3=heating treatment. The ruminal degradability of CP and DM was measured using four rumen fistulated Mehraban sheep. For digestibility trial twelve intact Mehraban sheep were used. The results showed that neutral detergent insoluble nitrogen (NDIN) contents were 5.28%, 5.29%, 6.25% and 5.16% and acid detergent insoluble nitrogen (ADIN) contents were 4.46%, 4.59%, 4.44% and 4.50% for T0, T1, T2 and T3, respectively (P>0.05). Considering nitrogen fractions, A+B1 and B2 showed differences among treatments (P<0.05) with B3 and C being similar among treatments. The degradability kinetic parameters for DM (a, b and c) differed among treatments (P<0.05). The lowest effective degradability of DM was for control treatment. The parameters a, b and c for CP degradability also were affected by treatments (P<0.05). Ruminal degradation rates of DM and CP were decreased and the highest degradability for both DM and CP was observed in untreated CM. The digestibility of DM and OM showed no difference among treatments; however, CP digestibility was different among treatments (P<0.05). Regardless of CM treatment method, treated CM had greater B2 and lower A+B1 fractions compared with untreated CM and solubility of protein in CM decreased with different treatments. The results of the present study suggest that untreated CM has the greatest degradation rate in rumen and treating CM considerably decreased the solubility of protein and ruminal degradation rate. In conclusion the results suggest the treatment CM with formaldehyde to increase apparent digestibility of protein and the treatment CM with acetic acid to decrease ruminal degradation rate of protein.

Effects of non-enzymatic browning reaction intensity on in vitro ruminal protein degradation and intestinal protein digestion of soybean and cottonseed meals

The effects of non-enzymatic browning reactions on in vitro ruminal gas production and in vitro ruminal and intestinal crude protein (CP) digestibilities of soybean (SBM) and cottonseed (CSM) meals were investigated. Non-enzymatically browned SBM and CSM samples were prepared using two xylose levels (10 or 30g/kg dry matter), two heating lengths (30 or 60min) and two heating temperatures (120 or 150°C) for a total of one untreated (commercially solvent-extracted, Control) and eight treated samples for each protein source. The control SBM had higher (P<0.001) in vitro ruminal CP degradability values than the treated samples. Intestinal protein digestibility and total-tract CP digestibility of CSM and SBM were affected by the treatment (P<0.01). The results of the study indicate that not only ruminal CP degradability is reduced but also intestinal and total-tract CP digestibilities may be lowered depending on protein source and intensity of the non-enzymatic browning reaction.

Chemical characterization, in vitro dry matter and ruminal crude protein degradability and microbial protein synthesis of some cowpea (Vigna unguiculata L. Walp) haulm varieties

A study was carried out to evaluate the chemical composition, in vitro apparently and truly degraded dry matter (DM), utilizable crude protein at the duodenum (uCP) (total CP at the duodenum minus endogenous CP), methane production, and short chain fatty acid production of haulms of six cowpea varieties. The study was arranged in a 2×2×2 factorial design, with three replicates. Three improved (ITA2, ITA6 and ITA8) and three commercial (Oloyin, Peu and Sokoto) cowpea varieties harvested during wet and dry seasons were used for the study. After an initial gas test to evaluate 96h gas production profiles of haulms with and without polyethylene glycol (PEG), the time to half maximal gas production was calculated and a second incubation conducted with fermentation stopped at substrate specific half time (t1/2) and 24h for each substrate. True DM degradability was measured from incubated residues and combined with gas volume to estimate the partitioning factor. Crude protein flow to the duodenum was estimated by combining gas volume with the measured ammonia nitrogen in the incubated fluid. Addition of PEG did not have any effect (P>0.05) on all the variables determined. Interaction between group (improved vs. commercial) and season was observed for CP (P=0.002), lignin (P=0.003) and hemicellulose (P=0.030) contents of the haulms. A group×season interaction was also observed for some of the variables at both substrate specific t1/2 and 24h. Commercial cowpea haulms had greater (P=0.002) microbial mass and produced less (P<0.05) methane than the improved cowpea haulms. The improved cowpea haulms were less (P<0.001) degraded in the rumen and as a result ensured greater (P<0.001) amount of uCP. The results validated that cowpea haulm is an important agro-based by-product that is adequate in protein and energy to sustain ruminant animal production in Nigeria and other Sub-Saharan African countries during the extended dry season.

In vitro evidence for the importance of cultivation conditions on the effects of Calliandra tannins on ruminal escape of soybean protein and its post-ruminal degradability

Purified condensed tannins (CT) extracted from the legume Calliandra calothyrsus (var. San Ramón CIAT 22310), harvested in the dry and the rainy season and cultivated with low or high level of fertilization were added to soybean meal in a ratio of 600 mg/g of the incubated crude protein (CP). Effects on degradation either in ruminal fluid only, or in ruminal fluid followed by incubation in HCl/pepsin, were evaluated using a modified two-step in vitro method. Season was found to have larger effects on in vitro ruminal and post-ruminal CP degradation than fertilization. Condensed tannins from the rainy season harvest reduced ruminal CP degradation less than that from the dry season harvest. They had also less negative effects on the degradability of rumen escape protein and enhanced the proportion of post-ruminally degraded CP more than CT from the dry season harvest. An increase in level of fertilization reduced ruminal CP degradation in CT from the rainy season plants but this was not associated with effects on post-ruminal degradation. The study demonstrated the importance of environmental factors for the efficiency of CT in modifying ruminal and post-ruminal CP degradation.

Quantifying ruminal nitrogen metabolism using the omasal sampling technique in cattle—A meta-analysis

Mixed model analysis of data from 32 studies (122 diets) was used to evaluate the precision and accuracy of the omasal sampling technique for quantifying ruminal-N metabolism and to assess the relationships between nonammonia-N flow at the omasal canal and milk protein yield. Data were derived from experiments in cattle fed North American diets (n=36) based on alfalfa silage, corn silage, and corn grain and Northern European diets (n=86) composed of grass silage and barley-based concentrates. In all studies, digesta flow was quantified using a triple-marker approach. Linear regressions were used to predict microbial-N flow to the omasum from intake of dry matter (DM), organic matter (OM), or total digestible nutrients. Efficiency of microbial-N synthesis increased with DM intake and there were trends for increased efficiency with elevated dietary concentrations of crude protein (CP) and rumen-degraded protein (RDP) but these effects were small. Regression of omasal rumen-undegraded protein (RUP) flow on CP intake indicated that an average 32% of dietary CP escaped and 68% was degraded in the rumen. The slope from regression of observed omasal flows of RUP on flows predicted by the National Research Council (2001) model indicated that NRC predicted greater RUP supply. Measured microbial-N flow was, on average, 26% greater than that predicted by the NRC model. Zero ruminal N-balance (omasal CP flow=CP intake) was obtained at dietary CP and RDP concentrations of 147 and 106g/kg of DM, corresponding to ruminal ammonia-N and milk urea N concentrations of 7.1 and 8.3mg/100mL, respectively. Milk protein yield was positively related to the efficiency of microbial-N synthesis and measured RUP concentration. Improved efficiency of microbial-N synthesis and reduced ruminal CP degradability were positively associated with efficiency of capture of dietary N as milk N. In conclusion, the results of this study indicate that the omasal sampling technique yields valuable estimates of RDP, RUP, and ruminal microbial protein supply in cattle.

Dose response to eugenol supplementation in growing beef cattle: Ruminal fermentation and intestinal digestion

Eugenol (EUG; 4-allyl-2-methoxyphenol; C 10H 12O 2) is a phenolic compound with wide-spectrum antimicrobial activity against gram-positive and gram-negative bacteria. This study was conducted to determine whether EUG could be used as a rumen modifier in growing beef heifers fed high concentrate diets. The experiment was designed as a 4 × 4 Latin square using four ruminally and duodenally cannulated beef heifers with four treatments being: control (no EUG added); 400 mg/d EUG (low); 800 mg/d EUG (medium); and 1600 mg/d EUG (high), and four 21 d periods. The diets consisted of 150 g/kg barley silage, 800 g/kg dry-rolled barley grain, and 50 g/kg supplement (dry matter [DM] basis). Feed intake, rumen pH and fermentation characteristics, site and extent of digestion, microbial crude protein (CP) synthesis, blood metabolites and acute phase protein status were measured. Intake of DM averaged 9.6 kg/d and was not affected by EUG supplementation. Degradabilities of organic matter (OM) and starch in the rumen and the digestibilities in the total digestive tract were not affected. However, ruminal degradability of neutral detergent fibre linearly decreased and ruminal degradability of CP tended ( P=0.09) to linearly decrease with increasing dose of EUG. Flows (g/d) of microbial N to the duodenum tended ( P=0.08) to quadratically increase with EUG supplementation even though the amount of ruminal fermented OM did not differ. Rumen pH, concentration of total volatile fatty acids (VFA), and protozoa counts were not affected, whereas concentration of acetate linearly declined, and the molar proportion of propionate ( P=0.09), and ratio of acetate to propionate, tended ( P<0.10) to linearly decrease with increasing EUG supplementation. Plasma concentrations of non-esterified fatty acids, triglyceride, glucose and urea N were not changed by feeding EUG. Acute phase proteins including serum amyloid A and lipopolysaccharide in plasma were not affected by EUG, although plasma haptoglobin tended ( P<0.07) to linearly decrease with increasing EUG. Results indicate that supplementation of a high concentrate diet with EUG tended to provide more protein by tending to increase microbial CP production and lowering CP degradation in the rumen. Positive changes in ruminal N dynamics ( i.e., more rumen undegraded CP flowing to the small intestine) and VFA pattern of fermentation ( i.e., lower acetate to propionate ratio) were small, but may be enough to improve the growth rate of cattle. Overall, results indicate that EUG may have limited potential to improve the growth rate of cattle fed high concentrate diets.

Degradação ruminal e digestibilidade intestinal da proteína bruta de alimentos para bovinos

Este trabalho foi conduzido com os objetivos de determinar as frações A e B e a taxa de degradação ruminal (Kd) da matéria seca (MS) e da proteína bruta (PB) de 27 alimentos e avaliar a digestibilidade intestinal da proteína nãodegradada no rúmen pelas técnicas do saco de náilon móvel e de três estágios. Os alimentos avaliados foram farelos de arroz, babaçu, gérmen de milho e trigo; milho desintegrado com palha e sabugo, milho desintegrado com sabugo, milho, polpa cítrica, sorgo, amireia, farelos de algodão com 28, 38 e 46% de PB, farelos de amendoim, girassol e soja; feijão-bandinha, glúten de milho, grão de soja, levedura, promil, refinazil, cascas de cacau, café e soja e silagens de capim-elefante e milho. Para obtenção da degradabilidade ruminal da MS e PB dos alimentos, utilizaram-se sacos de náilon de 10 × 20 cm e os tempos de incubação de 0, 2, 4, 6, 12, 16, 24, 48 e 72 horas. A digestibilidade intestinal foi determinada pelas técnicas do saco de náilon móvel e de três estágios. Os dados de degradação ruminal da matéria seca e da proteína bruta, em sua maioria, estão de acordo com a literatura. A técnica dos três estágios não estimou de forma satisfatória a digestibilidade interstinal de todos os alimentos estudados em conjunto, mas foi adequada para os alimentos proteicos. A maioria dos alimentos possui aproximadamente 90% de digestibilidade da PB, com exceção das cascas de soja, café e cacau e das silagens de milho e capimelefante. A técnica de três estágios estimou corretamente a digestibilidade intestinal dos alimentos proteicos, mas recomenda-se a utilização da equação DIPB (%) = -5,1906 + 1,1053 × X para corrigir a digestibilidade obtida pela técnica dos três estágios para alimentos não-proteicos.

Effects of Protein Supply from Soyhulls and Wheat Bran on Ruminal Metabolism, Nutrient Digestion and Ruminal and Omasal Concentrations of Soluble Non-ammonia Nitrogen of Steers

Three beef steers fitted with permanent cannulae in the rumen and duodenum were used to determine the effects of protein supply from soyhulls (SH) and wheat bran (WB) on ruminal metabolism, blood metabolites, nitrogen metabolism, nutrient digestion and concentrations of soluble non-ammonia nitrogen (SNAN) in ruminal (RD) and omasal digesta (OD). In a 3×3 Latin square design, steers were offered rice straw and concentrates formulated either without (control) or with two brans to increase crude protein (CP) level (9 vs. 11% dietary DM for control and bran-based diets, respectively). The brans used were SH and WB that had similar CP contents but different ruminal CP degradability (52 vs. 80% CP for SH and WB, respectively) for evaluating the effects of protein degradability. Ruminal ammonia concentrations were higher for bran diets (p 20%). (Key Words : Soyhulls, Wheat Bran, Soluble non- ammonia Nitrogen, Omasal Digesta, Nutrient Digestion)

Ruminal in situ disappearance kinetics of six nutritive ingredients in leaves and stems of young tetraploid black locust in growing steers

Tetraploid black locust (Robinia pseudoacacia) is a woody plant with larger leaves and richer nutritional content than normal diploid black locust, with greater biomass and wider adaptability than herbaceous plant forage. However, currently no stockbreeders have adopted it as a major forage in China and other countries for a lack of information on the evaluation of nutritional ingredients of leaves and stems of young tetraploid black locust (YTBL) by in situ digesting tests. The objectives of this study were: 1) to assess the nutritive value of YTBL that bourgeoned from root stumps in the spring by determining the ruminal in situ disappearance kinetics of dry matter (DM), organic matter (OM), crude protein (CP), ether extract (EE), neutral detergent fiber (NDF) and acid detergent fiber (ADF) from leaves, stems and a mixture of both leaves and stems (MLS) of YTBL; 2) to compare these kinetic estimates with those of Leymus chinensis, a widely used ruminant forage in China. All samples were evaluated in situ by using five ruminally cannulated crossbred steers (550±22.7 kg BW). The results of 48 hours, the representative incubation period, indicate that in situ disappearance rates of DM and OM in YTBL leaves, stems and MLS are on average about 40% and can attain the level of digestibility of L. chinensis. In situ disappearance rates of leaves, stems and MLS of YTBL for CP and EE were 41% and 58% respectively, rates higher than those of L. chinensis. But the disappearance rates of NDF and ADF were, on average, respectively 30.62% and 24.89% and lower than those of L. chinensis. By analyzing synthetically all of our results it could be inferred that MLS of YTBL offers effective ruminal degradability of DM, NDF, ADF, CP, EE and OM, similar to the nutrients of L. chinensis. This supports our contention that the YTBL leaves, stems and MLS are suitable feed for those ruminants requiring high levels of nutrients, such as dairy cows and Boer goats, instead of plant forage, which is decidedly lacking in some parts of the world.

A meta-analysis of the effects of dietary protein concentration and degradability on milk protein yield and milk N efficiency in dairy cows

Data sets from North American (NA, 739 diets) and North European (NE, 998 diets) feeding trials with dairy cows were evaluated to investigate the effects of dietary crude protein (CP) intake and ruminal degradability on milk protein yield (MPY) and efficiency of N utilization for milk protein synthesis (MNE; milk N ÷ N intake) in dairy cows. The NA diets were based on corn silage, alfalfa silage and hay, corn and barley grains, and soybean meal. The NE diets were based on grass silage, barley and oats grains, and soybean and rapeseed meals. Diets were evaluated for rumen-degradable and undegradable protein (RDP and RUP, respectively) concentrations according to NRC (2001). A mixed model regression analysis with random study effect was used to evaluate relationships between dietary CP concentration and degradability and MPY and MNE. In both data sets, CP intake alone predicted MPY reasonably well. Addition of CP degradability to the models slightly improved prediction. Models based on metabolizable protein (MP) intake predicted MPY better than the CP or the CP-CP degradability models. The best prediction models were based on total digestible nutrients (TDN) and CP intakes. Similar to the MPY models, inclusion of CP degradability in the CP (intake or concentration) models only slightly improved prediction of MNE in both data sets. Concentration of dietary CP was a better predictor of MNE than CP intake. Compared with the CP models, prediction of MNE was improved by inclusion of TDN intake or concentration. Milk yield alone was a poor predictor of MNE. The models developed from one data set were validated using the other data set. The MNE models based on TDN and CP intake performed well as indicated by small mean and slope bias. This meta-analysis demonstrated that CP concentration is the most important dietary factor influencing MNE. Ruminal CP degradability as predicted by NRC (2001) does not appear to be a significant factor in predicting MPY or MNE. Data also indicated that increasing milk yield will increase MNE provided that dietary CP concentration is not increased, but the effect is considerably smaller than the effect of reducing CP intake.

Effects of linseed lipids fed as rolled seeds, extruded seeds or oil on organic matter and crude protein digestion in cows

Effects of fatty acids of linseed in different forms, on ruminal fermentation and digestibility were studied in dry cows fitted with ruminal and duodenal cannulas. Four diets based on maize silage, lucerne hay and concentrates (65/10/25 dry matter (DM)) were compared in a 4 × 4 Latin square design experiment where the diets were: control diet (C), diet RL supplied 75 g/kg DM rolled linseeds, diet EL supplied 75 g/kg DM extruded linseeds, and diet LO supplied 26 g/kg DM linseed oil and 49 g/kg DM linseed meal. The diets did not differ in total organic matter (OM) and fibre digestibility, in forestomach and intestinal OM digestibility, and in duodenal N flow. Microbial N duodenal flow tended to be lower for RL versus C diet (P<0.1). Extrusion did not reduce ruminal crude protein (CP) degradation in vivo and in situ. Volatile fatty acid concentration and pattern, and protozoa concentration in the rumen, did not vary among diets. Results confirm the absence of a negative effect of a moderate supply of linseed on rumen function, as well as no effect of extrusion on its ruminal CP degradability.

Effects of pressure toasting on in situ degradability and intestinal protein and protein‐free organic matter digestibility of rapeseed

AbstractBACKGROUND: Rapeseed is a protein supplement that contains up to 40% crude protein (CP) on a dry matter (DM) basis, but a large part of its protein can be easily degraded in the rumen. Therefore, before inclusion in ruminant's diet, the extent of its protein degradation in the rumen must be reduced without altering its intestinal digestibility. A study was conducted to investigate the effects of pressure toasting (T, 130 °C) at two residence times (1.5 and 10 min) alone or in combination with soaking in water (ST, 4 h) on ruminal degradability and intestinal digestibility of CP and protein‐free organic matter (PFOM) in whole full‐fat rapeseed.RESULTS: Regardless of the processing time (1.5 or 10 min), T significantly (P &lt; 0.05) increased the fraction of undegraded intake protein (UIP) compared to the untreated rapeseed samples. Soaking prior to further toasting did not improve the rumen degradation characteristics of rapeseed CP. Compared to the untreated rapeseed samples, both T and ST significantly (P &lt; 0.0001) improved the true protein digested in the small intestine (DVE) and degraded protein balance (OEB), effects that were more evident in samples heated for 10 min. Soaking prior to pressure toasting, however, did not further improve the DVE or OEB in the rapeseed samples in comparison with T treatment.CONCLUSIONS: It was concluded that ruminal protein degradability of rapeseed decreased after pressure toasting, without seriously affecting its intestinal digestibility. Copyright © 2008 Society of Chemical Industry

Chemical composition and ruminal degradability of grain pearl millet grown in southwestern Quebec

The objectives of this study were to determine the chemical composition and ruminal nutrient degradabilities of grain of five hybrids of pearl millet grown in southwestern Quebec. Hybrids were selected because they were poor hosts of the widely prevalent root lesion nematode (Pratylenchus penetrans). Neutral detergent fiber and acid detergent lignin were similar for all hybrids. However, acid detergent fiber (ADF) was higher for CGPMH-1 than CGPMH-7 and CGPMH-38 and was higher for CGPMH-11 and CGPMH-20 than CGPMH-7. Starch content was higher for CGPMH-7 (668 g kg-1 DM) than the other hybrids (average 635 g kg-1 DM). Crude protein (CP) was lower for CGPMH-7 (141 g kg-1 DM) than the other hybrids (average 181 g kg-1 DM). Fatty acid content was higher for CGPMH -11 and CGPMH-20 than CGPMH-38. Linoleic acid was the most abundant fatty acid in all hybrids and was lower for CGPMH-38 than the other hybrids. Ruminal dry matter degradability was similar for all hybrids (average 69.5%). However, ruminal CP and starch degradabilities were higher for CGPMH-1 and CGPMH-20 than CGPMH-11 and CGPMH-38. It was concluded that grain concentrations of CP, ADF, and starch, and ruminal CP and starch degradabilities of pearl millet varied among hybrid. Key words: Chemical composition, Pearl millet, Ruminal degradability

By‐products from viticulture and the wine industry: potential as sources of nutrients for ruminants

AbstractBACKGROUND: This work aimed to study the chemical composition, in vitro digestibility, ruminal degradability and intestinal digestibility of nutrients of vine shoot (VS), grape marcs (GMG and GMM), white (WL), red (RL) and sherry (SL) wine lees and grape marc plus lees (GML). The effect of polyethylene glycol (PEG) on nutrient availability was also studied.RESULTS: By‐products had variable crude protein (CP) and cell walls (from 44.8 to 203 and from 122 to 741 g kg−1 dry matter (DM) for CP and neutral detergent fibre (NDF) respectively). DM and CP in vitro digestibility ranged from 0.30 to 0.91 and from 0.51 to 0.84 respectively. The effective ruminal degradability of DM and CP was low (from 0.27 to 0.36 and from 0.34 to 0.53, respectively). The intestinal digestibility of the ruminally undegraded fraction was 0.25 and 0.29 for VS and GMG, respectively. The effect of PEG was different in VS and GMG.CONCLUSION: This is the first information available on ruminal and intestinal availability of nutrients from a diversity of vine and winery by‐products. The use of a combination of the different by‐products studied may represent a valuable source of energy and protein for ruminants. Further research on the effect of diets including these by‐products on animal performance and the quality of products is necessary. Copyright © 2007 Society of Chemical Industry