Ruminal Degradability Of Crude Protein Research Articles

Linkage of in situ ruminal degradation of crude protein with ruminal degradation of amino acids and phytate from different soybean meals in dairy cows

The objectives of this study were to determine the range in ruminal degradability of crude protein (CP) and intestinal digestibility of rumen undegradable protein in commercial soybean meal (SBM) and to investigate the range in in situ ruminal AA and phytate (InsP6) degradation and their relationship to CP degradation. An in situ study was conducted using 3 lactating Jersey cows with permanent rumen cannulas. Seventeen SBM variants from Europe, Brazil, Argentina, North America, and India were tested for ruminal CP and AA degradation, and in vitro intestinal digestibility of rumen undegradable protein. Nine variants were used to investigate the ruminal degradation of InsP6. The estimated rapidly degradable fraction (a) of CP showed an average value of 4.5% (range: 0.0%-9.0%), the slowly degradable fraction (b) averaged 95% (91%-100%), and the potential degradation was complete for all 17 SBM variants. The degradation of fraction b started after a mean lag phase of 1.7 h (1.1-2.0 h) at an average rate (c) of 10% per hour, but with a high range from 4.5% to 14% per hour. Differences in the degradation parameters induced a considerable range in CP effective degradation at a rumen passage rate of 6% per hour (CPED6) from 38% to 67%; hence, the concentration of rumen undegradable protein varied widely from 33% to 62%. The range in AA degradation between the SBM variants was high, with Ser showing the widest range, from 28% to 96%, and similar for the other AA. The regression equations showed close relationships between CP and AA degradation after 16 h of in situ incubation. However, the slopes of the linear regressions were significantly different between AA, suggesting that degradation among individual AA differs upon a change in CP degradation. The concentrations of InsP6 and myo-inositol pentakisphosphate in bag residues in the in situ study decreased constantly with longer ruminal incubation times. The ruminal degradation parameters of InsP6 ranged from 11% to 37% for fraction a, 63% to 89% for fraction b, and from 7.7% to 21% per hour for degradation rate c, with average values of 21%, 79%, and 16% per hour, respectively. The calculated InsP6 effective degradation at a rumen passage rate of 6% per hour (InsP6ED6) varied from 61% to 84% among the SBM variants. Significant correlations were detected between InsP6ED6 and CPED6 and between InsP6ED6 and chemical protein fractions A, B1, B2, B3, and C. Linear regression equations were developed to predict ruminal InsP6 degradation using CPED6 and chemical protein fractions B3 and C chosen by a stepwise selection procedure. We concluded that a high range in CP, AA, and InsP6 degradation exists among commercial SBM, suggesting that general degradability values may not be precise enough for diet formulation for dairy cows. Degradation of CP in SBM may be used to predict rumen degradation of AA and InsP6 using linear regression equations. Degradation of CP and InsP6 could also be predicted from the chemical protein fractions.

Brachiaria Hybrid and Pennisetum purpureum Supplemented with Pueraria phaseoloides Increased the Concentration of Rumen-Undegradable Protein in Forages for Ruminants

Supplementing tropical grasses with leguminous forages is known to improve the nutritive value of forage-based diets. However, it is not clear how basal grass forages supplemented with Kudzu (Pueraria phaseoloides) affect the nitrogen (N) and crude protein (CP) fractions of grass/legume forages. The aim of this study was to determine the N and CP fractions and in vitro ruminal CP degradability of Brachiaria hybrid (B. ruziziensis × B. decumbens × B. brizantha) and elephant grass (Pennisetum purpureum) supplemented with Kudzu at a target CP content of 133 ± 0.6 g/kg of dry matter (DM). The grass/legume forages were evaluated for total N, buffer-soluble N (BSN), buffer-insoluble N (BISN), non-protein nitrogen (NPN), neutral detergent-insoluble N (NDIN), acid detergent-insoluble N (ADIN), CP fractions A, B1, B2, B3, C, rumen-degradable protein (RDP), rumen-undegraded protein (RUP), and in vitro ruminal CP degradability. The CP concentration of Kudzu was 217 g/kg DM, while grass forages ranged between 79.9 and 112 g/kg DM. The BISN, CP degradability parameters b, and potential degradability were approximately 56, 41, and 74%, respectively, higher in grass forages supplemented with Kudzu. The concentrations of RUP in the grass forages (23.9–32.5 g/kg DM) were significantly improved when they were supplemented with Kudzu (72.0–79.9 g/kg DM). Therefore, we concluded that basal grass forages supplemented with Kudzu to a target CP content can improve the amount of RUP supplied by the forage portion of the diet. This can have a positive effect on forage utilization and animal performance while reducing the cost to feed for ruminants.

Extrusion of lupines with or without addition of reducing sugars: Effects on the formation of Maillard reaction compounds, partition of nitrogen and Nε-carboxymethyl-lysine, and performance of dairy cows

The extrusion of leguminous seeds induces the formation of Maillard reaction compounds (MRC) as a product of protein advanced glycation and oxidation, which lowers protein degradability in the rumen. However, the quantitative relationship between the parameters of pretreatment (i.e., addition of reducing sugars) and extrusion, and the formation of MRC has not been established yet. Moreover, the fate of the main stable MRC, Nε-carboxymethyl-lysine (CML), in the excretory routes has never been investigated in ruminants. We aimed to test the effects of the temperature of extrusion of white lupines with or without addition of reducing sugars on the formation of MRC, crude protein (CP) degradability in the rumen, N use efficiency for milk production (milk N/N intake), and performance of dairy cows. Two experiments with a replicated 4 × 4 Latin square design were conducted simultaneously with 16 (3 rumen-cannulated) multiparous Holstein cows to measure indicators of ruminal CP degradability (ruminal NH3 concentration, branched-chain volatile fatty acids), metabolizable protein supply (plasma essential AA concentration), N use efficiency (N isotopic discrimination), and dairy performance. In parallel, apparent total-tract digestibility of dry matter, organic matter, neutral detergent fibers, N, total Lys and CML, and partition of N and CML were measured with 4 cows in both experiments. The diets consisted on a DM basis of 20% raw or extruded lupines and 80% basal mixed ration of corn silage, silage and hay from permanent grasslands, pelleted concentrate, and a vitaminized mineral mix. Expected output temperatures of lupine extrusion were 115°C, 135°C, and 150°C, without and with the addition of reducing sugars before extrusion. The extrusion numerically reduced the in vitro ruminal CP degradability of the lupines, and consequently increased the predicted supply of CP to the small intestine. Nitrogen balance and urinary N excretion did not differ among dietary treatments in either experiment. Milk yield and N use efficiency for milk production increased with extrusion of lupines at 150°C without addition of reducing sugars compared with raw lupines. Nitrogen isotopic discrimination between dietary and animal proteins (the difference between δ15N in plasma and δ15N in the diet) were lower with lupines extruded at 150°C without and with addition of reducing sugars. Regardless of sugar addition, milk true protein yield was not affected, but milk urea concentration and fat:protein ratio were lower with lupines extruded at 150°C than with raw lupines. In the CML partition study, we observed that on average 26% of the apparently digested CML was excreted in urine, and a much lower proportion (0.63% on average) of the apparently digested CML was secreted in milk, with no differences among dietary treatments. In conclusion, we showed that the extrusion of white lupines without or with addition of reducing sugars numerically reduced enzymatic CP degradability, with limited effects on N partition, but increased milk yield and N use efficiency at the highest temperature of extrusion without addition of reducing sugars.

Linkage of in situ ruminal crude protein degradation with ruminal degradation of amino acids and phytate from different soybean meals in dairy cows

Linkage of in situ ruminal crude protein degradation with ruminal degradation of amino acids and phytate from different soybean meals in dairy cows

Degradability of Vicia ervilia Grain Using In Situ and CNCPS Methods, and Model-Based Analysis of Its Ruminal Degradation

Using nylon bag techniques, Cornell net carbohydrates and protein systems (CNCPS), and scanning electron microscopy, the authors examined the digestibility and structure of Vicia ervilia (ervil, bitter vetch) after steam flaking, roasting, and microwave processing. During the in situ technique, the samples were incubated at 0, 2, 4, 6, 8, 12, 16, 24, 36, and 48 h. For the description of the ruminal DM (dry matter) and CP (crude protein) degradation kinetics of treated and untreated Vicia ervilia, different models were selected as the best fit for the dry matter (DM) and crude protein (CP) degradation parameters of steam flaked samples. The results showed that both the steam flaking and microwave treatment samples contained high levels of non-protein nitrogen and buffer soluble protein, respectively. In comparison with steam flaking and microwave treatment, roasting decreased and increased the buffer soluble protein and neutral detergent insoluble protein, respectively. The control treatments showed the highest levels of neutral detergent soluble protein and the lowest levels of acid detergent soluble protein. Moreover, steam flaking and roasting decreased and increased the amount of acid detergent insoluble protein, respectively. When using dry heat (microwave and roasting), the acid detergent soluble and insoluble protein fractions were increased. As a result of this experiment, the nitrogen fractions were altered using heat processing. Hence, protein fermented feed and ruminal fermentation conditions can be expressed using these results.

Linkage of in situ ruminal crude protein degradation with ruminal degradation of amino acids and phytate from different soybean meals in dairy cows

Linkage of in situ ruminal crude protein degradation with ruminal degradation of amino acids and phytate from different soybean meals in dairy cows

Feed Clusters According to In Situ and In Vitro Ruminal Crude Protein Degradation.

Effective degradation (ED) of crude protein (CP) was estimated in vitro at 0.02, 0.05 and 0.08 h-1 assumed ruminal passage rates for a total of 40 feedstuffs, for which in situ ED was available and used as reference degradation values. For this, the Streptomyces griseus protease test was used. The differences between in vitro CP degradation and the in situ CP degradation values were lowest in legume grains and highest in cereal by-products and barley. The differences between in situ and in vitro ED were expressed using a degradation quotient (degQ), where degQ = (EDin vitro - EDin situ)/EDin situ. Among the tested feedstuffs, eight specific clusters were identified according to degQ for the assumed passage rates. The feedstuffs clustered in an unspecific way, i.e., feedstuffs of different nutrient composition, origin or treatment did not necessarily group together. Formaldehyde-treated rapeseed meal, soybean meal, wheat, a treated lupin, sunflower meal and barley could not be assigned to any of the clusters. Groupwise degradation (range of degQ for assumed passage rates are given in brackets) was detected in grass silages (-0.17, -0.11), cereal by-products together with sugar beet pulp (-0.47, -0.35) and partly in legume grains (-0.14, 0.14). The clustering probably based on different specific nutrient composition and matrix effects that influence the solubility of feed protein and limit the performance of the protease. The matrix can be affected by treatment (chemically, thermally or mechanically), changing the chemical and physical structure of the protein within the plant. The S. griseus protease test had reliable sensitivity to reflect differences between native feedstuffs and treatments (thermally or chemically) that were found in situ. The in situ results, however, are mostly underestimated. The clustering results do not allow a clear conclusion on the groupwise or feed-specific use of carbohydrate-degrading enzymes as pre- or co-inoculants as part of the S. griseus protease test and need to be tested for its potential to make this test more conform with in situ data.

O30 Does ruminal degradability of crude protein and individual amino acids from ryegrass differ at different residence times?

O30 Does ruminal degradability of crude protein and individual amino acids from ryegrass differ at different residence times?

Siyah Alacalarda Beyaz Çürükçül Funguslar Kullanılarak Buğday Samanın İn-Situ Parçalanabilirliğinin Belirlenmesi

The Phanerochaete chrysosporium (PC) and Pleurotus eryngii (PE) were observed for their potential to increase the in situ dry matter (DM) and crude protein (CP) degradability of wheat straw. The wheat straw samples were inoculated with the PC and PE fungi (10% weight/volum) and incubated under solid state fermentation conditions at 30 ◦C for 30 days to determine their in-situ degradability and chemical composition. In situ ruminal degradability was determined by using four ruminal cannulated Holstein bulls (approximately 400 kg BW) fed on a diet a concentrate-to-roughage ratio of 45:55 (dry matter (DM) basis). The samples were incubated in nylon bags for 0, 4, 8, 16, 24, 48, 72 and 96 h in the rumen. The results showed that increased in situ ruminal degradation of DM and CP in PC and PE groups in comparison to the control group (P < 0.01). The wheat straw incubated with PC had the greatest in situ DM degradability after incubation for 24 h (P < 0.01). The inoculation of PC and PE increased in situ ruminal crude protein (CP) degradation (P < 0.01) in comparison to the other treatments. As a result, the fungal inoculants and urea treatment increased the degradability of DM and CP in wheat straw.

In situ ruminal disappearance of crude protein and phytate from differently processed rapeseed meals in dairy cows.

The influence of different processing conditions of rapeseed meal on ruminal degradation of crude protein and phytate in dairy cows was investigated. Following oil extraction from the rapeseed, five residence times in the desolventizer/toaster were chosen to remove the solvent from the meal. Rapeseed cake and rapeseed meals were incubated in situ in the rumen of three fistulated dairy cows to determine ruminal degradation parameters. With increasing residence time in the desolventizer/toaster the ruminal degradation of crude protein decreased significantly for every treatment step. Ruminal phytate degradation and crude protein degradation were affected almost identically. The processing conditions of rapeseed meal have a major impact on the ruminal degradation of crude protein and phytate, indicating a potential conflict of interest regarding the production process. Large amounts of undegradable rumen protein are often intended for high-yielding dairy cows whereas a high level of ruminal degradation is preferred for phytate to increase absorption of phosphorus in the small intestine. © 2021 The Authors. Journal of The Science of Food and Agriculture published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

Comparison of Ruminal Degradability, Indigestible Neutral Detergent Fiber, and Total-Tract Digestibility of Three Main Crop Straws with Alfalfa Hay and Corn Silage.

Simple SummaryCorn straw (Zea mays, CS), rice straw (Oryza sativa, RS), and wheat straw (Triticum aestivum, WS) are the three main crop straws worldwide. Few studies on indigestible neutral detergent fiber (iNDF) and total-tract digestibility (TTD) of crude protein (CP), neutral detergent fiber (NDF), and acid detergent fiber (ADF) of these crop straws are available, which limits their utilization in dairy diets. Here, we compared the ruminal degradability, iNDF288 content, intestinal digestibility, and TTD for the CP, NDF, and ADF of these three crop straws with alfalfa hay (Medicago sativa, AH) and corn silage (Zea mays, CSil). The results showed that CS, RS, and WS had higher ruminal potential NDF degradation, intestinal digestible CP, and lower iNDF288 content compared to AH. Greater accuracies for regression equations capable of predicting the iNDF288 content and TTD were also generated based on chemical composition and ruminal degradation kinetics. Incorporating this information into rations could improve our ability to optimize the utilization of main crop straws in balanced dairy diets.Three main crop straws including corn straw (Zea mays, CS), rice straw (Oryza sativa, RS), and wheat straw (Triticum aestivum, WS), and two forages including alfalfa hay (Medicago sativa, AH) and corn silage (Zea mays, CSil) were analyzed in order to compare their ruminal degradability, indigestible neutral detergent fiber (iNDF), intestinal digestibility (ID), and their total-tract digestibility (TTD) of crude protein (CP), neutral detergent fiber (NDF), and acid detergent fiber (ADF) using both an in situ nylon bag technique and a mobile nylon bag technique. The forage samples were incubated in the rumen for 6, 12, 16, 24, 36, 48, 72, and 288 h, respectively, to determine their ruminal degradability. Prior to intestinal incubation, forage samples were incubated in the rumen for 12 h and 24 h to determine the ruminal degradable content of CP, NDF, and ADF, respectively, and for 288 h to determine their iNDF288 content. Residues from the ruminal undegradable fractions (12 h for CP, 24 h for NDF and ADF) were subsequently inserted into the duodenum through a cannula to determine their intestinal digestible content. Here, the TTD of CP, NDF, and ADF were determined as the ruminal degradable content + intestinal digestible content. The results showed that AH had the highest iNDF2.4 (calculated as acid detergent lignin content × 2.4) and iNDF288 values (379.42 and 473.40 g/kg of NDF), while CS and CSil had the lowest iNDF2.4 values (177.44 and 179.43 g/kg of NDF). The ruminal degradability of CP, NDF, and ADF for CS, RS, and WS were lower than those of AH and Csil during the first 48 h of incubation. The potential degradation fraction of CP, NDF, and ADF for CSil was the highest; CS, RS, and WS were intermediate; and AH was the lowest (p < 0.05). CS, RS, and WS had a lower intestinal digestibility with respect to their rumen undegradable content of NDF (p < 0.05), and lower TTD of CP, NDF, and ADF (p < 0.05) compared to AH and CSil. General regression equations with satisfactory accuracy (R2 ≥ 0.828) were derived to predict iNDF288 and TTD based on their chemical compositions and the ruminal degradation kinetics of different forages. Incorporating this information into rations could improve our ability to optimize main crop straws utilization and milk production.

In situ crude protein and starch degradation and in vitro evaluation of pea grains for ruminants

ABSTRACT Thirteen pea grain samples from different origins were used to examine the variation in in situ ruminal degradation of crude protein (CP) and starch as well as in vitro gas production (GP) kinetics. In vitro GP was used to estimate the digestibility of organic matter (dOM), metabolisable energy (ME) and utilisable CP at the duodenum (uCP). Protein fractions were also determined according to the Cornell Net Carbohydrate and Protein System. Degradation of CP and starch from all pea grains in the rumen was almost complete, with a high proportion of the instantly disappearing fraction. The variation in the degradation constants among pea grain variants was high, and degradation of CP and starch showed a significant initial lag phase in the rumen. The mean effective degradation (ED) calculated for a rumen outflow of k = 8%/h of CP (EDCP8) was higher than ED of starch (EDST8), averaging 77.0 and 71.5%, respectively, with low variation among variants. A correlation analysis between GP parameters and in situ degradation constants showed no clear relationship, but the rates of in vitro GP and in situ starch degradation were similar. Most of the protein in the pea grains was buffer-soluble with fast and intermediate degradation. Variation in the protein fractions among the pea grain variants was low and not suitable for predicting differences in in situ degradation characteristics. The mean in vitro uCP of pea grains was 198 g/kg dry matter (k = 8%/h) and variation was low and consistent with that of GP kinetics and in situ rumen undegradable crude protein values. The estimation of dOM and ME from 24 h GP led to very high values indicating that the existing prediction equations may not be suitable for pea grains as a single feed.

Crude protein fractionation, in situ ruminal degradability and FTIR protein molecular structures of different cultivars within barley, corn and sorghum cereal grains

The objectives of current study was to determine protein characteristics, including crude protein fractionation according to the Cornell Net Carbohydrate and Protein System (CNCPS), in situ ruminal crude protein (CP) degradability and Fourier Transformed Infrared Spectroscopy (FTIR), among barley, corn, and sorghum cultivars. Cereal grains were collected from the central part of Iran and included 1) moderate, cold, and dry climate barley cultivars, 2) early and late maturity corn cultivars and 3) new and conventional sorghum cultivars. The main differences among cereal types were that corn and sorghum contained more starch and less fibre (NDF) than barley (P < 0.05), while soluble CP fractions (PA and PB1), slowly degradable true protein (PB3) and rate and extent of ruminal CP degradation (in situ) were greater (P < 0.05) for barley than corn and sorghum. The FTIR absorbance intensities for amide I, amide II, the ratio of amide I to amide II, α-helix and β-sheets were greater for barley compared with corn and sorghum grain (P < 0.05). Within barley, the moderate type cultivar contained less soluble CP and NPN and more ADICP than the cold and dry type cultivars (P < 0.05), while in situ CP degradation characteristics were similar among cultivars. Protein molecular structures in different cultivars of barley were similar. In corn grain, the early maturing cultivar contained more ash, EE, soluble CP and PB1 and less PB2, PB3 and NDICP than the late maturing cultivar (P < 0.05). Furthermore, FTIR protein molecular structures amide I and II had different between the two corn cultivars. In sorghum, the new cultivar contained less starch, more CP and PB3, and had slower degradation rate (kd) of CP than the old cultivar (P < 0.05). The FTIR protein molecular structures were similar between the sorghum cultivars according to univariate analysis, but cluster and principal component analysis largely separated the FTIR spectra of the two cultivars in the amide region. In conclusion, differences among three cereal grains and their cultivars were mainly observed for protein sub-fractionation, with minor effects on in situ ruminal protein degradability. Barley had different FTIR protein molecular structure compared with corn and sorghum.

Validation of in situ disappearance curves utilizing mathematical models for incubating fish meal and cottonseed mea

our mathematical models were used to describe the ruminal disappearance of dry matter (DM) and crude protein (CP) of fish meal and cottonseed meal. Results of DM degradability particularity showed that all the models fitted well (R2 &gt; 0.95), however, considering that values below 0 or above 100 are not biologically justified in ruminal degradability, they are not acceptable. The models I and II were accepted to ruminal DM degradability of fish meal and cottonseed meal data. Only models I and II were successfully fitted to CP degradability of fish meal (R2 &gt; 0.96), and the I, II and III models were acceptable to ruminal CP degradability of cottonseed meal (R2 &gt; 0.98). In terms of effective degradability (ED) of DM and CP, model II generated higher values than other models. To appreciate fully the role of mathematical modelling in the biological sciences, it is necessary to consider the nature of feeds that evaluated and to review the types of models that may be constructed.

In situ ruminal degradation kinetics and blood metabolites as affected by feeding different sources of tannin and flavonoids to small-tailed Han rams

The objective of this study was to determine the effects of feeding two kinds of alfalfa varieties, Gannon No. 3 (G3) and Gannon No. 9 (G9), with variable contents of tannin and flavonoids and compare their effects to dietary supplements of tannin and flavones on ruminal degradation kinetics and serum metabolites. Fifteen ruminally cannulated small-tailed Han rams were divided into five groups and fed the following diets for 30 days as follows: CONT (basal diet), G3 (200 g of G3 + basal diet), G9 (200 g of G9 + basal diet), TAN (2 g of hydrolysable tannin (HT) + basal diet) and FLV (2 g of Puerariae flavones + basal diet). Animals were weighed, serum samples were collected, and in situ ruminal incubation of soybean was performed to determine the degradation kinetics of the dry matter (DM), crude protein (CP), and organic matter (OM). Animals’ weight increased significantly at the end of the experiment in all groups. The greatest serum total protein concentration was found in the TAN group. Also G9 and FLV increased the ruminal degradation of DM and CP. Meanwhile CONT followed by TAN and G3 decreased the rumen degradable fractions of CP and increased significantly the undegradable CP fraction. We concluded that G9 had a similar effect as Puerariae flavone, while G3 followed the same effect of HT on the ruminal degradation. However, they showed different impacts on serum metabolites.

Effects of Different Growth Stages of Amaranth Silage on the Rumen Degradation of Dairy Cows.

Simple SummaryThe production of some crops is limited in parts of the world because of the shortage of water resources. Therefore, it is an irresistible trend to make full use of roughage resources. Amaranth is one of the crops which can grow in the poor soils and areas with high temperature and limited rainfall. In addition, the quality and yield of forage depend on harvest stage, and the appropriate growth stage is an important influencing factor of forage quality. The purpose of this study was to investigate the rumen degradation characteristic of amaranth silage including four kinds of growing stages. The results showed that with the extension of the growing period, the crude protein contents decreased gradually, and the contents of dry matter, neutral detergent fiber, and acid detergent fiber exhibited an opposite trend. Besides, the ruminal dry matter, crude protein, neutral detergent fiber, and acid detergent fiber degradability was significantly affected by growth stage. Our result suggested that amaranth silage can be used as a roughage in the diet of dairy cow. However, growth stage is an essential factor to influence the ruminal degradability, thus the growth stage of amaranth should be taken into consideration when making silage.The purpose of this study was to investigate the rumen degradation characteristic of amaranth silage (Amaranthus hypochondriacus) including four kinds of growing stages (budding stage (BS), 50 d after planting (DAP); early flowering stage (ES), 58 DAP; peak flowering stage (PS), 70 DAP; heading stage (HS), 90 DAP). Four Holstein dairy cows with permanent ruminal cannulas were used as experimental animals. Nylon-bag method was used to assess the ruminal degradability of dry matter (DM), crude protein (CP), neutral detergent fiber (NDF), and acid detergent fiber (ADF). The results showed that the concentration of DM in HS was significantly higher than other stages (p < 0.05), whereas the contents of CP, were lower than in other stages (p < 0.05). With the extension of the growing period, the DM effective degradability of amaranth silage decreased gradually, and the difference was significant (p < 0.05). The ruminal CP degradation of 72 h was more than 80%, and compared with ES and HS, the degradation rate of BS and PS was significantly increased (p < 0.05). Compared to BS, the effective degradability of CP was increased (p < 0.05) in ES and HS. For ruminal NDF degradability, the effective degradability of HS was minimum, and it had a noticeable difference with BS and ES (p < 0.05). Thus, the different quality of amaranth growth stage including chemical contents and rumen degradation should be taken into consideration when making amaranth silage. In the present study, the optimal growth stage of amaranth was from the peak flowering stage to heading stage for ensiling.

Estimating ruminal crude protein degradation from beef cattle feedstuff

We estimated ruminal crude protein degradation of twelve feedstuffs commonly used in China using in vitro and in vivo methods. The in vivo net protein utilization (NPU) levels of corn, sorghum, barley, wheat, Chinese wild rye grass, corn stalk, rice straw, soybean straw, soybean meal, distillers’ dried grains with solubles (DDGS), Brewers’ spent grains, and sunflower meal were 52.57, 49.68, 65.38, 72.58, 82.41, 72.26, 68.57, 76.95, 54.75, 56.27, 29.03 and 41.88%, respectively. The linear regression between NH3-N incorporated into microbial proteins and gas production after incubation (6, 12, and 24 h) was significant (r = 0.9948 and P < 0.001, r = 0.9874 and P < 0.01, and r = 0.9912 and P < 0.01, respectively). Based on the linear regression equations, we estimated in vitro protein degradability (IVPD) and generated the regression equations between IVPD and NPU. The linear regression equations between IVPD and NPU after 6 h incubation in the energy, protein, and roughage feed groups were Y = 0.5633X + 33.20 (R2 = 0.8517, P < 0.05), Y = 0.8482X+ 34.81 (R2 = 0.8650, P < 0.05), and Y = 1.6295X − 17.70 (R2 = 0.909, P < 0.05), respectively. The in vitro gas production method is useful for the determination of protein degradation in feedstuffs.

The Effect of Herbage Conservation Method on Protein Value and Nitrogen Utilization in Dairy Cows

Ruminant production systems frequently rely on grassland utilization and conservation of herbage as hay or silage. Conservation affects the crude protein (CP) composition and protein value, which is particularly recognized during ensiling. The aim of the current study was to describe the effect of the conservation method on forage protein value and N utilization in dairy cows. Herbage from the same sward was cut and conserved as silage (SI), barn-dried hay (BH), or field-dried hay (FH). Laboratory evaluation indicated differences in CP fractions and ruminal degradability of CP. Conserved forages were fed to six lactating Holstein cows in a replicated 3 × 3 Latin square design, and N balance was assessed. Partitioning of N into milk, feces, and urine was affected only moderately. Lower concentrations of serum, milk, and also urinary urea indicated lower N turnover for FH compared to SI and BH, likely due to lower N intake for FH. However, the use efficiency of feed N for milk N did not differ between the types of forage. Further, high CP concentrations and the unbalanced concentrations of CP and energy in the forages led to excess excretion of N in all treatments and presumably superimposed effects of the conservation method on N utilization.

Silage fermentation, chemical composition and ruminal degradation of king grass, cassava foliage and their mixture

AbstractIn order to improve the fermentation quality and nutritional value of king grass (KG) by using available local feed resources, silages were prepared using KG, KG supplemented with 10%, 20%, 30%, 40%, 50% fresh cassava foliage (CF), and CF. Their fermentation quality, chemical composition and ruminal degradation were examined after 30 days of ensiling. The results showed that CF silage contained 22.67% crude protein (CP) and 41.19% neutral detergent fiber (NDF) per dry matter (DM), while KG silage contained 8.36% CP and 60.44% NDF, indicating that KG silage had poor fermentation quality and low ruminal degradability. In addition, silage prepared with increased CF content had increased lactic acid, ether extract (EE), CP contents and relative feed value (p &lt; 0.05), decreased butyric acid, NDF and acid detergent fiber (ADF) contents (p &lt; 0.05) and increased ruminal degradability of DM, CP, NDF and ADF (p &lt; 0.05). The results confirmed that CF supplementation could improve fermentation quality, chemical composition and ruminal degradation of mixed silage, and the optimal ratio of CF to KG for mixed silage was 50:50.

Replacing maize silage plus soybean meal with red clover silage plus wheat grain in diets of dairy cows: Modelling the utilizable crude protein at the duodenum, a precursor to metabolizable protein

The aim was to evaluate the effect of replacing maize silage (MS) plus soybean meal with red clover silage (RCS) plus wheat grain in total mixed rations (TMR) on utilizable crude protein at the duodenum (uCP), and to evaluate the modified Hohenheim gas test (moHGT) for estimation of uCP supply in dairy cows. The TMR comprised forage and concentrates (0.75:0.25), and the forage portion comprised of MS and RCS. The RCS accounted for 0.15, 0.30, 0.45, or 0.60 of the TMR dry matter. The uCP of the TMR was calculated using the “standard German procedure” as the reference value (uCPGfE) as the sum of ruminally undegraded feed crude protein (RUPGfE) and ruminally synthesized microbial crude protein (MCPGfE). For this, the RUPGfE content was calculated from RUP content based on in situ ruminal degradation of crude protein, and the MCPGfE was calculated based on the contents of crude protein, RUP and metabolizable energy. The moHGT was used to determine the in vitro uCP (uCPmoHGT) and was compared with uCPGfE. The RUPGfE, MCPGfE, uCPGfE and uCPmoHGT were estimated assuming passage rates out of the rumen of 2, 5 and 8%/h. At all assumed passage rates, replacing MS with RCS linearly decreased (P < 0.001) the RUPGfE, MCPGfE and uCPGfE content of the TMR. The uCPmoHGT at passage rates of 5 and 8%/h was closely correlated with uCPGfE (R2 = 0.94, P = 0.03, and R2 = 0.95, P = 0.02, respectively), whereas for a passage rate of 2%/h there was no significant correlation (R2 = 0.72, P = 0.15). In conclusion, increasing the proportion of RCS plus wheat grain in the diet of dairy cows reduced the amount of uCPGfE and this was caused more by a reduction in the RUPGfE than in the MCPGfE content. The moHGT has considerable potential as an accurate method for estimating the uCP of TMR, but further studies on standardization of the method and validation with a greater number of TMR samples are recommended.