Rumen Degradability Of Crude Protein Research Articles

Effects of grass silage, preserved using formic acid or lactic acid bacteria, on milk production of dairy cows, supplemented with concentrates high or low in metabolizable protein

A continuous production experiment was conducted in Norway with 48 Norwegian Red dairy cows in early- to mid-lactation, to investigate the effect of grass silage with lactic acid bacteria (LAB) or formic acid (FA) additives, on milk yield (MY) and milk protein yield (MPY). Grass wilted to 250 g dry matter (DM)/kg was inoculated with homofermentative LAB to obtain LAB silage, whilst FA silage was produced adding a FA-based additive. The two silages were fed ad libitum and supplemented with an average 10.3 kg of either high (H) or low (L) metabolizable protein (MP) concentrates, in a 2 ✗ 2 factorial arrangement of treatments. The treatments were LAB silage and L concentrate, LAB silage and H concentrate, FA silage and L concentrate and FA silage and H concentrate. The use of FA resulted in lower levels of residual water-soluble carbohydrates (WSC), and higher levels of ammonia nitrogen (NH3N), compared to LAB. In situ results for FA silage showed lower rumen degradability of crude protein (CP), while gas in vitro results showed lower utilizable CP (uCP), compared to LAB silage (782 vs. 750 g/kg DM and 128 vs. 119 g/kg DM, respectively). The purine over creatinine (PDC) index did not indicate any effects on the microbial protein synthesis (MPS) from any of the treatments. The higher daily intake of FA silage (12.5 vs.13.7 kg DM for LAB and FA, respectively, P < 0.001), did not result in significant differences in daily MY (31.0 vs. 30.2 kg, P = 0.208), nor MPY (1.08 vs.1.07 kg/day, P = 0.878) for LAB and FA, respectively. Feeding H concentrate gave higher MPY (P = 0.036), higher urea in milk (P < 0.001), plasma (P < 0.001) and urine (P = 0.008) and tended to give higher MY (P = 0.063) for both silages. For amino acids (AA) in plasma, alanine was higher for FA silage than for LAB silage (P = 0.030), while histidine (P = 0.001), leucine (P = 0.015) and glutamine (P = 0.007) were higher for both silages when cows were fed H concentrate. In conclusion, the FA and LAB additives did not affect MY or MPY any differently. Feeding H concentrate resulted in higher MPY for both silages, but reduced nitrogen (N) efficiency.

PSVII-35 Late-Breaking Abstract: Microwave heat treatment feed effect on ruminal degradability and intestinal protein digestibility - a brief review

Abstract Rumen degradability of crude protein (CP) of feed is a major factor that determines the utilization of CP in ruminant production. This study briefly reviewed the findings from six international studies of microwave (MW) heat treatment effect on feed CP rumen degradability and intestinal CP digestibility. Six in vitro studies of concentrate feed (canola seed, canola meal, soya bean meal, cottonseed meal, corn, and barley) showed a decrease in effective rumen degradability of dry matter and protein by 4–40% and 17–40%, respectively compared to control group (untreated concentrate feed). Among the six studies, four studies identified the MW heat treatment effect on intestinal protein digestibility. Due to MW heat treatment, canola seed, canola meal, soya bean meal, and cottonseed meal showed an increase in intestinal CP digestibility by 17%, 20%, 21%, and 19%, respectively. Overall the briefly reviewed studies showed that, MW heat treatment substantially reduced feed CP ruminal degradability and increased in vitro CP digestibility of ruminally undegraded CP.

Ruminal degradability of high moisture triticale (X. Triticosecale Wittmack) silage with chemical and biological additives

The objective of this study was to evaluate the ruminal degradability of dry matter and crude protein of high moisture triticale silage ensiled with different chemical and biological additives. Urea, sodium benzoate and an enzyme-bacterial inoculant were used as treatments. Four samples from each treatment were incubated in rumen on four sheep. Effective degradability was estimated for ruminal passage rate of 2%, 5% and 8% hour-1. Bayesian procedures were used to estimate potential degradation parameters in situ. The high moisture triticale silage with urea showed highest value for the soluble fraction (70.46%) and the best effective dry matter degradability, with a passing rate of 2% h-1 (90.63%), of control silage at other rates of passage. In relation to control silage, the addition of sodium benzoate and enzyme-bacterial inoculant decreased the effective degradability of dry matter, regardless of rate passage evaluated. Due to high solubility of urea, the silage added with this additive had the highest soluble fraction of crude protein (76.42%). The addition of enzyme-bacterial inoculant accelerated the ruminal passage rate of dry matter and protein to 0.26 and 0.20% h-1, respectively, providing less potential degradability of both in relation to other silages. As enzyme-bacterial inoculation reduces rumen degradability of crude protein, it tends to increase the availability of amino acids for intestinal absorption. The addition of urea to high moisture triticale silage may be recommended for sheep feeding at a low level of consumption, as it improves the effective dry matter degradability.

Effect of heat treatment and heat treatment in combination with lignosulfonate on in situ rumen degradability of canola cake crude protein, lysine, and methionine

The aim of this study was to determine the effect of heat treatment alone or in combination with the addition of lignosulfonate (LSO3) on canola cake protein, lysine, and methionine degradation in the rumen. Cold-pressed canola cake was left untreated, heated at 90, 110, 130, or 150 °C, or processed with 5% of LSO3 (in dry matter) and then heated. Effective rumen degradability of crude protein (CP), lysine, and methionine was less for treated than untreated canola cake (P &lt; 0.05) and decreased with increased temperature of heating, but particularly when canola cake was heated at 150 °C (quadratic, P &lt; 0.01). In general, effective rumen degradability of CP, lysine, and methionine was less for canola cake heated at 130 °C in combination with LSO3 compared with canola cake heat treated only (quadratic × LSO3 interaction, P ≤ 0.07). Results of this study indicate that high temperature heating (130 °C or greater for 60 min) may be necessary to protect canola cake protein from degradation in the rumen, and the combination of heat treatment and LSO3 may be more effective in protecting canola cake protein, lysine, and methionine from degradation in the rumen than the use of heat treatment only.

Effects of pomegranate peel extract on ruminal and post-ruminal in vitro degradation of rumen inoculum of the dairy cow

This experiment was carried out to study the effect of water extracted pomegranate peel extract (PE) on ruminal protein degradation and post-ruminal digestion in the dairy cow. PE was added at six levels of total phenolics (g/kg of the basal diet); 3.75 (PE1); 4.4 (PE2); 5.05 (PE3); 5.70 (PE4); and 6.35 (PE5). Rumen degradable crude protein (rdCP) decreased with PE addition (L < 0.0001), but total CP degradability (tdCP) was not affected. Compared to PE0, PE2, and PE3 diets showed higher (L = 0.054, Q = 0.029) digestibility of bypass CP (dBCP). Increasing levels of PE resulted in a decrease in proteolytic bacteria numbers (p < 0.0001). At PE4 and PE5 levels, total VFA and acetate concentrations linearly decreased compared to PE0. PE inclusion lowered the acetate:propionate ratio (L = 0.0001) and Ammonia-N production after 24 h (L = 0.0008) of incubation. The total number of protozoa, genera Dasytricha and Isotricha, and subfamilies Entodiniinae, Diplodiniinae, and Ophrioscolecinae decreased with increasing dietary PE concentration (p < 0.0001). The results suggest that all levels of PE addition reduce the protozoal population and Ammonia-N concentration. All PE levels slowed down protein degradation in the rumen but PE2 and PE3 showed the greatest effect.

Forage and protein use efficiency in dairy cows grazing a mixed grass-legume pasture and supplemented with different levels of protein and starch

The aim was to analyze the effects of a supplementation of concentrate mixtures (CM) differing in their concentrations of rumen-degradable crude protein and readily fermentable carbohydrates on feed intake, diet digestibility, milk performance, and nitrogen (N) partitioning in lactating dairy cows grazing a mixed grass-legume sward.Three dietary treatments were tested with two groups of dairy cows during three experimental periods (14 d adaptation and 5 d sampling) following a 2 × 3 Youden square design. Each cow daily received 4.12 kg CM (as-fed basis) distributed over two meals in addition to maize silage and the grazing of an alfalfa-clover-rye grass sward. The three CM contained (as-fed basis): 4 kg/d of dried distillers’ grains with solubles (DDGS) and no maize kernel meal (MM) (HPLS; high protein-low starch), 2.5 kg/d DDGS and 1.5 kg/d MM (MPMS; medium protein-medium starch), and 1 kg/d DDGS and 3 kg/d MM (LPHS; low protein-high starch). Additionally, 0.12 kg/d of a mineral-vitamin mixture was added to each CM. Fecal excretion was determined using the external marker titanium dioxide and apparent total tract digestibility of ingested organic matter (OM) estimated from crude protein concentration in fecal spot samples in order to calculate daily OM and N intakes of cows.Total OM intake and OM intake during grazing did not differ between CM. However, digestibility of ingested OM and daily milk yield were lowest for LPHS. Total N intake and urinary N excretion decreased from HPLS to MPMS and LPHS. Accordingly, N use efficiency (in g milk N per g of N intake) was higher for LPHS (0.249) than for HPLS (0.189) and MPMS (0.209).Feeding CM low in rumen-degradable crude protein and rich in readily fermentable carbohydrates may slightly reduce diet digestibility and milk yield in dairy cows grazing mixed grass-legume swards, but can greatly improve N use efficiency and lower the risk of N emissions into the environment.

Effect of quantity and source of rumen nitrogen on the efficiency of microbial protein synthesis in steers consuming tropical forage

Low values for the efficiency of microbial protein synthesis (EMPS) in cattle consuming tropical forages are related to low rumen degradable crude protein (RDP) intakes. This study examined the effect on the EMPS of the quantity and source of nitrogen (N) supplied to the rumen of eight entire and four rumen-fistulated Brahman steers consuming mature tropical grass hay (57.3 g crude protein/kg DM). Four treatment diets were fed in a Latin square design and included a basal diet of mature pangola grass (Digitaria eriantha) hay (control) and hay plus supplements estimated to provide 150 g RDP/kg digestible organic matter intake (DOMI), as urea or casein, or 300 g RDP/kg DOMI as casein. The EMPS was only increased (P &lt; 0.05) above that for the control diet (167 vs 123 g microbial crude protein (MCP)/kg DOMI) when RDP was provided at the highest rate of 293 g/kg DOMI. This increase was also associated with an ~4-fold increase in the concentration of NH3-N (277 vs 73 mg/L) and of branched-chain volatile fatty acids (44 vs 10 mmol/mol of total volatile fatty acids) in rumen fluid of the steers. However, the source of rumen degradable N (urea or casein) had no effect on the EMPS (109–115 g MCP/kg DOMI) when supplied at ~150 g RDP/kg DOMI. There was no effect of treatment on in vivo neutral detergent fibre digestibility (599 g/kg DM) or the rate (0.037/h) or extent (potential degradable fraction: 636 g/kg OM) of in sacco disappearance of pangola grass hay. In addition, rumen particle dilution rate was unaffected by treatment (0.022/h) and rumen fluid dilution rate, although showing some treatment differences (0.048–0.062/h), was poorly correlated with EMPS. It was concluded that only high amounts of RDP supply to the rumen, in the form of true protein, resulted in increased EMPS whereas at the lower intakes of RDP formulated to achieve EMPS in the range suggested in the feeding standards (130–170 g MCP/kg DOMI) there was no difference in providing the RDP as non-protein N or degradable-protein.

Effects of canola meal pellet conditioning temperature and time on ruminal and intestinal digestion, hourly effective degradation ratio, and potential nitrogen to energy synchronization in dairy cows

The increase in bio-oil production in North America has resulted in millions of tonnes of co-products: canola meal and carinata meal. Little research has been conducted to determine the effect of pellet conditioning temperature, time, and their interaction on processing-induced changes in nutrient digestibility in the rumen and intestine (in vitro) of dairy cattle. The objectives of this study were to investigate the effects of conditioning temperature (70, 80, and 90°C), time (50 and 75 s), and their interaction (temperature × time) during the pelleting of canola meal on (1) rumen degradation kinetics and effective rumen degradability of dry matter, crude protein (CP), and neutral detergent fiber; (2) intestinal digestibility of rumen-undegradable protein (RUP); and (3) hourly effective rumen degradation ratio and potential N to energy synchronization in dairy cattle. The results showed that the temperature and duration of pellet conditioning significantly altered the degradation characteristics of nutrients in the rumen. Pelleting increased CP degradation in the rumen, and CP digestion site was shifted to the rumen rather than to the small intestine. When conditioning temperature was set 80°C, the rumen degradation of CP and neutral detergent fiber was highest, but postrumen digestion was lowest. With respect to intestinal digestion, the available CP for intestinal digestion became less because of reduced RUP supply to the small intestine. The pelleting process tended to significantly affect the intestinal digestibility of RUP. However, the total digestible CP content of canola meal was not affected. In conclusion, pelleting induced changes in rumen and intestinal digestion profiles, and altered the potential N to energy synchronization and hourly effective rumen degradation ratio of canola meal in dairy cattle.

Relationship of feeds protein structural makeup in common Prairie feeds with protein solubility, in situ ruminal degradation and intestinal digestibility

The objectives of this study were to determine the relationship between the intrinsic molecular structures of protein feeds and protein solubility, in situ rumen degradability and intestinal digestibility. The feeds investigated were barley, corn, oat, wheat, lentil, peas, canola meal, expeller meal (extruded canola meal), soybean meal, mill feeds (pelleted byproducts from cereal grains), lantic sugar beet pulp, blood meal and meat meal. The protein molecular structures were quantified from spectral data on unique bands such as amid I and amide II, and protein secondary structures such as α-helix and β-sheet and their ratios using attenuated total reflectance-Fourier transform infrared molecular spectroscopy (ATR-FTIR). The feeds were analyzed for protein solubility, in situ ruminal degradation and intestinal digestibility. The water-based (10.5–70.3g/100g crude protein (CP)) and buffer-based (4.4–76.3g/100g CP) protein solubility had a large variation among the feeds. The effective ruminal degradability (13.8–77.0g/100g CP), intestinal digestibility of rumen undegraded protein (RUP; 57.0–89.1g/100g RUP) and total protein digestibility (76.1–96.4g/100g CP) had a large variation among the feeds. Significant differences were observed in protein amide I and amide II area, model-fitted α-helix and β-sheet height and in the ratio of amide I to II area. The protein molecular structural characteristics were strongly correlated with protein solubility, ruminal degradation and intestinal digestibility. Amide II area had the highest correlation with the contents of CP (r=0.713), water-soluble CP (r=0.730), buffer-soluble CP (r=0.436) and intestinal digestible CP (r=0.735). Whereas the area ratio of amide I:II showed strong correlation (r=0.707) with the content of rumen degradable CP. The protein amide II area and β-sheet height could be used to predict the contents of intestinal digestible RUP (R2=0.826) and total digestible CP (R2=0.808) of prairie feeds in dairy cattle. This study report a novel data on feed protein molecular structures and showed that protein structural makeup was associated with protein nutritional value and digestive behaviour in dairy cattle.

Rumen degradability and ileal digestibility of proteins and amino acids of feedstuffs for cows

Knowledge of the profile of amino acids of the rumen-undegradable protein can help in the formulation of diets to provide amino acids that complement microbial protein as well as supply amino acids, which are most limiting for milk production. Three non-lactating cows fitted with rumen cannulas were used to determine the effect ofin siturumen degradation on crude protein and amino acid profile of rumen-undegraded protein of feedstuffs. The obtained values of rumen degradability of crude protein with significant difference (P&lt; 0.001) between feeds ranged from 20.3 to 76.3% (mean 62.0 ± 17.9%) and values of total amino acids ranged from 30.9% in corn gluten meal to 83.8% in corn gluten feed (mean 67.5 ± 16.4%). Anin vitromodified 3-step method was used to determine intestinal digestibility. Intestinal digestibility of undegraded protein varied from 54.5 ± 1.4% in raw soybean to 95.2 ± 1.0% in corn gluten feed. The absorbable amino acid profile of rumen-undegraded protein for each feedstuff was compared with profiles of the original feedstuff and the rumen-exposed undegraded protein. Absorbable lysine (9.3 ± 1.1 g/kg of crude protein) was higher in products of soybean and sunflower cake. Corn gluten feed and meal supplied more absorbable methionine (3.6 ± 0.6 g/kg of crude protein). This study showed that the digestibility factor of crude protein and amino acid based onin situandin vitromethods for thermal treatment of protein feeds can be used in models to optimize the amino acid nutrition of dairy cows and expand knowledge about rumen degradability and ileal digestibility of amino acids in feedstuffs.

Variation of in situ rumen degradation of crude protein and amino acids and in vitro digestibility of undegraded feed protein in rapeseed meals

In this study, 10 samples of rapeseed meal (RSM) from 10 different oil plants in Germany were examined. In situ rumen degradation of CP was determined by incubation over 1, 2, 4, 8, 16, 32 and 72 h in duplicate per time point using three rumen fistulated dry cows. Degradation kinetics were estimated by an exponential model and effective CP degradation was calculated. Degradation was corrected for small particle loss as the difference between washing loss and water-soluble fraction. Amino acid analysis was carried out in the samples and in the residues after 8 and 16 h of incubation in situ and degradation of individual amino acids was calculated for these incubation times. In vitro pepsin–pancreatin digestibility of CP (IPD) was determined in the samples as well as in the 8 and 16 h residues. Effective CP degradation for a rumen outflow rate of 8%/h (ED8) averaged 54.3% with a considerable variation among samples ranging from 44.3% to 62.7%. A multiple regression equation containing acid detergent insoluble N, total glucosinolates and petroleum ether extract as independent variables predicted ED8 with satisfying accuracy (R2 = 0.74; RSD = 6.4%). Degradation of amino acids was different from that of CP for most amino acids studied, especially after 8 h of incubation. Compared with CP, degradation of essential amino acids was predominantly lower while degradation of non-essential amino acids was higher in most cases. However, for lysine and methionine no distinct difference with CP degradation was found. Degradation of individual amino acids was predicted from CP degradation with high accuracy using linear regression equations. Average IPD of RSM was 79.8 ± 2.6%. IPD was lower in the incubation residues and decreased with longer incubation time and increasing rumen degradation, respectively.

Variations in chemical composition and in vitro and in situ ruminal degradation characteristics of dried distillers’ grains with solubles from European ethanol plants

The objective of this study was to characterise variations in the composition and nutritive value of dried distillers’ grains with solubles (DDGS) for ruminants, and to estimate the undegradable crude protein (UDP) in DDGS. Thirteen samples originating from wheat, corn, barley and blends of different substrates were studied. The rumen degradation of crude protein (CP) was determined using the nylon bag technique. Samples were incubated for 0, 1, 2, 4, 8, 16, 32 and 72 h, and in situ degradation kinetics were determined. The UDP was estimated using a passage rate of 8%/h. In vitro gas production was measured to estimate the metabolisable energy (ME), net energy for lactation (NEL) and in vitro digestibility of organic matter (IVDOM). Chemical profiles varied among samples [in g/kg dry matter (DM) ± standard deviation]; the values were 310 ± 33 CP, 86 ± 37 ether extract, 89 ± 18 crude fibre, 408 ± 39 neutral detergent fibre, 151 ± 39 acid detergent fibre and 62 ± 31 acid detergent lignin, as well as in protein fractions according to the Cornell Net Carbohydrate and Protein System [in g/kg CP]; the values were for fractions A, 161 ± 82; B1, 24 ± 11; B2, 404 ± 105; B3, 242 ± 61; and C, 170 ± 87. The ME, NEL [MJ/kg DM] and IVDOM [%] also varied among samples: 12.1 ± 0.59, 7.3 ± 0.39 and 72.5 ± 4.30, respectively. The in situ rapidly degradable CP fraction (a) varied from 10.2% to 30.6%, and the potentially degradable fraction (b) averaged to 66.8%. The UDP varied from 8.6% to 62.6% of CP. The present study suggests significant variations in composition and nutritive value among different sources of DDGS. The UDP could be predicted on the basis of analysed CP fractions, but the accuracy of UDP prediction improved upon the inclusion of neutral-detergent insoluble nitrogen, explaining 94% of the variation in the UDP values. We conclude that chemical protein fractions may be used to predict the UDP values of DDGS and that the variability in the protein fractions of DDGS should be considered when formulating diets for dairy cows.

Effect of niacin supplementation on rumen fermentation characteristics and nutrient flow at the duodenum in lactating dairy cows fed a diet with a negative rumen nitrogen balance

The aim of the present experiment was to ascertain if a daily niacin supplementation of 6 g/cow to lactating dairy cow diets can compensate for the decrease in rumen microbial fermentation due to a negative rumen nitrogen balance (RNB). A total of nine ruminally and duodenally fistulated lactating multiparous German Holstein cows was used. The diets consisted of 10 kg dry matter (DM) maize silage and 7 kg DM concentrate and differed as follows: (i) Diet RNB- (n = 6) with energy and utilisable crude protein (CP) at the duodenum (uCP) according to the average requirement of the animals, but with a negative RNB (−0.41 g N/MJ metabolisable energy [ME]); (ii) Diet RNB0 (n = 7) with energy, uCP, and RNB (0.08 g N/MJ ME) according to the average requirement of the animals; and (iii) Diet NA (nicotinic acid; n = 5), which was the same diet as RNB-, but supplemented with 6 g niacin/d. The negative RNB affected the rumen fermentation pattern and reduced ammonia content in rumen fluid and the daily duodenal flows of microbial CP (MP) and uCP. Niacin supplementation increased the apparent ruminal digestibility of neutral detergent fibre. The efficiency of microbial protein synthesis per unit of rumen degradable CP was higher, whereby the amount of MP reaching the duodenum was unaffected by niacin supplementation. The number of protozoa in rumen fluid was higher in NA treatment. The results indicated a more efficient use of rumen degradable N due to changes in the microbial population in the rumen when niacin was supplemented to diets deficient in RNB for lactating dairy cows.

The effect of ruminal incubation of bioactive yeast (Saccharomyces cerevisiae) on potential rumen degradability of Panicum maximum and Centrosema pubescens in West African Dwarf Sheep.

The rising interest in the use of organic and inorganic substances in manipulating rumen function for improved fermentative activity has provided avenues for the inclusion of various species of yeast cultures in ruminant diets. In this study, we investigated the effect of bioactive yeast (Saccharomyces cerevisiae), on rumen degradative function of the West African Dwarf Sheep (WADS) in terms of fermentable organic matter, crude protein and crude fiber of Panicum maximum and Centrosema pubescens. Three inclusion levels of Saccharomyces cerevisiae, 200, 500 and 800 milligrams were infused into the rumen of three groups (A, B and C), of three WAD sheep each. Another group (D) of same animal number served as the control. In vivo rumen potential degradability studies, using the nylon bag technique was performed using Panicum maximum and Centrosema pubescens in all the groups. The result of the study showed that bioactive yeast improved the potential rumen degradability of crude protein, crude fibre and organic matter fractions of Panicum maximum and Centrosema pubescens in a rather dose dependent manner compared to the control. There was a significant correlation (r = 0.56) between degradability, dose and time of incubation for crude fibre and organic matter fractions but not for crude protein. These observations suggest that regulated dietary inclusion of bioactive yeast can be used to bioengineer the rumen towards efficient fibre breakdown, particularly forages of poor protein quality and high fibre content, for efficient production of volatile fatty acids as well as probably enhancing other aspects of rumen functions. Keywords: Bioactive Yeast, Degradability, Forages, Rumen, WADS.

Effect of carbohydrates in grass silage-based diets on in sacco ruminal degradability of barley (Hordeum vulgare L. cv. Lomerit) grain ground to different particle sizes

The effect of carbohydrates included in grass silage-based diets on &lt;I&gt;in sacco&lt;/I&gt; degradability of dry matter (DM), crude protein (CP), neutral detergent fibre (NDF) and cellulose (CE) of barley (&lt;I&gt;Hordeum vulgare&lt;/I&gt; L. cv. Lomerit) grain ground to different particle sizes was studied using 3 ruminally cannulated cows. The measurements were carried out as a 3 × 2 Latin square design with treatments being carbohydrates in the concentrate portion of diets (starch in diet I vs. pectin in diet II vs. sucrose in diet III) and particle size of ground barley grain (1.0 vs. 5.7 mm). The diet synchronization index between N and energy supply during the day was an average of 0.8. The rumen degradability of barley grain compounds was influenced by the type of carbohydrates included in grass silage-based diets. Higher rumen degradation rates (&lt;I&gt;P&lt;/I&gt; &lt; 0.05) of barley CP, NDF and CE after 8 h of incubation and of CP and CE after 16 h of incubation were found in the rumen of cows receiving the diet containing sucrose compared with degradation rates found in the rumen of cows receiving the diet containing pectin or starch. The effective degradability of DM, CP, NDF and CE of barley grain in the rumen of cows receiving diets I, II and III was similar (77, 74, 39 and 41%, respectively). Replacing barley starch or beet pulp pectin with molasses sucrose in the grass silage-based diet resulted in the higher rate of barley CP, NDF and CE degradation after 8 h of incubation and of CP and CE after 16 h of incubation. It seems that the energy availability from carbohydrates affected the ruminal microbial activity as a consequence of the degradation rate of substrates. Higher (&lt;I&gt;P&lt;/I&gt; &lt; 0.01) rumen degradability of CP, NDF and CE after 2, 4, 8, 16 and 24 h of incubation was estimated for 1.0 mm particle size in comparison with that found for grain ground to 5.7 mm particle size, and the degradability of CP after 48 h of incubation was not different (&lt;I&gt;P&lt;/I&gt; &gt; 0.05). The degradability of barley grain CP, NDF and CE during incubation time was not influenced by the diet composition by particle size interaction (&lt;I&gt;P&lt;/I&gt; &gt; 0.05). The increase in barley grain particle size from 1.0 to 5.7 mm slowed down the rumen digestion of barley DM, CP, NDF and CE, probably due to restricted access to microbial digestion.

Protein value of a new genotype oat (CDC SO-I) for the NRC dairy model: Protein degradation balance and kinetics, protein fractions and total metabolizable protein supply

Recently, a new genotype of oat has been developed specifically for feed purposes by the Crop Development Centre called CDC SO-I (“SuperOat”) containing a low-lignin hull and a high-fat groat. However, no quantitative evaluation of protein supply from CDC SO-I to dairy cow has been done in terms of potential protein degradation balance (PDB) and total metabolizable protein (MP) supply. These data are crucial in order to develop more efficient, competitive and optimal feeding the new genotype of oat (CDC SO-I) for livestock. Unlike DVE/OEB, PBI, ARC and NKJ-NJF models, NRC-2001 is a total digestible nutrient (TDN-) based model which is more popular in North America. The objectives of this study were to use the NRC model with inputs based on laboratory and in situ techniques to predict the potential nutrient supply to dairy cows from CDC SO-I in comparison with two conventional oat varieties, CDC Dancer and Derby, in western Canada. The quantitative predictions were made in terms of: (1) Rumen-synthesized microbial protein truly absorbed in the small intestine (AMCP); (2) Rumen undegraded feed protein truly absorbed in the small intestine (ARUP); (3) Endogenous protein in the digestive tract (AECP); (4) Total metabolizable protein supply in the small intestine (MP), and (5) Protein degraded balance (PDB). The results show that using the NRC model, the predicted PDB and total MP supplies to dairy cattle were significantly increased from the newly developed genotype of oat (CDC SO-I). Compared with the normal oat, CDC Dancer, CDC SO-I significantly increased (P &lt; 0.05) ARUP, by 24%, and total MP supply by 9%, but did not change (P &gt; 0.05) AMCP, AECP and PDB, with averages of 55.7, 4.5 and -11.96 g kg-1 dry matter (DM), respectively. Compared with the normal variety, Derby, CDC SO-I significantly increased (P &lt; 0.05) AMCP, by 19%, total MP supply by 13% and increased PDB by 114%, but did not change (P &gt; 0.05) ARUP and AECP values with averages of 19.2 and 4.5 g kg-1 DM, respectively. In conclusion, CDC SO-I oat increased total absorbed metabolizable protein supply to dairy cattle by 9–13% in comparison with the two conventional oat varieties used in western Canada. However, although CDC SO-I improved protein degraded balance, it still had a negative value (-10.6 g kg-1 DM), indicating the potential imbalance between microbial protein synthesis from available rumen-degradable crude protein (CP) and potential energy from fermentation in the rumen. Key words: TDN-based model, dairy cattle, oat genotype, protein degradation balance, metabolizable protein supply

The estimation of duodenal utilizable true protein in sheep fed mixed rations using the nitrogenous fractions of the Cornell Net Carbohydrate and Protein System

The objective of the experiment is to study the relationship between the nitrogenous fractions of the Cornell Net Carbohydrate and Protein System (CNCPS) and the duodenal utilizable true protein (uTP) in sheep, and the possibility of predicting duodenal uTP flow based on the CNCPS nitrogenous fractions intake. Twelve typical mixed rations for sheep were formulated as experimental rations and the chemical composition of the rations, i.e. CP (crude protein), SCP (soluble crude protein), NDICP (neutral detergent insoluble crude protein) and ADICP (acid detergent insoluble crude protein) was analyzed. The CNCPS nitrogenous fractions, i.e. PA (non-protein nitrogen), PB 1 (rapidly rumen degradable crude protein), PB 2 (intermediately rumen degradable crude protein), PB 3 (slowly rumen degradable crude protein) and PC (bound crude protein) were calculated using the CNCPS based on the chemical composition of the rations. The duodenal uTP of sheep was determined in an earlier study using three sheep in four 3 × 3 Latin square designs by Li and Zhao [Li, Y.X., Zhao, G.Y., 2007. The prediction of the uTP of mixed rations for sheep using in vitro incubation technique. Arch. Anim. Nutr. 61(2), 103–113]. Statistical analysis indicated that the duodenal uTP flow (g/day) was closely correlated with the nitrogenous fractions intake of the sheep (g/day) in a multiple way: uTP = 9.27 PA − 35.76 P B 1 + 10.12 P B 2 − 2.20 P B 3 − 37.38 PC − 16.82 , r 2 = 0.94 , P = 0.001 , n = 12 where the unit for all indices is g/day. It was concluded that the duodenal uTP flow of sheep fed mixed rations could be reliably estimated based on the CNCPS nitrogenous fractions intake using the model above.

Using the unique degradation ratio system (DRS) as an alternative method for feed evaluation and diet formulation: A review

ABSTRACTRecently obtained information on applications of the unique degradation ratio system (DRS) as an alternative method for feed evaluation and diet formulation is reviewed, in relation to optimum rumen fermentation and nutrient utilization and availability. The DRS ratio values show the balance between potentially microbial protein synthesis from rumen degradable crude protein and that potentially from the energy extracted during anaerobic fermentation in the rumen. In modeling feed evaluation and diet formulation, the degradation ratios can be used in assisting to detect effects of feed processing and optimize the composition of ruminant diets. Unfortunately, few researchers provide such crucial ratio data when they studied rumen degradation characteristics of a feed or diet mainly due to lack of knowledge of the DRS system. The emphasis of this article is on: (i) systematic introduction of the DRS system; and (ii) prediction the optimal rumen fermentation using the DRS system. The information described in this article may give better insight into the principal, computation and applications of the DRS system for feed and diet evaluation. A focus of the article is on evaluation of the DRS system as an alternative new approach to establishment of a feed evaluation system that more accurately accounts for feed digestive processes in the ruminant on a quantitative basis.

Herbage biomass production and nutritive value of mulberry ( Morus alba) and Calliandra calothyrsus harvested at different cutting frequencies

Effects of cutting frequencies on herbage biomass production and nutritive value of Morus alba and Calliandra calothyrsus were investigated. Forage regrowth was harvested at frequencies of 1, 2, 4 and 6 months which constituted the four treatments. Degradabilities, to establish nutritive values, were measured at 0, 3, 6, 12, 24, 48, 72, 96 and 120 h of rumen incubation by a nylon bag technique using three rumen fistulated steers. Crude protein (CP) of M. alba declined linearly (P<0.05) from 234.4 to 169.3 g/kg DM as it matured from 1 to 6 months, while in C. calothyrsus CP decreased (P<0.05) at a decreasing rate from 232.7 to 156.0 g/kg DM with increasing maturity. Neutral detergent fibre (NDF) and acid detergent lignin increased (P<0.05) with increasing maturity. C. calothysus and M. alba leaf:stem ratio decreased from 3.3 to 0.4 and 2.9 to 0.7, respectively, with increasing maturity. While C. calothyrsus had the highest total herbage biomass yield of 45.9 t/(ha yr −1) at the 4 months cutting frequency, M. alba had yields of 18.6 and 18.4 t/(ha yr −1) at 2 and 6 months, respectively. Highest (P<0.05) effective CP degradability of 901.3 g/kg CP occurred in M. alba at a cutting frequency of 1 month while in C. calothyrsus the highest (P<0.05) value was 492.8 g/kg CP at 2 months. Consequently, in all treatments, rumen degradable CP (RDP) was consistently higher in M. alba (96.5–199.2 g/kg CP) than in C. calothyrsus (52.5–105.2 g/kg CP) but decreased (P<0.05) with increasing maturity. Digestible undegradable CP (DUP) was affected (P<0.05) by increasing maturity, but was lower in M. alba compared to C. calothyrsus. Although C. calothyrsus was superior to M. alba in annual herbage biomass production and DUP, it had lower RDP than M. alba and the nutritional value of both greatly depends on maturity and leaf:stem ratio. Cutting management options that involve harvesting C. calothyrsus and M. alba at maturities between 2 and 4 months, when leaf:stem ratio is greater than 1.0, is crucial in making a decision when to harvest fodder of high nutritional value. This suggests that smallholder farmers in Uganda can efficiently use M. alba and C. calothyrsus in rations to improve dairy cattle productivity, if harvested at maturities between 2 and 4 months.

Attempts to deactivate tannins in fodder shrubs with physical and chemical treatments

Chopping, water sprinkling, storage under aerobic and anaerobic conditions, urea, wood ash, activated charcoal and polyethylene glycol 4000 (PEG) treatments were evaluated for their efficiency in deactivating tannins in shrub foliage. In a first trial, fresh leaves of Acacia cyanophylla Lindl. (acacia) were stored after chopping or without chopping and spraying or without spraying with water under aerobic or anaerobic conditions. The plant material was stored for 1, 7 and 14 days and analysed thereafter for extractable total phenols (TP), extractable total tannins (TT) and extractable condensed tannins (CT) contents. Chopping and water spraying substantially decreased the levels of TP, TT and CT of acacia. The rate of tannin deactivation increased in acacia stored under anaerobic conditions. Acacia stored for 7 days exhibited lower TP, TT and CT contents than that stored for only 1 day. Compared to the 7-day storage period, there was a further non-significant decrease in the level of these phenolic compounds when the storage duration was extended to 14 days. The highest level of rumen degradation of crude protein (CP) in sheep rumen was obtained with chopped, water sprinkled acacia leaves stored under anaerobic conditions. The second trial investigated the effect of increasing levels of urea (0, 20, 40, 60 and 80 g/kg) and treatment duration (7, 14, 21 and 28 days) on CP, TP, TT and CT in acacia leaves. The 20 g/kg urea level was sufficient to totally deactivate tannins in acacia even with the shortest storage period, i.e. 7 days. However, urea treatment increased ash-free neutral detergent fibre content and did not improve in sacco acacia degradation. In the third trial air-dried 1 mm ground samples of acacia and kermes oak ( Quercus coccifera L.) leaves were added to water (control), acacia wood ash, activated charcoal or PEG solutions (100 g/kg) at 1:10 (w/v) and shaken for 20 min. All these four treatments decreased TP, TT and CT contents and could be classified on the basis of their deactivation rate as wood ash = PEG > activated charcoal = water. In conclusion, the physical techniques tested in this study were found to be efficient in decreasing phenolic compounds in acacia leaves. The ideal treatment would be to spray water on the chopped leaves, which thereafter should be stored in sealed bags for at least 7 days. Although urea treatment deactivated these secondary compounds totally, it did not improve the nutritive value of acacia. Wood ash treatment seems to be a promising technique to deactivate tannins in shrub foliage and further studies on this inexpensive and locally available product should be encouraged.