Ruminal Dry Matter Degradability Research Articles

Dry Matter Degradation Kinetics and Metabolizable Energy of Chickpea (Cicer arietinum) Straw in Ruminants

Chickpea straw is the main by-product which is produced in large amounts after chickpea grain threshing. There is a little information about its nutritive value. This experiment was carried out to determine the fiber and non-fibre component, ruminal dry matter degradability and Metabolizable Energy (ME) of chickpea straws using nylon bags (in situ) technique. Replicated samples were incubated at 0, 2, 4, 8, 12, 24, 48 and 72 h in 3 rumen canulated male Ghezel rams with 50±3 kg body weight. Dry Matter (DM), Neutral Detergent Fibre (NDF), Acid Detergent Fibre (ADF) and Non-Fibrous Carbohydrates (NFC) content of chickpea straws were 92.18, 57.80, 37.40 and 22.65%, respectively. The dry matter soluble fraction (a), non-soluble but potentially degradable fraction (b) and potential degradability (a+b) of chickpea straws were 19.50, 38.60 and 58.10%, respectively. Effective degradability at different passage rates (2, 5 and 8% h-1) were 53.70, 48.60 and 44.80%, respectively. Estimated metabolizable energy of chickpea straw was 8.55 MJ kg-1 DM. Based on the DM degradation kinetics and energy content, beseems chickpea straw could be used as a valuable feedstuff in ruminants diet

Ruminal Degradability of Dry Matter and Crude Protein from Moist Dehulled Lupin and Extruded Rapeseed Meal

The flow of ruminal undegradable protein (RUP) to the small intestine can be increased if ruminal degradation of dietary protein is reduced. The objective of this study was to evaluate the effect of extrusion on ruminal degradability of dry matter (DM) and crude protein (CP) from dehulled lupin (Lupinus albus L.) (DL) and rapeseed (Brassica napus L.) meal (RM). Unextruded soybean (Glicine max L.) meal (SBM) was used as a control. The DL was extruded at 130 oC with 20% moisture and RM was extruded at 120 oC with 20% moisture. Ruminal degradability was evaluated in situ by incubating feed samples for 2, 4, 8, 12, 24, and 48 h of fermentation in the rumen using three rumen-fistulated dairy cows. Values of CP soluble fraction (�a�) in SBM, DL, extruded dehulled lupin (EDL), RM, and extruded rapeseed meal (ERM) was lower in the extruded feeds (P < 0.05). The slowly degradable fraction (�b�) of SBM, DL, EDL, RM, and ERM was 858, 593, 622, 451, and 457 g kg-1, respectively, and was increased by extrusion (P < 0.05). Extrusion reduced the effective degradability (ED) of CP in lupin from 807 to 788 g kg-1; kp = 0.05 h-1 while ED was reduced from 868 to 789 g kg-1; kp = 0.05 h-1 in ERM. This resulted in an increase in RUP of 8.95% in EDL (P < 0.05); the increase was 37.35% (P < 0.05) in ERM. It may be concluded that extrusion in the presence of moisture reduced the degradability of CP, particularly in the case of ERM.

Assessment of genetic parameters of degradability in maize grains due to indentation scores

Maize (Zea mays L.) cultivars with dent grains present higher starch and dry matter ruminal degradability than those with flint grains. This study aimed to assess genetic parameters of degradability in maize grains of different textures and to verify whether there is an association between grain indentation score and ruminal dry matter (RDM) degradability. The evaluated progenies were obtained from the cross between the varieties Cristal (flint) and Cunha (dent), previously selected for grain hardness. Progenies were evaluated for an indentation score using a visual grading scale ranging from 1 (flint) to 5 (dent). To assess the RDM degradability, 5 g were cut into halves, weighed (five grams), stored in bags made of 100% "failet" cloth and incubated for 24 h in the rumen of three ruminally cannulated cows. There was genetic variability for RDM degradability and heritability was 46%, indicating the possibility of success using a selection. There was no association between indentation score and RDM degradability percentage; thus, visual evaluation not always reflects grain hardness per se since it indicates the pericarp aspect but not the endosperm constitution.

Effect of increasing levels of white mulberry leaves (Morus alba) on ruminal dry matter degradability in lambs

A study was conducted to estimate dry matter (DM) degradability in the rumen of lambs offered a basal soybean meal and sorghum grain diet with three levels of white mulberry (WM) leaves (Morus alba). Diets consisted of 90% concentrate and 10% sorghum straw, which was incrementally replaced by WM leaves at 0% (control diet, T1), 2.5% (T2), and 5% (T3) of the total ration. Crude protein (CP) in WM was 21.8% (DM basis). Diets had equal CP (14% DM basis) and metabolizable energy (10.8MJ/kg DM) content. Three non-castrated Pelibuey male lambs fitted with permanent rumen cannula were utilized in a 3 × 3 Latin square design. Each experimental period consisted of 10days of adaptation followed by sampling. DM degradability was determined using the nylon bag technique. Bags contained the experimental diets offered in each period and were incubated in rumen in pairs for 4, 8, 12, 24, and 48h. The potential degradation was higher (P < 0.05) for T2, followed by T3 and T1. WM level did not influence the degradation rate or the effective degradation at the three passage rates modeled. It was concluded that WM forage may have useful application in feedlot diets for growing lambs, as this forage increases potential degradation of high-grain diets. The incorporation of WM in diets for feedlot lambs in tropics may reduce the use of expensive conventional protein supplements.

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.

Influence of corn processing provided in the diet on the ruminal dynamics of dairy steer

The objective of the present study was to evaluate the ruminal dynamics of dairy steer fed diets containing whole corn grains, grains ground into grits or whole grain treated with urea. Thus, six rumen-fistulated animals were kept in confinement and fed diets with similar contents of energy and protein. The diet was formulated with 40:60 roughage:concentrate ratio in the dry matter using sorghum silage as roughage. The experiments followed a 3 × 3 latin square design, with three animals and three periods and they were repeated eith-er two or four times depending on the studied parameter, totaling six or 12 replicates per diet. Corn grain treatment did not affect the pH of the ruminal fluid neither the ruminal degradability of dry matter, acid detergent fiber and cellulose. All diets provided a concentration of amoniacal nitrogen suitable for ruminal microbial growth; however, for animals fed whole corn grain treated with urea, this concentration was significantly lower. Bacterial activity was lower in animals fed diets containing ground corn and they do not differ among animals fed whole corn grain or corn grains treated with urea.

Effects of ruminal infusion of a slow-release polymer-coated urea or conventional urea on apparent nutrient digestibility, in situ degradability, and rumen parameters in cattle fed low-quality hay

Four ruminally cannulated beef steers were used in a 4 × 4 Latin square design experiment conducted to compare ruminal infusion effects of different sources of non-protein nitrogen (NPN) on intake; digestibility; ruminal dry matter (DM) and neutral detergent fiber (NDF) degradability; ruminal pH; and ammonia nitrogen (N-NH 3) of beef cattle fed Brachiaria humidicola cv. Llanero hay [CP = 24.9 g/kg DM; ash-free NDF corrected for contamination of CP (NDFom,cp) = 782.4 g/kg DM]. Treatments were: Control (hay only); U [hay + conventional urea (204.2 g/d)]; SRU [hay + slow-release polymer-coated urea (297.5 g/d)]; U + SRU [hay + a combination of 1:1 by weight of both urea types (130.4 g/d U + 130.4 g/d SRU)]. Supplements were infused into the rumen through the rumen cannula. Treatments SRU and U + SRU had an increasing of hay dry matter intake (DMI) (9.44 and 9.02 kg/d, respectively; P<0.01, compared with 7.62 kg/d for the control), as well as total NDF (P<0.01) and crude protein (CP, P<0.01). The CP digestibility was higher (P<0.01) for all treatments with NPN when compared to control. There were differences on DM and NDF degradability curves (P<0.05) between rumen exposure times, in which the disappearance was increased up to 120 h after incubation. On the first day of collections, the lowest pH values (6.89 and 6.91) were observed on SRU and U + SRU 6 h after the afternoon infusion, and the highest pH was observed immediately after the afternoon infusion of U (7.39). High levels of ammonia-N were kept for 8 h after the last infusion daily of SRU, which resulted in the most constant values of NH 3-N in the rumen. In general, our data suggested that SRU had a more adequate concentration of N during the fermentation of low-quality hay, and also had a proper pH for rumen activity.

Effect of fibrolytic enzyme application to low- and high-concentrate diets on the performance of lactating dairy cattle

The objective of this study was to examine the effect of applying a fibrolytic enzyme preparation to diets with high (48% of diet dry matter, DM) or low (33% of diet DM) proportions of concentrate on production performance of lactating dairy cows. Sixty lactating Holstein cows (589kg ± 20; 22±3 d in milk) were stratified according to milk production and parity and randomly assigned to 4 treatments with a 2 × 2 factorial arrangement. Dietary treatments included the following: 1) low-concentrate diet (LC); 2) LC plus enzyme (LCE); 3) high-concentrate diet (HC); and 4) HC plus enzyme (HCE). The enzyme was sprayed at a rate of 3.4mg of enzyme/g of DM on the total mixed ration daily and the trial lasted for 63 d. A second experiment with a 4 × 4 Latin square design used 4 ruminally fistulated cows to measure treatment effects on ruminal fermentation and in situ ruminal dry matter degradation during four 18-d periods. Enzyme application did not affect dry matter intake (DMI; 23.9 vs. 22.3 kg/d) or milk production (32.8 vs. 34.2 kg/d) but decreased estimated CH4 production, increased total volatile fatty acid concentration (114.5 vs. 125.7mM), apparent total tract digestibility of DM (69.8 vs. 72.6%), crude protein (CP; 69.2 vs. 73.3%), acid detergent fiber (50.4 vs. 54.8%), neutral detergent fiber (53.7 vs. 55.4%), and the efficiency of milk production (1.44 vs. 1.60kg of milk/kg of DMI). Feeding more concentrates increased DMI (21.5 vs. 24.8 kg/d), milk yield (32.2 vs. 34.7 kg/d), milk protein yield (0.89 vs. 0.99 kg/d), and DM (69.9 vs. 72.6%), but decreased ruminal pH (6.31 vs. 6.06). Compared with cows fed HC, those fed LCE had lower DMI (20.8 vs. 25.7 kg/d) and CP intake (3.9 vs. 4.8 kg/d), greater ruminal pH (6.36 vs. 6.10), and similar milk yield (33.2±1.1 kg/d). Consequently, the efficiency of milk production was greater in cows fed LCE than those fed HC (1.69 vs. 1.42kg of milk/kg of DMI). This fibrolytic enzyme increased the digestibility of DM, CP, neutral detergent fiber, and acid detergent fiber and the efficiency of milk production by dairy cows. Enzyme application to the low-concentrate diet resulted in as much milk production as that from cows fed the untreated high-concentrate diet.

Ruminal degradability of dry matter and neutral detergent fibre of grasses

A study was conducted (I) to determine rumen degradability (in sacco) of dry matter (DM) and neutral detergent fibre (NDF) of the most important grass species grown in the Czech Republic, (II) to compare grass species (n = 5) according to calculated degradation parameters, and (III) to establish prediction equations for degradation parameters from chemical composition. Forty samples of the most important grass species (Dactylis glomerata, Phleum pratense, Lolium perenne, Festuca arundinacea, Felina hybrid) were harvested in 2004 and 2005 and analyzed for chemical composition, and DM and NDF in sacco degradability. Results from the in sacco method were used to calculate DM and NDF degradation parameters. Linear and stepwise multiple regression analyses were used to develop prediction equations for DM and NDF degradation parameters from nutrient concentrations. The highest DM and NDF degradation parameters were found for Lolium perenne. DM and NDF rumen degradation parameters were successfully predicted from chemical composition, with a single predictor adequate for most parameters. For all parameters R&lt;sup&gt;2&lt;/sup&gt;-values increased with addition of more predictors into regression equations. Effective degradability (ED) of DM calculated at a rumen outflow rate (k) of 0.05 h&lt;sup&gt;&amp;ndash;1&lt;/sup&gt; was the best predicted by NDF (R&lt;sup&gt;2&lt;/sup&gt; = 0.878), and ED of NDF at k = 0.02 h&lt;sup&gt;&amp;ndash;1&lt;/sup&gt; by crude protein (CP) (R&lt;sup&gt;2 &lt;/sup&gt;= 0.653).

In situ 방법을 이용한 수확시기별 총체벼 사일리지의 한우 생체 사료가치 평가

Three Hanwoo steers (BW ) with ruminal and duodenal cannulae were used to investigate nutrients degradability and total digestible nutrient (TDN) of whole crop rice silage (WRS) harvested at different mature stages using in situ technique. Crude protein content (mean 4.81%) decreased with progressed maturity at harvest except for WRS harvested at yellow stage. Ruminal dry matter degradability of WRS at milk stage tended to be slightly lower than that of the other stages during the entire incubation time from 12 h post-incubation. The rapidly degradable N (a-fraction) of WRS harvested at milk stage was significantly (p0.05) between the harvest stages. TDN of WRS harvested at yellow stage in Hanwoo steers was statistically (compared with milk stage) and numerically (compared with dough and mature stages) higher than TDN of the other WRS. Overall, taking present feed evaluation into consideration, WRS harvested at yellow stage may be recommended for Hanwoo steers. Further studies on in vivo rumen fermentation pattern and minimizing nutrients loss during harvest should be required for accurate feed evaluation.

Changes in Nutritive Value and Digestion Kinetics of Canola Seed Due to Microwave Irradiation

This study aimed to evaluate effects of 800 W microwave irradiation for 2, 4 and 6 min on chemical composition, antinutritional factors, ruminal dry matter (DM) and crude protein (CP) degradability, and in vitro CP digestibility of canola seed (CS). Nylon bags of untreated or irradiated CS were suspended in the rumen of three bulls from 0 to 48 h. Protein subfractions of untreated and microwave irradiated CS before and after incubation in the rumen were monitored by sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE). Microwave irradiation had no effect on chemical composition of CS (p>0.05). There was a linear decrease (p by 4.7, 12.3 and 21.0%, respectively. Microwave irradiation increased linearly (p

Bayesian analysis for comparison of nonlinear regression model parameters: an application to ruminal degradability data

This paper shows the Bayesian approach as an alternative to the classical analysis of nonlinear models for ruminal degradation data. The data set was obtained from a Latin square experimental design, established for testing the ruminal degradation of dry matter, crude protein and fiber in neutral detergent of three silages: elephant grass (Pennisetum purpureum Schum) with bacterial inoculant or enzyme-bacterial inoculant and corn silage (Zea mays L.). The incubation times were 0, 2, 6, 12, 24, 48, 72 and 96 hours. The parameter estimates of the equations fitted by both methods showed small differences, but by the Bayesian approach it was possible to compare the estimates correctly, that does not happen with the frequentist methodology because it is much more restricted in the applications due to the demand for a larger number of presuppositions.

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.

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.

Effects of bale moisture and bale diameter on spontaneous heating, dry matter recovery, in vitro true digestibility, and in situ disappearance kinetics of alfalfa-orchardgrass hays

Alfalfa (Medicago sativa L.)-orchardgrass (Dactylis glomerata L.) hay was made in 96 large-round bales over 3 harvests during 2006 and 2007 to assess the effects of spontaneous heating on dry matter (DM) recovery, in vitro true digestibility (IVTD), and in situ disappearance kinetics of DM. Throughout these harvests, bales were made at preset diameters of 0.9, 1.2, or 1.5m and at moisture concentrations ranging from 9.3 to 46.6%. Internal bale temperatures were monitored daily during an outdoor storage period, reaching maxima of 77.2°C (MAX) and 1,997 heating degree days >30°C (HDD) for one specific combination of bale moisture, bale diameter, and harvest. Following storage, regressions of DM recovery on HDD and MAX indicated that DM recovery declined linearly in close association with measures of spontaneous heating. For HDD, slopes and intercepts differed across bale diameters, probably because the greater surface area per kilogram of DM for 0.9-m bales facilitated more rapid dissipation of heat than occurred from 1.2- or 1.5-m-diameter bales. Regardless of bale diameter, coefficients of determination were high (r2≥0.872) when HDD was used as the independent variable. Regressions of DM recovery on MAX also exhibited high r2 statistics (≥ 0.833) and a common slope across bale diameters (−0.32 percentage units of DM/°C). Changes in concentrations of IVTD during storage (poststorage – prestorage; ΔIVTD) also were regressed on HDD and MAX. For HDD, the data were best fit with a nonlinear model in which ΔIVTD became rapidly negative at <1,000 HDD, but was asymptotic thereafter. When MAX was used as the independent variable, a simple linear model (y = −0.23x + 9.5) provided the best fit. In both cases, coefficients of determination were comparable to those for DM recovery (R2 or r2 ≥0.820). Changes (poststorage – prestorage) in ruminal DM degradation rate (ΔKd) and effective ruminal degradability of DM (ΔDEG) were assessed similarly. Although the most appropriate statistical model varied, ΔKd and ΔDEG both became increasingly negative at low to moderate levels of heating, but generally stabilized thereafter. Both HDD and MAX were excellent predictor variables for both ΔKd and ΔDEG; r2 or R2 statistics ranged from 0.788 to 0.921. Measures of spontaneous heating are consistently effective indicators of DM recovery following storage, as well as good indicators of concurrent changes in IVTD or in situ disappearance of DM for heated alfalfa-orchardgrass hays.

Chemical Composition and Ruminal Degradability of Spineless Cactus Grown in Northeastern Brazil

A study was conducted to determine chemical composition and ruminal nutrient degradability of eight spineless cactus cultivars grown in northeastern Brazil. Results showed that neutral detergent fiber was similar for all cultivars and averaged 249 g · kg-1 ± 7.3 SEM. Acid detergent fiber ranged between 148 g · kg-1 and 207 g · kg-1 with some significant differences between cultivars. Starch and water-soluble carbohydrates were similar for all cultivars and averaged 198 g · kg-1 ± 6.3 SEM and 155 g · kg-1 ± 9.0 SEM, respectively. Protein content was less than 50 g · kg-1 with some significant differences between cultivars. Calcium was the mineral with the highest concentration followed by potassium and magnesium with no differences between cultivars. Effective ruminal degradability of dry matter and neutral detergent fiber were unaffected by cultivar and averaged 701 g · kg-1 ± 8.4 SEM and 503 g · kg-1 ± 5.8 SEM, respectively. It was concluded that cultivars had little impact on chemical composition and ruminal degradability of spineless cactus. Based on chemical composition and in situ ruminal degradability, spineless cactus can be considered an excellent source of fermentable carbohydrates for grazing and nongrazing ruminants. Because of its high carbohydrate quality, spineless cactus can be used an emergency feed or as part of a complete diet providing that the diet contains an adequate amount of degradable protein. Se llevó a cabo un estudio para determinar la composición química y la degradación de nutrientes a nivel ruminal de ocho especies de cactus sin espinas producidas en el Noreste de Brazil. Los resultados demuestran que la fibra neutro detergente fue similar para todas la variedades con un promedio de 249 ± 7.3 g · kg-1. La fibra ácido detergente presentó un rango de 148 a 207 g · kg-1 con algunas diferencias significativas entre especies. El almidón y los carbohidratos solubles en agua fueron también similares para todas las variedades con un promedio de 198 ± 6.3 y 155 ± 9.0 g · kg-1, respectivamente. El contenido de proteína fue menor que 50 g · kg-1 con algunas diferencias significativas entre variedades. Calcio fue el mineral con las concentraciones más altas seguidas por K y Mg sin encontrar diferencias entre especies. La degradación ruminal efectiva tanto de la materia seca como de la fibra neutra detergente no fueron afectados por las especies y tuvieron un promedio de 701 ± 8.4 y 503 ± 5.8 g · kg-1, respectivamente. Se puede concluir que las especies tienen poco impacto en la composición química y la degradación ruminal de los cactus sin espinas. Basándose en la composición química y la degradabilidad ruminal in situ, los cactus sin espinas pueden considerarse como una fuente excelente de carbohidratos fermentables para rumiantes tanto en pastoreo como en no-pastoreo. Debido a la alta calidad de carbohidratos los cactus sin espinas pueden utilizarse como un alimento de emergencia o como parte de una dieta completa cuando esa dieta contiene una cantidad adecuada de proteína degradable.

Urinary calcium excretion in non-lactating dairy cows in relation to intake of fat-coated rice bran

At calving, many older cows fail to compensate the sudden demand of calcium by an adequate activation of intestinal absorption. This results in a variable degree of hypocalcaemia. Reducing intestinal availability of calcium during the close-up period can prevent milk fever. Fat-coated rice bran (FCRB) was investigated for its potential to reduce Ca availability in pre-calving cows. Fat-coated rice bran was incubated in situ to estimate ruminal degradation of dry matter and phytic acid. Also, seven dry multiparous dairy cows were used for a feeding trial in three periods of approximately 1 week each: P1: adaptation; P2: feeding of 2 kg of FCRB and P3: withdrawal of FCRB. Feed intake was recorded and daily urine samples were analysed for pH, Ca and creatinine. The bypass fraction of phytic acid (passage rate: 5%/h) was 30%. Fat-coated rice bran depressed dry matter intake in P2, resulting in a lower Ca intake. In P2 urine pH and calcium excretion were lower. Daily calcium excretion decreased after introduction of FCRB, peaked after withdrawal and dropped 2 days later. Changes in urinary Ca excretion by feeding FCRB indicate that FCRB affected Ca homeostasis in dry multiparous dairy cows.

Effects of purified condensed tannins extracted from Calliandra, Flemingia and Leucaena on ruminal and postruminal degradation of soybean meal as estimated in vitro

Purified condensed tannins (CT) extracted from the legumes Calliandra calothyrsus (var. San Ramón CIAT 22310 and var. Patulul CIAT 22316), Flemingia macrophylla (CIAT 17403) and Leucaena leucocephala (CIAT 734) were added to soybean meal in proportions of 0 (control), 300, 600 or 900 mg/g of the incubated crude protein (CP). Effects on degradation in ruminal fluid and ruminal fluid followed by incubation in HCl/pepsin were evaluated using a modified two-step in vitro method. When CT were added, dry matter (DM) and CP degradation in ruminal fluid were reduced (P<0.001). With the highest concentration of CT (i.e., 900 mg/g CP), ruminal DM degradation was reduced to 30% of the CT-free control. There was a 25–63% reduction in CP degradation in the rumen due to the addition of CT. The extent of the effect was dependent on the CT source (P<0.001). Depending on CT source, an increase in CT concentration also reduced (P<0.001) total DM and CP degradation (ruminal fluid+HCl/pepsin) by 24–73% and 16–55%, respectively. The proportion of incubated CP which was not degraded in ruminal fluid (estimated rumen escape CP) but degraded in HCl/pepsin increased by 18 and 412% depending on CT source and CT concentration (P<0.001). The highest increase was observed with CT from C. calothyrsus and the lowest with CT from L. leucocephala. HCl/pepsin degradability of rumen escape CP was also reduced with CT addition by 10 and 82% depending on CT concentration and source (P<0.001). In ruminal fluid, CT from L. leucocephala seemed to have less effect on degradation of soybean meal than CT from F. macrophylla and C. calothyrsus. In contrast, when HCl/pepsin was added to soybean meal, the complexes formed between CP and CT from L. leucocephala were more resistant to degradation than those formed with the other CT. This suggests that CT from L. leucocephala were less effective in increasing degradable rumen escape CP than CT from either C. calothyrsus or F. macrophylla.

The effect of glucose treatment on ruminal dry matter and crude protein degradability characteristics of soybean meal, full fat soybean and soybean seed

A high ruminal protein degradation is especially undesirable in high producing dairy cows and beef cattle, since these animals have high requirements of protein and the amount of protein that is not degraded by ruminal microorganisms and therefore enters the small intestine (so-called UDP = undegraded protein) is crucial. In this study, Merino rams with ruminal fistulas were used (n = 4) to determine the effect of glucose treatment of soybean meal (SBM), full fat soybean (FFSB) and soybean seed (SBS) on the ruminal degradability of dry matter (DM) and crude protein (CP). All these feedstuffs were grinded, diluted with water and heated (2 h; 100 degrees C) either without or with supplementation of 2 or 3% glucose (20 or 30 g glucose per kg dry feed). For the determination of the ruminal degradability nylon bag technique was used (incubation times: 2-48 h). In general ruminal degradability of protein in all three soy products was reduced by glucose treatment. In FFSB CP disappearance started to decrease after 8 h of incubation, whereas in SBM (+ 3% glucose) and SBS (+ 2 or 3% glucose) reduction of CP disappearance were time-independent. Further, effective degradability (Pe) of DM and CP of all feedstuffs were significantly reduced by glucose treatment, with the reduction being more pronounced when the glucose level was increased. When adding 3% of glucose, the Pe for CP was reduced by 6 (FFSB), 16 (SBM) and 18% (SBS), respectively. Explanation for the observed effects of a glucose supplementation (incl. water and heat treatment) is the reductive activity of glucose within these conditions.

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