True OM Digestibility Research Articles

In vitro evaluation of paddy straw based complete feed pellets as livestock feed

This study was taken up to find out if paddy straw (PS) based complete feed pellets (CFPs) could be prepared by using guar gum as a binder in place of molasses and to assess in vitro nutritional worth as livestock feed. The 8 mm CFPs contained roughage to concentrate ratio of 55:45. The roughage portion was made up of PS and alfalfa hay. With the increase in PS level from 15 to 30%, the level of alfalfa hay was reduced from 40 to 25%. The CFPs were prepared successfully and contained 14.35 to 17.4% CP and 2.99 to 3.31% EE. The bulk density varied between 580.28 to 603.57 kg/m3. With the increase in PS in the CFPs, the NDF and cellulose content increased and CP content decreased linearly. The NGP, true OM digestibility and partitioning factor were not affected by the level of PS in the CFPs. The NDF digestibility increased, while ammonia production and ME availability decreased with the increase in PS level in CFPs. The total and individual VFAs concentration decreased with the increase in PS in CFPs. The relative proportion of propionate and that of isovalerate were improved with the increase in PS in CFPs. The efficiency of rumen fermentation, efficiency of conversion of fermented hexose energy to VFA energy and efficiency of conversion of fermented hexose energy to methane energy declined with the increase in the level of PS in CFPs, resulting in depressed microbial biomass production. It was concluded that CFPs containing graded levels of PS can be developed successfully. However,the efficiency of nutrient utilization, VFA production and microbial biomass production declined at higher levels of PS in CFPs.

In vitro evaluation of paddy straw based complete feed pellets as livestock feed

This study was taken up to find out if paddy straw (PS) based complete feed pellets (CFPs) could be prepared by using guar gum as a binder in place of molasses and to assess in vitro nutritional worth as livestock feed. The 8 mm CFPs contained roughage to concentrate ratio of 55:45. The roughage portion was made up of PS and alfalfa hay. With the increase in PS level from 15 to 30%, the level of alfalfa hay was reduced from 40 to 25%. The CFPs were prepared successfully and contained 14.35 to 17.4% CP and 2.99 to 3.31% EE. The bulk density varied between 580.28 to 603.57 kg/m3. With the increase in PS in the CFPs, the NDF and cellulose content increased and CP content decreased linearly. The NGP, true OM digestibility and partitioning factor were not affected by the level of PS in the CFPs. The NDF digestibility increased, while ammonia production and ME availability decreased with the increase in PS level in CFPs. The total and individual VFAs concentration decreased with the increase in PS in CFPs. The relative proportion of propionate and that of isovalerate were improved with the increase in PS in CFPs. The efficiency of rumen fermentation, efficiency of conversion of fermented hexose energy to VFA energy and efficiency of conversion of fermented hexose energy to methane energy declined with the increase in the level of PS in CFPs, resulting in depressed microbial biomass production. It was concluded that CFPs containing graded levels of PS can be developed successfully. However,the efficiency of nutrient utilization, VFA production and microbial biomass production declined at higher levels of PS in CFPs.

In vitro evaluation of short duration cassava varieties as livestock feed

This study was taken up to assess the nutritional value of short duration cassava varieties, Sree Jaya (V1), Sree Vijaya (V2) and Vellayani Hraswa (V3). The tuber, stem and leaves of above varieties were evaluated by in vitro gas production technique in a 3×3 factorial design. The tuber yield was the highest in V3 variety, followed by that in V1 and the lowest yield was observed in V2 variety. Irrespective of cassava variety, the total ash, CP, EE and ADL content was highest in leaves. The other cell wall contents were highest in stem portion. Irrespective of the part of plant, the CP and hemicellulose contents were highest in V3. The NDF and ADF content was highest in V1. The protein fractionation revealed that the albumin in V1 was higher than that in V2 but comparable with that of V3. The globulin in V1 was higher than V3. Reverse trend was observed in case of prolamins. Irrespective of cassava variety, the net gas production (NGP), NDF and true OM digestibility, ME content, methane emission, total and individual VFAs production, fermentation efficiency and efficiency of conversion of fermented hexose energy to VFA energy were highest in cassava tubers followed by stem and lowest was observed in leaves. These parameters were not affected by cassava variety, except that ME was the highest and methane emission was the lowest in V3. It was concluded that Vellayani Hraswa variety and amongst different parts of cassava plant, tubers irrespective of cassava variety were observed to be highly nutritious.

Preparation of paddy straw based complete feed pellets and their impact on the performance of buffalo calves

This study was planned to prepare paddy straw based complete feed pellets and to assess their impact on the performance of buffalo calves. Iso-nitrogenous and isocaloric complete feed pellets containing 25, 35 and 45% paddy straw, alfalfa hay and concentrate mixtures were prepared. The roughage to concentrate ratio in the pellets was maintained at 65:35. The CP, EE and cell wall contents in all pellets were comparable. The bulk density of complete feed pellets increased (p<0.05) with the increase in paddy straw level. The in vitro studies revealed that NGP, true OM digestibility and ME content decreased linearly with the increase in paddy straw level from 25 to 45% in the pellets. The 104 days growth trial on buffalo calves revealed that the daily DM intake, digestibility of most of nutrients and N-retention decreased (P<0.05) linearly with the increase in level of paddy straw in buffalo calves fed complete feed pellets. The rumen studies revealed that total VFAs, acetate, propionate and isovalerate production; and microbial biomass synthesis was the highest in calves fed pellets containing 35% paddy straw, statistically comparable with those fed pellets containing 25% paddy straw. But these parameters were depressed (P<0.05) in animals fed pellets containing 45% paddy straw. It can be concluded that isonitrogenous and iso-caloric complete feed pellets containing paddy straw up to 35% can be utilized effectively without affecting the health and performance of buffalo calves.

Paddy Straw Pelletization with other Feedstuffs and its In Vitro Evaluation as Livestock Feed

This study was taken up to pelletize paddy straw with other feedstuffs and to assess up to what extent paddy straw can be incorporated in such pellets and their nutritional evaluation by in vitro gas production technique. The sundried paddy straw and alfalfa hay were ground in a hammer mill and lifted in a bucket elevator to the mixer where these feedstuffs were mixed with rice bran and molasses and pellets were prepared in pellet mill fitted with 8mm stationary die. Pellets containing paddy straw up to 90% were prepared successfully, but beyond 60% paddy straw there was excessive load on the machine and supporting motor. Therefore, pellets containing paddy straw up to 60% were evaluated by in vitro gas production technique. With the increase in the level of paddy straw in pellets, the ash and ADF content increased linearly (P<0.01), while OM, CP, and EE contents decreased (P<0.01). The NDF, hemicellulose and cellulose contents remained similar up to 30% paddy straw in the pellets; thereafter these constituents increased (P<0.01) linearly. Compared to pellets without paddy straw (control), the total ash, NDF, ADF and cellulose content increased by 19.5, 29.5, 31.6 and 35.8% in pellets containing 60% paddy straw. The bulk density of paddy straw-based pellets varied between 560.33 to 655.35 kg/m3, and it increased with the increase in paddy straw level and was highest (P<0.01) in pellets containing 60% rice straw. The in vitro fermentation of pellets resulted in a linear decrease (P<0.01) in net gas production (NGP), true OM digestibility and availability of ME with the increase in the level of paddy straw in the pellets. However, the partitioning factor and ammonia concentration increased (P<0.01). The results revealed that total VFA production in control pellets was comparable to those containing paddy straw up to 30%, but decreased (P<0.05) in pellets containing paddy straw at 45 and 60% levels. The individual VFA production was not affected by the level of paddy straw, except that of acetate, which was depressed (P<0.05) in pellets containing more than 15% paddy straw. The microbial biomass synthesis decreased (P<0.05) with the increase in the level of paddy straw in pellets. The pellets containing 70, 80 or 90% paddy straw cannot be fed exclusively to any category of ruminants because of very low CP and EE content and do not meet the recommended levels of these nutrients in the complete feed of low yielders. It was concluded that paddy straw could be pelletized successfully; best results on net gas production, digestibility of nutrients, VFA production, microbial biomass production and ME were obtained in pellets containing paddy straw up to 30%.

In vitro evaluation of kinnow waste as substitute of cereal grains in the concentrate mixture and empty pea pods as that of berseem hay in total mixed ration for livestock

This study was taken up to assess the extent to which kinnow mandarin (Citrus reticulata) waste (KW) could substitute cereal grains in the concentrate mixture and empty pea (Pisum sativum) pods (EPPs) as that of berseem (Trifolium alexandrium) hay in total mixed ration (TMR) for livestock. In the first experiment, sundried finely ground kinnow waste replaced barley grains on N basis at 0, 25, 50, 75 and 100% levels in concentrate mixtures. The comparable N-content indicated that the concentrate mixtures were iso-nitrogenous. The EE and cell wall constituents (CWC) increased linearly with the increase in level of KW. The replacement of barley with KW did not affect net gas production (NGP), true OM digestibility and ME availability up to 50% level of replacement. Total and individual volatile fatty acids (VFAs) and microbial biomass production improved up to 50% level of replacement but declined thereafter. In the second experiment, sundried finely ground EPPs replaced berseem hay on N basis at 0, 25, 50, 75 and 100% levels in TMR. The EE and CWCs content was not affected up to 50% level but thereafter EE content decreased, whereas CWCs content increased. The NGP, digestibility of true DM and OM, VFAs production, ME availability and microbial biomass synthesis improved up to 50% level of replacement of berseem hay with EPPs, thereafter it declined. The hydrogen recovery, hydrogen consumption and fermentation efficiency were not affected upto 50% level of EPPs but at higher levels these parameters were depressed. Therefore, KW could replace barley grains in concentrate mixture while EPPs could replace berseem hay in TMR up to 50% level without affecting nutrient utilization, VFA production, ME availability and microbial biomass production under in vitro conditions.

390 Effects of dietary-induced pH changes on feed digestion, nitrogen metabolism, fermentation, and biohydrogenation of polyunsaturated fatty acids in dual-flow continuous culture fermenters

Abstract Ruminal pH decreases as greater concentrations of grain are consumed, and as a result, reduces biohydrogenation of polyunsaturated fatty-acids. Our objective was to investigate effects of diet on pH and biohydrogenation activity in vitro. Eight dual-flow, continuous culture fermenters were blocked by side of the room and randomly assigned, within block, to 1 of 4 treatments. Treatments consisted of 100:0 roughage-to-concentrate (Grass), 50:50 roughage-to-concentrate plus flax oil supplement (Mix+F), 10:90 roughage-to-concentrate plus corn oil supplement (Con+C), or 10:90 roughage-to-concentrate plus flax oil supplement (Con+F). Fermenter pH, area under the curve, and maximum pH were lowest for Con+C and Con+F (P &amp;lt; 0.05). Apparent and true DM, OM, and NDF digestibility were greater with grain inclusion (P &amp;lt; 0.05) while ADF digestibility was not affected by treatment (P &amp;gt; 0.10). Protein degradation was lowered as grain inclusion increased (P &amp;lt; 0.05). Total VFA concentrations were lowest for Grass, highest for Con+C and Con+F, and intermediate for Mix+F (P &amp;lt; 0.05). Acetate-to-propionate was lowest for Con treatments (P &amp;lt; 0.05). Biohydrogenation of 18:2n-6 and 18:3n-3 fatty-acids were reduced (P &amp;lt; 0.01) with inclusion of concentrate regardless of roughage-to-concentrate ratio. Concentrations of stearic acid recovered from effluent were greatest for Grass, intermediate for Mix+F, and lowest for both Con+C and Con+F (P &amp;lt; 0.05). Linoleic acid proportions in effluent were greatest for Con+C and Con+F and intermediate for Mix+F (P &amp;lt; 0.05), and inclusion of concentrate, regardless of amount, increased the amount linoleic acid recovered from fermenter overflow (P &amp;lt; 0.01). Between Con+C and Con+F concentrations of alpha-linolenic acid (ALA) was greater when flax oil was supplemented (P &amp;lt; 0.01). Proportions of ALA in effluent was similar (P &amp;gt; 0.10) between Grass and Con+C; however, between Mix+F and Con+F ALA concentrations tended (P = 0.06) to be greater for Con+F. Omega6-to-omega3 ratios were similar across Grass, Mix+F, and Con+F (P &amp;gt; 0.10) and greatest for Con+C (P &amp;lt; 0.05).

In vitro Digestibility, In situ Degradability, Rumen Fermentation and N Metabolism of Camelina Co-Products for Beef Cattle Studied with A Dual Flow Continuous Culture System of Camelina Co-Products for Beef Cattle.

Simple SummaryCurrently, vegetable protein sources such as soybean meal and rapeseed meal are expensive and with volatile prices. These economic circumstances are driving the research of potential new protein resources for beef cattle diets that can reduce the ration cost without compromising animal productive yields. As possible candidates, camelina meal and camelina expeller have been studied; they are co-products with a high protein percentage, obtained after oil extraction from the oil seeds of Camelina sativa. The objectives of this study were to characterize these camelina co-products and ascertain if they could be useful ingredients for beef cattle diets. The results indicate that the diets formulated with camelina meal and camelina expeller do not show differences in the efficiency of microbial protein synthesis compared to the current reference proteins, camelina meal diet being the most similar to soybean meal and rapeseed meal diets, and camelina expeller the diet with the highest fermentation potential. The results of soybean meal as an individual ingredient reveal more differences with camelina co-products. In vivo studies are necessary to draw conclusions, but in vitro results obtained suggest that camelina meal and camelina expeller are potential substitutes for rapeseed meal in beef cattle diets.Camelina meal (CM) and camelina expeller (CE) were compared with soybean meal (SM) and rapeseed meal (RM). Trial 1 consisted of a modified Tilley and Terry in vitro technique. Trial 2 was an in situ technique performed by incubating nylon bags within cannulated cows. Trial 3 consisted in dual-flow continuous culture fermenters. In Trial 1, CM, CE and RM showed similar DM digestibility and OM digestibility, and SM was the most digestible ingredient (p < 0.05). Trial 2 showed that CE had the numerically highest DM degradability, but CP degradability was similar to RM. Camelina meal had a DM degradability similar to SM and RM and had an intermediate coefficient of CP degradability. In Trial 3, CE diet tended to present a higher true OM digestibility than SM diet (p = 0.06). Total volatile fatty acids (VFA) was higher in CE and CM diets than in SM diet (p = 0.009). Crude protein degradation tended to be higher (p = 0.07), and dietary nitrogen flow tended to be lower (p = 0.06) in CE diet than in CM diet. The efficiency of microbial protein synthesis was not affected by treatment (p > 0.05). In conclusion, CE and CM as protein sources differ in CP coefficient of degradability but their results were similar to RM. More differences were detected with regard to SM.

Effect of supplementation of Kappaphycus alvarezii based seaweed product on rumen fermentation parameters under in vitro conditions

In vitro trials were conducted to study the effect of supplementation of different levels (0, 0.5, 1.0, 1.5, 2.0, 2.5 and 3.0%) of K. alvarezii based seaweed product ( K. Alvarezii powder: Gracilaria salicornia powder : K. alvarezii sap powder in 1: 1: 1 ratio) to basal substrate on digestibility and rumen fermentation parameters. The results showed that supplementation of different levels (0, 0.5, 1.0, 1.5, 2.0, 2.5 and 3.0%) of K. alvarezii based seaweed product to the basal substrate (sugargraze fodder and concentrate mixture in 60: 40 ratio) did not affect in vitro true DM and OM digestibility, total gas production, methane production, ammonia-N, microbial biomass production and metabolisable energy values to any significant extent.

Comparison of warm season and cool season forages for dairy grazing systems in continuous culture.

The objective of this study was to compare warm-season annual grasses to cool-season perennial (CSP) grasses for ruminal nutrient digestibility and N metabolism in a dual-flow continuous culture fermentation system. Dietary treatments were 1) fresh alfalfa, 2) CSP grasses and legumes, 3) brown-midrib sorghum-sudangrass (BMRSS), and 4) teff grass from an organic dairy production system. Eight dual-flow continuous culture fermenters were used during two consecutive 10-d periods consisting of 7 d for stabilization followed by 3 d of sampling. Fermenter samples were collected on days 8, 9, and 10 for analysis of pH, NH3-N, and VFA. Apparent DM, OM, NDF, and ADF digestibility were on average lesser (P < 0.05) in CSP grasses and legumes and warm-season annual grasses compared with alfalfa. True DM and OM digestibility were lesser (P < 0.05) for CSP grasses and legumes and warm-season annual grasses compared with fresh alfalfa. Total VFA were not affected (P > 0.05) by forage. The NH3-N concentrations were highest (P < 0.05) with alfalfa compared with the other CSP grasses and legumes and warm-season annual grasses. CP digestibility was not affected (P > 0.05) by forage treatment. Flow of NH3-N was greatest (P < 0.05) for alfalfa, reflecting the greatest NH3-N concentration. Flow of total N was greatest (P < 0.05) for alfalfa, intermediate for teff, and lowest for CSP grasses and legumes and BMRSS. Flows of bacterial N, efficiency of bacterial N, non-NH3-N, and dietary N were not affected (P > 0.05) by forage source. Overall, fermentation of warm-season grasses was similar to the cool-season grasses and legumes which indicate dairy producers may use warm-season grasses without concerns about negative impact on rumen health.

Effects of bismuth subsalicylate and dietary sulfur level on fermentation by ruminal microbes in continuous culture.

In ruminants, excess dietary sulfur can be associated with a reduction in DM intake, poor feedlot performance and sulfur-associated polioencephalomalacia. Bismuth subsalicylate (BSS) has been shown to decrease hydrogen sulfide in vitro. The objective of this experiment was to evaluate effects of BSS inclusion (0 or 0.5% of diet DM) and dietary sulfur (0.21 or 0.42% of diet DM) on microbial fermentation in continuous culture. Treatments were arranged in a 2 × 2 factorial design. Eight dual-flow continuous culture fermenters were used during 2 consecutive 10-d periods consisting of 7 d for stabilization followed by 3 d of sampling. A pelleted feedlot diet containing 39% dry rolled corn, 32% earlage, 21% wet distillers grains, 3.2% corn silage, 1.5% soybean meal, 0.6% urea and 2.7% mineral premix (DM basis) was provided as substrate for microbes at a rate of 75 g of DM × fermenter–1 × d–1. Effluents from sampling days were composited by fermenter within period, resulting in 4 replicates/treatment. Bismuth subsalicylate inclusion decreased (P < 0.01) true OM digestion, while no effects were observed for NDF and ADF digestion. Total VFA concentrations, molar proportions of acetic, propionic, and branched-chained VFA decreased (P < 0.01) with BSS addition. The ratio of acetic to propionic acid and the molar proportion of butyric acid increased (P < 0.01) with BSS addition. In regard to nitrogen metabolism, BSS increased NH3–N concentration, NH3–N and dietary-N flows (P < 0.01), and decreased non-NH3–N flow, microbial-N flow, CP degradation, and efficiency of microbial protein synthesis (P < 0.01). Inclusion of BSS increased mean, minimum, and maximum fermentation pH (P < 0.01). Amount of dietary sulfur and BSS inclusion influenced flows of amino acids and fatty acids from fermenters. Influences on fatty acid biohydrogenation and amino acid flows demonstrated an overall suppression of microbial fermentation. Results from this experiment indicate that BSS inclusion at 0.5% of diet DM has detrimental effects on in vitro rumen fermentation in continuous culture.

Effect of dried fermentation biomass on microbial fermentation in continuous culture and in vitro intestinal digestibility

The objective of the current experiment was to determine if fermentation biomass (FB), a dried bacterial by-product derived from lysine production (Ajinomoto Heartland, Inc.) can be used as a protein source in ruminant diets. Eight dual-flow continuous culture fermenters were inoculated with rumen fluid and used during one experimental period consisting of a 7-d adaptation period followed by 3 sampling days. Microbial substrate was provided by one of two isonitrogenous diets, CON or DFB. In CON, soybean meal (SBM) provided 57% of total CP, and in DFB, SBM and FB provided 12 and 45% of total CP, respectively. CON contained 3% molasses, 16% ground corn, 13% grass hay, 48% corn silage, and 20% SBM on a DM basis; DFB contained 3% molasses, 18.4% ground corn, 13% grass hay, 50% corn silage, 8.5% SBM, and 6.7% FB. On sampling days, liquid and solid effluent were collected, combined, and homogenized to be used for chemical analysis and in vitro estimation of intestinal digestibility (ID). Treatment did not affect average, maximum, or minimum fermenter pH. There was no effect on apparent or true OM, NDF, or ADF digestibility (%). Total and branched-chain VFA as well as acetate (mM) were higher in CON, and isobutyrate concentration (mol/100mol) tended to increase with CON treatment. Source of N had no effect on total, dietary, or bacterial-N flows. Addition of FB decreased NH3-N flow from 0.4 to 0.2±0.05g/d and tended to decrease effluent NH3-N concentration from 17.1 to 9.7±2.21mg/100mL. His and Met flows increased from 0.48 to 0.53±0.012 and 0.18–0.20±0.005g/d, respectively, when FB partially replaced SBM in the diet, but there were no effects on other AA or total AA flows. There was a trend in percent non-essential AA input (CON=73.6% vs. DFB=82.2%; SE=2.83) in effluent; however, there was no effect on percent of essential or total AA input in effluent. Effluent from the DFB treatment was higher in ID than CON (CON=70.4% vs. DFB=79.6%; SE=1.64), although there was no difference in estimated amount of protein available for intestinal absorption (g). These results indicate that FB elicited a similar response in N metabolism and AA flows to SBM but had a greater estimated ID and depressed VFA production, and has potential use as a protein source in ruminant diets.

Effect of pH on in vitro microbial fermentation and nutrient flow in diets containing barley straw or non-forage fiber sources

Roughage in beef diets could be reduced or removed if replaced with less costly non-forage fiber sources, but there is little information about their effects on microbial fermentation and nutrient flow in different ruminal conditions. In the present experiment, eight dual-flow continuous culture fermenters (1320ml) were used in three periods (5 days adaptation, 3 days sampling) to study the effect of pH and different sources of non-forage fiber in beef diets on rumen microbial fermentation. In each period, fermenters were randomly assigned to treatments. Temperature (39°C), solid (0.05h−1) and liquid (0.10h−1) dilution rates were maintained constant. Fermenters were fed 97g of DM/day in three equal portions. A factorial arrangement of treatments was used, the factors being the culture pH (5.5 and 6.2) and the main fiber source in the diet: barley straw (BS; 100g/kg DM), beet pulp (BP; 170g/kg DM), soybean hulls (SH; 170g/kg DM) and whole cottonseed (WCS; 160g/kg DM). Diets were formulated to have similar crude protein (150g/kg DM), metabolizable energy (2.95Mcal/kg of DM) and NFC level (550g/kg DM). Low pH (5.5) reduced apparent DM and OM digestibility, total and branched chained volatile fatty acid concentrations, and acetate proportion, and increased propionate proportions, as expected. Replacement of BS with BP and SH increased OM, aNDF and ADF digestibility. An interaction diet×pH was detected for aNDF and ADF digestibility because the level of reduction in fiber digestibility at low pH was different among diets. Total volatile fatty acid concentration was lower in BS than in BP, SH and WCS and acetate proportion was higher in BP compared with WCS (50.3 vs 44.4mol/100mol). Low pH decreased NH3-N concentration (2.24 vs 4.10mg/100ml) and increased non-ammonia N flow (2.77 vs 2.70g/day) compared with high pH. There were no differences among treatments in the flow of bacterial N and the efficiency of microbial protein synthesis. These results suggest that the effect of low pH on fiber and true OM digestibility was different among fiber sources. Replacing straw with non-forage fiber had no detrimental effects on in vitro fermentation, suggesting that these sources could be potentially useful in beef diets. However, many important differences exist between in vitro and in vivo experiments, which can influence the digestion and fermentation processes, so data need to be interpreted with the understanding of the nature and limitations of the technique used.

RUMINANT NUTRITION SYMPOSIUM: The utility of lipid extracted algae as a protein source in forage or starch-based ruminant diets1,2

Two experiments were conducted to determine the influence of lipid extracted algae (LEA) on OM digestibility, N flow, and rumen fermentation. Six samples of LEA were evaluated representing 2 genus of microalgae (Nannochloropsis spp. [n = 3] or Chlorella spp. [n = 3]). Four dual-flow continuous flow fermenters (2,700 mL) were used in a Latin square design to evaluate LEA in forage or concentrate diets compared with soybean meal. Temperature (39 °C), pH, solid (5%/h) and liquid (10%/h) dilution rates, and feed schedule were maintained constant for all experiments. Each experimental period consisted of 6-d adaptation and 4-d sampling periods. There were 7 treatments consisting of 6 different samples of LEA and a soybean meal control (SOY). Diets for Exp.1 were formulated to be 13.0% CP (DM basis) using either soybean meal or LEA and met or exceeded the requirements of a nonpregnant and nonlactating beef cow (450 kg). The forage portion consisted of sorghum-sudan hay (6.4% CP and 46.2% TDN, DM basis) and alfalfa (26.1% CP and 82.3% TDN, DM basis). Concentrate diets used in Exp. 2 met or exceeded the nutrient requirements of a (400 kg) growing steer and contained 85% fine ground corn and included 7% (DM basis) soybean meal or LEA. Data were analyzed as mixed model considering the effect of each LEA compared with soybean meal. Orthogonal contrasts were used to determine the overall effect of LEA genus vs. SOY. True OM digestibility were not influenced by LEA addition to forage diets (P ≥ 0.08) but increased with Chlorella LEA addition to concentrate diets (P < 0.01) but not Nannochloropsis LEA. Degradation of N was greater for SOY with forage diets and LEA for concentrate diets (P < 0.0001). Total VFA production was greatest for SOY in forage diets and increased when LEA was added to concentrate diets (P < 0.0001). Microbial efficiency did not differ between SOY and LEA in forage diets (P ≤ 0.08). In concentrate diets Nannochloropsis decreased microbial efficiency (P < 0.01). Microbial efficiency results for Chlorella were more variable for Nannochloropsis with 1 Chlorella spp. increasing microbial efficiency by 36% over SOY (P < 0.05) and the other Chlorella spp. decreasing microbial efficiency by approximately 42% compared with SOY (P < 0.01). Overall, the results from both experiments are promising for LEA as a protein feedstuff in ruminant diets. Further research is necessary to fully understand the interactions and consequences of upstream processes and what role algal strain plays in LEA quality.

Effects of glycerin on receiving performance and health status of beef steers and nutrient digestibility and rumen fermentation characteristics of growing steers1

One experiment was conducted to evaluate the influence of glycerin (GLY) on animal performance and health when used as a partial replacement for roughage in receiving diets. The second experiment was conducted using ruminally and duodenally cannulated steers in a 4 × 4 Latin square to determine the site of nutrient digestion and ruminal fermentation characteristics when GLY replaced roughage at 0%, 2.5%, 5%, and 10% of diet DM. In Exp. 1, steers (initial BW = 245 ± 2.3 kg) were fed treatment diets over a 42-d period that consisted of a control diet based on steam-flaked corn with GLY inclusion in replacement of dietary roughage at 0%, 5%, and 10% of diet DM. A linear reduction in DMI was observed as GLY increased (P = 0.01). Glycerin incorporation tended to improve G:F in a linear manner (P = 0.07); efficiency was improved 5.4% and 4.7% at 5% and 10% GLY. The number of animals receiving treatment for bovine respiratory disease did not differ among treatments. Furthermore, there were no differences among treatments for mortality or the frequency of steers that were seropositive for serum antibody titers to infectious bovine rhinotracheitis on d 28. In Exp. 2, apparent OM and apparent and true starch digestibility increased linearly (P < 0.05) as GLY concentration increased, whereas true OM digestibility responded in a quadratic (P < 0.01) manner. Bacterial OM and bacterial starch flow responded quadratically (P ≤ 0.02), and flow increased from 0% to 5% GLY inclusion and decreased thereafter. Feed OM flow responded quadratically (P ≤ 0.05), where it decreased from 0% to 2.5% GLY and increased from 2.5% to 10% GLY inclusion. Feed starch (P = 0.02) and total starch (P = 0.02) flow from the duodenum decreased linearly as the concentration of GLY increased in the diet. Bacterial N flow to the duodenum responded quadratically (P < 0.01); it increased with increasing GLY in the diet up to 5% and then decreased from 5% to 10%. The acetate to propionate (A:P) ratio in the ruminal fluid decreased (P < 0.05) as the concentration of GLY in the diet increased, which could have implications on improved G:F. The decrease in the A:P ratio as GLY increased in the diet, coupled with the linear decrease in DMI and improvement in G:F with GLY addition up to 5% of DM in place of roughage, implies that GLY is a viable dietary ingredient in growing and receiving diets.

Nutritional evaluation of baby corn husk — A new feed resource for livestock

This study was taken up to assess the nutritional worth of baby corn husk (BCH) for ruminants. Fresh chaffed BCH, or BCH wilted for 2–3 days and ensiled for 42 days or fresh BCH mixed with chaffed rice straw in 70: 30 ratio (BCH- RS) and ensiled for 42 days in lab silos in triplicate. The in-vitro gas production studies revealed that the net gas production (NGP), NDF and true OM digestibility, and ME availability was highest in BCH followed by that in ensiled BCH and lowest in ensiled BCH-RS. The methane production as per cent of net gas production was also lowest in BCH and highest in ensiled BCH-RS. The total and individual volatile fatty acid production was highest BCH, statistically, comparable with that of ensiled BCH but higher than BCH-RS silage. The relative proportion of individual volatile fatty acid was comparable in all the groups. For in vivo evaluation, 10 male Murrah buffalo calves divided into 2 equal groups were offered ad lib. either chaffed conventional green maize fodder or fresh chaffed BCH with daily supplementation of 25g mineral mixer and common salt for 30 days. The daily DM intake was significantly higher in buffalo calves fed conventional green fodder as compared to chaffed BCH. The digestibility of all the nutrients was higher in fresh BCH as compared to green maize fodder. The N-retained and apparent biological valve of protein was high in fresh BCH as compared to green maize fed group, but the differences were statistically nonsignificant. The calves offered BCH as compared to those offered green maize had higher total-N, TCA-N but slightly lower TVFAs. In another in vivo trial, the digestibility of nutrients and N-retention were considerably higher in 5 male Murrah buffalo calves offered concentrate mixture, ensiled BCH and wheat straw in 40: 30: 30 ratio on DM basis as total mixed ration (TMR) as compared to those offered fresh BCH. The higher digestibility of nutrient, N-retention, apparent biological valve and favourable rumen environment conclusively revealed that fresh or ensiled BCH was highly acceptable and palatable as compared to conventional maize fodder.

Effect of milk by-products on forage in vitro fermentation by ruminal microflora

ABSTRACT The effect of milk-based by-products containing lactose and sucrose on alfalfa (ALF) and tall fescue (TF) hay fermentation by ruminal microflora was studied using a single-flow, continuous-culture and batch-culture procedure. Continuous-culture fermentation used only ALF as a forage source and tested buttermilk (BM) and ice cream by-product with cone (ICBPWC). Levels of by-products were 0, 50, and 100% of total DM. For the batch-culture experiment (n = 5) 5 levels of ALF or TF (0, 10, 20, 50, and 75% of DM) were combined with BM, ICBPWC, or ice cream by-product without cone (ICBP). In continuous culture, addition of BM increased apparent OM digestibility and true OM digestibility linearly (P 0.05). The addition of ICBPWC quadratically decreased (P

Relationship Between Supplemental Protein and Ruminal Fermentation of an Orchardgrass-Based Herbage Diet

Even though many vegetative, cool-season pastures contain more than 25% CP on a DM basis, lactating dairy cows are commonly overfed supplemental protein while grazing. A dual-flow continuous culture fermenter system was used to assess the effect of supplemental CP on ruminal fermentation of an orchardgrass (Dactylis glomerata L.) herbage diet. Treatments were 30 g DM of a 16, 14, 12, and 10% CP (corn- and soybean-based) supplement plus 45 g DM of herbage. Fermenters were sampled for pH, NH3-N, and VFA 4 times daily at feeding (0700, 1030, 1430, and 2030 h). Effluents were analyzed for DM, CP, NDF, OM, nonstructural carbohydrates (NSC), purine concentration, and bacterial production. The DM, OM, NSC, and CP digestibility values were calculated. Neither NDF nor CP digestibility was affected (P>0.05) by supplemental CP. Apparent DM, OM, and NSC digestibility values, as well as the true OM digestibility value, increased (P<0.05) linearly with decreasing proportional content of supplemental CP. Mean ruminal pH decreased (P<0.05) from 6.46 to 5.99 as proportional content of CP decreased. Propionate concentration increased (P<0.05) with decreased supplemental CP. Ruminal NH3-N concentration decreased (P<0.05) linearly with decreasing supplemental CP. The percentage of total N flows of NH3-N and non-NH-N decreased (P<0.05) with decreasing supplemental CP. Bacterial efficiency increased (P=0.05) linearly with decreasing supplemental CP. A nonproportional increase in supplemental CP in relation to NSC may impair the ruminal fermentation and bacterial efficiency of orchardgrass herbage, resulting in decreased ruminal digestive efficiency. Even though many vegetative, cool-season pastures contain more than 25% CP on a DM basis, lactating dairy cows are commonly overfed supplemental protein while grazing. A dual-flow continuous culture fermenter system was used to assess the effect of supplemental CP on ruminal fermentation of an orchardgrass (Dactylis glomerata L.) herbage diet. Treatments were 30 g DM of a 16, 14, 12, and 10% CP (corn- and soybean-based) supplement plus 45 g DM of herbage. Fermenters were sampled for pH, NH3-N, and VFA 4 times daily at feeding (0700, 1030, 1430, and 2030 h). Effluents were analyzed for DM, CP, NDF, OM, nonstructural carbohydrates (NSC), purine concentration, and bacterial production. The DM, OM, NSC, and CP digestibility values were calculated. Neither NDF nor CP digestibility was affected (P>0.05) by supplemental CP. Apparent DM, OM, and NSC digestibility values, as well as the true OM digestibility value, increased (P<0.05) linearly with decreasing proportional content of supplemental CP. Mean ruminal pH decreased (P<0.05) from 6.46 to 5.99 as proportional content of CP decreased. Propionate concentration increased (P<0.05) with decreased supplemental CP. Ruminal NH3-N concentration decreased (P<0.05) linearly with decreasing supplemental CP. The percentage of total N flows of NH3-N and non-NH-N decreased (P<0.05) with decreasing supplemental CP. Bacterial efficiency increased (P=0.05) linearly with decreasing supplemental CP. A nonproportional increase in supplemental CP in relation to NSC may impair the ruminal fermentation and bacterial efficiency of orchardgrass herbage, resulting in decreased ruminal digestive efficiency.

Effect of Molasses, Corn Meal, or a Combination of Molasses plus Corn Meal on Ruminal Fermentation of Orchardgrass Pasture During Continuous Culture Fermentation

Although molasses is being used by dairy farmers, particularly certified organic dairies, as a lower cost energy alternative to corn, little research currently exists evaluating the effects of molasses as the sole supplement on the ruminal fermentation of grazing dairy cows. This study evaluated the effects of pasture supplementation with molasses, corn meal, or a combination of molasses and corn meal, on ruminal nutrient digestibility and bacterial N synthesis in continuous culture fermenters. Experimental treatments were 1) orchardgrass (Dactylis glomerata L.) pasture only (control; 70 g DM/d); 2) molasses plus orchardgrass pasture (MOL; 3.5 g DM/d of molasses plus 66.5 g DM/d of pasture); 3) corn meal plus orchardgrass pasture (CM; 4.9 g DM/d of corn meal plus 65.1 g DM/d of pasture); and 4) molasses plus corn meal plus orchardgrass pasture (MOL + CM; 3.5 g DM/d of molasses plus 4.9 g DM/d of corn meal plus 61.6 g DM/d of pasture). Treatment did not affect (P > 0.05) apparent DM, OM, and NDF digestibility values; true DM and OM digestibility values; molar proportions of VFA; or acetate-to-propionate ratio. Mean ruminal pH tended (P = 0.071) to be greater for MOL. Maximum ruminal pH was greatest (P 0.05). At low levels of inclusion, molasses showed results similar to corn meal in improving ruminal fermentation and N utilization, with both supplements showing only minimal improvement compared with a pasture-only diet.

Effect of nutrient composition of feeds on digestibility of organic matter by cattle: A review1

Estimates of nutrient availability, calculated as TDN for 106 different feedstuffs generated from various published equations, were compared with TDN for similar feeds listed in the 1961 text by F. B. Morrison titled Feeds and Feeding. Incomplete analysis of carbohydrate fractions limited accuracy of evaluations. Although published equations may satisfactorily rank feeds in energy value, the absolute values, correlations, and SE of the estimates revealed that most equations were inaccurate. Across all feeds and forages, TDN was related most closely to crude fiber (R(2) = 0.68) within data sets from Morrison's text and from the NRC publications concerning Nutrient Requirements for Dairy and for Beef Cattle in 1989 and 2000, respectively. Within the latter data set, of the total variation, ADF accounted for 65% of the variation in TDN across all feeds, 62% of the variation in TDN for concentrate feeds, but only 41% of the variation in TDN of forages. Within the 2001 publication for dairy cattle from the NRC, ADF content was related most closely to TDN for all feeds, but nonfiber carbohydrate was most closely related to TDN of forages (R(2) = 0.81 and 0.69, respectively). To separate true from apparent digestibility of nutrients, fecal excretions of components (i.e., CP, fat, crude fiber, nitrogen free extract) were regressed against concentrations of these nutrients in feedstuffs and summed to estimate fecal loss. Metabolic fecal loss of OM (MFOM), the difference between true and apparent OM digestibility, was correlated closely with crude fiber content of feedstuffs (R(2) = 0.86) and increased from 7 to 25 g/100 g of diet as dietary crude fiber concentration increased. This may explain why most TDN equations are based on crude fiber or ADF. Whether dietary NDF similarly increases metabolic OM excretion is not certain, but when humans were fed NDF-enriched diets, fecal excretion of nonfiber carbohydrate increased markedly. The impact of crude fiber on nutrient availability of feeds appears to be related more closely to its adverse effect on apparent digestibility of other nutrients than to the amount of energy that fiber itself contributes. Refinements to laboratory methods for measuring fiber digestibility that match apparent in vivo digestibility coefficients for fiber by ruminants is needed, and the origin, composition, and cost of replacing MFOM need additional research.