True Dry Matter Digestibility Research Articles

Mutating alfalfa COUMARATE 3-HYDROXYLASE using multiplex CRISPR/Cas9 leads to reduced lignin deposition and improved forage quality.

Alfalfa (Medicago sativa L.) forage quality is adversely affected by lignin deposition in cell walls at advanced maturity stages. Reducing lignin content through RNA interference or antisense approaches has been shown to improve alfalfa forage quality and digestibility. We employed a multiplex CRISPR/Cas9-mediated gene-editing system to reduce lignin content and alter lignin composition in alfalfa by targeting the COUMARATE 3-HYDROXYLASE (MsC3H) gene, which encodes a key enzyme in lignin biosynthesis. Four guide RNAs (gRNAs) targeting the first exon of MsC3H were designed and clustered into a tRNA-gRNA polycistronic system and introduced into tetraploid alfalfa via Agrobacterium-mediated transformation. Out of 130 transgenic lines, at least 73 lines were confirmed to contain gene-editing events in one or more alleles of MsC3H. Fifty-five lines were selected for lignin content/composition analysis. Amongst these lines, three independent tetra-allelic homozygous lines (Msc3h-013, Msc3h-121, and Msc3h-158) with different mutation events in MsC3H were characterized in detail. Homozygous mutation of MsC3H in these three lines significantly reduced the lignin content and altered lignin composition in stems. Moreover, these lines had significantly lower levels of acid detergent fiber and neutral detergent fiber as well as higher levels of total digestible nutrients, relative feed values, and in vitro true dry matter digestibility. Taken together, these results showed that CRISPR/Cas9-mediated editing of MsC3H successfully reduced shoot lignin content, improved digestibility, and nutritional values without sacrificing plant growth and biomass yield. These lines could be used in alfalfa breeding programs to generate elite transgene-free alfalfa cultivars with reduced lignin and improved forage quality.

426 Forages Containing Plant Secondary Compounds Can Improve Digestibility, Rumen Ammonia and Rumen Metabolites of Pasture: an in Vitro Continuous Culture Case Study

Abstract Forages containing plant secondary metabolites (PSM) have been investigated for use in reducing nitrogen waste in feedlot and dairy cattle diets but use as supplements to grazing beef cattle to capture the positive effects of PSM is unclear. Here we investigate potential improvement in rumen digestibility and metabolome, rumen ammonia production and flow from feed protein due to PSM bioactivity in forages used to supplement pasture grass using in vitro methods. Can PSM-containing forages offer a practical way to improve range nutrition and provide delivery of phytochemical benefits? Phytochemical- containing forages birdsfoot trefoil (BFT), sainfoin (SAN), small burnet (SMB) and cicer milkvetch (CMV) supplemented grass pasture diets (200 g/kg of DM). In vitro true dry matter digestibility was determined using 2-stage in vitro methods. Randomly assigned diets of PAS supplemented with one of the PSM-containing forage diets (PAS+X) or not supplemented (PAS) were randomly applied to in vitro dual flow continuous culture (CC) vessels inoculated with grazing beef cow rumen fluid as a metabolic host. For 2-stage digestibility, SMB digestibility exceeded that of CMV, followed by BFT and SAN. The grass diet (PAS) was the least digestible (Table 1). Saponin was detected in CMV samples, which is a new finding. For CC, compared with PAS, minimum culture pH for PAS+CMV was highest (P < 0.02) but no differences were observed in pH between PAS, and PAS+BFT and PAS+SAN. Compared with PAS, the molar proportion of the fatty acid propionate increased with PAS+CMV(P = 0.03) in contrast to the acetate- to- propionate ratio found highest for PAS and decreased for all diets with supplementation of PSM forages. Concentration of rumen NH3–N flow to rumen fluid per gram of protein intake was lower (P < 0.01) with PAS+CMV and PAS+SMB, compared with grass only. Feeding CMV and SMB to grazing cattle may improve nutrient utilization, metabolome, and environmental sustainability of beef cattle production by improving diet digestibility and reducing ammonia waste.

The effect of seaweed formulations on in vitro fermentation, nutrient utilization and growth performance in crossbred calves

The aim of this research was to study the effect of seaweed formulations on in vitro rumen fermentation, nutrient utilization and growth performance of crossbred calves. The study included 18 male crossbred calves of 130±7.56 kg body weight, divided into 3 groups of 6 each following a completely randomized design. Calves in the control (T0) were fed a standard diet, while treatment groups T1 and T2 were supplemented with AF-KWP or AFRD-5 at the rate of 4% of concentrate mixture, with 1% calcium carbonate and 1% dicalcium phosphate replacing the mineral mixture, and common salt offered in T0 . The experiment was conducted for a period of 120 days. At the end of the experiment, a metabolism trial was conducted to study the nutrient utilization. In vitro total gas and methane production was significantly (P<0.05) lower in the seaweed supplemented groups. A significant difference (P<0.05) was also observed in the retention of calcium and phosphorus between the different groups. A non-significant difference was observed in nutrient digestibility, dry matter intake, total gain in body weight, average daily gain and feed conversion ratio between the three treatment groups. It might be concluded that seaweed formulations significantly reduced in vitro total gas and methane production without affecting true dry matter digestibility and true organic matter digestibility. Moreover, seaweed formulation supplementation did not affect the growth performance and nutrient utilization in the crossbred calves.

Effect of single or combined homo- and heterofermentative silage additives on the quality, nutritive value, and in vitro digestibility of ensiled wheat harvested at early dough stage of maturity

The present study was conducted to evaluate the effect of single or combined homo- and heterofermentative silage additives on silage quality, nutritional composition, feed value, and in vitro digestibility of ensiled wheat harvested at early dough stage of maturity. The study was carried out as a completely randomized design with a 2 × 2 factorial arrangement of two levels of homofermentative silage inoculant (0 or 0.8 mg/kg) and two levels of heterofermentative silage inoculant (0 or 500 mg/kg) consisting of 4 groups with 4 replicates in each group. Control group received no silage additive. Remaining groups received either HMF, HTF, or a combination of both silage additives (HMF + HTF). pH and Flieg point of silage prepared with HMF and HTF alone or in combination were respectively lower and greater compared to control group. Nutritional composition, feed value, and in vitro true dry matter and organic matter digestibilities were unaffected among the treatments. In conclusion, the study shows that the application of single or combined HMF and HTF inoculants yields well-preserved wheat silage whereas the nutritional composition and in vitro digestibility may remain unaffected.

Effects of the Incubation Period of Pleurotus ostreatus on the Chemical Composition and Nutrient Availability of Solid-State-Fermented Corn Stover.

The current study aimed to optimize and improve the feeding value of Pleurotus ostreatus-fermented corn stover by evaluating the effects of five solid-state fermentation times and three in vitro fermentation periods on the chemical composition, dry matter disappearance (DMD), microbial mass and volatile fatty acid (VFA) production of treated and untreated corn stover. The study utilized a 3 × 5 factorial design, with eight replicates per treatment. Dry matter, crude protein (CP), ash and non-fiber carbohydrate (NFC) contents increased quadratically (p < 0.05) with increases in the solid-state fermentation time. Increases of 44.4-59.1%, 20.6-78.6% and 40.5-121% were noted for the CP, ash and NFC contents, respectively. Organic matter, ether extract, neutral detergent fiber and hemicellulose contents decreased quadratically (p < 0.05) across the treatments. Similar trends were noted for DM and fiber disappearance in the treatments. The total gas production and in vitro true dry matter digestibility (IVTDMD) increased quadratically, while microbial mass and in vitro apparent DMD increased in a linear manner. The total VFA, propionate and butyrate contents increased linearly. Both the acetate content and the A:P ratio decreased in a linear manner. The results show that the rumen fermentation pathway favors the production of propionate, with increases in propionate production of 7.46 and 8.30% after 2 and 4 wk, respectively. The study showed that a 2 wk period of solid-state fermentation is sufficient to provide a bio-transformed cow-calf feed resource from P. ostreatus-treated corn stover.

The effects of fumaric acid on in vitro true digestibility of tea wastes produced with different cultivation methods

This study aims to determine the effects of adding different fumaric acid (FA) levels to tea factory wastes (TFW) produced by different cultivation methods on in vitro true digestibility. In vitro true digestibility of feed (IVTDAs feed), dry matter (IVTDDM), organic matter (IVTDOM), and neutral detergent fibre (IVTDNDF) were performed with a Daisy Incubator. Fumaric acid did not add to the control group and added 0.1%, 0.2%, or 0.3% FA to the experimental groups. When the cultivation methods were compared (conventional and organic tea wastes), it was seen that FA made a significant difference (P0.05). There was a significant difference (P

Agronomic and structural responses of stockpiled alfalfa–bermudagrass mixtures

AbstractThe incorporation of alfalfa (Medicago sativa L.) into bermudagrass [Cynodon dactylon (L.) Pers.] forage systems in the southern United States has increased. Stockpiling this mixture may extend the grazing season into the fall and winter months with high‐quality forage. The objective of this 2‐year study was to evaluate agronomic and structural responses of alfalfa–bermudagrass mixtures managed under five stockpiling periods (6, 8, 10, 12, or 14 weeks) in two locations (Shorter, AL, and Tifton, GA). Across locations, stockpiling mixtures for 8 weeks or longer (2400 lb DM ac−1, on average) resulted in greater (P = 0.001) herbage accumulation than 6 weeks (3185 lb DM ac−1). The alfalfa proportion was similar among stockpiling periods in Shorter but greater (P = 0.043) at 10 and 14 weeks than 6, 8, and 12 weeks in Tifton. A location × year × stockpiling interaction was observed for crude protein (CP, P &lt; 0.001) and in vitro true dry matter digestibility over 48 h (IVTDMD48, P &lt; 0.001). Crude protein concentrations were similar among stockpiling periods in 2020 in both locations. In 2019, however, CP concentrations reduced with increasing stockpiling period length in Shorter and were similar among treatments in Tifton, except for the lesser CP at 8 than at 10, 12, and 14, weeks. Forage IVTDMD48 concentrations declined with increasing stockpiling period length at both locations, with a more pronounced decline in Shorter in 2019. Results suggest that stockpiling alfalfa–bermudagrass mixtures for up to 8 weeks is a viable option to supply high nutritive value forage and lower lodging losses into the early winter months.

Nutrient profile, digestibility, and feeding value of common vetch (Vicia sativa) alone or intercropping with different forages

The present study was conducted to assess the nutrient profile, digestibility and feeding values of common vetch alone or intercropping combinations with different cereal and legume forages in central district of Burdur, Türkiye. Approximately 2 kg fresh matter of common vetch alone or 9 different intercropping combinations was harvested from different locations. Nutrient composition and in vitro true dry matter digestibility were analyzed whereas feeding values were calculated. The study showed that intercropping largely decreased the crude protein of common vetch while an increase in fiber and carbohydrate fractions was noted except acid detergent fiber and acid detergent lignin that decreased in intercropping mixtures compared to common vetch alone. In addition, there was an increase in digestibility and feeding values in intercropping mixtures in comparison with common vetch alone. In conclusion, intercropping of common vetch with cereal forages improves the nutrient profile, in vitro digestibility, and feeding values despite a reduction in the crude protein content of intercropping mixtures compared to common vetch.

Effect of Sodium Hydroxide Treatment on Chemical Composition and Feed Value of Common Reed (Phragmites australis) Straw

This research was undertaken with the aim of determining the effect of sodium hydroxide (NaOH) treatment on the chemical composition, in vitro gas production, neutral detergent fiber digestibility (NDFD) and true dry matter digestibility (TDMD), dry matter intake (DMI), and relative feed value (RFV) of common reed (Phragmites australis) straw. Reed straw was treated with 0% (control), 1%, 2%, and 3% NaOH and stored in 1.5-L glass jars in triplicate for 21 days. NaOH treatment had a significant effect on the chemical composition, in vitro gas production, NDFD and TDMD, DMI, and RFV of the reed straw. While it decreased the cell wall content of the reed straw, it significantly increased the NDFD, TDMD, DMI, and RFV. The neutral detergent fiber content of the reed straw decreased with NaOH treatment in a dose-dependent manner and ranged from 56.03% to 65.05%, whereas the NDFD increased and ranged from 53.10% to 59.99%. Metabolizable energy, organic matter digestibility, and TDMD values were improved, ranging from 9.15 to 10.19 MJ/kg DM, 58.46% to 65.05%, and 55.29% to 62.33%, respectively. The estimated RFV and DMI also improved, ranging from 84.70% to 95.58% and from 1.87% to 2.14% of body weight, respectively. The most effective treatment dose of NaOH was 3%. Therefore, it can be suggested that NaOH treatment has the potential to improve the nutritive value of reed straw. However, before large applications, further in vivo investigations are required to determine the effects of NaOH treatment on the feed intake and production of ruminant animals.

An increase in livestock density increases forage nutritional value but decreases net primary production and annual forage nutritional yield in the alpine grassland of the Qinghai-Tibetan Plateau.

Pasture biomass and quality are dependent on herbivore grazing and precipitation, but the responses of vegetation to the interactive effects of climate and grazing regimes remain unclear. We conducted an eight-year sheep grazing experiment with 4 stocking rates (0, 3.5, 5.5, and 7.5 sheep/ha) in an alpine meadow of the northeastern Tibetan Plateau. The above-ground net primary productivity (ANPP) and forage nutritional value (FNV) of four dominant species (Poa annua, Kobresia humilis, Astragalus adsurgens and Potentilla fruticosa) were measured during a wet year (360 mm rainfall) and a drought year (216 mm rainfall). The FNV was used as indicator of forage quality and was calculated from the crude protein (CP) content, in vitro true dry matter digestibility (IVTD), metabolic energy (ME) yield, and neutral detergent fiber (NDF) content of the plant. The stocking rate explained a minimum of 76% of the variations of ANPP, and the precipitation sub-additive effect for ANPP ranged from 5% to 12%. The interaction of sheep stocking rate and precipitation affected ANPP of the 4 species, except for P. fruticosa. The FNV of the pasture increased with increasing grazing pressure, but ANPP and forage nutritional yield (FNY) decreased. In calculating FNY, the increase in FNV did not compensate for the decrease in ANPP. In non-grazed plots, the CP yield declined sharply (18%-55%) in response to drought, but there was no effect on ME yield. The interaction between stocking rate and precipitation affected forage quality of the 4 plant species differently. The grassland ANPP and FNY could be maintained at a grazing intensity of 3.5 sheep/ha in wet and dry years. Our results highlight that stocking density affects pasture ANPP and FNV, and is contingent on rainfall.

Impact of Moringa oleifera on rumen fermentation and methane emission under in vitro condition

Exploring innovative methods to provide essential nutrients and reducing ruminant greenhouse gas emission is crucial for animal production and diminishing global warming. This study was conducted to examine the efficacy of Moringa oleifera leaves (ML) in ruminants at 0%, 5%, 10%, 15%, 20%, 30% and 40% level in different roughage (R) and concentrate (C) (80R:20C, 70R:30C and 60R:40C) under in vitro conditions. Chemical composition of ML, concentrate mixture and berseem were estimated. Rumen fermentation parameters of male goat kids viz., total gas production, CH4, true dry matter digestibility (TDMD), organic matter digestibility (TOMD), partial fraction (PF), microbial biomass (MBP), ammonia (N), acetate, propionate, butyrate and acetate propionate ratio were observed under in vitro conditions. Results revealed that crude protein, organic matter and ethyl ether content were higher in ML as compared to concentrate mixture and berseem. Magnesium and iron content were also higher in ML as compared to concentrate and berseem. Total gas production, digestibility of DM and OM, MBP, acetate and propionate level were improved (P < 0.05) upto 10–20% replacement. In contrast, decreased in CH4 (%) and CH4 (mL/100 mg dDM) was noted with increased levels of ML incorporation. There was no change observed in ammonia, acetate: propionate ratios at all the three planes of nutrition. In this study, it is concluded that mixing Moringa oleifera leaves in feed can be used as protein supplement and reduce the methane emission without causing any effect on digestibility and rumen fermentation parameters. However, ML can be suggested for widespread practice to attain the sustainable animal production (10–20%) and to alleviate the global warming.

PSXII-11 Evaluation of Yellow-Flowered Subspecies Falcata Alfalfa to Purple Flowered Medicago Sativa for Northern Plains: Productivity, Nutrient Profile, and in Vitro True dry Matter Digestibility

Abstract The protein content and nitrogen fixation capabilities of alfalfa (Medicago sativa L.) make it valuable in cropland and rangelands. However, the semi-arid Northern Great Plains climate negatively affects stand establishment and persistence. Falcata alfalfa (Medicago sativa subs. Falcata) produces adventitious shoots from roots, improving stress and drought resistance. This study compared production and forage quality for yellow- flowered falcata alfalfa (FAL) to a conventional alfalfa (var. Vernal [MSP]). Plots were established as randomized complete block design with four replications. Each cultivar was seeded in 2019 as a monoculture. In 2020, two harvests were made and sampled. Dry matter yield (DMY) and nutritive value of alfalfa were determined. Results showed first cut DMY was 4,228±361 and 3,442±720 kg/ha for the FAL and MSP, respectively. Results for forage quality for first harvest indicate that FAL alfalfa had greater (P &amp;lt; 0.05) ash (10.36 vs. 9.85 %), lignin (7. 86 vs. 7. 14 %), acid detergent fiber (ADF: 38.4 vs. 33.4%), neutral detergent fiber (NDF: 45.4 vs. 39.0 %) but less crude protein (CP; 18.7 vs. 21.2 %, DM basis), total digestible nutrients (TDN: 59.2 vs. 55.5%), non- fiber carbohydrates (NFC; 186 vs. 164), sugar (8.4 vs. 7.0 %), in vitro true dry matter digestibility after a 48-h incubation (IVTDMD48: 58.6 vs. 55.8%), compared with FAL. However, for the second harvest, DMY was 2,837±361 kg/ha for FAL, which had greater CP (20.4 vs. 19.4%), similar ADF (35.4 vs. 35.0), NDF (42.7 vs. 41.8 %), and IVTDMD48 (65.6 vs. 64.0%), but lower lignin (7.68 vs. 7.84%) and TDN (58.1 vs 58.9%) than MSP which yielded 2546 ±515 kg/ha. Falcata had greater nutritive value at second cutting and greater yield compared with Medicago but generally differed little for quality, suggesting falcata can be a viable alternative legume for Northern Plains.

Determining The Feed Value, Feed Quality, and in Vitro Fermentation Properties of Italian Ryegrass (Lolium multiflorum L.) Harvested in Different Periods

The purpose of this study was to determine the chemical content, in vitro gas and methane production, relative feed value (RFV), relative feed quality (RFQ), in vitro digestibility parameters, and microbial protein production of the Italian ryegrass plants harvested in different periods of the 2020 production season in Erzincan. In this study an ANKOM Daisy Incubator was used to determine the in vitro digestibility parameters. In vitro gas production technique was used todetermine gas production and predicted parameters. It was found that there were significant differences between the Italian ryegrass plants harvested in different periods in terms of composition, RFV, RFQ, and in vitro digestibility and fermentation parameters. The RFV, metabolizable energy (ME), net energy (NE), true NDF digestibility (TNDFD), organic matter digestibility degree (OMDD), total digestible nutrient (TDN), dry matter intake (DMI), and RFQ values of the Italian ryegrass plants were found to be 247.32, 9.13, 5.68, 62.26%, 54.15%, 55.35%, 4.82%, and 215.81, respectively. On the other hand, after 24 hours of incubation it’s in vitro gas (GP), and methane production (ml and %), true dry matter digestibility (TDMD) values, partitioning factor (PF), microbial protein (MP), microbial protein synthesis efficiency (MPSE), and true digestibility (TD) were found to be 105.41, 17.35, 16.42, 281.72, 2.68, 57.68, 20.32, and 59.82, respectively. In conclusion, determining the digestibility of plants via the measurement of RFV, RFQ, digestion parameters, and gas production in different harvest periods provided insights into the potential of Italian ryegrass as a feed material.

Isolation and characterization of sulphate reducing bacteria from goat rumen and its inclusion to improve in vitro feed fermentation

In the present study sulphate-reducing bacteria (SRB) were isolated from the rumen of goats fed a diet of wheat straw and concentrate in 50:50 ratio using specific medium followed by phenotypic and phylogenetic characterization. Based on the biochemical characteristics, four best SRB isolates were evaluated for their efficacy to reduce in vitro CH4 production and stimulate fibre digestion. It was found that true dry matter digestibility (IVTD) and production of metabolites were higher but methane emission was low by inclusion of live culture of SRB4 isolate as compared to control. Sequencing of 16S rDNA revealed 99% homology of SRB4 with Streptococcus caviae strain NR156902. The isolate also exhibited expression of dissimilatory sulphite reductase gene (dsR) gene substantiating sulphate reducing ability of the isolate. The results indicate the ability of SRB4 to reduce in vitro CH4 emissions and improve fibre digestibility, hence can be explored as an effective candidate for microbial feed additive to modify rumen fermentation, so that enteric methane production can be controlled.

Effects of fall stocking rates on naturalized cool‐season stockpiled pastures

AbstractThe potential of tall fescue (Schedonorus arundinaceus Dumort) and orchardgrass (Dactylis glomerata L.) as stockpiled forages has been documented; however, limited information describes the characteristics of other species, especially complex mixtures of cool‐season naturalized pastures. A 3‐yr study assessed the herbage mass, forage quality, and botanical composition of mixed cool‐season naturalized pastures [orchardgrass, tall fescue, clover (Trifolium spp.), narrowleaf plantain (Plantago lanceolata L.), and quackgrass (Elymus repens [L.] Gould)] in response to two stocking rates based on daily herbage allowances of 3.5% (low) or 7.0% (high) of heifer bodyweight. The stocking rate for the entire pasture area, including unoccupied paddocks during the grazing period, was 2.4 and 1.3 heifers acre−1 for the low and high treatments, respectively. Stockpiling began in August; grazing began in early November. The initial herbage mass and botanical composition were determined at the end of the stockpiling period. Herbage samples were taken throughout the fall grazing period at intervals of 11 to 19 d. The stocking rate had no effect on changes in botanical composition. Total legume percentage increased from 6% in Year 1 to 31% in Year 3 (P &lt; .05). Herbage mass declined more quickly in Year 3 than in Years 1 and 2 (P &lt; .05), probably because of the high percentage of legumes. As fall grazing progressed, crude protein content and in vitro true dry matter digestibility declined, and neutral detergent fiber content increased. Mixed cool‐season naturalized pastures could be used for stockpiling and grazed intensively without detrimental effects on subsequent stockpiling periods.

Evaluating warm‐season annual forages to fill summer forage gaps in short‐season climates

AbstractAnnual warm‐season forages have been used to fill productivity and nutritional gaps during summer months throughout the southeastern United States. However, their performance and nutritive value in cooler, short‐season temperate climates above 40 °N has been less well studied. This study evaluated the forage mass and nutritive value of four warm‐season annual forages {brown midrib [BMR] sudangrass [Sorghum bicolor ssp. Drummondii (L.) Moench], buckwheat (Fagopyrum esculentum Moench), Japanese millet [Echniochloa esculenta (A. Braun) H. Scholz], and teff [Eragrostis tef (Zuccagni) Trotter]} compared with a cool‐season small grain forage, oat (Avena sativa L.), and a cool‐season annual forage legume, chickling vetch (Lathyrus sativus L.). Monocultures of the six annual forage species, along with a mixture of all six species, were evaluated over 2 years in southeastern New Hampshire. Forage mass and nutritive value were assessed at weekly intervals over 3 weeks in July–August, approximately 4‐to‐5 weeks post‐germination. Across all three harvests, buckwheat, Japanese millet, and the summer mix produced greater forage mass than oat, while chickling vetch and teff produced the least. Conversely, chickling vetch had greater crude protein (CP), acid detergent fiber, and neutral detergent fiber compared with oat, while buckwheat had the lowest CP, in vitro true dry matter digestibility, and in vitro neutral detergent fiber digestibility of all the species assessed. Japanese millet produced greater forage mass while providing similar nutritive value as oat, making it a good alternative warm‐season annual forage for use under cool, short growing seasons.

Identifying optimal early‐season harvest timing in annual fall forages

AbstractFall forage production in the northeastern United States is complicated by early onset of cool temperatures, limiting forage availability in cool‐season perennials. Annual forages planted in late summer as cover crops or supplemental forage crops may fill this niche; however, data on their nutritive value over the short fall harvest window is lacking. This study compared six annual forage crops for their forage mass and nutritive value and identified optimal harvest times based on changes between forage mass and digestibility. Monocultures of canola (Brassica napus L.), forage radish (Raphanus sativus L.), oat (Avena sativa L.), spring triticale (×Triticosecale Wittm. ex A. Camus [Secale × Triticum]), spring wheat (Triticum aestivum L.), sunn hemp (Crotolaria juncea L.), and a mixture of all six species were sown in August of 2015 and 2016 then harvested at three time points (6, 8, and 10 weeks after planting [WAP]) over the fall (September–November). Canola, oat, and spring wheat had the greatest forage mass, while sunn hemp had the least across all harvests. Canola and forage radish had the lowest neutral detergent fiber (NDF) and acid detergent fiber (ADF) and greatest in vitro true dry matter digestibilities (IVTDMd) across all harvests, while sunn hemp and the grasses declined in IVTDMd after first and second harvest. Forage mass of the fall mix was comparable to the highest yielding monoculture at third harvest only. Results suggest that forage brassicas can be harvested without compromising mass or nutritive value, while cereal grasses gained forage mass at the expense of nutritive value.

The effect of season on in vitro degradability and fermentability of feeds in red deers’ (Cervus elaphus L.) rumen fluid

Transition from summer to winter changes red deer digestive tract physiology and digestive processes. The objective of the trial was to determine the effects of season on in vitro apparent (ivADMD) and true dry matter (ivTDMD) digestibility, in vitro gas production parameters and short-chain fatty acid synthesis (SCFA) in red deer hinds of eleven substrates naturally occurring in Slovenia (chestnut fruits, acorns of common and sessile oak, two fresh grasses) and those frequently used in supplemental red deer feeding (two grass hays and two grass silages, apple pomace and sugar beet roots). There were no differences in ivADMD, ivTDMD, determined by incubation of feeds in buffered rumen fluid, as there were no differences in majority of gas production parameters between autumn and winter season. Only the parameter “C” (specific gas production rate) was frequently higher (p &lt; 0.05) in winter season than in autumn season. The amounts of SCFA were similar between two seasons. However, the proportion of acetic acid tended to be higher in winter, while the proportions of propionic and butyric acid tended to be higher in autumn than in winter especially in high fibre feeds. On contrary, in high starch feeds such as oak acorns and chestnut fruits, the proportion of propionic acid was higher (p &lt; 0.05) in winter, while of butyric acid in autumn (p &lt; 0.05). Despite the fact that the number of used substrates (n = 11) and animal rumen fluid donors (n = 6) were small, these results indicate a shift in rumen microbial metabolism between autumn and winter season.

Potential effect of some essential oils on rumen methane reduction and digestibility by In Vitro incubation technique

Since excessive use of in-feed antibiotics and chemical feed supplements can potentially affect health risks and environmental problems, organic feed supplement became alternative save material. Organic material such as essential oils (EO) is potential for feed additive in the livestock industry because of their main activity as rumen manipulator. Their potential as rumen manipulators has not enough for type and doses of essential oils experiment. Therefore, the objective of this study was to evaluate 6 essential oils/EO’s (garlic/, thyme, clove, orange peel, mint, and cinnamon) with different doses (100, 200 and 300 ppm) on in vitro rumen methane reduction and in vitro digestibility using in vitro gas production technique. The experiment resulted highest level in in-vitro methane reduction potential (MRP, %) 72.83% at orange peel oils 300 ppm after 6 h incubation, while using clove oils 300 ppm had highest in vitro true digestibility of dry matter (IVTDDM) 81.41% after 30-hour incubation. Using Cinnamon oils had high value both of MRP level and IVTDDM (48.91 and 79.12 %). In Conclusion, all essential oils reduced in vitro rumen methane production at 6 h incubation compared to control at 300 ppm and there was no negative effect on In Vitro Digestibility.

295 Effects of Live Yeast and Ruminal Environment on Beef Cattle Diet Digestibility: An in vitro Approach

Abstract The effects of live yeast (Saccharomyces cerevisiae) and ruminal environment on in vitro true digestibility of dry matter, organic matter, and fiber components were evaluated. Ruminally-cannulated beef steers (n = 4; BW = 520 ± 30 kg) were used in a cross-over design to serve as donors of ruminal content. In vitro substrates (6 grower and 6 finisher diets) and individual ingredients (steam-flaked corn, wet corn gluten feed, and old-world bluestem hay) were dehydrated (55o C), ground (1 mm), and incubated using a 2 × 2 factorial arrangement of treatments: a) the presence or not of yeast (8×109 CFU/animal-daily adjusted to a 70 L ruminal content volume), and b) two ruminal inoculums collected from donors fed a grower (50:50) or a finisher (92:08) diet (concentrate:forage). Four incubation batches (experimental unit) were performed, in which the initial two batches were performed followed by another two after animals switched diets and were adapted again during 21d. A Daisy in vitro incubation system was used, and samples incubated for 48h (39°C). The GLIMMIX procedure of SAS was used for the statistical analysis. No 3-way interactions (P ≥ 0.71) or 2-way interactions with substrate were observed (P ≥ 0.25). The in vitro true digestibility of DM, OM, NDF, and hemicellulose increased when yeast was added to the incubator containing a 50:50 ruminal content (Rumen × Yeast; P ≤ 0.02). The ADF digestibility increased (P = 0.02) with yeast addition regardless of ruminal content type (50:50 or 92:08). As expected, finisher substrate diets were more (P &amp;lt; 0.01) digestible than grower diets. The combination of live yeast and a specific ruminal environment seemed to be more important than substrate type, in which live yeast improved in vitro digestion within a 50:50 ruminal inoculum more evidently.