In Vitro Dry Matter Digestibility Research Articles

In vitro Fermentation Profile and Methane Production of Kikuyu Grass Harvested at Different Sward Heights

Highly digestible forages are associated with anin vitrolow-methane (CH4) rumen fermentation profile and thus the possibility of reducing CH4emissions from forage-based systems. We aimed to assess thein vitroruminal fermentation profile, including CH4production, of the top stratum of Kikuyu grass (Cenchrus clandestinus - Hochst. ex Chiov) harvested at different sward heights (10, 15, 20, 25, and 30 cm). Herbage samples (incubating substrate) were analyzed for their chemical composition,in vitroorganic matter digestibility (IVOMD), and morphological components.In vitroincubations were performed under a randomized complete block design with four independent runs of each treatment. Gas production (GP),in vitrodry matter digestibility (IVDMD), CH4production, total volatile fatty acid (VFA) concentration, and their acetate, propionate, and butyrate proportions were measured following 24 and 48 h of incubation. Herbage samples had similar contents of organic matter, neutral detergent fiber, and crude protein for all treatments. However, a higher acid detergent fiber (ADF) content in taller sward heights than in smaller sward heights and a tendency for metabolizable energy (ME) and IVOMD to decrease as sward height increased were found. Similarly, the stem + sheath mass tended to increase with increasing sward height. Amongst the nutrients, ME (r= −0.65) and IVDMD (r= −0.64) were negatively correlated with sward height (p< 0.001) and ADF was positively correlated with sward height (r= 0.73,p< 0.001). Both the GP and IVDMD were negatively related to the sward height at both incubation times. Sward heights of Kikuyu grass below 30 cm display anin vitroprofile of VFAs high in propionate and low in acetate, with a trend toward lower methane production of CH4per unit of IVDMD. These findings are important to aid decision-making on the optimal sward height of Kikuyu grass and manage animal grazing with the opportunity to reduce CH4production.

The Effect of Zinc-Proteinate Supplementation on the In Vitro Digestibility and Ruminal Fermentation in Goat

This study aimed primarily to investigate the effect of Zn-Proteinate (Zn-Prot) supplementation on in vitro rumen digestibility and rumen fermentation. This research used a completely randomized design with four treatments and four replicates. The experimental treatment was the supplementation of various levels of Zn-Prot (0; 12.5 ppm; 25 ppm, and 37.5 ppm) on a dry matter basis. Parameters determined were in vitro dry matter digestibility (IVDMD), in vitro organic matter digestibility (IVOMD), partial volatile fatty acid (VFA) (acetate, propionate, and butyrate), A/P ratio, CH4, and the efficiency of the conversion hexose to VFA. Data were analyzed using ANOVA. The results showed that goats fed with a diet supplemented with 25 ppm Zn-Prot had the highest IVDMD and IVOMD values. There was no significant effect on the VFA and CH4 concentrations, A/P ratio, and the efficiency of the hexose-VFA conversion within treatment groups. In conclusion, supplementing 25 ppm of Zn-Prot into the diet of dairy goat increase the dry matter and organic matter digestibility.

Genetic Analysis of Yield and Quality Traits in Switchgrass Based on Population Crosses

Obtaining greater genetic gains, particularly for biomass yield, requires a good understanding of the gene action governing the inheritance of traits with economic importance in switchgrass (Panicum virgatum L.). Individual genotypes from three different accessions were crossed in single-pair matings with reciprocals to assess the relative importance of additive to nonadditive genetic variation and the potential of using inter-ecotypic crosses to improve dry matter yield (DMY), in vitro dry matter digestibility (IVDMD), lignin content (ADL and KL), and ethanol yield (ETOH). Crosses and four reference populations were planted in a randomized complete block design with eight replications of single family-rows plots, with five-plants each and 1 m spacings. A linear mixed model was applied as per the restricted maximum likelihood method, integrated with a pedigree tracing back to the original founders of these parental populations, and augmented with the designation of four genetic groups. Variation due to SCA (specific combining ability) was predominant for all traits, contributing from 20% to 57% of the total phenotypic variation and with Baker’s ratios (GCA/SCA) varying from 0.003 to 0.67. Heritability values calculated at the fullsib-family mean level were moderate to very high. Variation due to GCA (general combining ability) was detected with a lesser significance for DMY and ETOH. A reciprocal GCA effect was present in the form of maternal inheritance for DMY, suggesting the use of the highest biomass-yielding parent as female in inter-ecotypic breeding. Selecting and deploying fullsib families, deploying clonal hybrids, and adopting an introgression breeding approach are all possibilities available to switchgrass breeders to exploit the complementary genes from this germplasm and capitalize on the non-additive genetic variation present in these crosses.

Evaluation of in vitro digestibility and pH of Acacia seed pods (Acacia sp.)

This study aimed to determine the rumen fluid’s in-vitro dry matter digestibility (IVDMD), in-vitro organic matter digestibility (IVOMD), and pH of different species Acacia seed pods as a single feed ingredient. The Acacia species in this study were Acacia mangium, Acacia auriculiformis, and Acacia crassicarpa. The method used was in vitro two-stages with the first 48 hours of incubation (the rumen) and the second 48 hours of incubation (post-rumen), and analyses of pH. The research design used was a completely randomized design (CRD) with 3 treatments and 5 replications based on the Acacia species. The data were analysed with oneway analysis of variance (ANOVA) followed by Duncan’s multiple range test (DMRT). The results showed that IVDMD stage one was 34.59-37.59%; IVOMD stage one was 38.66-43.06%. Stage two of IVDMD was 58.02-59.23%; stage two of IVOMD was 51.67-55.01% and rumen fluid pH were 6.58-7.02. Different Acacia seed pods had significant differences in IVDMD and IVOMD stage one in the rumen and stage two in the post-rumen (P<0.05), but not in the pH value (P>0.05). We concluded that different acacia seed pods had different digestibility values in the rumen and post-rumen. However, it does not affect the rumen acidity.

Improving the nutritional value and digestibility of wheat straw, rice straw, and corn cob through solid state fermentation using different Pleurotus species.

The growing food-feed-fuel competition, declining availability of traditional feeds, higher prices, and the urgent need to provide long-term sustainability for animal production have all triggered global research into the optimum extraction of energy and nutrients from lignin-rich plant biomass. Recent studies have shown that the Pleurotus species of white rot fungus can selectively degrade lignin in lignin-rich plant biomass; however, its effectiveness in selectively degrading lignin depends on the type of substrate and species of fungus. This study was therefore designed to treat wheat straw, rice straw, and corn cob, with Pleurotus eryngii, P. ostreatus, and P. florida for 30 days under solid-state fermentation, to identify a promising fungus-substrate combination for the selective degradation of lignin and optimal improvement in the nutritional value and digestibility of each substrate. The type of fungus strongly influenced (P < 0.01) selectivity in lignin degradation, and the level of improvement in crude protein (CP), in vitro dry matter digestibility (IVDMD), and in vitro gas production (IVGP), in wheat straw, rice straw, and corn cob. Fungus-substrate interaction data revealed that P. ostreatus caused maximum (P < 0.05) degradation of lignin, and greater (P < 0.05) improvement in CP, IVDMD, and IVGP in wheat straw and rice straw. The lowest (P < 0.05) degradation of lignin and improvement in CP, IVDMD, and IVGP was caused by P. eryngii in corn cob. Among the fungi, the maximum (P < 0.05) degradation of lignin, and greater (P < 0.05) improvement in CP, IVDMD, and IVGP were caused by P. florida as compared with those of P. ostreatus and P. eryngii. The results highlight significant influence of fungus-substrate combination for selective lignin degradability and the consequent improvement in the nutritional value of the substrates. Maximum selective lignin degradability and improvement in nutritional value and digestibility was caused by P. ostreatus in wheat straw and in rice straw, and by P. florida in corn cob. © 2021 Society of Chemical Industry.

Comparing the in vitro digestibility of leaves from tropical trees when using the rumen liquor from cattle, sheep or goats

This study compared the effect of ruminal inoculum from different donor species (goat vs. cattle and sheep vs. cattle) on the in vitro dry matter digestibility (IVDMD) and in vitro organic matter digestibility (IVOMD) of leaves from tropical plant species. Comparisons were performed with and without the addition of N and polyethylene glycol (PEG). Leaves from six tropical trees with different condensed tannin content were used (Caesalpinia gaumeri, Cordia alliodora, Gymnopodium floribundum, Neomillspaughia emarginata, Piscidia piscipula and Senegalia gaumeri). Donors of ruminal liquor included a ruminal cannulated adult cow (500 kg live weight [LW]), two growing Criollo goats (22 ± 3 kg LW, study one) and two growing Pelibuey lambs (24.8 ± 0.28 LW, study two). Donors were maintained in individual pens and received a basal diet with concentrate feed and Pennisetum purpureum grass. The IVDMD and IVOMD using sheep or goat vs. cow rumen liquor were determined from dry samples of a commercial concentrate feed, P. purpureum grass, and the leaves from experimental plants with a 2 × 2 factorial arrangement: with or without N-enriched media (+N and -N), and with or without polyethylene glycol (+PEG and -PEG). Respective standard linear regressions and orthogonal regressions were used to compare equivalence of IVDMD and IVOMD results between ruminal inoculum from different donor species (cattle vs. goat in study one and cattle vs. sheep in study two). The standard linear regressions suggested strong associations between the ruminal inocula compared, in both IVDMD and IVOMD with the four treatments (R2 > 87 % for study one and R2 > 89 % for study two, P < 0.001). However, orthogonal regressions showed differences between inocula of cattle and goats on IVDMD, when using + PEG media, and on IVDMD and IVOMD when using + N media (P < 0.05). Differences between inocula of cattle and sheep were only evident in the absence of PEG (P < 0.05). The standard linear and orthogonal regressions suggested that the IVDMD and IVOMD of leaves from tropical trees obtained with sheep or goats’ ruminal liquors, within the evaluated range of digestibilities (c. 0.2 to 0.65), can be predicted from the IVDMD and IVOMD obtained with the cattle ruminal liquor. However, when evaluating digestibilities of leaves from tropical trees it is important to evaluate the specific incubation conditions using the donor species of interest to improve accuracy of results.

Classification of Megathyrsus Maximus Accessions Grown in the Colombian Dry Tropical Forest by Nutritional Assessment During Contrasting Seasons

The diversity and use of tropical forages for cattle feeding are the protagonists in livestock systems. The production and nutritional quality of forages represent a strategy of continuous research in animal feeding to help mitigate the environmental impact generated by tropical livestock. The objective of this study was to classify the nutritional behavior in contrasting seasons and the relationship with agronomic traits of a collection of 129 CIAT (Centro Internacional de Agricultura Tropical) accessions of Megathyrsus Maximus established in the Colombian dry tropics. By means of the near-infrared reflectance spectroscopy (NIRS) technique, crude protein (CP), neutral detergent fiber (NDF), acid detergent fiber (ADF), and in vitro dry matter digestibility (IVDMD) were determined under rainy and dry seasons as fixed effects. We measured plant height, dry matter biomass (DMB) and flowering in field. Aspects such as plant height and DMB did not show correlation with nutritional aspects, whereas flowering was correlated with the content of structural carbohydrates. Despite genotype and precipitation affecting nutritional value, there is relative nutritional steadiness in NDF, ADF, and IVDMD between seasons for some accessions. According to the cluster analysis carried out for each season, it was evidenced that from the total collection, 51.2% of the accessions during the dry season and 19.4% of the accessions during the rainy season were classified with a better nutritional profile, thus, showing a higher number of materials with better nutritional behavior in the dry season. Both the genotypic characteristics of M. maximus and environmental conditions during contrasting seasons are factors that might influence the variability of the nutritional content, productive parameters, and flowering. Additionally, fodder material classification under Hotelling's T-squared test and Nutritional Classification Index suggests accessions that might be promising for resilient nutritional quality and adequate DMB, which proves that M. maximus could become an alternative for animal feeding and sustainable livestock production during critical dry periods in tropical agroecosystems.

PSX-B-1 Effect of exposure time and dose of effective microorganisms (EM®) on feed in vitro rumen fermentation and digestibility

Abstract The objective was to evaluate the effect of feed inoculation with effective microorganisms (EM®) (mainly containing Lactobacillus spp.,Rhodopseudomona palustrisand Saccharomyces cerevisiae) on rumen fermentation using in vitrogas production technique. We hypothesized that increasing doses and allowing exposure of EM® for up to 48 hours, would improve digestibility and rumen fermentation. The experimental design was a 4×4 completely randomized block design including 4 EM® levels [(0(EM0), 0.5(EM0.5), 1.0 (EM1) and 1.5 (EM1.5) mL EM® / kg DM] and 4 preincubation times [0 (T0), 12(T12), 24(T24), 48 (T48) h], with four repetitions per treatment. Treatments were evaluated using 100ml glass bottles with 0.5g of the diet (20% corn stover, 20% oat hay, 48.8% ground corn, 7% molasses, 1.2% urea, 1% soybean meal, 0.9% mineral premix,1.1% salt, dry matter basis) incubated with sheep ruminal fluid in 3 different occasions. Data were analyzed with PROC MIXED of SAS and orthogonal contrasts to determine the linear and quadratic effects of EM dose and exposure time. Interaction (P &amp;lt; 0.05) of EM x T was observed for in vitrodry matter digestibility (IVDMD), maximum gas volume (Vmax), total volatile fatty acids (VFA), acetate (ACE), propionate (PROP), butyrate (BUT) and ammonia-nitrogen (NH3), IVDMD was higher (P &amp;lt; 0.01, 4.8 and 3.72%) for T48EM1.5 than T12EM0 and T0EM0, PROP was higher (P &amp;lt; 0.05) for T48EM0, T48EM1 and 1.5 than T12EM0. The ACE:PROP ratio was higher (P &amp;lt; 0.05, 17.2%) for T12EM0 than T48EM1.5. IVDMD, PROP and NH3 linearly increased (P &amp;lt; 0.01) with increasing exposure time. EM levels have a quadratic effect (P &amp;lt; 0.01) with maximum response at EM0.5. It was concluded that the addition of 0.5 to 1.5 mL/kg DM of EM® to a sheep diet and increasing preincubation time, up to 48h, improve feed fermentation and digestibility.Project was supported by UNAM, DGAPA, PAPIIT (IT202120).

Rhodaneses Enzyme Addition Could Reduce Cyanide Concentration and Enhance Fiber Digestibility via In Vitro Fermentation Study

The use of cyanide-containing feed (HCN) is restricted because it causes prussic acid poisoning in animals. The objective of this study was to see how adding rhodanese enzyme to an HCN-containing diet affected gas dynamics, in vitro ruminal fermentation, HCN concentration reduction, and nutrient digestibility. A 3 × 4 factorial arrangement in a completely randomized design was used for the experiment. Factor A was the three levels of potassium cyanide (KCN) at 300, 450, and 600 ppm. Factor B was the four doses of rhodanese enzyme at 0, 0.65, 1, and 1.35 mg/104 ppm KCN, respectively. At 96 h of incubation, gas production from an insoluble fraction (b), potential extent (omit gas) (a + b), and cumulative gas were similar between KCN additions of 300 to 450 ppm (p &gt; 0.05), whereas increasing KCN to 600 ppm significantly decreased those kinetics of gas (p &lt; 0.05). Supplementation of rhodanese enzymes at 1.0 to 1.35 mg/104 ppm KCN enhanced cumulative gas when compared to the control group (p &lt; 0.05). Increasing the dose of rhodanese up to 1.0 mg/104 ppm KCN significantly increased the rate of ruminal HCN degradation efficiency (DE) by 70% (p &lt; 0.05). However, no further between the two factors was detected on ruminal fermentation and in vitro digestibility (p &gt; 0.05). The concentration of ammonia-nitrogen (NH3-N) increased with increasing doses of KCN (p &lt; 0.05), but remained unchanged with varying levels of rhodanese enzymes (p &gt; 0.05). The in vitro dry matter digestibility (IVDMD) was suppressed when increasing doses of KCH were administered at 600 ppm, whereas supplementation of rhodanese enzymes at 1.0–1.35 mg/104 ppm KCN enhanced IVDMD (p &lt; 0.05). Increasing doses of KCN affected reduced total volatile fatty acids (TVFA) concentration, which was lowest when 600 ppm was added (p &lt; 0.05). Nevertheless, the concentration of TVFAs increased when rhodanese enzymes were included by 1.0–1.35 mg/104 ppm KCN (p &lt; 0.05). Based on this study, it could be concluded that supplementation of rhodaneses enzyme at 1.0–1.35 mg/104 ppm KCN could enhance cumulative gas, digestibility, and TVAF, as well as lowering ruminal HCN concentration.

Fatty acid profile and in vitro rumen fermentation characteristics of maize silage augmented with canola silage

The objective was to investigate the effect of replacing maize silage (MS) with canola silage (CS) on the chemical composition and fatty acid (FA) profile of total mixed rations (TMR) containing these silages, and on in vitro rumen fermentation and methane production from them. The canola (Brassica napus var. Monty) was cultivated on a small-scale agricultural farm and harvested at 148 days after sowing. Maize silage in a TMR was replaced with 0%, 15%, 25%, and 35% CS to make the rations CS0, CS15, CS25, and CS35, respectively. Proximate analyses of the rations were evaluated in a completely randomized design. The results showed that linolenic acid increased linearly with the level of CS, primarily at the expense of linoleic acid. In vitro dry matter digestibility (IVDMD) was similar among treatments. However, in vitro neutral detergent fibre digestibility (IVNDF) decreased linearly (P &lt;0.05) when the CS proportion increased in the TMR. The lowest ammonia nitrogen content (P &lt;0.05) was observed in CS35. The soluble fraction (A) increased (P &lt;0.05) when the CS increased in the TMR from 0% to 35%. In vitro methane (CH4) production was lowest with CS25 and CS35, decreasing 34% and 23.9%, respectively, compared with CS0. Linolenic acid had a negative correlation with IVNDF (r = -0.94; P &lt;0.05). The IVDMD and methane production were positively correlated (r = 0.60) (P &lt;0.05). In conclusion, 25% and 35% augmentation of MS with CS in a TMR was an important source of linolenic acid (C18:3) and decreased in vitro methane production.

Dwarf and Tall Elephantgrass Genotypes under Irrigation as Forage Sources for Ruminants: Herbage Accumulation and Nutritive Value.

Simple SummaryCyclical droughts negatively impact agriculture, with deficits of water availability for the maintenance of crops destined for human food and animal production. Seasonality of forage quantity and quality is a critical obstacle to support domesticated herds over the year. Elephantgrass (Pennisetum purpureum Schum.) is a tropical forage widely used for feeding ruminants, mainly in the form of cut-and-carry, which has the potential to increase tropical pasture productivity, due to the large amount of roughage produced per unit of area. Research evaluated the response of tall and dwarf elephantgrass genotypes under irrigation considering its potential for complementing ruminant diets. This study showed that irrigation of elephantgrass, particularly during the dry season, may improve the regularity of forage production with good nutritive value.This two-year study evaluated the effect of Pennisetum purpureum genotypes under rainfed or irrigated conditions, during the dry and rainy seasons, on herbage, leaf, and stem dry matter (DM) accumulation rates, nutritive value, and carbohydrate and protein fractionation. Treatments were tall (Iri 381 and Elefante B) or dwarf (Mott and Taiwan A-146 2.37) genotypes under rainfed or irrigated conditions. Taiwan A-146 2.37 (146 kg DM ha per day) showed similar herbage accumulation rate (HAR) to tall genotypes during the rainy season (124 and 150 kg DM/ha per day, respectively). Dwarf genotypes showed differences in leaf accumulation rate (LAR) (66 and 49 kg DM/ha per day). Mott leaf had less neutral detergent fiber (NDF) (589 g/kg DM) than Taiwan A-146 2.37 (598 g/kg DM), and tall genotypes had generally greater NDF (668 g/kg DM) than the dwarf genotypes. Irrigation increased fiber deposition in the leaf. Stems of all genotypes had lower in vitro digestible dry matter (IVDDM) (378 g/kg DM) under rainfed conditions in the rainy season. Leaf from irrigated plots had 23% more carbohydrate C fraction (160 g/kg CHO) than those from rainfed plots (122 g/kg CHO). Dwarf genotypes had generally greater nutritive value than tall genotypes. These genotypes show promise under irrigation to fill forage gaps during dry periods.

Cutting Time and Regrowth Age Affect the Quality of Elephant Grass Silage

The objective of this study was to evaluate the effects of regrowth age (RA) and cutting time (CT) of elephant grass (Cenchrus purpureus cv. Cameroon) on the fermentation profile, microorganism population, and nutritive value of the silage in two simultaneous trials at different sites. A 2 × 2 factorial scheme with two CTs (08:00 and 14:00) and two RAs (8 and 16 weeks) at ensilage was used in a completely randomized design, with four replicates in each trial, totaling 16 experimental units per trial. Results showed that ammonia nitrogen to total nitrogen content (N-NH3/TN) ranged from 71.8 (14:00; 16 weeks) to 137.0 g kg -1 (14:00; 8 weeks). Elephant grass silage harvested at 14:00 at 8 weeks had the lowest pH (3.53) and highest lactic acid content (39.7 g kg-1 dry matter). The in vitro dry matter digestibility (IVDMD) was higher (P &lt; 0.05) in the silage of plants harvested at 8 weeks than in the silage harvested at 16 weeks (59.9 vs. 46.8%, respectively). In trial 2, elephant grass silage harvested at 14:00 had lower pH and acetic acid content. The IVDMD was higher in elephant grass silage harvested at 14:00, with values of 65.3% and 56.2% at 8 and 16 weeks, respectively. We recommend elephant grass harvested at 8 weeks of regrowth and cut at 14:00 to produce silage with better nutritive value and fermentative profile.

Utilization of Yeast Waste Fermented Citric Waste as a Protein Source to Replace Soybean Meal and Various Roughage to Concentrate Ratios on In Vitro Rumen Fermentation, Gas Kinetic, and Feed Digestion

The objective of this study was to determine the application of citric waste fermented yeast waste (CWYW) obtained from an agro-industrial by-product as a protein source to replace soybean meal (SBM) in a concentrate diet. We also determined the effect of various roughage to concentrate ratios (R:C) on the gas production kinetics, ruminal characteristics, and in vitro digestibility using an in vitro gas production technique. The experiment design was a 3 × 5 factorial design arranged in a completely randomized design (CRD), with three replicates. There were three R:C ratios (60:40, 50:50, and 40:60) and five replacing SBM with CWYW (SBM:CWYW) ratios (100:0, 75:25, 50:50, 25:75, and 0:100). The CWYW product’s crude protein (CP) content was 535 g/kg dry matter (DM). There was no interaction effect between R:C ratios and SBM:CWYW ratios for all parameters observed (p &gt; 0.05). The SBM:CWYW ratio did not affect the kinetics and the cumulative amount of gas. However, the gas potential extent and cumulative production of gas were increased with the R:C ratio of 40:60, and the values were about 74.9 and 75.0 mL/0.5 g, respectively (p &lt; 0.01). The replacement of SBM by CWYW at up to 75% did not alter in vitro dry matter digestibility (IVDMD), but 100% CWYW replacement significantly reduced (p &lt; 0.05) IVDMD at 24 h of incubation and the mean value. In addition, IVDMD at 12 h and 24 h of incubation and the mean value were significantly increased with the R:C ratio of 40:60 (p &lt; 0.01). The SBM:CWYW ratio did not change the ruminal pH and population of protozoa (p &gt; 0.05). The ruminal pH was reduced at the R:C ratio of 40:60 (p &lt; 0.01), whereas the protozoal population at 4 h was increased (p &lt; 0.05). The SBM:CWYW ratio did not impact the in vitro volatile fatty acid (VFA) profile (p &gt; 0.05). However, the total VFA, and propionate (C3) concentration were significantly increased (p &lt; 0.01) by the R:C ratio of 40:60. In conclusion, the replacement of SBM by 75% CWYW did not show any negative impact on parameters observed, and the R:C ratio of 40:60 enhanced the gas kinetics, digestibility, VFA, and C3 concentration.

Management of Aries and Aruana Guinea grass cultivars under rotational stocking based on canopy light interception

AbstractEfforts were made to obtain forage cultivars with high production capacity and quality and to determine the ideal time to start animal grazing, respecting the morphological characteristics of the grasses. For this purpose, the nutritional value, digestibility and characteristics of the forage canopy of Aries and Aruana (Megathyrsus maximus (Jacq.) or Panicum maximum) cultivars kept under rotational stocking with sheep were evaluated and the management height was determined based on 95% light interception (LI). The experiment was evaluated with repeated measures over time (grazing cycles by season, in 2 years) with a treatment factor (grass cultivar) in a completely randomized block design with eight replicates, using 800 m2 paddocks. The height of the forage canopy before grazing (pre-grazing) determined by 95% LI stabilized around 29 cm. The highest proportion of Aruana leaf blades was observed in winter. Aries grass presented similar leaf blade percentages in summer, autumn and spring. Similar forage accumulation (FA) was observed for both cultivars, decreasing in spring, autumn and winter. Higher crude protein and in vitro dry matter digestibility (IVDMD) were seen in Aries grass, while Aruana grass presented higher neutral and acid detergent fibre and cellulose and lower IVDMD. The nutritional quality of the grasses was maintained throughout the year. The height of the forage canopy of Aries and Aruana recommended for entry into the paddock is 29 cm to maintain nutritional quality. The successful management strategy adopted for grasses combined with nitrogen fertilization provided a greater forage mass quality.

Chemical Composition and Digestibility of Major Feed Resources in Tanqua-Abergelle District of Central Tigray, Northern Ethiopia.

Background A detailed study on the feed quantity and quality is required to document the available feeds and their nutritional values. Aim The study was aimed to investigate and document the chemical composition and in vitro dry matter digestibility of major feed resources available in Tanqua-Abergelle district of central Tigray, northern Ethiopia. Methods Ten different feed resources were evaluated for their nutritive values. Representative feed samples were collected and prepared following appropriate procedures. The samples were subjected to analysis of chemical composition and in vitro dry matter digestibility (IVDMD) using proper scientific procedures. Results Wide variations were observed in nutritive values of the investigated feeds. The highest crude protein (CP) was measured in Atella (15.90%) followed by green grass (13.20%), mill waste (10.90%), groundnut straw (9.18%), and cowpea straw (8.11%) in descending order. Mill waste (11.84 MJ/kg DM) and Atella (11.81 MJ/kg DM) had the highest metabolizable energy (ME) followed by green grass (9.83 MJ/kg DM), groundnut straw (9.28 MJ/kg DM), Teff straw (8.56 MJ/kg DM), and cowpea straw (8.39 MJ/kg DM) in that order. The highest NDF was recorded in groundnut null (79.80%) and the lowest NDF in mill waste (35.00%) and Atella (40.60%). The highest IVDMD was seen in mill waste (81.43%) and Atella (81.21%) and the lowest in groundnut hull (39.95%). Conclusion The nonconventional feeds have moderate protein and reduced fiber contents, and thus, they can be utilized as supplement for poor-quality feeds. These feeds need further investigation using animals to substantiate the current study.

Re‐ensiling effects on sorghum silage quality, methane emission and sheep efficiency in tropical climate

AbstractThe objective of the present study was to evaluate whether sorghum silage exposure to air for 8, 16 or 24 hr before re‐ensiling reduces silage quality and animal feed efficiency. Sorghum was ensiled in 52 metal drums (13 for each exposure time) with 200‐L capacity, and after 112 days, 39 drums were opened and silage was exposed to air for 8, 16 or 24 hr. Thirteen silos were not opened and considered control treatment. Subsequently, silage was re‐ensiled, and after 56 days, all silos were opened to determine silage quality variables. In addition, the silage was offered to sheep to determine animal feed efficiency. The experimental design was completely randomized with five replications per treatment, and orthogonal polynomials were used to determine linear or quadratic effects of the exposure time. The non‐fibrous carbohydrate (NFC) (minimum of 278 g/kg), in vitro dry‐matter digestibility (IVDMD) (minimum of 570 g/kg) and lactic acid (1.51 g/kg for each hour) decreased with longer exposure. The pH (0.011 for each hour), ammonia nitrogen (0.057 g/kg for each hour), acetic acid (maximum of 17.9 g/kg) and aerobic stability (maximum of 62.4 hr) increased with longer exposure. Although silage exposure reduced NFC and IVDMD and increased pH and ammonia nitrogen, animal feed efficiency was not compromised. These results indicate that sorghum silage exposure for up to 24 hr does not compromise its use.

196 Effect of Exogenous Enzyme Supplementation and Fermentation of Oilseed By-products on in vitro Digestibility and Production of Short Chain Fatty Acid

Abstract An experiment was conducted to investigate the effect of exogenous enzyme supplementation and solid-state fermentation (SSF) with a mixed bacterial culture on in vitro dry matter digestibility (IVDMD) and short chain fatty acid (SCFA) production of soybean meal (SBM) or rapeseed meal (RSM). A 2 × 2 factorial design was used and included the factors of 1) exogenous enzyme cocktail (supplemented and non-supplemented), 2) microbial fermentation (fermented and non-fermented) applied to SBM or RSM in vitro. The exogenous enzyme cocktail consisted of non-starch polysaccharide (NSP) degrading enzymes (NSP-EZ) with phytase (10,000 FTU/kg), and the SSF were carried out using Bacillus subtilis. The fermented feed ingredients were collected after 48 h incubation at 37oC. Samples were hydrolyzed in two steps using pepsin and pancreatin to calculate IVDMD. Subsequently, the hydrolyzed residues were filtered, dried, and pooled for incubation in a buffered mineral solution with fresh swine feces. Gas production kinetics during fermentation was measured for 72 h and analyzed by fitting data to an exponential model. The fermentation residues were filtered, and the supernatant was analyzed for concentration of SCFA. The IVDMD from simulated gastric and small intestinal hydrolysis was greater (P &amp;lt; 0.01) for SSF in both SBM and RSM. During fermentation, the hydrolysis residue from SBM treated with SSF required less time to reach half asymptote, had greater maximal gas production, and greater fractional degradation (P &amp;lt; 0.01, respectively) compared with non-fermented SBM. The IVDMD from simulated total tract digestion was greater (P &amp;lt; 0.01) for SSF in RSM compared with SBM, while SBM had greater IVDMD for both SSF and NSP-EZ (P &amp;lt; 0.01). Production of butyric acid was greater for SSF (P &amp;lt; 0.01) compared with non-SSF in both SBM and RSM. These results suggest that SSF can improve IVDMD and produce greater amounts of butyric acid compared with NSP-EZ supplementation in SBM and RSM.

48 Evaluation of soybean cultivars for forage yield and nutritive qualities

Equine producers frequently utilize legumes, such as alfalfa ( Medicago sativa ) and perennial peanut ( Arachis glabrata ), as forages in their feeding programs. Due to challenges related to production and shipping in the Southeast, producers may be looking for other viable legume options to reduce feeding costs. Soybean ( Glycine max L.) may prove to be a useful option. The current study evaluated 3 forage soybean varieties (V), ‘Tower of Leaves’ (T), ‘Stonewall’ (S), and ‘Laredo’ (L), and 2 grain varieties, ‘AG64 × 8’ (A) and ‘AG79 × 9’ (X), during the 2019–2020 growing seasons for forage yield and nutritive value. Row spacing (RS; 36 and 71 cm), harvest height (HH; 10, 15, and 20 cm), and location [E.V. Smith Research and Extension Center (EVS) and Wiregrass Research and Extension Center (WG)] were also evaluated. Plots were harvested using a small plot harvester. A subsample was dried in a 55°C forced air oven and then ground to 1 mm. Crude protein (CP), neutral detergent fiber (NDF), and acid detergent fiber (ADF) was determined using NIRS analysis. Wet chemistry was performed on 10% of samples for verification. In vitro dry matter digestibility (IVDMD) was determined using batch culture inoculated with an equine fecal matter (10%) and buffer solution (90%) mixture. This study was a randomized, complete block design (n = 4) and stats were analyzed using PROC Glimmix of SAS version 9.4 (SAS Inst., Cary, NC). There was no effect of RS on any parameter evaluated ( P > 0.17). All dependent variables were affected by HH ( P < 0.01), V ( P < 0.01), and location ( P < 0.05). Yield was greatest in S and T ( P < 0.02; 2074 and 1961 kg ha −1 , respectively), while yield was least in L ( P < 0.01; 1340 kg ha −1 ). Neutral detergent fiber and ADF were less in S than L ( P < 0.01; 46 and 37 vs 47 and 38%, respectively), and A ( P < 0.02; 46 and 37 vs 47 and 38%, respectively), while X was also less than L ( P < 0.01; 46 and 37 vs 47 and 38%, respectively) and T ( P < 0.03; 46 and 37 vs 47 and 38%, respectively). Crude protein was greatest in A and X ( P < 0.05; 16.9 and 16.4%, respectively), while it was least in S and T ( P < 0.05; 15.8 and 15.7%, respectively). There was no effect ( P = 0.20) of soybean variety on IVDMD. The EVS location had greater forage yield ( P < 0.0001), CP ( P < 0.0001), and NDF ( P < 0.05), but lesser ADF ( P < 0.0001) than WG. The cultivar S showed the greatest forage yield and the least NDF and ADF, while the CP seen in S was less than other varieties; however, S was only 1% lower than A, which had the greatest CP. This indicates that S has the greatest promise as a forage option and should be further tested in mixtures with other forage species.

Fermentation characteristics and nutritive value of sweet sorghum silage with Paiaguas palisadegrass and Ipypora grass

Ensiling sorghum with tropical forages has been shown to be a promising alternative for ruminant feed production, as this approach improves the quality of the sorghum silage. In this context, the goal of this study was to evaluate the fermentation characteristics and nutritive value of sweet sorghum silage made with different levels of Paiaguas palisadegrass and Ipypora grass. The experiment was conducted in a completely randomized 2 x 6 factorial design with four replications. Two forages (Paiaguas palisadegrass and Ipypora grass) were added to sorghum at six levels (0, 20, 40, 60, 80 and 100%), for a total of 48 experimental silos. After 50 days of fermentation, the silos were opened, and the fermentation profile and chemical composition of the silage were analysed. The results showed that the addition of Paiaguas palisadegrass and Ipypora grass to the sorghum silage increased the pH, buffering capacity and NH3-NT of the silage and reduced its dry matter content but did not affect its fermentation characteristics, which remained within an appropriate range. The addition of increasing levels of Paiaguas palisadegrass and Ipypora grass to the sorghum silage increased the crude protein and in vitro dry matter digestibility (IVDMD) of the silage and decreased the fibre fraction (neutral detergent fibre, acid detergent fibre and lignin) and ether extract contents. Adding tropical forages to sorghum silage material at levels above 40% is recommended. Among forage crops, addition of Paiaguas palisadegrass to sorghum silage resulted in higher content of crude protein and IVDMD. Mixed silages can be an effective alternative to improve the quality of forage sorghum silage.

Palisadegrass pastures with or without nitrogen or mixed with forage peanut grazed to a similar target canopy height. 1. Effects on herbage mass, canopy structure and forage nutritive value

AbstractNitrogen (N) inputs to pasture systems coupled with grazing management strategies based on monitoring and control of canopy structure may provide conditions for greater productivity and enhanced forage nutritive value. This 2‐year study assessed canopy structure and nutritive value responses of three pasture treatments, namely, (1) mixed Marandu palisadegrass (Brachiaria brizantha [Hochst. ex A. Rich.] R.D. Webster [syn. Urochloa brizantha Stapf]) cv. Marandu and forage peanut (Arachis pintoi Krapov. &amp; W.C. Greg.) cv. BRS Mandobi pastures without N fertilizer (GRASS + LEGUME); (2) monoculture Marandu palisadegrass pastures fertilized with 150 kg N/ha (GRASS + N); and (3) monoculture Marandu palisadegrass without N fertilizer (GRASS). Grazing management was similar across pasture treatments, using continuous stocking and a target canopy height of 20–25 cm. Herbage mass was greater in GRASS + N and GRASS + LEGUME pastures than in GRASS in summer and spring (p = .014). The leaf:stem ratio in the grass mass (p = .731) was similar between treatments. Grass crude protein (CP) and in vitro digestible dry matter (IVDDM) were greatest in the GRASS + N pasture (p &lt; .001). Grass neutral detergent fibre (NDF) concentration was greater at GRASS and GRASS + LEGUME pastures than in GRASS + N (p &lt; .001). Forage peanut had a greater IVDDM and CP concentration and a lower NDF concentration than Marandu palisadegrass. Nitrogen application or the presence of the legume increased green herbage mass and improved forage nutritive value in canopies with similar height.