In Vitro True Dry Matter Digestibility Research Articles

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.

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.

PSIII-7 Seasonal effects on nutritional value of Oklahoma prairie grass when grazed in extensive or intensive systems

Abstract The objectives of this study were to determine the effects of sampling month and grazing system on tallgrass prairie forage nutritive value. Native tallgrass prairie pastures (n = 6) were assigned to either an extensive (EXT) or intensive (INT) grazing system for 5 consecutive years. Extensive system pasture annual stocking rate was 6.1 hectares per cow-calf pair with cows remaining in their respective pastures year-round. Intensive system pasture annual stocking rate was 3.0 hectares per cow-calf pair with cows present in the pastures 160 days per year [mid-May through mid-July (58 ± 6 d) and mid-September through mid-December (102 ± 4 d)]. Forage samples were collected monthly from two to four locations within each pasture. Samples were dried, separated into subsamples of leaf material and whole plant matter, ground, and analyzed using near-infrared spectroscopy. Data were analyzed using a mixed model (SAS 9.4) with grazing system, month, sample type (leaf or whole), and all two-way interactions as fixed effects and year as a random effect. Forage crude protein (CP) was not different between leaf or whole plant samples (P = 0.97) and increased (P &amp;lt; 0.001) in May (10.8% CP), declined in the fall, and stayed low (2 – 4% CP) in both systems. Neutral detergent fiber (NDF) was greater during May to July (P = 0.040) in the EXT than the INT pastures. Acid detergent fiber (ADF) differed by month (P &amp;lt; 0.001) and was lowest between April and May. In vitro true dry matter digestibility (IVTDMD) was greater in INT (63.7%) than EXT (62.3%) pastures regardless of month (P &amp;lt; 0.001), and both systems were greater during May through August (65 – 75%; P &amp;lt; 0.001) than the winter months (56 – 60%). These data indicate that protein supplementation is likely required outside of May and June, especially for lactating cows.

Increasing nutrient quality and in vitro digestibility of mixed feed oil palm waste for ruminant feed by solid-state fermentation technology

Palm oil cake (BS) and Solid ex decanter (SD) are feed ingredients produced from palm oil processing which is available in large quantities. BS and SD have high protein content could be used as ruminant feed but have high fat content could be decreased rumen metabolism. Therefore. solid-state fermentation (SSF) technology is one way to overcome this problem. This study aims to improve the nutritional quality and digestibility of mixed feed palm oil cake and solid ex decanter (BS/SD) which is fermented by Rhizopus oligosporus (RO) mushroom. Application SSF technology for different combination of mixed feed BS/SD (70/30, 50/50 and 30/70) was carried out for 6 days which was then analyzed on the quality of the proximate. fiber fractions and in vitro true dry matter digestibility (IVTDMD) value (daisy incubator ANKOM Technology). The result showed that the mixed feed BS/SD 50/50 was the best combination with Rhizopus oligosporus inoculum with doses of 0.2, 0.4 and 0.8%. Hence, this SSF technology was effective process for increasing protein content and in vitro true dry matter digestibility (IVTDMD) 60% - 67.26% with combination BS/SD 50/50 and RO inoculum with doses 0.2 and 0.4 percent.

Comparison of benchtop and handheld near‐infrared spectroscopy devices to determine forage nutritive value

AbstractThe quality of predicted plant‐, soil‐, and animal‐response values from near‐infrared (NIR) reflectance spectra depends on the ability to generate appropriate NIR models. The first step in the development of NIR models is collection of spectral data. Limited work, however, has been reported that compares NIR models for prediction of forage nutritive value when the spectra are obtained from devices with different spectral ranges and resolutions. The objectives of this study were to (a) develop and evaluate NIR spectroscopy models using a benchtop‐type (FOSS) and two handheld NIR devices (microPHAZIR and DLP NIRscan Nano EVM) to predict crude protein (CP), acid detergent fiber (ADF), amylase and sodium sulfite‐treated neutral detergent fiber (aNDF), and in vitro true dry matter digestibility (IVTD) of dried ground forage grass samples and (b) compare predictions among the three NIR devices. Switchgrass (Panicum virgatum L.) and bermudagrass [Cynodon dactylon (L.) Pers] hay samples were scanned with the NIR devices and analyzed with wet chemistry for development of NIR prediction models. Among devices, the r2 of validation values for aNDF models ranged from .81 to .87; all other r2 values were &gt;.86 and as high as .98 with standard error of prediction (SEP; g kg−1) ranging from 8.1 to 11.5 for CP, 19.1 to 23.8 for aNDF, 14.2 to 20.0 for ADF, and 26.8 to 49.9 for IVTD. The FOSS benchtop NIR prediction models consistently had the highest r2 and lowest SEP values; however, the predictive power for both handheld devices was similar to the benchtop‐type device.

Managing harvest of ‘Russell’ and ‘Tifton 44’ bermudagrass receiving broiler litter for nutritive value and phosphorus removal

AbstractBermudagrass [Cynodon dactylon (L.) Pers.] hay fields receiving broiler litter offer a means to both produce high quality forage and export excess manure nutrients, for example P. This 3‐yr study determined the nutritive value, P removal, and soil P for ‘Russell’ and ‘Tifton 44’ bermudagrass receiving 4 ton ac−1 broiler litter and 98 lb ac−1 N (as NH4NO3) annually and cut at 21‐, 35‐, and 49‐d intervals with residual stubble heights of 1.2 and 3.5 inches. Forage cut every 49 d at 1.2‐inch stubble height had the greatest dry matter (DM) yield and low nutritive value; weighted‐sum crude protein (CP) ranged from 7.2 to 8.2% and weighted‐sum in vitro true DM digestibility (IVTDMD) ranged from 56.8 to 62.0%, depending on year. With a 35‐d interval, forage CP and IVTDMD amounts generally exceeded 9.6 and 62.0%, respectively. Forage IVTDMD was greater in Tifton 44 than Russell in 2006 and 2007, when values with a 35‐d interval were approximately 3.0 and 0.3% greater, respectively. Cutting at a 1.2‐inch height increased P removal by approximately 23% in Russell and 30% in Tifton 44 compared with a 3.5‐inch height. Phosphorus removal was maximized with a 49‐d interval and 1.2‐inch height in 2005 (29.8 lb ac−1) and 2006 (19.3 lb ac−1) and with a 35‐d interval and 1.2‐inch height in 2007 (29.3 lb ac−1). Managing the balance between high DM and nutritive value in both cultivars can be achieved with a 35‐d interval and 1.2‐inch height. A prolonged harvest interval of 49 d is a valuable consideration for P removal via biomass.

Improving Nutritive Value of Native Warm‐Season Grasses with the Plant Growth Regulator Trinexapac‐Ethyl

Core Ideas Gibberellin inhibitors may decrease stem growth, improving late fall forage nutritive value during late summer and fall. Examining the short‐ and long‐term impacts of suppressed stem growth or altered tiller number could result in improved forage nutritive traits. Warm‐season grasses are characterized by high forage mass but low nutritive value, especially when mature. Livestock producers in the southeastern United States utilize native warm‐season grasses (NWSG), however, the best management practice to not harvest during late‐summer and fall results in large quantities of low quality forage. Gibberellin inhibitors can alter plant regrowth and forage value. This study assessed the impact of trinexapac‐ethyl [TE; ethyl 4‐(cyclopropyl‐hydroxy‐methylene)‐3,5‐dioxo‐cyclohexane‐1‐carboxylate] on fall NWSG forage. Application of TE occurred in late July at four levels (0, 0.3, 0.6, and 1.2 kg a.i. ha−1) to switchgrass (SG; Panicum virgatum L.) and a mixed sward (BBIG) of big bluestem (Andropogon gerardii Vitman) and indiangrass (Sorghastrum nutans L.) during 2016 and 2017. Forage mass (FM) and nutritive value [crude protein (CP), neutral detergent fiber (NDF), in vitro true dry matter digestibility (IVTDMD)] were evaluated monthly. Application reduced fall FM (SG: 37%; BBIG: 42%). Switchgrass nutritive value did respond to TE application. Application of TE reduced BBIG NDF overall, but strong annual variation occurred due to a drought (2016). Analyzed separately, 2017 treated BBIG samples (1.2 kg a.i. ha−1) exhibited altered FM (−57%), CP (up to 54%), NDF (−9.2%), and IVTDMD (11%). Further analysis provided tentative evidence that TE improved leaf nutritive value and increased leaf proportion, although overall leaf yield was not improved. Overall, TE improved BBIG nutritive value but at a substantial FM loss. Since poor nutritive content forage has negligible value regardless of quantity, growth regulators could improve outcomes of fall NWSG management by adding value to an unutilized resource.

Harvest Management Effects on ‘Tifton 44’ Bermudagrass Phosphorus Removal and Nutritive Value

Core Ideas The impact of harvest management on forage nutritive value is vital to farm income.Results validate management practices commonly used but heretofore without statistical basis.Bermudagrass P removal maximized with prolonged harvest interval and short stubble height.Forage nutritive value was similar between stubble heights when harvested every 35 d. Haying bermudagrass [Cynodon dactylon (L.) Pers.] to maximize recovery of P applied in broiler litter may adversely affect forage quality. This 3‐yr study (2005–2007) determined harvest management effects on dry matter (DM) yield, P removal, and forage nutritive value in ‘Tifton 44’ bermudagrass at Noxapater and South Farm, MS. Fertilization annually comprised 8.96 Mg ha−1 broiler litter (as‐is basis) that provided 243 and 122 kg ha−1 of N and P, respectively, supplemented with 67–110 kg ha−1 N (as ammonium nitrate). After an initial harvest in May, forage was harvested at 28‐, 35‐, and 49‐d intervals and at 3‐ and 9‐cm residual cutting heights. Seasonal trends in P removal closely followed those observed for DM yield and short stubble increased yields of DM and P by approximately 31%. Prolonged regrowth and 3‐cm stubble height resulted in the greatest yields of DM and P. Annual P removal at Noxapater did not differ between 35‐ and 49‐d harvest intervals (21.3 vs. 23.0 kg ha−1); whereas it was greatest (P &lt; 0.05) at South Farm for 49‐d intervals (23.9 vs. 25.8 kg ha−1). Prolonged regrowth resulted in crude protein (CP) and in vitro true DM digestibility (IVTDMD) below 95 and 610 g kg−1, respectively, suggesting less forage could be consumed by ruminant livestock. In 2007, CP and IVTDMD levels were greatest for 9‐cm stubble. Tifton 44 bermudagrass receiving litter should be harvested every 35 d and at 3‐cm stubble height to provide the best compromise between DM yield, nutrient removal, and forage nutritive value.

In vitro ruminal fermentation of treated alfalfa silage using ruminal inocula from high and low feed-efficient lactating cows

To assess the effect of two additives on alfalfa silage and on invitro ruminal fermentation when using ruminal inocula from high feed-efficient (HE) and low feed-efficient (LE) lactating cows. First- and second-cut alfalfa was harvested at 40% bloom stage, treated with control (no additive), Lactobacillus plantarum (LP) or formic acid (Formic), ensiled in 1·0l minisilos, and fermented for 60days. Fermented alfalfa was incubated invitro for 24h using ruminal inoculum from HE and LE lactating cows. The pH was lower in alfalfa silage treated with LP and Formic, and produced lower ammonia-N than did the control. In vitro true dry matter digestibility (IVTDMD) was higher with ruminal inoculum from HE than LE cows, but there was no consistent effect of treated alfalfa on microbial biomass yield and invitro volatile fatty acids. The IVTDMD was numerically greater with ruminal inoculum from higher feed-efficient cows although statistical significance was only demonstrated with the first-cut alfalfa. However, treated alfalfa silage did not show the effect expected on invitro microbial biomass yield. The feed efficiency of cows used as a source of ruminal inocula may affect IVTDMD and be a source of variation across invitro runs. Differences in ruminal fermentation between cows of different feed efficiency could help to explain differences in milk yield and other parameters of dairy cattle performance.

In Vitro protein digestibility and fermentability of mulberry (Morus alba)-Leucaena foliage mixed feed

&lt;p class="abstrak2"&gt;This experiment was carried out to determine the effect of mulberry-leucaena foliage mixed feed on protein digestibility and VFA production using an in vitro gas production study. Mulberry was mixed with one of 2 leucaena varieties (&lt;em&gt;Leucaena leucocephala&lt;/em&gt; hybrid and &lt;em&gt;Leucaena leucocephala&lt;/em&gt; local) at 3 levels (0, 25 and 50%). Study was conducted in completely randomized design. Mulberry foliage, leucaena and mixtures of mulberry-leucaena were incubated for 24 hours in glass syringes. Parameter recorded were gas production, in vitro true dry matter digestibility (IVTDMD), in vitro N digestibility (IVND) and VFA production. Results of the study showed that supplementation of leucaena to mulberry decreased IVOMD, gas production and protein digestibility in the rumen buffered medium. The mixture of mulberry and leucaena hybrid at ratio 50% resulted in the lowest IVND than other treatment. However it increased protein digestibility in acid pepsin incubation as an estimate of protein availability in intestine. Gas production decreased in mulberry leucaena mixtures was followed by decreased total VFA production. Tannin derived from leucaena hybrid supplementation to mulberry at ratio 1 : 1 was most effective to decrease protein digestion in the rumen and to increase protein digestibility in acid pepsin incubation. In conclusion mixing of hybrid leucaena hybrid with mulberry foliage was able to protect protein degradation from mulberry in the rumen.&lt;/p&gt;

NUTRITIVE VALUE OF FRESH, DRIED (HAY) AND ENSILED VINES OF FOUR SWEET POTATO (Ipomoea batatas) VARIETIES GROWN IN SOUTHERN ETHIOPIA

&lt;p&gt;Chemical composition and in vitro true dry matter digestibility (IVTDMD) of fresh, dried (hay) and ensiled vines of two early maturing (Belela and Temesgen) and two medium maturing varieties (Beletech and Tulla) were investigated. Hay was made by sun drying for 3 days. Silages were S1: vine alone, S2: vine+2%molasses, S3: vine+4% molasses, S4: vine+10% sweet potato root (SPR, % of wilted vine weight), S5: vine+20%SPR and S6: vine+30%SPR. They were ensiled in plastic buckets (8 liter) with airtight press cape in triplicate for 90 days in a lab at room temperature of 22&lt;sup&gt;0&lt;/sup&gt;C. Data were analyzed using SPSS version 20. Hay of Belela, Temesgen, Beletech and Tulla had 17.5, 13.9 and 15.2 %CP (%DM); 36.3, 35.6, 40.5 and 38.8% NDF (%DM) and 81.1, 82.2, 75.0 and 76.7% IVTDMD, respectively, were found. There was a decrease in pH of silages (p&amp;lt;0.05), with increasing levels of both molasses and SPR, respectively (3.91-3.66 and 3.91-3.64 in Belela; 3.92-3.72 and 3.92-3.68 in Temesgen; 3.99-3.81 and 3.99-3.75 in Beletech; 4.02-3.92 and 4.02-3.74 in Tulla); CP (19.8-15.8 and 9.8-13.9 in Belela; 20.0-14.2 and 20.0-12.3 in Temesgen; 17.2-11.2 and 17.2-10.9 in Beletech; 17.9-14.3 and17.9-11.6 inTulla); NDF (29.9-27.7 and 29.9-22.9 in Belela; 26.4-25.0 and 26.4.0-20.8 in Temesgen;36.1-29.3 and 36.1-25.4 in Beletech; 34.5-29.0 and 34.5-24.4 in Tulla); ADF (26.7-18.2 and 26.7-15.5 in Belela; 25.5-17.1 and 25.5-14.7 in Temesgen;30.0-20.2 and 30.0-16.0 in Beletech;29.3-19.1 and 29.3-16.2 in Tulla); and ADL (7.1-4.6 and 7.1-3.5 in Belela; 6.9-4.1 and 6.9-2.7 in Temesgen;9.1- 5.1 and 9.1-4.9 in Beletech; 7.9-5.0 and 7.9-4.1 in Tulla) but increased IVTDMD ( 82.5-85.7 and 82.5-87.4, in Belela; 82.1-86.1 and 82.1-88.2 in Temesgen; 79.1-84.1 and 79.1-86.1 in Beletech; 78.9-84.0 and 78.9-85.6 in Tulla). Silages at all additive levels had acceptable pH and good IVTDMD, but 4% molasses, 20 and 30% SPR gave higher IVTDMD. Hay had lower nutrient content and IVTDMD than fresh vine and silages. In conclusion, Belela and Temesgen had better nutritive value than Beletech and Tulla; silage making was better than hay making. Animal evaluation is recommended for further confirmation of the results.&lt;/p&gt;&lt;p&gt;Key words: Chemical composition; In vitro true dry matter digestibility; Sweet potato varieties&lt;/p&gt;&lt;p&gt; &lt;/p&gt;&lt;p&gt;Key words: Chemical composition; In vitro true dry matter digestibility; Sweet potato varieties&lt;/p&gt;

Co-production of feed and furfural from dried distillers’ grains to improve corn ethanol profitability

Dried distillers’ grains (DDG) was chosen as the starting material for a two-step furfural conversion process aiming at increasing the value of corn ethanol byproducts and thus further decreasing the cost of corn ethanol. Modeling the experimental data, dilute acid extraction was predicted to be able to extract 86.7% of total pentose in DDG. Batch and reactive distillation dehydration (BRD) processes were used to convert the pentose-rich dilute acid hydrolysate into furfural giving maximum furfural yields of 47% and 68%, respectively. In parallel, analyses of composition and in vitro true dry matter digestibility (IVTDMD) of DDG-residue after dilute acid hydrolysis suggested potential animal feed values. An economic analysis of the process was performed using the optimized process parameters predicted from the statistical models. The models confirms that making furfural and selling the DDG-residue as animal feed would make the process more profitable than selling DDG solely as animal feed.

Fibre digestion potential in sugarcane across the harvesting window

AbstractThe objectives of this study were to determine the proportion of indigestible neutral detergent fibre (iNDF) in the neutral detergent fibre (NDF) fraction of sugarcane, to estimate changes in NDF digestibility (NDFD) during the harvesting window and to predict sugarcane digestibility based on its fibre fractions. Whole plants of the IAC86‐2480 and IAC93‐3046 varieties were collected during the harvesting windows in 2007 and 2009, respectively. The in vitro true dry matter digestibility (IVTDMD) and fibre contents (NDF, iNDF, acid detergent fibre) were determined by near infrared reflectance spectroscopy (NIRS). The NDFD and potentially digestible NDF digestibility (pdNDFD) were estimated, and the fractional digestion rate of pdNDF was calculated. There was no relationship between growing days and iNDF as a proportion of NDF (P = 0·28) or with the fractional digestion rate of pdNDF (P = 0·30). Therefore, NDFD (mean = 335 g kg−1) and pdNDFD (mean = 657 g kg−1) remained almost constant during the harvesting window (P = 0·70 and P = 0·32 respectively). Acid detergent fibre and NDF were the best predictors of sugarcane dry matter (DM) digestibility. In conclusion, NDFD seems to be unchanged during crop growth. The point at which to harvest sugarcane as a forage source should therefore be decided based on NDF concentration, which is greatly influenced by sucrose accumulation.

Effects of tillage and nitrogen fertilisation on triticale grain yield, chemical composition and nutritive value

Given the interest in the development of cultivation systems with low agronomic input and environmental impact, the aim of this study was to determine the influence of tillage system (conventional tillage (CT), two-layer tillage (TT), surface tillage (ST) and minimum tillage (MT)) and nitrogen (N) fertilisation rate (0, 50 and 100 kg ha(-1)) on triticale grain and protein yields, chemical composition and nutritive value. There were no significant differences among tillage treatments in grain and protein yields. ST resulted in significantly higher crude protein (CP) and true soluble protein (TSP) contents as well as in vitro crude protein digestibility (CPD). Neutral detergent fibre concentration was significantly higher with ST than with MT, and this led to a small reduction (2 g kg(-1) dry matter (DM)) in in vitro true DM digestibility (IVTDMD). N fertilisation significantly increased grain and protein yields as well as CP, non-protein nitrogen and TSP contents and CPD. IVTDMD was significantly lower with 0 kg N ha(-1) than with 50 and 100 kg N ha(-1). Reducing tillage intensity improved the CP content and CPD of triticale grain. The application of 50 kg N ha(-1) resulted in good grain quality parameters and grain and protein yields.

Grazing Schedule Effect on Forage Production and Nutritive Value of Diverse Forage Mixtures

The use of complex mixtures (mixtures of more than three species) may increase yield of pastures; however, we know little about how grazing management affects the productivity of mixtures. A grazing experiment was performed during 2005 and 2006 near State College, PA, to compare mixtures of grasses, legumes, and chicory (Cichorium intybus L.) for their botanical composition, nutritive value, and forage production under two grazing schedules: when the sward reached 25 cm in height (sward height schedule, SH) or when alfalfa (Medicago sativa L.) reached the bud stage (morphology or MP schedule). The SH schedule produced 30% more dry matter (DM) than the MP schedule averaged for 2 yr. Forage yield of the five‐species (6427 kg ha−1 in 2005 and 6624 kg ha−1 in 2006) and seven‐species (6816 kg ha−1 in 2005 and 6772 kg ha−1 in 2006) mixtures was stable during the contrasting weather of 2005 and 2006. Grass monoculture with N and simple mixtures (two species, grass–legume) produced 989 kg ha−1 more DM than the complex mixtures in 2006 when weather conditions were favorable. The SH schedule produced forage of better nutritive value compared with the MP schedule at first harvest in both years [20 g kg−1 less acid detergent fiber (ADF) in 2006; 25 g kg−1 in 2005, 53 g kg−1 in 2006 more neutral detergent fiber (NDF); 21 g kg−1 in 2005, 30 g kg−1 in 2006 more crude protein (CP); and 33 g kg−1 in 2006, 53 g kg−1 more in vitro true dry matter digestibility (IVTDMD)]. Complex mixtures of forage species provide more consistent yields of DM than binary grass–legume mixtures or grass monocultures in variable environments.

Chemical composition of Mopane worm sampled at three sites in Botswana and subjected to different processing

Effects of site and degutting on chemical composition of mopane worm were investigated. Samples were cooked for 30 min in either brine or in plain water. Samples from Moreomabele were high in acid detergent fibre (ADF) (P < 0.05) and acid detergent insoluble nitrogen (ADIN) (P < 0.01) while samples from Sefophe had least ADF and ADIN concentrations. In vitro true dry matter digestibility (IVTDMD) tended (P = 0.06) to be high in samples from Maunatlala than those from Moreomabele and Sefophe. No site difference (P > 0.05) was observed on the rest of the variables. Degutted samples had high crude protein (CP), ADF and IVTDMD (P < 0.05) but lower (P < 0.001) concentrations of ash, acid detergent lignin (ADL) and condensed tannins. Acid detergent insoluble nitrogen was significantly higher (P < 0.001) in degutted than whole samples. Salting did not (P > 0.05) change concentrations of all but ADF which tended (P = 0.09) to be high in salted samples. Samples which were degutted and salted had higher (P < 0.01) ADF and ADIN than degutted and salted or those left whole and salted or left unsalted. Leaving samples as whole diluted the concentration of CP but increased the fibre components and condensed tannins content. However, mopane worm destined for livestock feeding may be left whole and salt added.

Yield and nutritive value of timothy as affected by temperature, photoperiod and time of harvest

AbstractScenarios of global climate change forecast an increase in air temperature of 3°C over the next 100 years in eastern Canada. Growth and nutritive value of cool‐season grasses are known to be affected by air temperature. It is also believed that grasses grown at high latitude have a greater nutritive value. The objectives of this study were to assess the effect of four combinations of day/night temperature and photoperiod (15 h–17/5°C; 15 h–22/10°C; 15 h–28/15°C; and 17 h‐17/5°C) on dry‐matter (DM) yield, in vitro true DM digestibility (IVTD), in vitro digestibility of neutral‐detergent fibre (NDF), and concentrations of NDF, acid‐detergent fibre (ADF), lignin, minerals and non‐structural carbohydrates (NSC) in timothy grown under controlled conditions. Furthermore, herbage was harvested in the morning and in the afternoon to assess the impact of the time of harvest. The dietary cation–anion difference [DCAD = (K+ + Na+) − (Cl− + 0·6 S2−)] and the grass tetany index [GT index = K+/(Ca2+ + Mg2+)] were also calculated. Higher temperature regimes significantly decreased IVTD and digestibility of NDF but had a limited effect on concentrations of NDF, ADF and lignin. DM yield of herbage was less and the concentration of NSC was greater in timothy grown under a temperature regime of 28/15°C than the 17/5°C and 22/10°C regimes; this effect is mainly explained by a response to temperature stress. Values of DCAD and the GT index of herbage were also lower under the 28/15°C than the 17/5°C and 22/10°C regimes as a result of a decreased plant K concentration. Under the 17/5°C regime, an increase in 2 h of photoperiod resulted in increased DM yield, decreased concentrations of K, Ca, Mg, Cl and N, and an increased starch concentration; IVTD or digestibility of NDF were not affected, although lignin concentration was reduced. Harvesting timothy in the afternoon rather than in the morning resulted in higher NSC, mainly sucrose, concentrations, and decreased ADF and NDF concentrations. The forecasted increase in air temperature in eastern Canada over the next 100 years will result in lower yields and nutritive value of timothy.

Valor nutritivo de silagens de capim-marandu submetidas aos efeitos de umidade, inoculação bacteriana e estação do ano

O estudo foi realizado para avaliar o efeito da estação do ano, do teor de matéria seca (MS) e da inoculação bacteriana sobre o valor nutritivo de silagens de Brachiaria brizantha cv. Marandu. O delineamento experimental foi o inteiramente casualizado, disposto em arranjo fatorial (2 × 3 × 3), com duas estações do ano (verão e inverno), três teores de MS (com ou sem emurchecimento ou adição de polpa cítrica peletizada, PCP) e ausência ou presença de inoculante (Lactobacillus plantarum ou Lactobacillus buchneri), perfazendo 18 tratamentos, cada um com quatro repetições. As silagens foram confeccionadas em baldes de plástico de 20 L. Após 90 dias do fechamento, os silos foram abertos para as avaliações. O emurchecimento elevou os teores de matéria seca (MS), fibra em detergente neutro (FDN) e lignina (LIG) em ambas as estações, porém não alterou o coeficiente de digestibilidade verdadeira in vitro da MS (DVIVMS) das silagens. A adição de PCP aumentou os teores de proteína bruta (PB) e carboidratos solúveis (CHO) e reduziu os teores de FDN, o que resultou em silagens com maior DVIVMS em ambas as estações. A inoculação não alterou a fração fibrosa e não aumentou a DVIVMS das silagens. As silagens de verão apresentaram maiores teores de PB e menores constituintes da parede celular, com exceção da hemicelulose (HEMI), o que resultou no maior coeficiente médio de DVIVMS dessas silagens. O baixo valor nutritivo das silagens de inverno contraria os resultados descritos na literatura, principalmente em virtude da maior idade de rebrotação do capim-marandu nesta estação. Desta forma, silagens de verão podem ser recomendadas como volumoso suplementar, principalmente quando acrescidas de PCP.

Temporal and Vertical Distribution of Nonstructural Carbohydrate, Fiber, Protein, and Digestibility Levels in Orchardgrass Swards

Herbage nonstructural carbohydrates (NC) contribute to livestock performance and silage fermentation. Knowledge of the distribution patterns of NC and other nutritional constituents in orchardgrass (Dactylis glomerata L.) swards could support harvest management decisions. Our objective was to determine diurnal and vertical patterns of total NC (TNC), crude protein (CP), and neutral detergent fiber (NDF) concentrations, and in vitro true dry matter digestibility (IVTDMD) and NDF digestibility (NDFD) in orchardgrass swards in October, June, and August. Herbage was sampled at 6‐h intervals between 0100 and 1900 h from horizons positioned 40 to 27, 27 to 18, 18 to 12, and 12 to 8 cm above soil surface. Herbage composition varied among horizons in all months, and diurnally only in June and August. In June and August, only TNC with maxima of 109 to 123 g kg−1 at 1900 h exhibited consistent diurnal patterns. Swards harvested to residual heights of 18, 12, or 8 cm exhibited little spatial variation in TNC during June and August, but CP, NDF, and IVTDMD varied with harvest depth on all dates. As swards were harvested to successively greater depths, TNC increased in October, but not in June and August. In contrast, CP and IVTDMD decreased, and NDF increased, for harvests to successively greater depths in all months. For harvests in June and August, manipulation of depth would capture more variation in CP, NDF, and IVTDMD, but manipulation of time of day of harvest would capture more variation in TNC to meet animal performance and silage fermentation requirements.

Effect of traditional processing methods on chemical composition and in vitro true dry matter digestibility of the Mophane worm ( Imbrasia belina)

Effects of traditional processing methods on the nutritional value of Mophane worm ( Imbrasia belina) were evaluated. Samples were degutted or not degutted. The worms were further subjected to either cooking for 1 h (remaining in boiling water for 45 min), hot ash roasted for 5–7 min or not treated (control). Treatment had an effect on the level of most minerals, on the in vitro true dry matter digestibility (IVTDMD) ( P<0.001), crude protein (CP) and magnesium (Mg) ( P<0.05). Fiber components, acid detergent insoluble nitrogen (ADIN) and manganese (Mn) and available CP (CP av) were not affected ( P>0.05). Degutting had an effect on CP, fiber components, minerals, ( P<0.001), ADIN, IVTDMD and Mn ( P<0.01). Leaves from Mophane vegetation in the undegutted Mophane worm samples diluted levels of CP, ADIN, Zn, Mn and IVTDMD but increased the levels of ash, fibre components, Ca, and P. Mg and CP av were not ( P>0.05) affected by degutting. There were no interactions ( P>0.05) between treatment and degutting for ash CP, CP av, ADF, ADL, ADIN, P, Zn, Mn or Mg. An interaction was observed for NDF ( P<0.01), Ca ( P<0.001) and IVTDMD ( P<0.05). A significant and negative correlation was observed between ADF and IVTDMD ( r=−0.86, P<0.001). CP and IVTDMD were positively correlated ( r=0.88, P<0.001). Therefore, it will not be necessary to degut Mophane worms destined for livestock feeding. High fibre levels in the undegutted Mophane worms would make it necessary to degut worms which are destined for human consumption. Given the scarcity of protein in Botswana it is important to evaluate locally available feed resources as potential livestock feeds.