Greater Neutral Detergent Fiber Research Articles

73 Effects of Fatty Acids Sources and Lysophospholipids on Nutrient Digestibility in Lactating Cows

Abstract Fatty acids (FA) are a common supplement for lactating cows to increase energy supply, potentially improving feed efficiency and milk and milk fat yields. However, different FA can cause varying responses probably because of different FA digestibility and interactions with other nutrients (e.g., fibers). Lysophospholipids (LPL) are natural emulsifiers and LPL as a feed additive have shown increases in FA digestibility and nutrient absorption in non-ruminant animals. This study aimed to investigate the effects of FA sources with LPL supplementation on nutrient digestibility in lactating cows. Mid-lactation cows (n = 48) were allocated into 12 blocks, and cows in each block were randomly assigned to the following dietary treatments:1) a diet with a FA supplement [1.8% of dietary dry matter (DM)] mainly containing palmitic acid (PA); 2) the PA diet with LPL (0.003% of dietary DM); 3) a diet with a FA supplement (1.8% of dietary DM) mainly containing stearic acid (SA); and 4) the SA diet with LPL (0.003% of DM). The experiment was conducted for 6 weeks, and spot samples of feces and urine were collected over 3 days (every 3 hours within a 24-hour cycle) during the last week of the experiment to determine nutrient digestibility and utilization. Data were analyzed using the mixed model with FA source, LPL, and their interaction as fixed effects and block as a random effect. The digestibility of DM, organic matter, and crude protein were not affected by the FA source and no interaction between FA and LPL was observed. However, PA had greater neutral detergent fiber (NDF) digestibility (41.4 vs. 38.8%; P = 0.04) than SA with no interaction between the FA source and LPL. In addition, as expected, PA decreased (P < 0.01) the digestibility of 16-carbon FA compared with SA due to the greater C16:0 supply, and SA decreased (P < 0.01) that of 18-carbon FA compared with PA due to the greater C18:0 supply. Supplementation of LPL did not affect digestibility of DM, OM, CP, and NDF, but increased total FA digestibility (64.7 vs. 60.5%; P = 0.02) compared with no LPL. In addition, LPL increased 18-carbon FA digestibility (68.2 vs. 74.1%; P < 0.01) compared with no LPL. An interaction between LPL and FA was observed for 16-carbon digestibility because LPL increased 16-carbon digestibility with SA but not with PA. In conclusion, PA supplementation improved fiber digestibility compared with SA, which could be a factor for increased productivity (e.g., milk fat). Supplementation of LPL was effective in increasing FA digestibility and may have potential to increase dietary energy supply or provide a similar energy supply with less dietary fat content in practice. However, more studies are needed to understand different interactions of LPL with FA sources.

Chemical, Physical, and Degradation Characteristics of Ryegrass Cultivars Grown in Autumn and Winter for Dairy Cows.

During winter and early spring, pasture supply is usually lower than the demand in New Zealand dairy farming systems and thus the 'autumn saved pastures' (stockpiling) are introduced to fill the gap. This study aimed to investigate the chemical, physical, and degradation characteristics of ryegrass pastures, the predominant forage in New Zealand, grown in autumn and winter. To serve as 'autumn saved pasture', nine ryegrass cultivars, comprising three types (three perennial, three hybrid, and three Italian), were grown in late autumn (Autumn) and early winter (Winter) and harvested after 7 and 9 weeks of regrowth, respectively. The experiment had two experimental factors: ryegrass type (or cultivar) and harvest season. These experimental factors were in a randomised block design with the forage plot as the experimental unit. The degradation characteristics were assessed in the rumen of fistulated cows using the in situ incubation technique. Perennial ryegrass had a greater neutral detergent fibre (NDF) concentration (468 g/kg dry matter (DM)) than the hybrid (435 g/kg DM) or Italian (414 g/kg DM) ryegrasses. Italian ryegrasses had the greatest soluble fraction of DM (64.2% vs. 46.7% and 40.7%) and the greatest degradation rate of an insoluble but degradable fraction of DM (0.221 vs. 0.189 and 0.145/h) than the hybrid and perennial ryegrasses. Compared with the Winter ryegrass, the Autumn ryegrass had a greater crude protein concentration (246 vs. 208 g/kg DM) and a greater NDF concentration (486 vs. 392 g/kg DM) but a lower calculated soluble carbohydrate concentration (152 vs. 263 g/kg DM). It is concluded that there are notable variations among the cultivars, highlighting distinctions in parameters, such as NDF concentration, soluble fractions, degradation rates, and nutrient content among the perennial, hybrid, and Italian ryegrasses, as well as the seasonal variations observed between autumn and winter growth. These findings will not only facilitate enhanced nutrition for dairy cows as they undergo the transition phase but also have practical implications for future research and dairy cow nutrition.

Effect of Feeding Different Percentages of Acacia saligna Foliage Hay on Barki Ewes Performance

The study was conducted to evaluate the effect of replacing berseem hay (BH) with dried Acacia saligna foliage (AFH) on the performance and some blood parameters of pregnant Barki ewes. Thirty-Two aged 2-3 years old at the last third of pregnancy (eight in each group, 40.5 ± 0.96 Kg body weight) were fed 0 (Control), 25, 50 and 75% of AFH in replacement of BH. All animals fed 2% of their body weight concentrate feed mixture and ad libitum quantities of BH or AFH forages for 84 days. Average daily change in body weight of ewesduring lactation, milk yield and composition, rumen liquor parameters (pH, volatile fatty acids, ammonia-N and protozoa count), lamb’s growth performance and some serum biochemical parameters weredetermined.Economic evaluation for the tested levels of forages was also estimated. Data were statistically analyzed using SAS computer program software utilizing the general linear model (GLM) procedure. The findings revealed that while AFH had greater neutral detergent fiber (NDF), acid detergent fiber (ADF) andcrude proteins (CP) values than BH, it had lower amounts of dry matter (DM), crude fiber (CF), ether extracts (EE) and fiber fractions. Total DM intake (g/h/day or g/Kg W ) of lactating ewes did not influence significantly by AFH 0.75 replacement in the diets. The replacement of BH with AFH at the rate of 75% resulted in increasing (P<0.05) individual (Acetic, butyric and propionic) and total volatile fatty acids (VFA) concentrations compared with the control treatment. The tested incorporation levels of AFH did not influence the live body weight during the lactation period. Neglecting the lamb's sex, the tested levels of AFH had noeffect onbirth weight and body weight changes from birth till weaning. Ewes fed 75% AFH recorded the highest total milk yield and daily milk yield compared to the other tested diets.Treatmentsaffects insignificantlyfat and protein yields. Moreover, no significant effect noticed among the experimental groups in serum biochemical tested parameters. Ewes fed ration containing 75% AFH recorded the best economic efficiency compared to other tested rations.

20 Forage Production and Nutritive Quality of Dual-purpose Wheat Managed Under Three Different Grazing Frequencies in the Southeastern United States

Abstract Grazing of dual-purpose wheat is an established management system in the Great Plains regions of the United States. Varietal and climatic differences between regions has limited use of dual-purpose systems in the Southeast. The objective of this study was to evaluate four wheat varieties, [feed wheat (mixed variety, Feed), seed wheat (‘GA Gore’) and two forage varieties, ‘AGS 2024’ (AGS) and ‘Pioneer 26R41’ (Pioneer)], under three grazing treatments [no-grazing (NG), low frequency (LF), high frequency (HF)]. The experiment was a randomized complete block design (n = 4) using mob-grazing. Forage samples were taken using three 0.1m2-quadrats before (Pre) and after (Post) each grazing event. Crude protein (CP), neutral detergent fiber (NDF) and acid detergent fiber (ADF) were determined on all Pre samples. Wheat grain yield was determined at the end of the season. Data were analyzed using PROC GLIMMIX of SAS (SAS Inst., Cary, NC), a < 0.05. Pre-grazed, AGS seasonal forage production was greater (P < 0.01) than all other varieties (1,517 kg/ha vs 1,031 kg/ha, respectively). Post-grazing biomass from AGS and Pioneer was greater than GA Gore (817 vs 512 kg DM/ha, respectively; P = 0.04). Pre-grazing, Feed, GA Gore and Pioneer had greater (P < 0.01) CP than AGS (31.6 vs. 30.1%, respectively). The concentration of NDF was greatest for AGS (39.1%) compared with all other varieties (34.9%, P < 0.01). Grazing frequency did not affect CP (P = 0.67). The NG plots had greater NDF and ADF than LF and HF (37.5 vs. 35.2% and 19.8 vs. 18.6%, respectively; P < 0.01). Pioneer had the greatest grain yield but was not different from AGS (57.6 and 52.4 kg/ha, respectively; P = 0.41). Management of wheat as a dual-purpose crop is feasible in the Southeast. More information is needed to determine the economic impact of this management practice.

Intake, ruminal fermentation parameters, and apparent total-tract digestibility by beef steers consuming Pensacola bahiagrass hay treated with calcium oxide.

To determine the effect of CaO-treated Pensacola bahiagrass (Paspalum notatum) hay on intake, ruminal fermentation parameters, and apparent total-tract digestibility of nutrients, nine ruminally cannulated Angus-crossbred steers were used in a triplicated 3×3 Latin square design. Steers had ad libitum access to either 1) untreated dry hay (DH; n = 8); 2) hay at 50% DM treated with 8.9% CaCO3 (dry matter [DM] basis; CC; n = 9); or 3) hay at 50% DM treated with 5% CaO (DM basis; CO; n = 8). Water was added to reach 50% DM in the CC and CO diets. Ruminal fluid and blood samples were collected every 3h for 24h. Ruminal fluid was analyzed for pH, volatile fatty acids (VFA), and ammonia-nitrogen (NH3-N). Blood was analyzed for plasma urea nitrogen (PUN). Hay and fecal samples were collected for 4 d, four times daily for hay and twice daily for feces, to determine apparent total-tract digestibility of nutrients. The hay provided to steers during the digestibility period was analyzed for in vitro organic matter digestibility (IVOMD) for 48h. Data were analyzed as repeated measures for blood and ruminal fermentation parameters. Total DM intake was not affected (P ≥ 0.674) by treatment. A treatment effect (P < 0.001) was observed for average ruminal pH, where steers consuming CO had the greatest pH (P < 0.001). Ruminal concentration of NH3-N tended (P = 0.059) to be reduced in steers consuming CO. There was a treatment × time interaction (P = 0.023) on concentrations of PUN, where at 3h DH and CO were lesser than CC (P ≤ 0.050) and at 21h DH was lesser than CC (P = 0.020). Total VFA, acetate, propionate, butyrate, branched-chain VFA, and valerate concentrations were affected by treatment (P ≤ 0.035), where a reduction (P ≤ 0.034) occurred in steers consuming CO. No treatment differences were observed for total-tract digestibility of DM (P = 0.186), organic matter (P = 0.169), or crude protein (P = 0.152); however, steers consuming DH had greater neutral detergent fiber (P = 0.038) than CC and tended to be greater than CO (P = 0.082). The CO hay had greater (P = 0.005) IVOMD compared with DH and tended (P = 0.100) to be greater than CC. Bahiagrass hay treated with CaO may reduce ruminal fermentation, as indicated by decreased total VFA concentration without altering DM intake. The addition of CaO did not improve the digestibility of bahiagrass hay in vivo; however, in vitro results are contradictory and warrant further elucidation.

Effect of concentrate supplement to ewes on nutritive value of ingested Caatinga native forage nutritive value as affected by season.

The objective of this study was to identify by microhistological technique the reference chemical components for use as indicators of the nutritive value of Caatinga plants forage grazed by sheep throughout the year. A flock of twenty mixed-race meat ewes, multiparous, in production, with an average 34.84 ± 1.75kg live weight and 36months of age was assigned to supplement treatment of 0, 200, 350, and 500g concentrate/head/day for 3years. The experiment was designed as a randomized complete design with repeated measures over time. Supplementation with concentrate did not influence chemical composition of selected forage. In contrast, season heavily influenced diet chemical composition. Canopy stratum, season, and plant botanical family of selected species affected forage chemical composition selected by ewes. The ewes selected forage with greater nutritive value during the rainy season. Based on principal component analysis of the nutritive value of the primary forage species selected, ewes preferentially grazed plants contained greater neutral detergent fiber, acid detergent fiber, crude protein (CP), C fraction of nitrogenous compounds, and carbohydrate fractions A + B1 and C compared to the average native Caatinga herbage. Rangeland botanical composition and ewe diet varied during the year, affecting forage nutrients on offer, with the best diet selected during the rainy season because of the presence of dicotyledonous herbaceous species rich in CP as well as soluble carbohydrates and nitrogenous compounds. Concentrate supplement strategies for ewes on rangelands, such as Caatinga, should be determined by herbaceous species nutritive value during the rainy season and deep-rooted perennial dicotyledons during the dry season. These include the need to monitor ewe selection of forage species and their nutritive value, which is effectively accomplished with fecal microhistological techniques.

Bromatological composition and ruminal degradability of Xaraés palisade grass under grazing in integrated systems

To evaluate the bromatological composition and ruminal degradability of dry matter (DM), crude protein (CP), neutral detergent fiber (NDF) and acid detergent fiber (ADF) of Xaraés palisade grass (Urochloa brizantha ‘Xaraes’ syn Brachiaria brizantha) under grazing in integrated crop, livestock (ICL), and forest (ICLF) systems, we conducted an in situ degradability trial in randomized blocks with three non-lactating 3/4 Gyr × 1/4 Holstein cows, provided with ruminal cannula. The management of Xaraés palisade grass was similar in both systems, differing only regarding shading in the ICLF system provided by eucalyptus trees (average 65% crown cover). Grass samples were incubated for 0, 3, 6, 9, 12, 24, 36, 48, 72, and 96 hours. Considering the passage rate 2% h-1, the Xaraés palisade grass of ICL system had greater NDF effective degradability in relation to ICLF (46.38% vs 44.98%). However, the palisade grass CP potential degradability was greater in the ICLF than in the ICL system (68.92% vs. 65.40%). The presence of trees in the pasture has effect on nutritional traits of the Xaraés palisade grass, increasing its protein content and degradability and reducing its fiber degradability.

Fractional Harvest of Fodder Galega for Improved Herbage Nutritive Value

Fodder galega (Galega orientalis Lam.) is a long-lived perennial legume grown for forage and green manure in northern and central Europe. It is distinguished by a high proportion of leaves in the aboveground mass, tall hollow stems, and rhizomes. A method to harvest galega allowing the separation of leaves, upper stem fragments, and inflorescences from the thick, woody parts of the stem is therefore justified. This would significantly expand the possibilities of using galega herbage, including as feed for monogastric animals. A modified flail chopper (MFC), a machine originally used for harvesting green forage, was used for the fractionated harvest of galega. The aim of this study was to evaluate the yield potential of various plant fractions of the first and second cut of fodder galega at three development stages and their nutritive value when harvested with an MFC. With this harvest system, 68–78% of the potential dry matter yield of galega was harvested, where leaves accounted for 73% of the dry matter on average, while the proportion of leaves in the yield of galega harvested with a mower (M) ranged from 50% to 60%. In the biomass of the first cut of galega, harvested with the MFC, protein concentration was 215 g kg−1, 11.5% greater than in the biomass of the whole aboveground mass harvested with a mower. In the second cut, this difference, in favor of the MCF, was greater by 14%. The concentration of neutral detergent fiber (NDF) was 7.5% lower and acid detergent fiber 11% lower in galega forage harvested with the MFC compared to with a mower. Furthermore, galega harvested with MFC had 13% greater NDF digestibility and 6% greater in vitro true digestibility. The stubble remaining after MFC harvest accounted for 33% of the total height and 27% of the plant dry mass, and its qualitative composition indicates that it could be used in rations of livestock with low nutritional requirements or for non-forage purposes. Galega harvest with the MFC resulted in greater protein concentrations and overall improved nutritive value of the forage even at advanced development stages.

Effects of harvest date and grass species on silage cell wall components and lactation performance of dairy cows

This study evaluated the effect of harvest date and forage species on the concentration of hydroxycinnamic acids in silage and its relationship to dairy cow performance. Tall fescue and timothy were harvested at a regular date on June 27 and July 8, respectively, or at a late date on July 8 and 25, respectively, in the first regrowth. Forage was treated with a salt-based additive and ensiled in hard-pressed round bales. Forty-seven lactating dairy cows were used in a block design. Cows received 1 of 4 treatments: (1) tall fescue harvested at regular date (RTF), (2) timothy harvested at regular date (RTI), (3) tall fescue harvested at late date (LTF), and (4) timothy harvested at late date (LTI). Diets were formulated to have the same forage-to-concentrate ratio (46:54 on a dry matter basis). Harvesting at late date increased fiber components, but only for timothy, where LTI contained greater neutral detergent fiber, acid detergent fiber, and acid detergent lignin concentrations than the other silages. Concentrations of hydroxycinnamic acids were affected by forage species, where concentrations of esterified ferulic acid and p-coumaric acid were greater for tall fescue silages than for timothy silages. Cows fed the RTI diet showed the greatest intakes of dry matter, organic matter, and crude protein. Feeding diets containing timothy silages increased milk yield and energy-corrected milk yield compared with tall fescue diets when averaged over harvest dates. Cows fed the RTI diet had greater milk protein yield than cows fed the RTF and LTF diets, and milk lactose yield was greater for cows fed diets containing timothy silage compared with tall fescue silage when averaged over harvest dates. Cows fed the LTF diet showed greater urinary N excretion compared with the LTI diet, but RTI showed the lowest urinary N and urea N excretions when calculated as percent of N intake. Cows fed diets containing timothy silage excreted more uric acid than cows fed tall fescue diets. Allantoin excretion was greater for cows eating the RTI and LTI diets compared with cows eating the RTF diet. Cows fed the RTI diet had a greater estimated microbial N flow and a greater excretion of hippuric acid than the RTF and LTF groups. In conclusion, besides the effect of harvest date on increasing the fiber components of timothy, concentrations of hydroxycinnamic acids were mainly affected by forage species; consequently, milk production was only affected by forage species. This indicates that hydroxycinnamic acids, such as ferulic acid, which cross-links to glucuronoarabinoxylans, was a major factor regulating milk production of cows fed tall fescue- and timothy silage-based diets, where lower hydroxycinnamic acid concentrations were responsible for greater milk yield.

Yield and nutritive value of grazed complex legume–grass mixtures under increasing nitrogen application rates

Complex pasture mixtures are advantageous, but little information exists on the best forage species and nitrogen (N) management in eastern Canada. We compared under mob stocking four complex mixtures of one of two legume species [alfalfa (Medicago sativa L.) and birdsfoot trefoil (Lotus corniculatus L.)] plus one of two grass mixes [No. 1 — timothy (Phleum pratense L.), meadow fescue (Schedonorus pratensis (Huds.) P. Beauv.), reed canarygrass (Phalaris arundinacea L.), and Kentucky bluegrass (Poa pratensis L.); No. 2 — tall fescue (Schedonorus arundinaceus (Schreb.) Dumort., nom. cons.), meadow bromegrass (Bromus biebersteinii Roem. and Schult.), reed canarygrass, and Kentucky bluegrass] under three N application rates at three sites over the first three post-seeding years. Legume species had little effect on most forage attributes mainly because of their low contribution to forage dry matter (DM) yield (&lt;30%) in second and third years. The grass mix with tall fescue and meadow bromegrass (No. 2) yielded similar or slightly better than the one with timothy and meadow fescue (No. 1) but tended to have a greater neutral detergent fibre concentration, and lower N and total digestible nutrient concentrations. Nitrogen fertilization increased forage DM yield only in second and third years when the legume contribution to forage DM yield was &lt;30%, and it increased N concentration and decreased nonstructural carbohydrate concentration. These results highlight the challenge of maintaining legume species in rotationally grazed pastures of eastern Canada and confirm recommendations of applying no or little N fertilizer on grazed legume–grass mixtures when the legume contribution to forage DM yield is &gt;30%.

Short communication: Diet digestibility measured from fecal samples and associations with phenotypic and genetic merit for milk yield and composition

Selection for improved feed utilization is of high interest globally but is limited by the high cost of obtaining feed intake for individual cows and relies on indirect measures of feed efficiency. Supplementing selection with mechanistic measures of feed use could make selection for feed utilization more direct and effective. The objectives of this study were to evaluate fecal sampling as a method of determining digestive efficiency of individual cows and to evaluate associations of digestive efficiency with genetic and phenotypic merit for milk yield and composition. Fecal samples were obtained manually from the rectum of 90 Holstein cows in the morning, afternoon, and evening on a single date and composited across the day. The fecal samples were dried, ground, and stored. Diet and fecal neutral detergent fiber (NDF) were determined using the filter bag method, and indigestible NDF was determined in situ with a 12-d rumen incubation. Fecal NDF (60.1%) and indigestible NDF (41.9%) were higher than that from feed samples (14.2 and 35.9%, respectively). Total-tract digestibility was calculated using the marker ratio method. Total-tract dry matter (DM) digestibility averaged 66.0 ± 2.4% and total-tract NDF digestibility averaged 42.8 ± 3.0%. Higher milk fat percent and genetic merit for milk fat percent were associated with greater NDF and DM digestibility. Milk yield was negatively associated with NDF and DM digestibility. Fecal sampling is a feasible method to directly measure digestive efficiency, and substantial variation was observed among cows. Given significant between-cow variation and associations with milk fat percent and genetic merit for milk fat percent, potential selection for total-tract NDF digestibility estimated via fecal sampling warrants further exploration.

Forage yield, nutritive value, and ensilability of sweet pearl millet and sweet sorghum in five Canadian ecozones

Sweet pearl millet [Pennisetum glaucum (L.) R. Br.] and sweet sorghum [Sorghum bicolor (L.) Moench], previously tested for ethanol production, were evaluated as high sugar crops for animal feeds to possibly replace silage corn (Zea mays L.). We compared the forage yield, nutritive value, and ensilability of one hybrid of sweet pearl millet and two of sweet sorghum to a locally adapted silage corn hybrid in five Canadian ecozones. Forage yields of sweet pearl millet and sorghum were similar to that of silage corn in the Boreal Shield, Mixedwood Plain, and Atlantic Maritime ecozones, greater in the Prairies, and lower in the Pacific Maritime ecozone. Across sites, forage dry matter concentration was less for sweet pearl millet (289 g kg−1) and sweet sorghum (245 g kg−1) than for silage corn (331 g kg−1). Sweet pearl millet had a lower total digestible nutrient (TDN) concentration (452 g kg−1 DM) and aNDF digestibility (NDFd) than sweet sorghum and silage corn along with greater neutral detergent fibre (aNDF) and water-soluble carbohydrate (WSC) concentrations than silage corn. Sweet sorghum had greater aNDF and WSC, lower starch, and similar TDN (534 g kg−1 DM) concentrations, but greater NDFd compared with silage corn. Sweet pearl millet and sorghum fermented as well as silage corn, reaching low pH values and acceptable concentrations of lactic and volatile fatty acids. Sweet sorghum is therefore a viable alternative to silage corn in Canada except in the Pacific Maritime ecozone, but early-maturing hybrids with acceptable DM concentration at harvest are required.

Effects of microbial feed additives on feed utilization and growth performance in growing Barki lambs fed diet based on peanut hay

The effects of supplementing diet of growing lambs with microbial feed additive mixture (direct-fed microbial; DFM) based on Saccharomyces cerevisiae, lactic acid bacteria and exogenous enzymes on feed intake, nutrient digestibility, nitrogen (N) utilization, ruminal fermentation, blood chemistry and growth performance were studied. The study was a completely randomized design with 12 growing Barki lambs divided into two groups of six lambs per treatment. Lambs were offered a control diet of peanut hay and concentrates (1:1 dry matter (DM) basis) or the control diet supplemented with DFM at 0.5 g/day (Bactozyme treatment) for 16 weeks. There was no effect on feed efficiency but Bactozyme lambs had increased (p = 0.009) feed intake, average daily gain (p = 0.042) and final body weight (p = 0.047). Bactozyme treatment had greater neutral detergent fiber (p = 0.020) and acid detergent fiber (p = 0.034) digestibility compared with the control treatment. Metabolism experiment showed that the feed additive mixture increased (p<0.05) N intake and N retention. Bactozyme treatment had greater blood total protein (p = 0.027), and globulin (p = 0.025) concentrations compared with the control treatment. It is concluded that supplementing growing Barki lambs with DFM at 0.5 g daily enhanced final body weight gain and fiber digestion without affecting feed efficiency.

Variability in the Chemical Composition and In Vitro Ruminal Fermentation of Olive Cake By-Products.

Simple SummaryOlive cake is a by-product of oil production that can be used in ruminant feeding, but its composition can vary with multiple factors. The objective of this study was to determine the variability in the chemical composition and in vitro ruminal fermentation of 42 olive cake samples to evaluate their nutritive value for ruminants. The results showed that the chemical composition of olive cake is highly variable and is markedly affected by processing type and its storage time before processing. Cyclone olive cake had greater nutritive value for ruminants than both crude and extracted olive cake. All olive cake types were poorly degraded in vitro and, therefore, their nutritive value is highly dependent on their ether extract content. Statistical models using olive cake processing type, and either the chemical composition or storage time before processing as covariates, can be used in the practice to predict in vitro ruminal fermentation variables of olive cake samples. The obtained information may contribute to increase the use of olive cake in ruminant feeding.The objective of this study was to determine the variability in the chemical composition and in vitro ruminal fermentation of olive cake (OC) by-products. Forty-two OC samples with different storage times (1–14 months) and processing (25 crude (COC), 9 exhausted (EOC) and 9 cyclone (CYOC)) were fermented in vitro with sheep ruminal fluid. Exhausted OC samples had a lower ether extract content than COC and CYOC (15.9, 110 and 157 g/kg dry matter (DM), respectively), but greater neutral detergent fiber (NDF; 645, 570 and 441 g/kg DM) and acid insoluble nitrogen (9.76, 8.10 and 8.05 g/kg DM) content. Exhausted OC had the greatest (p < 0.05) average gas production rate (AGPR), whereas the greatest fermented organic matter (FOM) was obtained for EOC and CYOC. The best single predictor of the AGPR was total sugars content (R2 = 0.898), whereas NDF was the best one for FOM (R2 = 0.767; p < 0.001). Statistical models using storage time as a predictor variable had lower accuracy and R2 values than those from the chemical composition. In summary, the nutritive value of OC was highly dependent on its processing, but its ether extract content did not negatively affect ruminal fermentation parameters, which could be estimated from either carbohydrate composition or storage time.

Nutritive value, fermentation characteristics, and in situ disappearance kinetics of sorghum silage treated with inoculants

Fibrolytic enzymes and microbial inoculants have the potential to improve the value of sorghum feedstuff and feedstock. An experiment was conducted to determine nutritive value, ensiling characteristics, and in situ disappearance kinetics of 4 sorghum (Sorghum bicolor L.) silage varieties: Dairy Master BMR (DBMR; brown midrib; Richardson Seed, Vega, TX), PS 747 (PS; photoperiod sensitive; Pogue Seed, Kenedy, TX), Silo 700D (S700D; conventional forage type; Richardson Seed), and MMR 381/73 (MMR; conventional forage type; Richardson Seed) pretreated with fibrolytic enzyme (xylanase plus cellulase, XC; 50:50 mixture of Cellulase Plus and Xylanase Plus; Dyadic, Juniper, FL) or microbial [Promote ASB (Lactobacillus buchneri and Lactobacillus plantarum); Cargill Animal Nutrition, Indianapolis, IN; PRO] inoculants. The greatest yield was for cultivar PS and the least for MMR. Neutral detergent fiber (NDF) concentration was least for XC-treated silage, and acid detergent fiber (ADF) concentration was least for XC- and PRO-treated silage. When silage was treated with XC, concentrations of NDF concentrations decreased, on average, 4.81% across all cultivars and ADF concentrations decreased, on average, 3.23% in all cultivars except MMR. Inoculant PRO reduced the NDF concentration of DBMR by 6.47%. The ADF concentrations of DBMR and PS treated with PRO were decreased by 3.25%. Treating sorghum silage with XC or PRO reduced the NDF and ADF fractions, which increased cell wall degradability. In vitro true digestibility was greatest for PRO-treated DBMR, whereas acid detergent lignin was least for PRO-treated DBMR. Aerobic stability was not improved by PRO; however, aerobic stability of XC-treated MMR was 63h greater than that of the control. Acetate concentrations were greatest for XC-treated MMR, which explains the 63-h improvement in aerobic stability due to the inhibition of fungi. However, inoculant PRO did not improve yeast and mold counts or aerobic stability of sorghum silage compared with the control, which may be due to the lesser acetate concentrations, especially of PRO-treated S700D silage. Generally, in situ disappearance kinetics were improved with the application of XC and PRO, and XC had the greatest effect on silage with greater NDF and ADF concentrations.

Rumen fermentation and microbial yield of high- or low-protein diets containing ground soybean seeds or homemade rapeseed expellers evaluated with RUSITEC

Guadagnin, M., Tagliapietra, F., Cattani, M., Schiavon, S., Worgan, H. J., Belanche, A., Newbold, C. J. and Bailoni, L. 2013. Rumen fermentation and microbial yield of high- or low-protein diets containing ground soybean seeds or homemade rapeseed expellers evaluated with RUSITEC. Can. J. Anim. Sci. 93: 363–371. This experiment aimed to compare diets containing two crude protein (CP) concentrations [147 or 109 g kg−1in dry matter (DM)] and two protein sources containing ground soybean seed (GSS) or rapeseed expeller (RSE). Diets were compared in terms of digestibility, volatile fatty acids (VFA) and ammonia concentrations, and N flows, using rumen simulation fermenters (RUSITEC). Home−made RSE (CP=287 g kg−1dry matter and ether extract=199 g kg−1DM) was produced using equipment adopted by small farms. Reduction of dietary CP content did not affect digestibility, except for a reduction of N apparent digestibility (P&lt;0.01), but increased efficiency of N utilization (P=0.001) without affecting microbial N production (P=0.82). Total VFA concentration was not (P=0.56) influenced by CP content. Compared with GSS, RSE exhibited a greater neutral detergent fibre digestibility (P&lt;0.01), it did not influence total volatile fatty acids (VFA; P=0.10) but decreased the proportions of acetate and propionate on total VFA (P&lt;0.001) and increased those of butyrate and branched-chain VFA (P&lt;0.001). Microbial efficiency was comparable for GSS and RSE. Results suggest that reduction of dietary CP concentration in DM did not impair in vitro digestibility and microbial growth. The protein mixture containing homemade RSE showed in vitro fermentative properties and microbial growth comparable with those of GSS.

Chemical characterization and in vitro biological activity of four tropical legumes, Styzolobium aterrimum L., Styzolobium deeringianum, Leucaena leucocephala, and Mimosa caesalpiniaefolia, as compared with a tropical grass, Cynodon spp. for the use in ruminant diets

Leucaena leucocephala (LEU) and three under-utilized tanniferous legumes, Styzolobium aterrimum L. (STA), Styzolobium deeringianum (STD), and Mimosa caesalpiniaefolia Benth (MIC) were chemically characterized and the biological activity of tannins was evaluated using in vitro simulated ruminal fermentation through tannin-binding polyethylene glycol (PEG) and compared with a non-tanniferous tropical grass hay, Cynodon spp. (CYN). The Hohenheim gas test was used and gas production (GP) was recorded at 4, 8, 12, 24, 32, 48, 56, 72, 80, and 96 h incubation with and without PEG. Kinetic parameters were estimated by an exponential model. STA, STD, and LEU contained higher (P &amp;lt; 0.05) crude protein than MIC, which had greater neutral detergent fibre and acid detergent fibre. Total phenols, total tannins, and condensed tannins (CT) were consistently the highest in MIC. Gas production was the lowest from MIC (P &amp;lt; 0.05) and the highest in LEU and STA. MIC + PEG largely reduced (P &amp;lt; 0.05) the lag phase and the fractional rate of fermentation and increased potential GP. Kinetic parameters of STA + PEG and LEU + PEG were not affected. LEU + PEG produced greater gas increment (P &amp;lt; 0.05) than STD + PEG, although both legumes had the same CT. All legumes except MIC were more extensively degraded than CYN. However, fermentation of the legumes was differently affected by the presence and proportions of CT, indigestible fibre or both. &amp;nbsp;

Digestibility and Intake of Hays from Upland Switchgrass Cultivars

Switchgrass (Panicum virgatum L.) cultivars with improved forage quality would fill a forage gap during summer when hot dry weather reduces production of cool‐season forages on marginal lands of the northeastern United States. ‘Cave‐in‐Rock’, ‘Trailblazer’, ‘Shawnee’, and ‘Pathfinder’ switchgrass hays were harvested and baled from field plots at Rock Springs, PA, on 29 June 2007, 16 June 2008 (Cut 1), and 8 Aug. 2008 (Cut 2) and fed to mature wether sheep. In 2008, Trailblazer was unavailable so Pathfinder was substituted. Morphological development stage and leaf and stem proportions were determined at each harvest. In 2007, cultivars did not differ in digestion of dry matter (DM) or fiber constituents and sheep consumed switchgrass hays similarly. In 2008, sheep consumed hay of switchgrass cultivars similarly but consumed more of Cut 1 than Cut 2 hay. Cut 1 hay also had greater neutral detergent fiber (NDF) and hemicellulose digestibility than Cut 2 hay. Shawnee consistently had lower DM, fiber, and crude protein digestibility (CPD) than Pathfinder in both cuts. Switchgrass cultivars selected for improved DM disappearance in vitro did not have greater DM or fiber digestion compared with Cave‐in‐Rock when fed to sheep. Differences among cultivars in nutritive value and in vivo fiber and DM digestion mostly were due to differences in plant maturity and leaf‐to‐stem ratio.

Ensiling characteristics, nutrient composition, and in situ ruminal and whole tract degradability of brown midrib and leafy corn silage

A study was conducted to compare the ensiling characteristics, chemical composition, and the ruminal and total tract nutrient degradabilities of leafy (Cargill F227) and brown midrib (Mycogen TMF94) corn silage hybrids. Corn was grown in Saint-Jean-sur-Richelieu, Quebec, Canada, harvested at a target 350 g kg−1 dry matter (DM) content, and ensiled in mini-silos for 0, 2, 4, 8, 16, and 45 d. Two non-lactating Holstein cows fitted with ruminal and proximal duodenal cannulae were used to determine ruminal and whole tract nutrient degradability. Forage from both hybrids went through a rapid fermentation with a sharp decline in pH during the first 2 d of ensiling, pH in both silage being less than 4.0 after 45 d. Lactic acid concentration was however greater for leafy than brown midrib corn. Chemical analysis of silage after 45 d of ensiling revealed that hybrids differed in their composition. Compared to leafy corn, brown midrib corn had lower neutral detergent fiber (NDF), acid detergent fiber (ADF), acid detergent lignin (ADL), crude protein (CP), and neutral detergent and acid detergent insoluble proteins, but higher starch and net energy of lactation (NEL) values. Results of the in situ incubation experiment indicated that compared to leafy corn brown midrib corn had greater ruminal DM (64 vs. 54%), CP (73 vs. 71%), and NDF (32 vs. 24%) degradabilities. Brown midrib corn silage also had greater DM ruminal (53 vs. 48%) and total tract (67 vs. 61%) digestibilities, as well as greater NDF ruminal (34 vs. 25%), intestinal (10 vs. 8%), and total tract (43 vs. 33%) digestibilities. Type of corn hybrid will thus greatly affect silage chemical composition and nutrient digestibility.

Influence of Brown Midrib, Leafy, and Transgenic Hybrids on Corn Forage Production

Hybrid selection strongly influences corn (Zea mays L.) forage production. Limited forage production and quality information exists for leafy and transgenic hybrids [Bacillus thuringiensis (Bt) and herbicide resistant]. We compared dry matter (DM) yield, forage quality, and estimated milk yields of these and brown midrib hybrids with dual‐purpose hybrids for 3 yr at harvest densities of 66000 and 84000 plants ha−1. Transgenic hybrids had no effect on DM and milk yields, so we do not recommend Bt hybrids under conditions of low infestation of European corn borer (Ostrinia nubilalis Hubner). Leafy hybrids had similar DM and milk yields as hybrids of similar maturity. Brown midrib hybrids, which had DM yields that were about 20% less than those of hybrids of similar maturity, had 40 to 80 g kg−1 greater in vitro true digestibility (IVTD) and 70 to 200 g kg−1 greater neutral detergent fiber (NDF) digestibility. Brown midrib hybrids had the greatest or least milk yields among hybrids, depending on hybrid and year. Leafy and brown midrib hybrids mostly had low harvest index (HI) values, which had strong negative correlations with NDF in all years (−0.71, −0.44, and −0.90). Brown midrib hybrids had high NDF digestibility, which had strong positive correlations with IVTD (0.80, 0.88, and 0.86). Currently, we do not recommend brown midrib hybrids because of inconsistent milk yields and high seed costs. Development of brown midrib and leafy hybrids with greater HI values should result in excellent forage hybrids.