Organic Matter Digestibility Research Articles

Alnus viridis: an encroaching species with valuable nutritional value reducing livestock greenhouse gas emissions

Alnus viridis is a shrub species that has been increasing in many European mountains over the past decades, leading to a loss of agricultural areas and several negative environmental impacts. Recently, targeted livestock management systems have been investigated to reduce its encroachment. This study aims to provide an exhaustive assessment of A. viridis leaf composition and its temporal variation across the grazing season. A. viridis leaves were collected throughout the summers of 2020 and 2021 in four encroached sites across the Swiss and Italian Alps, characterized by different pedo-climatic conditions. Based on the data collected by meteorological stations, the growing degree days (GDD) were calculated for each site and year. The leaf functional traits (i.e., Leaf Dry Matter Content – LDMC – and Specific Leaf Area – SLA), chemical composition (macro- and micro-elements and fibre content), phenolic content, in vitro organic matter digestibility (IVOMD), and related gas production (CO2 and CH4) were assessed. The LDMC significantly increased throughout the season, whereas the SLA decreased. All macro- and micro-elements significantly varied during the season, with leaf nitrogen (N) and phosphorus (P) decreasing. In contrast, leaf fibre contents significantly increased as the season advanced. There was a significant increase in condensed tannin content during the summer season. Finally, adding A. viridis leaves (20% of diet on a dry matter basis) to cattle diets significantly reduced IVOMD, methane produced per digested organic matter (CH4/dOM) and CO2/dOM, compared to a 100% hay diet. Moreover, CH4/dOM and CH4/CO2 ratio increased during the summer season. These results highlight the potential of A. viridis leaves as a valuable forage resource, especially at the beginning of the summer. Such information could be used to optimize grazing of robust livestock in A. viridis-encroached alpine pastures in order to reduce its invasion and minimize greenhouse gases production at the same time.

Comparative assessment of emulsifiers for in vitro ruminal gas production and fermentation measurements: Tween 80 is a suitable emulsifier.

Emulsifiers are essential for achieving a homogenous distribution of lipophilic supplements in in vitro rumen fluid incubations. Since emulsifiers can alter rumen fermentation, it is crucial to select one that minimally impacts fermentation parameters to reduce potential biases. This study aimed to evaluate seven emulsifiers' impact on in vitro ruminal fermentation using the Hohenheim Gas Test in order to identify the most inert emulsifier. Rumen fluids were collected from three non-lactating Original Brown-Swiss cannulated cows before morning feeding and incubated for 24 hwith a basal diet in triplicates. The emulsifiers tested were ethanol, ethyl acetate, propylene glycol, glycerol, ethylene glycol, soy lecithin, and Tween® 80, each in two dosages (0.5% or 1% v/v). The untreated basal diet served as control. Compared to control, in vitro organic matter digestibility was enhanced by ethyl acetate (by 36.9 and 48.2%), ethylene glycol (by 20.6 and 20.1%), glycerol (by 46.9 and 56.8%) and soy lecithin (by 19.7 and 26.8%) at 0.5 and 1% dosage, respectively. Additionally, the 24-h methane production increased for ethanol (by 41.9 and 46.2%), ethylene glycol (by 50.5 and 51.5%), and glycerol (by 63.1 and 65.4%) for the 0.5 and 1% dosage, respectively, and 0.5% dosage for ethyl acetate (by 31.6%). The acetate molar proportion was 17.2%pt higher for ethyl acetate, and 25.5%pt lower for glycerol at 1% dosage, compared to the control. The propionate concentration was 22.1%pt higher 1% glycerol, and 15.2%pt and 15.1%pt higher for 0.5 and 1% propylene glycol, respectively, compared to the control. In summary, Tween® 80 did not significantly affect in vitro rumen fermentation parameters, making it the most suitable choice for in vitro incubations involving lipophilic substances in rumen fluid. Ethanol may be considered as an alternative emulsifier if methane production is not the variable of interest.

The Effects of Harvest Maturity of Eragrostis tef 'Moxie' Hay and Supplemental Energy Source on Forage Utilization in Beef Heifers.

The phenological stage of maturity of grasses and supplementation program can impact forage utilization in grazing beef cattle. However, the potential interaction between harvest maturity of Eragrostis tef (teff) hay and energy supplement source was yet to be fully evaluated. Therefore, our objective was to determine the effects of harvest maturity of teff hay and supplemental energy sources on nutrient intake, apparent total-tract nutrient digestion, nitrogen (N) utilization, and ruminal fermentation characteristics in beef heifers. A split-plot design with teff hay harvest maturity as the whole plot and supplemental energy source as the subplot was administered in a three-period (21 d), three × three Latin square design. Six crossbred beef heifers (804 ± 53.6 kg of body weight; BW) were allocated to two harvest maturities (early- (EH]) or late-heading (LH)) and to two supplemental energy sources (no supplement (CON), or rolled corn grain or beet pulp pellet fed at 0.5% of BW). Data were analyzed using SAS. There was no harvest maturity × energy supplement interaction. Although harvest maturity had no impact on total dry matter intake (DMI), crude protein (CP) intake was greater (p < 0.01) for EH than LH heifers. Total intakes of dry (DM) and organic matter (OM) were also greater (p < 0.01) for supplemented than CON heifers, whereas acid detergent fiber (ADF) intake was greater for beet pulp heifers compared to heifers fed the CON diet and supplemental corn grain. Harvest maturity had no impact on ruminal pH. However, mean ruminal pH was lower (p = 0.04), duration pH < 6.2, and molar proportions of butyrate and branched-chain fatty acids were greater (p ≤ 0.049) for heifers fed corn grain compared to CON and beet pulp diets. Heifers fed EH hay had greater (p ≤ 0.02) apparent total-tract DM, OM, CP, NDF, and ADF digestibility than heifers fed LH hay. Although there was no supplemental energy effect on microbial nitrogen (N) flow, it was greater (p < 0.01) for EH than LH heifers. Apparent N retention, which did not differ, was negative across all diets. In summary, delaying the harvest of teff hay from the EH to LH stage of maturity compromised nutrient supply, which was not attenuated by feeding supplemental corn grain and beet pulp at 0.5% of diet DM. Because N retention was negative across harvest maturity, there might be a need to provide both energy and protein supplements to improve growth performance when feeding teff hay to beef cattle.

SMART LIVESTOCK FOR SCIENCE…12 months later

The fourth issue of Slovak Journal of Animal Science 2023 gives to me the opportunity to overview our scientific publishing activity after the first 12 months together. Along four issues, our Journal has been faced with many different aspects of animal farm production, among them mainly circular economy strategy, non-conventional feed resources, and community-based livestock programs. All these different aspects have a common point: boost and develop the livestock farming system, in terms of competitiveness and profitability. Looking at the different articles collected and published during this year, the incorporation of locally available novel feed resource alternatives can promote circular economy concepts, increase food security, and improve sustainable livestock production. By exploiting locally accessible resources, the inclusion of these materials in animal feed nutrition has significant potential to enhance livestock performance, lower production costs, and promote bioeconomy concepts.&#x0D; On the other hand, analysis of genomic data is an important resource for the effective management of small and endangered animal populations. The research activity of scientists has deeply been focused on developing breeding programs able to conserve animal biodiversity and monitor animal biodynamics.&#x0D; &#x0D; In the last Editorial article of 2023, I am going to introduce the contents of the articles collected and published in the fourth issue of 2023 year.&#x0D; Formelova et al. performed a study to evaluate the effect of dried hempseed cake (by-product of oil production) supplementation (5% - EG1 and 10% - EG2) to rabbit feed mixture on livestock performances, quality of meat, digestibility of nutrients and animal health status. All obtained data let Authors to recommend the inclusion of hempseed cake up to 10% in rabbit diet without any negative effect on animal welfare, livestock performance and quality of meat.&#x0D; Osaiyuwu et al. organized a study to provide useful information for the creation of sustainable breeding programmes and developing a sustainable use and conservation strategy aimed at developing highly producing Muscovy ducks in Nigeria; consequently, increasing the food security index of the nation and source of income for small-scale farmers. In general, the ducks from all seven ecogeographic locations were rather homogeneous than heterogeneous.&#x0D; Mekonnen et al., had the prime objective to survey and characterize the husbandry practices of the different indigenous sheep populations. Authors concluded the study claiming a need of feed development, shift to modern husbandry practices, access to veterinary services, indigenous sheep conservation through utilization, control of inbreeding, ram-to-ewe ratio, fattening and castration should be of future attention of farmers and stakeholders.&#x0D; Ajayi et al., to justify the use of duckweed as an alternative and novel aquatic-derived fodder in ruminants' feeding strategies, performed preliminary investigation via in vitro gas production technique. The study assessed the nutrient and mineral potential, secondary metabolites and in vitro gas production characteristics of duckweed to estimate the short-chain volatile fatty acids, metabolizable energy, organic matter digestibility and apparent in vitro dry matter degradability. In conclusion, duckweed from earthen fish ponds is fairly degradable in vitro, and the nutrient contents elucidate its forage value for ruminants.&#x0D; Editorial Team looks forward to evaluating your submitted contributions and providing all necessary support to Authors in order to best serve animal science and the scientific community, with commitment to research integrity and the highest publishing ethics. Enjoy the reading!

Reducing dietary protein and supplementation with starch or rumen-protected methionine and its effect on performance and nitrogen efficiency in dairy cows fed a red clover and grass silage–based diet

The increasing cost of milk production, in association with tighter manure N application regulations and challenges associated with ammonia emissions in many countries, has increased interest in feeding lower crude protein (CP) diets based on legume silages. Most studies have focused on alfalfa silage, and little information is available on low-CP diets based on red clover silage. Our objectives were to examine the effects of dietary CP content and supplementing a low-CP diet with dietary starch or rumen-protected Met (RPMet) on the performance, metabolism, and nitrogen use efficiency (NUE; milk N output/N intake) in dairy cows fed a red clover and grass silage-based diet. A total of 56 Holstein-Friesian dairy cows were blocked and randomly allocated to 1 of 4 diets over a 14-wk feeding period. Diets were based on red clover and grass silages at a ratio of 50:50 on a dry matter (DM) basis and were fed as a total mixed ration, with a 53:47 ratio of forage to concentrate (DM basis). The diets were formulated to supply a similar metabolizable protein (MP) content, and had a CP concentration of either 175 g/kg DM (control [CON]) or 150 g/kg DM (low-protein [LP]), or LP supplemented with either additional barley as a source of starch (LPSt; +64 g/kg DM) or RPMet (LPM; +0.3 g/100 g MP). At the end of the 14-wk feeding period, 20 cows (5 per treatment) continued to be fed the same diets for a further 6 d, and total urine output and fecal samples were collected. We observed that dietary treatment did not affect DM intake, with a mean of 21.5 kg/d; however, we also observed an interaction between diet and week with intake being highest in cows fed LPSt in wk 4 and CON in wk 9 and 14. Mean milk yield, 4% fat-corrected milk, and energy-corrected milk were not altered by treatment. Similarly, we found no effect of dietary treatment on milk fat, protein, or lactose content. In contrast, milk and plasma urea concentrations were highest in cows fed CON. The concentration of blood plasma β-hydroxybutyrate was highest in cows receiving LPM and lowest in LPSt. Apparent NUE was 28.6% in cows fed CON and was higher in cows fed any of the low-protein diets (LP, LPSt, or LPM), with a mean value of 34.2%. The sum of milk fatty acids with a chain length below C16:0 was also highest in cows fed CON. We observed that dietary treatment did not affect the apparent whole-tract nutrient digestibility of organic matter, N, neutral detergent fiber, and acid detergent fiber, with mean values of 0.785, 0.659, 0.660, and 0.651 kg/kg respectively, but urinary N excretion was approximately 60 g/d lower in cows fed the low-CP diets compared with CON. We conclude that reducing the CP content of red clover and grass silage-based diets from 175 to 150 g/kg DM while maintaining MP supply did not affect performance, but reduced the urinary N excretion and improved NUE, and that supplementing additional starch or RPMet had little further effect.

The Trade-Off between Enteric and Manure Methane Emissions and Their Bacterial Ecology in Lactating Cows Fed Diets Varying in Forage-to-Concentrate Ratio and Rapeseed Oil

An experiment was conducted to examine how dietary interventions reducing enteric methane (CH4) emissions influence manure CH4 emissions in biogas production (as biochemical methane potential (BMP)) or under static conditions mimicking natural manure storage conditions. Experimental treatments consisted of a factorial arrangement of high (HF: 0.65) or low (LF: 0.35) levels of forage and 0 or 50 g of rapeseed oil per kg of diet dry matter. Oil supplementation reduced daily enteric CH4 emissions, especially in the HF diet, by 20%. Greater dietary concentrate proportion reduced CH4 yield and intensity (6 and 12%, respectively) and decreased pH, increased total volatile fatty acids, and molar proportions of butyrate and valerate in feces incubated under static conditions. Oil supplementation increased daily BMP and BMP calculated per unit of organic matter (OM) (17 and 15%, respectively). Increased dietary concentrate had no impact on daily BMP and BMP per unit of OM, whereas it reduced daily CH4 production by 89% and CH4 per unit of OM by 91% under static conditions. Dietary oil supplementation tended to decrease fecal CH4 production per unit of digestible OM (23%) under static conditions. Diets had no impact on the alpha diversity of ruminal prokaryotes. After incubation, the fecal prokaryote community was significantly less diverse. Diets had no effect on alpha diversity in the BMP experiment, but static trial fecal samples originating from the HF diet showed significantly lower diversity compared with the LF diet. Overall, the tested dietary interventions reduced enteric CH4 emissions and reduced or tended to reduce manure CH4 emissions under static conditions, indicating a lack of trade-off between enteric and manure CH4 emissions. The potential for increasing CH4 yields in biogas industries due to dietary interventions could lead to a sustainable synergy between farms and industry.

Adapting the grassland model BASGRA to simulate yield and nutritive value of whole-crop barley

Ensiling of whole-crop biomass of barley before full maturity is common practice in regions with a short growing season. The developmental stage of barley at harvest can have a large impact on yield and nutritive composition. The relationships between crop growth, environmental conditions and crop management can be described in process-based simulation models. Some models, including the Basic Grassland (BASGRA) model, have been developed to simulate the yield and nutritive value of forage grasses, and usually evaluated against metrics of relevance for whole-crop silage. The objectives of this study were to: i) modify the BASGRA model to simulate whole-crop spring barley; ii) evaluate the performance of this model against empirical data on dry matter (DM) yield and nutritive value attributes from field experiments, divided into geographical regions; and iii) evaluate DM yield, nutritive value and cutting date under current and future climate conditions for three locations in Sweden and four cutting regimes. Main model modifications included addition of a spike pool, equations for carbon (C) and nitrogen (N) allocation to the spike pool and equations for C and N translocation from vegetative plant parts to spikes. Model calibration and validation against field trial data from Sweden, including samples harvested from late anthesis stage to hard dough stage that were either pooled or divided into regions, showed better prediction accuracy, evaluated as normalised root mean squared error (RMSE), of neutral detergent fibre (NDF) (7.58–18.4%) than of DM yield (16.8–27.8%), crude protein (15.5–23.2%) or digestible organic matter in the DM (DOMD) (12.0–22.2%). Model prediction using weather data representing 1990–2020 and 2021–2040 climate conditions for three locations in Sweden (Skara, Umeå, Uppsala) showed lower DM yield, earlier harvest and slightly higher NDF concentration on average (across locations and developmental stage at cutting) when using near-future climate data rather than historical data. The model can be used to evaluate whole-crop barley performance under production conditions in Sweden or in other countries with similar climate, soils and crop management regimes.

Novel quality feed from a wasted resource: measuring the nutritional value of low-glycoalkaloids potato haulm in sheep

This study evaluated the potential of low-glycoalkaloid potato haulm (LGPH) as a high-quality feed for ruminants. The low-glycoalkaloid potato plants were grown in a net house following standard agricultural practices. Dehaulming was performed a fortnight before the harvest of the tubers, as commercially practiced. Four healthy female lambs (aged 4 months) were employed in a 4×4 Latin square feeding experiment design. The lambs were fed with either a maintenance diet consisting of 73% roughage (control), or treatment diets with supplementation of 10% (P10), 15% (P15), and 20% (P20) LGPH on a dry matter (DM) basis for a period of 21 days, including 14 days of adaption and 7 days of sampling. Refusals and feces were collected for 6 days and pooled followed by a 24 h urine collection on the 7th day. On the 6th day, an hour after morning feeding, blood, and rumen liquid samples were collected. All the samples were analysed, and the data generated were analysed using ANOVA with diet and period as fixed effects and sheep as a random effect. Orthogonal contrasts were used to detect linear and quadratic effects of LGPH in the diet. Linear or polynomial equations were produced to extract the nutrient digestibility and metabolizable energy (ME) of LGPH. No toxicological clinical signs were observed, and the haematology profiles were normal throughout the trial. LGPH did not affect the daily intake of nutrients and energy. However, the apparent digestibility of DM, organic matter (OM), crude protein (CP), and gross energy increased (P= 0.01) linearly (P&amp;lt; 0.01) with supplementation of LGPH in the diet. The inclusion of LGPH had a quadratic effect on neutral detergent fiber (NDF) digestibility (P= 0.027), reaching a peak of 54.8 % at 12.3 % LGPH supplement on a DM basis. The N retention in lambs fed with the P20 diet was nearly twice that of the control diet (P= 0.032; 19.1 vs. 10.2 g/d). The computed digestibility values of DM, OM, CP, and NDF for LGPH were 76.1, 79.7, 84.2, and 72.1 %, respectively, and ME was 2.62 Mcal/kg DM. Conclusively, by significantly reducing the glycoalkaloids’ content in potato haulm, we can safely repurpose the currently wasted foliage as a new source of high-quality roughage feed for ruminants, equivalent to alfalfa hay, without imposing any additional environmental burden. However, further research is necessary to assess impact of LGPH on growth performance, and milk productivity before practical application on commercial farms.

Synbiotics improve growth performance and nutrient digestibility, inhibit PEDV infection, and prevent intestinal barrier dysfunction by mediating innate antivirus immune response in weaned piglets.

This experiment was conducted to explore the effects of dietary synbiotics (SYB) supplementation on growth performance, immune function, and intestinal barrier function in piglets challenged with porcine epidemic diarrhea virus (PEDV). Forty crossbred (Duroc × Landrace × Yorkshire) weaned piglets (26 ± 1d old) with a mean body weight (BW) of 6.62 ± 0.36kg were randomly allotted to five groups: control (CON) I and CONII group, both fed basal diet; 0.1% SYB group, 0.2% SYB group, and 0.2% yeast culture (YC) group, fed basal diet supplemented with 0.1%, 0.2% SYB, and 0.2% YC, respectively. On day 22, all piglets were orally administrated with 40mL PEDV (5.6 × 103 TCID50/mL) except piglets in CONI group, which were administrated with the same volume of sterile saline. The trial lasted for 26d. Before PEDV challenge, dietary 0.1% SYB supplementation increased final BW, average daily gain (ADG), and decreased the ratio of feed to gain during 0 to 21d (P < 0.05), as well as improved the apparent nutrient digestibility of dry matter (DM), organic matter (OM), crude protein, ether extract (EE), and gross energy (GE). At the same time, 0.2% YC also improved the apparent nutrient digestibility of DM, OM, EE, and GE (P < 0.05). PEDV challenge increased diarrhea rate and diarrhea indexes while decreased ADG (P < 0.05) from days 22 to 26, and induced systemic and intestinal mucosa innate immune and proinflammatory responses, destroyed intestinal barrier integrity. The decrease in average daily feed intake and ADG induced by PEDV challenge was suppressed by dietary SYB and YC supplementation, and 0.1% SYB had the best-alleviating effect. Dietary 0.1% SYB supplementation also increased serum interleukin (IL)-10, immunoglobulin M, complement component 4, and jejunal mucosal IL-4 levels, while decreased serum diamine oxidase activity compared with CONII group (P < 0.05). Furthermore, 0.1% SYB improved mRNA expressions of claudin-1, zonula occludens protein-1, mucin 2, interferon-γ, interferon regulatory factor-3, signal transducers and activators of transcription (P < 0.05), and protein expression of occludin, and downregulated mRNA expressions of toll-like receptor 3 and tumor necrosis factor-α (P < 0.05) in jejunal mucosa. Supplementing 0.2% SYB or 0.2% YC also had a positive effect on piglets, but the effect was not as good as 0.1% SYB. These results indicated that dietary 0.1% SYB supplementation improved growth performance under normal conditions, and alleviated the inflammatory response and the damage of intestinal barrier via improving innate immune function and decreasing PEDV genomic copies, showed optimal protective effects against PEDV infection.

Acceptance and forage utilization responses of steers consuming low-quality forage and supplemented black soldier fly larvae as a novel feed.

As the insect-rearing industry scales in the United States and other developed nations, it has the potential to create multiple product streams (e.g., oil and protein-rich biomass) for existing markets. Black soldier fly larvae (BSFL; Hermetia illucens) has been identified as a potential livestock feed because it is not expected to compete in the human food sector and its production has a lesser environmental footprint than that of conventional feeds. Existing research on BSFL as feed focuses on full-fat BSFL for poultry and aquaculture. Therefore, the objective of our experiment was to evaluate the viability of defatted BSFL as an alternative protein source for beef cattle consuming forage. Procedures were approved by Texas State University IACUC (#7726). Two experiments were conducted using ruminally cannulated beef steers fed low-quality forage in 5 × 5 Latin squares. Experiment 1 assessed consumption of BSFL as a protein supplement and included five 5-d periods with 3-d for washout and 2-d for measurement of supplement intake and preference. There were five treatments delivered in addition to the basal forage: 100% soybean meal (SBM); 75% SBM/25% BSFL; 50% SBM/50% BSFL; 25% SBM/75% BSFL; and 100% BSFL. Supplement and forage intake did not differ between treatments (P ≥ 0.45) nor was there a treatment × day interaction (P ≥ 0.45). Experiment 2 evaluated the effect of BSFL supplementation on forage (5.3% crude protein) intake and digestion and included five 14-d periods with 8-d for treatment adaptation, 5-d for measurement of intake and digestion, and 1-d for determination of ruminal fermentation. There were four treatments of supplemental BSFL provided at graded N levels: 0, 50, 100, or 150mg N/kg BW and one level of SBM at 100mg N/kg BW. Increasing provision of BSFL linearly increased forage organic matter (OM) intake (P = 0.04), total OM intake (P < 0.01), total digestible OM intake (P < 0.01), dry matter digestibility (P = 0.01), and OM digestibility (P = 0.02). There were no significant differences (P ≥ 0.17) in intake or digestibility between levels of BSFL and SBM. Ultimately, defatted BSFL has potential to replace conventional feeds as a protein supplement without sacrificing forage utilization.

Effects of dietary forage neutral detergent fiber and rumen degradable starch ratios on chewing activity, ruminal fermentation, ruminal microbes and nutrient digestibility of Hu sheep fed a pelleted total mixed ration.

Pelleted total mixed ration (P-TMR) feeding, which has become a common practice in providing nutrition for fattening sheep, requires careful consideration of the balance between forage neutral detergent fiber (FNDF) and rumen degradable starch (RDS) to maintain proper rumen functions. The present study aimed to investigate the effects of the dietary FNDF/RDS ratio (FRR) on chewing activity, ruminal fermentation, ruminal microbes, and nutrient digestibility in Hu sheep fed a P-TMR diet. This study utilized eight ruminally cannulated male Hu sheep, following a 4 × 4 Latin square design with 31 d each period. Diets consisted of four FRR levels: 1.0 (high FNDF/RDS ratio, HFRR), 0.8 (middle high FNDF/RDS ratio, MHFRR), 0.6 (middle low FNDF/RDS ratio, MLFRR), and 0.4 (low FNDF/RDS ratio, LFRR). Reducing the dietary FRR levels resulted in a linear decrease in ruminal minimum pH and mean pH, while linearly increasing the duration and area of pH below 5.8 and 5.6, as well as the acidosis index. Sheep in the HFRR and MHFRR groups did not experience subacute ruminal acidosis (SARA), whereas sheep in another two groups did. The concentration of total volatile fatty acid and the molar ratios of propionate and valerate, as well as the concentrate of lactate in the rumen linearly increased with reducing dietary FRR, while the molar ratio of acetate and acetate to propionate ratio linearly decreased. The degradability of NDF and ADF for alfalfa hay has a quadratic response with reducing the dietary FRR. The apparent digestibility of dry matter, organic matter, neutral detergent fiber, and acid detergent fiber linearly decreased when the dietary FRR was reduced. In addition, reducing the dietary FRR caused a linear decrease in OTUs, Chao1, and Ace index of ruminal microflora. Reducing FRR in the diet increased the percentage of reads assigned as Firmicutes, but it decreased the percentage of reads assigned as Bacteroidetes in the rumen. At genus level, the percentage of reads assigned as Prevotella, Ruminococcus, Succinivibrio, and Butyrivibrio linearly decreased when the dietary FRR was reduced. The results of this study demonstrate that the dietary FRR of 0.8 is crucial in preventing the onset of SARA and promotes an enhanced richness of ruminal microbes and also improves fiber digestibility, which is a recommended dietary FRR reference when formulating P-TMR diets for sheep.

Improving feed intake and rumen fermentation in lambs using mixed-dimensional attapulgite clay to adsorb naturally occurring mycotoxins.

This experiment was conducted to evaluate the effects of including a mixed-dimensional attapulgite clay (MDA) into a naturally moldly diet for Hu lambs. Fifty male Hu lambs with similar initial body weight (28.24 ± 1.80kg) were randomly allocated into five dietary treatments: a basal diet containing naturally occurring mycotoxins with 0, 0.5, 1.0, and 2.0kg/t MDA, and basal diet with a commercial mycotoxin adsorbent Solis with montmorillonite as the major component at 1kg/t. Both MDA and Solis increased average daily gain (ADG) and dry matter intake (DMI; P ≤ 0.004), and there was no difference in growth performance between MDA and Solis (P ≥ 0.26). The final body weight, DMI, and ADG were linearly increased with increasing MDA supplementation (P < 0.01). Lambs treated with both MDA and Solis demonstrated greater apparent digestibility of dry matter (DM), organic matter (OM), and energy compared with the control group (P ≤ 0.03), and there were no differences in nutrient digestibilities between MDA and Solis (P ≥ 0.38). Digestibility of CP was linearly increased with the increasing MDA supplementation (P = 0.01). Neither MDA nor Solis affected rumen total volatile fatty acid (TVFA) concentration (P ≥ 0.39), but decreased the acetate-to-propionate ratio and molar proportion of n-butyrate (P ≤ 0.01), and MDA also increased the concentration of ammonia (P = 0.003). Besides, increasing MDA supplementation linearly reduced the acetate-to-propionate ratio and molar proportion of n-butyrate (P = 0.01), but linearly and quadratically increased the concentration of ammonia (P ≥ 0.003). These results showed that the incorporation of MDA into a naturally moldy diet of Hu lambs yielded comparable results to the Solis product, with higher growth performance and nutrient digestibility but lower acetate-to-propionate ratio observed. In conclusion, including ≥ 1kg/t of MDA in high mycotoxin risk diets for growing lambs improves feed intake and rumen fermentation.

Effects of feeding hybrid rye grain as a replacement for barley grain on dry matter intake, ruminal fermentation, and the site and extent of nutrient digestion in finishing beef heifers.

The objective of this study was to evaluate effects of increasing the inclusion of dry-rolled hybrid rye (HR) as a replacement for dry-rolled barley grain (DRB) on feed intake, ruminal fermentation, and the site and extent of nutrient digestion for finishing cattle. Eight ruminally and duodenally cannulated Hereford-cross heifers were used in a replicated 4 × 4 Latin square design with 21-d periods including 15 d of dietary adaptation and 6 d of data and sample collection. Dietary treatments included a control diet with 10.00% grass hay, 85.21% DRB, 4.51% of a vitamin and mineral supplement, and 0.28% of urea on a dry matter (DM) basis. Hybrid rye grain replaced 33%, 67%, or 100% of the DRB. Feed ingredients, feed refusals, ruminal pH, ruminal fluid, duodenal digesta, and fecal samples were collected from days 18 to 21 in each period. Data were analyzed using the Proc Glimmix procedure of SAS 9.4 (SAS Inst. Inc., Cary, NC) to evaluate the linear, quadratic, and cubic effects of increasing HR inclusion. Increasing HR inclusion as a substitute for DRB linearly decreased (P < 0.01) DM intake, linearly decreased mean ruminal pH (P < 0.01), and increased the duration (P < 0.01) and area (P = 0.02) that ruminal pH was < 5.5. There were no effects of HR inclusion on total short chain fatty acid and lactic acid concentrations in ruminal fluid. Likewise, the molar proportions of acetate and butyrate were not affected by HR inclusion. Propionate was cubically affected by HR inclusion (P = 0.02). Ruminal ash-free neutral detergent fiber (aNDFom) digestibility linearly increased (P = 0.03) with increasing HR, but there was no effect on ruminal starch digestibility averaging 71.1% (SEM = 3.611). Increasing HR inclusion linearly increased intestinal DM digestibility (% of flow to the duodenum; P = 0.03), tended to linearly increase intestinal digestibility of organic matter (P = 0.08), and tended to quadratically affect intestinal digestibility of aNDFom (P = 0.07). Increasing hybrid rye linearly increased apparent total tract DM, organic matter, crude protein, aNDFom, and starch digestibility (P ≤ 0.05). In addition, increasing HR inclusion linearly increased GE digestibility (P < 0.01) and the DE concentration (P < 0.01). Increasing the inclusion rate of HR grain as a substitute for DRB in finishing diets decreased DMI and increased risk for low ruminal pH, which may be influenced by greater digestible energy concentration arising from greater DM, OM, aNDFom, and starch digestibility.

Impact of Supplementing a Backgrounding Diet with Nonprotein Nitrogen on In Vitro Methane Production, Nutrient Digestibility, and Steer Performance.

Two experiments were conducted to evaluate the effect of nonprotein nitrogen (NPN) supplementation on in vitro fermentation and animal performance using a backgrounding diet. In experiment 1, incubations were conducted on three separate days (replicates). Treatments were control (CTL, without NPN), urea (U), urea-biuret (UB), and urea-biuret-nitrate (UBN) mixtures. Except for control, treatments were isonitrogenous using 1% U inclusion as a reference. Ruminal fluid was collected from two Angus-crossbred steers fed a backgrounding diet plus 100g of a UBN mixture for at least 35 d. The concentration of volatile fatty acids (VFA) and ammonia nitrogen (NH3-N), in vitro organic matter digestibility (IVOMD), and total gas and methane (CH4) production were determined at 24h of incubation. In experiment 2, 72 Angus-crossbred yearling steers (303 ± 29kg of body weight [BW]) were stratified by BW and randomly allocated in nine pens (eight animals/pen and three pens/treatment). Steers consumed a backgrounding diet formulated to match the diet used in the in vitro fermentation experiment. Treatments were U, UB, and UBN and were isonitrogenous using 1% U inclusion as a reference. Steers were adapted to the NPN supplementation for 17 d. Then, digestibility evaluation was performed after 13 d of full NPN supplementation for 4 d using 36 steers (12 steers/treatment). After that, steer performance was evaluated for 56 d (24 steers/treatment). In experiment 1, NPN supplementation increased the concentration of NH3-N and VFA (P < 0.01) without affecting the IVOMD (P = 0.48), total gas (P = 0.51), and CH4 production (P = 0.57). Additionally, in vitro fermentation parameters did not differ (P > 0.05) among NPN sources. In experiment 2, NPN supplementation did not change dry matter and nutrient intake (P > 0.05). However, UB and UBN showed lower (P < 0.05) nutrient digestibility than U, except for starch (P = 0.20). Dry matter intake (P = 0.28), average daily gain (P = 0.88), and gain:feed (P = 0.63) did not differ among steers receiving NPN mixtures. In conclusion, tested NPN mixtures have the potential to be included in the backgrounding diets without any apparent negative effects on animal performance and warrant further studies to evaluate other variables to fully assess the response of feeding these novel NPN mixtures.

The balance of rumen degradable protein and readily available carbohydrate in sheep rations on in vitro fermentability.

Protein and carbohydrates are substances needed by ruminants, especially sheep. Providing protein and carbohydrates must pay attention to their degradation. In addition, balancing nutrients to meet the nutritional needs of rumen microbes is very important because the unbalanced availability of rumen degradable protein (RDP) and readily available carbohydrate (RAC) at one time can cause suboptimal microbial protein synthesis efficiency. Completely randomized design with a nonfactorial pattern of five treatments with three replications. Treatment includes RDP and RAC ratios, namely R1 = 2.30, R2 = 2.00, R3 = 1.70, R4 = 1.50, and R5 = 1.30. The results showed that the balance of RDP and RAC in sheep ration formulation in vitro had a very significant effect (p < 0.01) on NH3, microbial protein synthesis, total gas, total microbes, and organic matter digestibility (OMD) but had no significant effect (p > 0.05) on rumen pH and dry matter digestibility (DMD). The optimal balance of RDP and RAC in the formulation of sheep rations in vitro was obtained at a ratio of 2.30 with NH3 (mM) 8.47, rumen pH 5.97, microbial protein synthesis (mg/100 ml) 123, gas (ml/g of material) 145, total microbes (cells/ml) 2.012 × 106, (log CFU cells/ml) 6.3025, DMD 61.0%, and OMD 63.1%.

Evaluation Additional of Synbiotic Powder in Feed to Improve Milk Production and Quality of Dairy Cattle

Evaluation Additional of Synbiotic Powder in Feed to Improve Milk Production and Quality of Dairy Cattle

Use of tannase-producing bacteria isolated from the rumen to improve the nutritional value of pomegranate peel for fattening lambs.

The use of plants and by-products, which are containing a high amount of secondary and anti-nutritional compounds such as tannins, in animal feed is limited. The methods that can reduce these compounds make facilitate their use in animal feed. The aim of this study was to reduce the adverse effects of pomegranate peel (PP) tannin for fattening lambs using the tannase-producing bacteria. Twenty-one Arabi male lambs (averagely 35±3.8kg weight and 8±1.0 months age) were used in a completely randomized design with three treatments and seven replications in the present experiment. The experimental treatments included 1 - control diet (CNT, no PP), 2 - diet containing untreated PP (raw PP, UTPP) and 3 - diet containing PP treated with tannase-producing bacteria (bacteria treating PP, BTPP). Using UTPP decreased nutrient intake compared to the control and treatment with tannase-producing bacteria again significantly increased nutrient intake compared to the UTPP (p<0.05). The digestibilities of organic matter, neutral detergent fibre and acid detergent fibre in the control treatment were significantly higher than UTPP and BTPP and in the BTPP were significantly higher than the UTPP (p<0.05). The use of UTPP in the diet significantly decreased the pH, ammonia nitrogen concentration and the total protozoa population of the rumen compared to the control (p<0.05), and treatment with bacteria increased them again. The lowest total protozoa population was observed in UTPP treatments (p<0.05). The highest concentration of blood glucose was observed in UTPP; however, the highest concentrations of blood urea nitrogen, cholesterol, triglyceride, high-density lipoprotein (non-significant) and low-density lipoprotein were in the control treatment. The effect of experimental treatments on the dry matter consumption of the whole period was significant; however, there was no significant effect on average daily gain, feed conversion ratio, feed efficiency and longissimus muscle colorimetric systems. Therefore, considering the positive effects of treatment PP with tannin-degrading bacteria relative to raw PP, using these bacteria is a proper way to reduce tannin, thus improving the nutritional value of PP for ruminants.

Productive Performance of Lactating Crossbred Dairy Cows Fed with Wheat Straw‐Based Densified Complete Feed Block

The experiment was designed to determine the effect of feeding densified complete feed block (DCFB) on the production performances of lactating F1 Friesian x Borena crossbred cows. Four mid‐lactating multiparous cows with 2–5 parity having similar milk yield (8–10 l·day−1) were evaluated using 4 × 4 Latin square design for a total of 84 days. The treatments include natural pasture hay supplemented with a concentrate mixture at the rate of 0.5 kg·l−1 of milk yield·cow−1 (T1) and three different wheat straw‐based DCFBs in the ratio of 50 : 50 (T2), 40 : 60 (T3), and 30 : 70 (T4). The result revealed that the average daily dry matter (DM) intake was similar among all dietary treatments except for T2 that had lower (P &lt; 0.05) daily DM intake. The crude protein (CP) and organic matter (OM) intakes for cows in T3 and T4 were comparable (P &gt; 0.05) but significantly higher (P &lt; 0.05) compared to T1 and T2. The neutral detergent fiber (NDF) intake remained the same among treatment groups while T1 consumed higher (P &lt; 0.05) acid detergent fiber (ADF) compared to other diets. Cows in T3 and T4 groups had higher (P &lt; 0.05) DM and OM digestibility but comparable (P &gt; 0.05) NDF and ADF digestibility compared to T1. The CP digestibility and daily average milk yield were higher (P &lt; 0.05) for T4. Daily fat, protein, and lactose yield in the DCFB group showed an increasing trend with the level of concentrate, whereas cows in the T4 group exceptionally produced higher (P &lt; 0.05) yields. Fat‐corrected milk yield (FCM) was lower (P &lt; 0.05) for T4 compared to T1 and T2 groups. Milk fat percentages were lower (P &lt; 0.05) but milk protein percentages were higher for cows in T4 but similar for the rest of the diets. Milk lactose did not vary (P &gt; 0.05) over all the treatments. Milk conversion efficiency was similar (P &gt; 0.05) among the DCFB but higher (P &lt; 0.05) for control cows. The partial budget analysis indicated that net profit and marginal return were much higher for diet in the ratio of 40 : 60. Inclusion of wheat straw at 40% could be an efficient feeding option for F1 Friesian x Borena lactating crossbred cows managed under indoor conditions. However, DCFB manufacturing and distribution at a large scale requires machineries (chopper/grinder, mixer, and compressor). Further study needs to evaluate the storability and strength of the DCFBs under varying storage conditions and the long‐term effect of DCFB on milk yield and quality of improved lactating dairy cows in Ethiopia.

O valor nutricional da gliricídia em diferentes formas de alimentação: uma revisão sistemática

ABSTRACT: Different types of supplied roughage may cause losses in the chemical composition and digestibility of gliricidia (Gliricidia sepium [Jacq.] Kunth ex Walp.) depending on their making and fed-out management. This study has summarized data from scientific studies on gliricidia and compared its nutritional value in various fed forms using a systematic review approach and principal component analysis (PCA). A robust survey of scientific papers was realized on web indexes of periodicals and databases from 1990 to 2023. Data from 100 scientific researches has been compiled and analyzed. In 40% of the trials, the gliricidia nutritional value was determined as fresh leaves, while 30% was in the form of ‘leaves + thin stems’. Gliricidia was evaluated as silage in 11% of the opportunities, followed by 10% as leaf meal and 9% as hay. Non-fiber carbohydrates, crude protein (CP), and organic matter digestibility (OM) had negative correlations with neutral detergent fiber (NDF), acid detergent fiber (ADF), and lignin. Only NDF, ADF, and CP contents could explain 71% of the total data variation (PC1 and PC2). There was no discrimination among fed forms, so they showed similar nutrient compositions. Eventual nutrient losses reported in the scientific researches owing to ensilage, haymaking, and leaf meal-making processes do not mischaracterize the gliricidia nutritional value. The assorted manners of roughage making, and fed-out management traditionally performed by farmers can conserve the excellent nutritional quality of gliricidia.

Effect of traditional roughage-based or limit-fed, high-energy diets on growth performance and digestion in newly received growing cattle and subsequent implications on feedlot growth performance and carcass characteristics.

The objective was to determine the effects of ad libitum-fed roughage-based diets or limit-fed high-energy diets on growth performance, behavior, health, and digestion in newly received growing cattle and subsequent implications on feedlot growth performance and carcass characteristics. In experiment 1, 409 crossbred heifers (initial body weight [BW] = 279 ± 24kg) in 32 pens were used in a randomized block design. Heifers were fed one of two dietary treatments: a total mixed ration with 0.99 Mcal net energy for gain (NEg)/kg dry matter (DM) fed ad libitum (0.99AL) or 1.32 Mcal NEg/kg DM limit-fed at 85% of intake of heifers fed 0.99AL (1.32LF85%). Both diets contained 40% DM as a branded wet corn gluten feed. In experiment 2, 370 crossbred heifers (initial BW = 225 ± 20kg) were used in a randomized block design and were fed a diet formulated to contain 0.99 Mcal of NEg/kg DM for ad libitum intake or a diet formulated to contain 1.32 Mcal of NEg/kg DM and fed at 2.2% of BW daily (DM basis; 1.32LF2.2). For experiments 1 and 2, treatment integrity was maintained through the finishing phase where cattle were fed a common diet. Cattle were sorted by BW into heavy and light groups prior to finishing, with light cattle fed longer than heavy cattle to reach similar harvest BW. In experiment 3, eight ruminally cannulated heifers (average BW = 305 ± 23kg) were used in a 2-period cross-over design and fed treatments from experiment 1 to assess digestibility and ruminal fermentation characteristics. Gain:feed was 47% and 35% greater (P < 0.01) in experiments 1 and 2, respectively, for limit-fed heifers compared with 0.99AL heifers. Rumination time was greater (P < 0.01) for 0.99AL compared with limit-fed treatments in experiments 1 and 2. Activity was greater (P < 0.01) for 1.32LF2.2 than for 0.99AL in experiment 2. In experiment 1, more (P = 0.03) carcasses from light-sort heifers than carcasses from heavy-sort heifers had livers with large, active abscesses. In experiment 2, finishing phase morbidity was greater (P < 0.01) for 1.32LF2.2 than for 0.99AL. Light-sort groups had fewer (P < 0.01) edible livers than heavy-sort groups, suggesting that greater number of days on feed may increase the risk of liver abscess prevalence and condemnation. In experiment 3, apparent total-tract DM and organic matter digestibilities were greater (P < 0.01) for 1.32LF85% than for 0.99AL. Overall, dietary treatments during the growing phase had little carryover effect on feedlot growth performance, carcass characteristics, or liver abscesses prevalence at harvest.