Ruminal Concentration Research Articles

Dietary supplementation with citrus peel extract in transition period improves rumen microbial composition and ameliorates energy metabolism and lactation performance of dairy cows

BackgroundDuring the transition period, excessive negative energy balance (NEB) lead to metabolic disorders and reduced milk yield. Rumen microbes are responsible for resolving plant material and producing volatile fatty acids (VFA), which are the primary energy source for cows. In this study, we aimed to investigate the effect of citrus peel extract (CPE) supplementation on rumen microbiota composition, energy metabolism and milk performance of peripartum dairy cows.MethodsDairy cows were fed either a basal diet (CON group) or the same basal diet supplemented with CPE via intragastric administration (4 g/d, CPE group) for 6 weeks (3 weeks before and 3 weeks after calving; n = 15 per group). Samples of serum, milk, rumen fluid, adipose tissue, and liver were collected to assess the effects of CPE on rumen microbiota composition, rumen fermentation parameters, milk performance, and energy metabolic status of dairy cows.ResultsCPE supplementation led to an increase in milk yield, milk protein and lactose contents, and serum glucose levels, while reduced serum concentrations of non-esterified fatty acid, β-hydroxybutyric acid, insulin, aspartate aminotransferase, alanine aminotransferase, and haptoglobin during the first month of lactation. CPE supplementation also increased the content of ruminal VFA. Compared to the CON group, the abundance of Prevotellaceae, Methanobacteriaceae, Bacteroidales_RF16_group, and Selenomonadaceae was found increased, while the abundance of Oscillospiraceae, F082, Ruminococcaceae, Christensenellaceae, Muribaculaceae UCG-011, Saccharimonadaceae, Hungateiclostridiaceae, and Spirochaetaceae in the CPE group was found decreased. In adipose tissue, CPE supplementation decreased lipolysis, and inflammatory response, while increased insulin sensitivity. In the liver, CPE supplementation decreased lipid accumulation, increased insulin sensitivity, and upregulated expression of genes involved in gluconeogenesis.ConclusionsOur findings suggest that CPE supplementation during the peripartum period altered rumen microbiota composition and increased ruminal VFA contents, which further improved NEB and lactation performance, alleviated lipolysis and inflammatory response in adipose tissue, reduced lipid accumulation and promoted gluconeogenesis in liver. Thus, CPE might contribute to improve energy metabolism and consequently lactation performance of dairy cows during the transition period.

Effect of artificial insemination, ruminal incubation, and esophageal tubing on cortisol concentration in blood of lactating dairy cows

Cortisol is a hormone associated with pain, fear, distress, or discomfort. We hypothesized that human interventions increase cortisol concentrations in plasma. Therefore, the objective of this study was to determine the concentration of cortisol in plasma before and after animals were subjected to routine on-farm and research procedures including artificial insemination, ruminal incubation, or esophageal tubing. Forty lactating Holstein cows were used in this study. Experimental treatments consisted of 4 interventions. Before any intervention, a first blood sample was collected from all cows. Following this bleeding, all cows were assigned to 1 of 4 treatments. A negative control treatment consisted of bleeding for a second time without any human intervention at least 30 min after the previous bleeding. Artificial insemination was performed by the herd managers from the Virginia Tech Dairy Complex. A rumen incubation treatment consisted of bleeding for a second time 30 min after opening the rumen cannula, inserting the operator's arm, and pulling ruminal contents out of the rumen for 2 min mimicking a ruminal in situ incubation, and placing back the cannula plug. An esophageal tubing treatment consisted of bleeding for a second time 30 min after inserting an esophageal tube into the esophagus and maintaining it inserted for 2 min mimicking a ruminal drenching procedure. Blood samples were collected from the coccygeal vessels. Cortisol concentration in plasma was measured by an independent laboratory using a chemiluminescence assay. The experiment was designed as a completely randomized design with repeated measures, where cow was the subject and the pre- and post-intervention bleeding were the repeated observations. The statistical model included the fixed effect of treatment, the random effect of cow, the fixed effect of time, the fixed effect of the treatment by time interaction, and the random residual error. According to Akaike's criterion, compound symmetry was utilized as the covariance structure for the repeated measures. Cortisol concentrations in plasma after the interventions did not differ from the cortisol concentrations in plasma before the interventions. Cows subjected to artificial insemination had greater cortisol concentrations than cow subjected to the other treatments. No interaction existed between treatment and time. Most cows subjected to insemination in a palpation rail had elevated cortisol concentrations before the intervention. Therefore, animal restraint seems to affect cortisol concentrations in plasma more than the actual human intervention. In conclusion, human interventions like artificial insemination, ruminal incubation, and esophageal tubing did not elevate the cortisol concentrations in the plasma of lactating dairy cattle under the conditions of this study.

Meta-analysis of dietary supplementation with flavonoids in small ruminants: Growth performance, antioxidant status, nutrient digestibility, ruminal fermentation, and meat quality

This study aimed to evaluate the effects of dietary supplementation with flavonoids on growth performance, antioxidant status, nutrient digestibility, ruminal fermentation, and meat quality of small ruminants through a meta-analytic approach. The data used in the meta-analysis were extracted from 29 scientific articles identified through systematic searches following the PRISMA methodology. Der-Simonian and Laird, random effects models, were used to assess effect sizes using weighted mean differences. Dietary supplementation with flavonoids increased (P < 0.05) dry matter intake, average daily gain, hot carcass weight, hot carcass yield, Longissimus dorsi muscle area, and backfat thickness. In contrast, the feed conversion ratio decreased (P < 0.05) in response to dietary flavonoid supplementation. Dietary supplementation with flavonoids increased (P < 0.001) the serum concentration of superoxide dismutase, catalase, glutathione peroxidase, and total antioxidant capacity but decreased (P < 0.001) the serum concentration of malondialdehyde (MDA). The digestibility of dry matter, organic matter, crude protein, neutral detergent fiber, and acid detergent fiber increased (P < 0.05) in response to dietary flavonoid supplementation. Dietary supplementation with flavonoids decreased (P < 0.001) the ruminal concentration of ammonia nitrogen and increased (P < 0.001) the ruminal concentration of total volatile fatty acids and acetate. Dietary supplementation with flavonoids decreased (P < 0.001) cooking loss, shear force, and MDA in meat. In conclusion, dietary supplementation with flavonoids can be used as a nutritional strategy to improve growth performance, antioxidant status in blood serum, nutrient digestibility, ruminal fermentation, and meat quality in small ruminants.

Effects of Pichia manshurica yeast supplementation on ruminal fermentation, nutrient degradability, and greenhouse gas emissions in aflatoxin B1 contaminated diets

Yeast feed additives present a natural approach for mitigating ruminal greenhouse gases (GHG) in an environmentally sustainable manner. This study aimed to isolate yeast strains from ruminal fluids capable of reducing GHG from Aflatoxin (AFB1) contaminated diets. Two isolates of Pichia manchuria (FFNLYFC1 and FFNLYFC2) were isolated and identified from the ruminal contents of dairy Zaraibi goats. An in vitro gas production assay was conducted to evaluate the impact of the yeast supplementations on a basal diet contaminated with AFB1 or not. The treatments were control (-AFB1; basal diet without supplements), control with AFB1 contamination (+ AFB1; basal diet containing 20 ppb AFB1), and yeast-supplemented diets (basal diet supplemented with Saccharomyces cerevisiae, and three treatments of P. manchuria [FFNLYFC1, FFNLYFC2, and their mixture at 1:1 ratio (Mix)]. High biological components were detected in abundance of both FFNLYFC1, FFNLYFC2 filtrates (e.g., diisooctyl phthalate). The Mix and FFNLYFC2 of P. manchuria reduced (P < 0.05) methane by 23.5 and 20.8%, respectively, while only Mix inhibited carbon dioxide by 44% compared to the + AFB1 diet. All yeast diets improved (P < 0.05) ammonia concentration, total protozoal and Entodinium spp. counts compared to + AFB1 diet. The Mix exhibited higher (P < 0.05) values of ruminal degraded cellulose, total short-chain fatty acids, acetate and propionate compared to the individual isolates diets. The results suggest synergistic interactions among P. manshurica isolates, leading to enhanced ruminal fermentation and reduced GHG emissions while alleviating the adverse effects of AFB1. Therefore, we recommended the Mix of P. Manchuria as a novel feed additive to ruminant diets.

Development of engineered IL-36γ-hypersecreting Lactococcus lactis to improve the intestinal environment

Interleukin (IL) 36 is a member of the IL-1-like proinflammatory cytokine family that has a protective role in mucosal immunity. We hypothesized that mucosal delivery of IL-36γ to the intestine would be a very effective way to prevent intestinal diseases. Here, we genetically engineered a lactic acid bacterium, Lactococcus lactis, to produce recombinant mouse IL-36γ (rmIL-36γ). Western blotting and enzyme-linked immunosorbent assay results showed that the engineered strain (NZ-IL36γ) produced and hypersecreted the designed rmIL-36γ in the presence of nisin, which induces the expression of the recombinant gene. We administered NZ-IL36γ to mice via oral gavage, and collected the ruminal contents and rectal tissues. Colony PCR using primers specific for NZ-IL36γ, and enzyme-linked immunosorbent assay to measure the rmIL-36γ concentrations of the ruminal contents showed that NZ-IL36γ colonized the mouse intestines and secreted rmIL-36γ. A microbiota analysis revealed increased abundances of bacteria of the genera Acetatifactor, Eubacterium, Monoglobus, and Roseburia in the mouse intestines. Real-time quantitative PCR of the whole colon showed increased Muc2 expression. An in vitro assay using murine colorectal epithelial cells and human colonic cells showed that purified rmIL-36γ promoted Muc2 gene expression. Taken together, these data suggest that NZ-IL36γ may be an effective and attractive tool for delivering rmIL-36γ to improve the intestinal environment.

20 Trace metal homeostasis in growing cattle

Abstract Apparent trace metal absorption and tissue retention upon incremental levels of supplemental Zn, Cu, and Mn were studied in growing cattle. A total of 60 Holstein bulls were enrolled for the study and fed for 28 d a diet consisting of barley straw (15%), molasses (10%) and pelleted concentrate (75%; Zn = 78 ppm, Cu = 15 ppm, Mn = 91 ppm). Thereafter, 20 bulls were randomly selected and slaughtered for determination of baseline tissue trace metal composition. The remaining 40 bulls [body weight (BW) = 394 ± 20 kg] were then blocked based on BW in 8 blocks of 5 bulls each. Bulls within a block were randomly assigned one of the diets differing in supplemental levels of Zn, Cu, and Mn (all from sulfate form) with the following dietary contents of Zn, Cu and Mn, respectively: No supplement (38, 7, and 47 ppm), Dose 1 (61, 11, and 68 ppm), Dose 2 (78, 15 and 91 ppm), Dose 3 (123, 26, 136 ppm) or Dose 4 (195, 43, and 214 ppm). These diets were fed for 12 wk, and complete collection of feces and urine were performed on wk 4, 8 and 12 for assessment of trace metals balance and apparent absorption. Gastrointestinal tissues, whole organs (heart, liver, spleen, and kidney), bile, cervical vertebra, and tibia were collected at slaughterhouse from all bulls. All samples were dried, ground, and analyzed for minerals. Data were processed using dietary treatment as a continuous variable and also as categorial variable. Both approaches adjusted for the fixed effect of block (Proc Mixed, SAS 9.4). Whole-body Zn, Cu and Mn balance quadratically increased (P &amp;lt; 0.05) with supplementation, with a significantly higher values for Dose 4 compared with all other dietary treatment (Figure 1, P &amp;lt; 0.05). Dose 4 also led to a 2-fold increase in urinary Zn and Cu excretions (P &amp;lt; 0.05), and a 4-fold increase in urinary Mn excretion (P &amp;lt; 0.01). Although magnitudes of change were moderate (8 to 15%), increasing dietary Zn supply linearly increased spleen Zn content (P = 0.03), and tended to increase ruminal and hepatic Zn content (P &amp;lt; 0.10). Hepatic Cu linearly increased from 264 to 667 mg/kg DM with increasing dietary Cu supply (P &amp;lt; 0.01), whereas Cu concentration in bile only increased at Doses 4 and 5 (P &amp;lt; 0.01). Increasing Mn supply resulted in quadratic increase of ruminal and biliary Mn content from 340 to 1140 mg/kg DM, and from 0.32 to 1.38 mg/L, respectively. Small intestine and cecum Mn concentrations linearly and quadratically increased (about 2-fold increase, P &amp;lt; 0.05) with incremental supply of Mn. Homeostatic regulation mechanisms were apparently overwhelmed at the greatest Zn, Cu and Mn supplementation levels evaluated in this study.

Phenotypic traits related to methane emissions from Holstein dairy cows challenged by low or high forage proportion

Limited literature is available identifying phenotypical traits related to enteric methane (CH4) production from dairy cows, despite its relevance in relation to breeding for animals with a low CH4 yield (g/kg DMI), and the derived consequences hereof. This study aimed to investigate the relationships between CH4 yield and different animal phenotypes when 16 2nd parity dairy cows, fitted with a ruminal cannula, were fed 2 diets differing in forage:concentrate ratio in a crossover design. The diets had either a low forage proportion (35% on DM basis, F35) or a high forage proportion (63% on DM basis, F63). Gas exchange was measured by means of indirect calorimetry. Spot samples of feces were collected, and indigestible NDF (INDF) was used as an internal marker to determine total-tract digestibility. In addition, ruminal evacuations, monitoring of chewing activity, determination of ruminal VFA concentration, analysis of relative abundance of methanogens, and measurement of liquid passage rate were performed. Statistical differences were analyzed by a linear mixed model with diet, days in milk, and period as fixed effects, and cow as random effect. The random cow estimates (RCE) were extracted from the model to get the Pearson correlations (r) between RCE of CH4 yield with RCE of all other variables measured, to identify possible phenotypes related to CH4 yield. Significant correlations were observed between RCE of CH4 yield and RCE of OM digestibility (r = 0.63) and ruminal concentration of valeric acid (r = -0.61), acetic acid (r = 0.54), ammonium (r = 0.55), and lactic acid (r = ‒0.53). Additionally, tendencies were observed for correlations between RCE of CH4 yield and RCE of H2 yield in g/kg DM (r = 0.47, P = 0.07), and ruminal isobutyric acid concentration (r = 0.43, P = 0.09). No correlations were observed between RCE of CH4 yield and RCE of ruminal pool sizes, milk data, urinary measurements, or chewing activity. Cows had a lower DMI and ECM, when they were fed F63 compared with F35. Cows fed F63 had higher NDF digestibility, CH4 emissions (g/d, g/kg of DMI, and g/kg of ECM), ruminal concentration of acetic acid, ruminal pH, degradation rate of digestible NDF (DNDF, %/h), and longer rumen retention time (h). Also, rumination and total chewing time (min/kg DMI) were higher for cows fed F63. The results in the present study emphasize the positive relation between cow's ability to digest OM and their CH4 emissions. The derived consequences of breeding for lower CH4 emission might be cows with lower ability to digest OM, but more studies are warranted for further documentation of this relationship.

The Influence of High-Concentrate Diet Supplemented with Tannin on Growth Performance, Rumen Fermentation, and Antioxidant Ability of Fattening Lambs.

This experiment aimed to study the effects of tannin supplementation on growth performance, rumen fermentation characteristics, apparent digestibility and serum biochemistry, and antioxidant and immune indexes in fattening lambs. A total of 36 male Hu sheep lambs (body weight = 15.83 ± 0.48 kg and days of age = 55 ± 2 d) were fed a high-concentrate diet and randomly divided into one of three groups of 12 animals each: control with no tannin (CON) and tannin treatments (TA1, 3 g/d per lamb; TA2, 6 g/d per lamb). The feeding experiment lasted for 60 d. The results showed that the average daily gain and ruminal propionate content of lambs in the TA1 group were higher (p < 0.05) than those in the CON group. Lambs fed tannin had significantly increased (p < 0.05) microbial protein and decreased (p < 0.05) ammonia nitrogen concentrations in the rumen. In addition, the crude protein and neutral detergent fiber digestibility of the TA2 group were significantly decreased (p < 0.05) as compared with the TA1 and CON groups, respectively. The serum concentrations of triglyceride, immunoglobulin A, and catalase and the total antioxidant capacity were higher (p < 0.05) in the TA1 group that those in the CON group, whereas an opposite trend of urea nitrogen, interleukin-1β, and malondialdehyde was found between the two groups. Also, tannin supplementation increased (p < 0.05) Lactobacillus and decreased (p < 0.05) Salmonella counts in the feces of lambs. Taken together, tannin supplementation can improve the growth performance, immunity, and antioxidant ability of fattening lambs fed a high-concentrate diet.

The Content and Nature of Rumination in Chinese Young and Middle-Aged Patients with Acute Coronary Syndrome: A Qualitative Study.

Individuals have different rumination patterns after experiencing traumatic events in different cultural backgrounds and situations. This study aimed to explore the experience of Chinese young and middle-aged patients with acute coronary syndrome (ACS) to understand the content and nature of their rumination. Sixteen participants were selected using the purposive sampling method in the First Affiliated Hospital of Soochow University from May 2023 to December 2023. Data were collected using semi-structured interviews and analyzed using Colaizzi's seven-step phenomenological method. The participants went through two successive stages: non-adaptive rumination and adaptive rumination. During the initial admission phase, all the participants experienced varying degrees of non-adaptive rumination. Non-adaptive rumination included four sub-themes: worry or anxiety of daily activities and medical therapy (37.50%), fear of unpredictable outcomes and death (37.50%), sadness of maladjustment (25.00%), and remorse of carelessness (12.50%). During the period of stable condition and pre-discharge, the participants received health education and gradually all transitioned to adaptive rumination. Adaptive rumination included four sub-themes: tracing of disease processes (100%), enhancement of disease cognition (81.25%), improvement of health awareness (62.50%), and adjustment of lifestyle cognition (100%). In conclusion, although the Chinese young and middle-aged patients with ACS experienced negative emotions after a traumatic cardiac event, they gradually made positive changes, and optimism and information support played important roles in this transition. The results of this study provide a fundamental understanding of rumination experiences in Chinese young and middle-aged patients with ACS and provide new data for healthcare providers when designing intervention programs to enhance post-traumatic growth in these patients.

Ruminal passage rate and digestibility of fiber from dairy cows consuming diets containing alfalfa and orchardgrass hays with different concentrations of undegradable neutral detergent fiber (uNDF)

This study aimed to evaluate the effect of feeding diets with different fractions of undegraded NDF (uNDF) and potentially degradable (pdNDF) on ruminal NDF degradation and passage kinetics of lactating dairy cows. Six rumen-cannulated (533 ± 43 kg BW and 122 ± 15 DIM) and 6 non-cannulated (558 ± 62 kg BW and 126 ± 16 DIM) primiparous Holstein dairy cows were randomly assigned to 1 of 2 experimental diets in a crossover design with 2 28-d periods. The experimental diets were formulated to include either alfalfa hay (ALFA) or orchardgrass hay (ORCH) in addition to corn silage. Rations were formulated to contain 30% NDF (DM basis), where the concentrate, corn silage, and each of the hays provided one third of the dietary NDF. The marker dilution technique was used to measure the passage rate utilizing a pulse dose of marked corn silage fiber. On d 17 and 24 of each period, ruminal contents were evacuated to determine ruminal pool size. Following the return of the ruminal contents containing the pulse dose of marked corn silage to the rumen, ruminal grab samples were collected at 0, 3, 6, 9, 12, 24, 36, 48, 60, and 72 h. Samples from each time point were separated into solids and liquid, and the solids were analyzed for NDF, uNDF, and marker concentration. Alfalfa hay had a higher concentration of CP (16.4 vs. 10.7%) and a lower concentration of NDF (38.0 vs. 63.2) than orchardgrass hay. Alfalfa hay had a greater concentration of uNDF than orchardgrass hay (36.5 vs. 32.8% uNDF; NDF basis). Cows consuming the ALFA diet had similar milk yield (39.1 kg/d) and similar milk fat and protein concentrations (3.72% fat and 3.24% protein, respectively) than cows consuming the ORCH diet. Cows consuming the ALFA diet consumed more DM (26.7 vs. 24.6 kg/d) and uNDF (2.7 vs. 2.3 kg/d), than cows consuming the ORCH diet. Cows consuming the ALFA diet digested more NDF and pdNDF than cows consuming the ORCH diet (3.3 vs. 2.8 kg/d). Even though cows consuming the ALFA diet had a smaller pool size of NDF than cows consuming the ORCH diet (5.4 vs. 6.7 kg), the pool size of uNDF did not differ between groups (2.4 kg). Cows consuming the ALFA diet had a faster rate of passage of uNDF than cows consuming the ORCH diet (5.02 vs. 4.03%/h). This translated into a shorter mean retention time of uNDF for cows consuming the ALFA diet relative to cows consuming the ORCH diet (21.0 vs. 26.2 h). In conclusion, cows consuming diets containing alfalfa hay had a faster ruminal passage rate and a shorter mean retention time of uNDF than cows consuming diets containing orchardgrass hay, and this occurred despite the greater concentrations of dietary uNDF in the alfalfa-based diet. These findings suggest that the kinetics of ruminal digestion and passage influence NDF degradation in ways beyond uNDF concentration or forage quality.

Meta-Analysis of Dietary Supplementation with Seaweed in Dairy Cows: Milk Yield and Composition, Nutrient Digestibility, Rumen Fermentation, and Enteric Methane Emissions

This study used a meta-analytic approach to evaluate the effects of dietary supplementation with seaweed on milk yield, milk composition, nutrient digestibility, ruminal fermentation, and enteric methane (CH4) emissions of dairy cows. Data used in statistical analyses were obtained from 23 peer-reviewed scientific articles. Effect size was assessed using weighted mean differences (WMD) between seaweed-supplemented and control treatments. Dietary supplementation with seaweed decreased (p &lt; 0.05) dry matter intake, milk protein content, milk urea nitrogen, and somatic cell count. In contrast, milk fat content, milk lactose content, and milk iodine increased (p &lt; 0.05) in response to dietary supplementation with seaweed. Dietary supplementation with seaweed did not affect (p &gt; 0.05) nutrient digestibility, total volatile fatty acids, acetate, and propionate. Dietary supplementation with seaweeds increased (p &lt; 0.05) ruminal pH and ruminal concentration of butyrate and valerate. In contrast, lower (p &lt; 0.05) ruminal ammonia nitrogen concentration, acetate/propionate ratio, daily CH4 emission, CH4 yield, and CH4 intensity were observed in response to dietary supplementation with seaweeds. In conclusion, dietary supplementation with seaweed modifies milk composition, improves ruminal fermentation, and decreases enteric methane emissions without negatively affecting milk yield or feed efficiency.

Soybean molasses can be used as a substitute for corn in grazing beef cattle supplements during the rainy season.

Soybean molasses (SBMO) is a byproduct derived from the production of soy protein concentrate, obtained through solubilization in water and alcohol. The utilization of SBMO as an animal feed ingredient shows promising potential, primarily due to its low cost and as a potential energy concentrate. This study aimed to assess the intake, digestibility, ruminal parameters (pH and ruminal ammonia - NH3), nitrogen retention (NR) and microbial protein synthesis in grazing beef cattle supplemented with SBMO as a substitute for corn during the rainy season. Five Nellore (10-month-old) bulls with an average initial weight of 246 ± 11.2kg were utilized in a 5 × 5 Latin square design. The animals were housed in five paddocks, each consisting of 0.34ha of Marandu grass (Urochloa brizantha). Five isonitrogenous protein-energy supplements (300g crude protein [CP]/kg supplement) were formulated, with SBMO replacing corn at varying levels (0, 0.25, 0.50, 0.75, or 1.00g-1g). The supplements were provided daily at a quantity of 2.0kg-1 animal. The inclusion of SBMO at any level of corn substitution did not significantly affect the intake of pasture dry matter or total dry matter (P > 0.10). Likewise, the intake of CP and, consequently, the ruminal concentration of NH3 did not differ among the SBMO levels. Increasing the inclusion of SBMO did not have a significant impact on NR (P > 0.10), indicating that animals receiving supplements containing 100% SBMO as a substitute for corn may perform similarly to animals receiving supplements with 100% corn (0% SBMO). Soybean molasses represents a viable alternative energy source for grazing beef cattle during the rainy season and can entirely replace corn without adversely affecting animal nutritional performance.

Evaluation of the effectiveness of the influence of the feed product Vinassa on milk productivity and rumen indicators of cows during the period of increasing the milk yield

By-products of processing of various industries in the agro-industrial complex with an optimal level of their introduction into the ration of farm animals make it possible to increase the productivity of farm animals by optimizing ruminal digestion. The purpose of the research was to assess the eff ectiveness of the infl uence of the feed product Vinassa on milk productivity and rumen indicators of cows during the period of increasing the milk yield. In order to conduct the experiment lactating fresh cows were selected during the period of increasing the milk yield (n=45), which were divided into three groups of 15 heads in each according to the method of pair-analogs. The introduction of diff erent levels of sugar processing products and domestically produced yeast production into the ration of cows in the 1st experimental group in the amount of 500 g/head/day and in the 2nd experimental group 1000 g/head/day has been examined in the work. The introduction of the feed product Vinassa in the amount of 1000 g/head/day as part of a totally mixed ration contributed to the optimization of rumen pH. The level of volatile fatty acids increased in the rumen contents of cows of the 2nd experimental group by 2.27 mmol/l, and the concentration of ammonia decreased by 4.48 mg% compared to the control group. Improving indicators of ruminal contents contributed to the growth and development of bacteria and ciliates. Thus, in cows of the 2nd experimental group the number of dry matter of ciliates was higher by 0.7 g/100 ml of dry matter of rumen contents. It was found during the experiment that optimization of ruminal digestion leads to increased milk productivity. Thus, in cows of the 2nd experimental group during the period of increasing the milk yield, the increase in the gross milk yield of milk with 4 % fat content for the period of increasing the milk yield was found to increase by 7.1 % and the increase in the gross yield of milk fat by 7.1 % (p &lt; 0.05).

Lactation Performance and Rumen Fermentation in Dairy Cows Fed a Diet Supplemented with Monensin or Gum Arabic-Nano Montmorillonite Compost.

The exploration of natural alternatives to antibiotics for enhancing productivity and performance in dairy cows is a crucial objective in farm animal management. This is the first study aimed at developing and evaluating the physicochemical properties and effects of Arabic gum-nano montmorillonite (AGNM) compost compared to ionophore monensin as feed additives on rumen fermentation, blood metabolites, and milk production of Holstein dairy cows. In a replicated 4 × 4 Latin square design, four multiparous mid-lactation Holstein dairy cows with an average body weight of 520 ± 15 kg were enrolled. The dietary treatments included a control diet (basal diet without feed additives), monensin diet [a basal diet supplemented with 35 mg/kg dry matter (DM) monensin], and AGNM diets comprising basal diet supplemented with two levels: low (L-AGNM) at 1.5 g/kg DM, and high (H-AGNM) at 3 g/kg DM. AGNM as a feed additive demonstrated promising physiochemical parameters, including containing highly bioactive components (α-amyrin and lupeol), functional groups (OH and Si-O), and essential mineral contents (Mg2+). Supplementations with H-AGNM significantly improved ruminal (p = 0.031) concentrations of total volatile fatty acids (VFAs), acetic (p = 0.05) and butyric (p = 0.05), enhanced (p < 0.05) digestibility of fiber and organic matter, while decreased (p = 0.013) estimated methane production. However, an increase (p = 0.04) in blood high-density lipoprotein levels and decrease (p < 0.05) in concentrations of creatinine (CREA), bilirubin (BILT), cholesterol (CHOL), and sodium (Na) were observed with H-AGNM supplementation. Both monensin and H-AGNM improved (p = 0.008) feed efficiency compared to L-AGNM; however, neither AGNM nor monensin affected the milk composition or energy status indicators of the dairy cows. The findings of this study highlight the potential of AGNM as a natural candidate to replace monensin in enhancing ruminal VFA production, nutrient digestibility, feed efficiency, blood metabolites, and milk yield in dairy cows.

A real-time PCR assay for the detection and quantification of Fusobacterium necrophorum and Fusobacterium varium in ruminal contents of cattle*

ObjectivesOur objectives were to develop and vali- date a quantitative PCR assay for the detection and quantification of the 2 subspecies of Fusobacterium nec- rophorum (ssp. necrophorum and ssp. funduliforme) and a recently recognized species, Fusobacterium varium, in ruminal contents of cattle collected at slaughter. Materials and MethodsA quantitative PCR assay with primers and probes designed to target hgdA, which encodes for 2-hydroxyglutaryl dehydratase, for F. necroph- orum (hgdA-n) and F. varium (hgdA-v), and the leukotox- in promotor region, lktA-n and lktA-f, for the 2 subspecies of F. necrophorum were developed and validated. A total of 345 ruminal fluid samples were collected in an abattoir immediately after slaughter, which included 181 (52.5%) samples from cattle with apparently healthy, nonabscessed livers and 164 (47.5%) from cattle with abscessed livers. Basal media with lactate or lysine as the major energy source and each with or without josamycin, vancomycin, and norfloxacin were used to enrich ruminal samples that were below the lower limit of quantification. Results and DiscussionThe ssp. necrophorum was quantified in 22% and 29% of samples from cattle with nonabscessed and abscessed livers, respectively. The ssp. funduliforme and F. varium were prevalent in almost all ruminal samples (98% to 100%) and were not different between cattle with or without abscessed livers. The mean concentrations of the 2 subspecies and F. varium were 103 to 104 cfu/mL and were not different between cattle with abscessed or nonabscessed livers. Implications and ApplicationsA major finding of the study was that only a small proportion of the ruminal contents harbored the ssp. necrophorum, which suggested that it is not a normal member of the ruminal microbial community. In contrast, the ssp. funduliforme and F. vari- um were prevalent in all ruminal contents tested. Because F. varium is a pathogen, the question whether the species contributes to the development of liver abscesses needs to be investigated.

First report of isolation of Fusobacterium varium from liver abscesses and ruminal and colonic epithelial tissues of feedlot cattle*

ObjectiveOur objective was to isolate and determine prevalence of Fusobacterium varium in liver abscesses and the corresponding ruminal and colonic epithelial tissues and ruminal and colonic contents of feedlot cattle. Materials and MethodsA total of 96 intact liver abscess samples and matched ruminal and colonic tissues and contents from cattle, originating from feedlots that did not receive in-feed tylosin, were collected at slaughter. Liver abscesses and ruminal and colonic tissue were ho- mogenized and then plated, before and after enrichment in lactate or lysine medium with selective antibiotics, onto blood agar and selective lactate or lysine agar for isolation of Fusobacterium and to determine prevalence and concentration. Putative colonies were tested by a quantitative PCR assay targeting the hgdA gene for species confirma- tion. Results and DiscussionNone of the liver abscess samples yielded F. varium by direct plating; however, F. varium was isolated from 3 of 96 (3.1%) following enrich- ment of the homogenate in lactate or lysine medium. In contrast to liver abscesses, F. varium was isolated by direct plating from 27.1% (26/96) of ruminal epithelial and 3.1% (3/96) of colonic epithelial tissue homogenates. Overall, 10.1%, 77.1%, 44.8%, 86.5%, and 70.1% of liver abscess, ruminal, and colonic epithelial tissues and ruminal and colonic contents were positive for F. varium, respectively. Implications and ApplicationsThe increased fre- quency of isolation and high prevalence of F. varium in ruminal tissue and, to a lesser extent, in the colonic tissue confirms its ability to invade tissues and possibly cause bacterial ruminitis. However, the relatively low frequency of F. varium isolation and low prevalence in liver abscesses suggest that it is unlikely to be an etiologic agent. Inter- estingly, there is some evidence that ruminal strains of F. varium were resistant to tylosin; therefore, it would be of interest to determine the prevalence in cattle receiving in-feed tylosin.

Ruminal microbiome changes across lactation in primiparous Holstein cows with varying methane intensity: Heritability assessment

Methane is a potent greenhouse gas produced during the ruminal fermentation and is associated with a loss of feed energy. Therefore, efforts to reduce methane emissions have been ongoing in the last decades. Methane production is highly influenced by factors such as the ruminal microbiome and host genetics. Previous studies have proposed to use the ruminal microbiome to reduce long-term methane emissions, as ruminal microbiome composition is a moderately heritable trait and genetic improvement accumulates over time. Lactation stage is another important factor that might influence methane production, but potential associations with the ruminal microbiome have not been evaluated previously. This study sought to examine the changes in ruminal microbiome over the lactation period of primiparous Holstein cows differing in methane intensity (MI) and estimate the heritability of the abundance of relevant microorganisms. Ruminal content samples from 349 primiparous Holstein cows with 14 to 378 DIM were collected from May 2018 to June 2019. Methane intensity of each cow was calculated as methane concentration/milk yield. Up to 64 taxonomic features (TF) from 20 phyla had a significant differential abundance between cows with low and high MI early in lactation, 16 TF during mid lactation, and none late in lactation. Taxonomical features within the Firmicutes, Proteobacteria, Melainabacteria, Cyanobacteria, Bacteroidetes, and Actinobacteria phyla were associated with low MI, whereas eukaryotic TF and those within the Euryarchaeota, Verrucomicrobia, Kiritimatiellaeota, and Lentisphaerae phyla were associated with high MI. Out of the 60 TF that were found to be differentially abundant between early and late lactation in cows with low MI, 56 TF were also significant when cows with low and high MI were compared in the first third of the lactation. In general, microbes associated with low MI were more abundant early in lactation (e.g., Acidaminococcus, Aeromonas, and Weimeria genera) and showed low to moderate heritabilities (0.03 to 0.33). These results suggest some potential to modulate the rumen microbiome composition through selective breeding for lower MI. Differences in the ruminal microbiome of cows with extreme MI levels likely result from variations in the ruminal physiology of these cows and were more noticeable early in lactation, probably due to important interactions between the host phenotype and environmental factors associated with that period. Our results suggest that the ruminal microbiome evaluated early in lactation may be more precise for MI difference, and hence, this should be considered to optimize sampling periods to establish a reference population in genomic selection scenarios.

A Meta-Analysis of 3-Nitrooxypropanol Dietary Supplementation on Growth Performance, Ruminal Fermentation, and Enteric Methane Emissions of Beef Cattle

This study aimed to evaluate the effects of dietary supplementation with 3-nitrooxypropanol (3-NOP) on growth performance, ruminal fermentation, and enteric methane emissions of beef cattle using a meta-analytic approach. The final meta-analysis database included results from 15 scientific articles. The response variables were analyzed through random effects models, where the results were reported as weighted mean differences (WMD) between the treatments without 3-NOP and those supplemented with 3-NOP. The dietary inclusion of 3-NOP decreased (p &lt; 0.001) dry matter intake but did not affect (p &gt; 0.05) average daily gain and increased (p &lt; 0.05) feed efficiency. In the rumen, 3-NOP supplementation increased (p &lt; 0.01) the pH and ruminal concentration of propionate, butyrate, valerate, isobutyrate, and isovalerate. In contrast, dietary supplementation with 3-NOP decreased (p &lt; 0.001) the rumen concentration of ammonia nitrogen, total volatile fatty acids, acetate, and the acetate/propionate ratio. Furthermore, daily methane (CH4) emission, CH4 yield, and CH4 emission as a percentage of gross energy ingested decreased (p &lt; 0.001) in response to 3-NOP dietary supplementation. In conclusion, dietary supplementation with 3-nitrooxypropanol can be used as a nutritional strategy to improve feed efficiency and ruminal fermentation in beef cattle and, at the same time, reduce enteric methane emissions.

Disturbances of Ruminal Microbiota and Liver Inflammation, Mediated by LPS and Histamine, in Dairy Cows Fed a High-Concentrate Diet.

The ecosystem of ruminal microbiota profoundly affects the health and milk production of dairy cows. High-concentrate diets are widely used in dairy farms and evoke a series of metabolic disorders. Several studies have reported the effects of high-concentrate diets on the ruminal microbiome, while the effect of changes in ruminal microbial flora, induced by high-concentrate diet feeding, on the liver of dairy cows has not been studied before. In this study, 12 mid-lactating Holstein Friesian cows (weight of 455 ± 28 kg; parities of 2.5 ± 0.5; starting milk yield of 31.59 ± 3.2 kg/d; DMI of 21.7 ± 1.1 kg/d; and a DIM at the start of the experiment of 135 ± 28 d) were fitted with ruminal fistulas, as well as with portal and hepatic vein catheters. All cows were randomly divided into 2 groups; then, they fed with low-concentrate diets (LC, concentrate: forage = 40:60) and high-concentrate diets (HC, concentrate: forage = 60:40) for 18 weeks. The forage sources were corn silage and alfalfa hay. After the cows of two groups were euthanized over two consecutive days, ruminal microbiota; the concentration of LPS in the rumen content; cecum content; the levels of blood and histamine in rumen fluid, blood, and the liver; the histopathological status of the rumen and cecum; and the inflammatory response of the liver were assessed in dairy cows under conditions of subacute ruminal acidosis (SARA). These conditions were caused by high-concentrate diet feeding. All data were analyzed using the independent t-test in SPSS. The results showed that high-concentrate diet feeding increased the concentration of LPS and histamine in the rumen and plasma of veins (p < 0.05). The abundance of Bacteroidetes at the phylum level, and of both Bacteroidetes and Saccharibacteria at the genus level, was decreased, while the abundance of Firmicutes at the phylum level and Oscillibacter at the genus level was increased by high-concentrate diet feeding. The decreased pH values of ruminal contents (LC = 6.02, HC = 5.90, p < 0.05) and the increased level of LPS in the rumen (LC = 4.921 × 105, HC = 7.855 × 105 EU/mL, p < 0.05) and cecum (LC = 11.960 × 105, HC = 13.115 × 105 EU/mL, p < 0.01) induced the histopathological destruction of the rumen and cecum, combined with the increased mRNA expression of IL-1β (p < 0.05). The histamine receptor H1R and the NF-κB signaling pathway were activated in the liver samples taken from the HC group. In conclusion, the elevated concentrations of LPS and histamine in the gut may be related to changes in the ruminal microbiota. LPS and histamine induced the inflammatory response in the ruminal epithelium, cecum epithelium, and liver. However, the cause-effect mechanism needs to be proved in future research. Our study offers a novel therapeutic strategy by manipulating ruminal microbiota and metabolism to decrease LPS and histamine release and to improve the health of dairy cows.

Spontaneous intoxication of sheep by the pollen beetle Astylus atromaculatus: 4 outbreaks in Uruguay and Argentina.

Astylus atromaculatus Blanchard is a native beetle of South America that feeds on pollen. During the summer of 2022-2023 in Argentina and Uruguay, an explosive infestation of these insects occurred in pastures in which ruminants were grazing. This was believed to be associated with a severe drought, which had significantly reduced the flowering of crops. Three farms in Uruguay and one in Argentina were visited to examine the flocks and perform autopsies. Affected sheep had watery diarrhea, anorexia, depression, and ruminal atony. The average morbidity, mortality, and case fatality rates were 7.5%, 4.3%, and 68%, respectively. The main gross findings in all animals were in the jejunum; the serosa had multifocal hemorrhages, and the mucosa was necrotic and covered by a pseudomembrane. Microscopically, the mucosa had partial-to-complete necrosis of the lamina propria, as well as loss of villus and crypt epithelium with neutrophilic infiltration. Overlying the necrotic mucosa was a pseudomembrane of fibrin, cell debris, desquamated epithelial cells, degenerate neutrophils, and bacteria. Many specimens of A. atromaculatus were in all paddocks in which sheep grazed, as well as in the ruminal content of the autopsied animals.