Ruminal pH Research Articles

Effects of Different Technological Forms of the Perilla frutescens in the Diet on Ruminal Fermentation, Milk and Plasma Fatty Acid Composition, Ruminal Biohydrogenation and Milk Quality in Dairy Goats.

Fatty acids can be protected by changing their structure or form against microbial activity, and the different forms of fatty acids can modulate the ruminal biohydrogenation rate and contribute to the desired fatty acid profile in milk fat. The study investigated the effects of perilla (Perilla frutescens) dietary supplementation in the diet in different technological forms (seed, oil and formaldehyde-treated oil) on milk, plasma and ruminal fatty acid composition, and milk quality in lactating goats. The four dietary treatments consisted of (1) no supplementation, basal diet (CON); (2) perilla supplementation as seed at 44.7g/kg (consisting of 20g/kg oil (PS)); (3) perilla supplementation as oil at 20g/kg (PO); (4) perilla supplementation as formaldehyde treated oil at 20g/kg (protected perilla oil [PPO]). The experiment was implemented in a double 4×4 Latin square trial design, and sampling was carried out for 7 days after 21 days of adaptation. Performance parameters were not affected by P. frutescens supplementation to the diet. PO decreased milk fat, whereas PPO increased milk fat. Milk cholesterol was not affected by P. frutescens dietary supplementation. Perilla oil supplementation in different forms to the diet did not affect ruminal pH, VFA and methane production. Perilla oil supplementation in different forms to the diet did not also affect the concentration of blood serum glucose, cholesterol and non-esterified fatty acids. Perilla supplementation to the diet increased the milk conjugated linoleic acid (CLA), C18:3n-3, C22:5n-3, C20:5n-3, C22:6n-3 and polyunsaturated fatty acid (PUFA) concentrations, and PPO group showed the greatest values. Ruminal palmitic (C16:0) acid was decreased, and in perilla groups, stearic acid (C18:0) concentration had the lowest, and ruminal c-9, t-11 CLA concentration had the highest value in PPO. It has been found that the most effective form of perilla oil in increasing milk quality is that with formaldehyde treatment (protected form). Perilla oil, which is a rich source of omega 3 in the diet, can be used to increase milk quality in goats without adversely affecting performance, ruminal fermentation and blood parameters.

Bioefficiency of microencapsulated hemp leaf phytonutrient-based extracts to enhance in vitro rumen fermentation and mitigate methane production.

The objective was to assess the supplementation with microencapsulation of hemp leaf extract (mHLE) utilized as a rumen enhancer on in vitro rumen fermentation and to enhance the bioavailability of active compounds for antimicrobial action, particularly in protozoa and methanogen populations. The feed treatments were totally randomized in the experimental design, with different levels of mHLE diet supplemented at 0, 4, 6 and 8% of total DM substrate and added to an R:C ratio of 60:40. During fermentation, gas kinetics production, nutrient degradability, ammonia nitrogen concentration, volatile fatty acid (VFA) profiles, methane production, and the microbial population were measured. The supplemented treatment at 6% of total DM substrate affected reductions in gas kinetics, cumulative gas production, and volatile fatty acid profiles, especially the acetate and acetate to propionate ratio. Whereas propionate proportion and total volatile fatty acid concentration were enhanced depending on the increase of nutrients in vitro dry matter degradability (IVDMD) after 12 h of post-fermentation at a R:C ratio of 60:40 (P < 0.05). Consequently, mHLE addition resulted in optimal ruminal pH and increased nutrient degradability, followed by ammonia nitrogen concentrations (P < 0.05), which were enhanced by dominant cellulolytic bacteria, particularly Ruminococcus albus and Ruminococcus flavefaciens, which showed the highest growth rates in the rumen ecology. Therefore, mHLE, a rich phytonutrient feed additive, affected the methanogen population, reduced the calculated methane production and can be a potential supplement in the ruminant diet.

Effect of High-Tannin and -Polyphenol Plant Material Supplement on Rumen Fermentation, Nitrogen Partitioning and Nutrient Utilization in Beef Cattle.

The current issue of ruminant methane emissions is still being researched by animal nutritionists in an effort to find new approaches. In this study, five beef cattle were randomly assigned in a 5 × 5 Latin square design to examine the effects of supplementation with high-tannin and -polyphenol plant materials on nutrient utilization, rumen fermentation, and nitrogen partitioning. Cattle offered total mixed ration (TMR) silage diets with or without tannin-rich tree leaf or plant herbs, such as Piper sarmentosum Roxb., Cymbopogon citratus (DC.) Stapf, Anacardium occidentale L., and Careya arborea Roxb., were supplemented at a dose of 10 g/d. Prior to TMR feeding, the animals' meals were supplemented with 10 g of fortified plant materials twice a day, along with 100 g of rice bran. The animals in the control group received only 100 g of rice bran and no other plant materials. The result showed that there was no difference in nutrient intake or digestibility between the supplemented and control groups. Although the effect of ruminal pH, NH3-N, Total VFA, acetate (C2), and butyrate (C4) was not significant (p > 0.05), the proportion of propionate (C3) tended to increase with supplementation (p = 0.07). There was no difference in the excretion of purine derivatives or the amount of microbial nitrogen supply, even though supplemented animals had significantly lower protozoal populations than the control group (p < 0.05). Moreover, when A. occidentale or C. arborea was added to the TMR silage diet, the nitrogen intake and retention increased considerably, although total nitrogen excretion decreased. In this approach, the leaves of Anacardium occidentale L. and Careya arborea Roxb. were particularly promising for strategic supplementation.

Effect of dietary supplementation of rubber seed kernel pellet on feed utilization, rumen fermentation, fatty acid profiles and health status in swamp buffalo.

Rubber seed kernel is a by-product of rubber cultivation and are high in oil and protein. This study was conducted to evaluate the effect of supplementing rubber seed kernel pellet (RUSKEP) on feed intake, nutrient digestibility, rumen fermentation, rumen fatty acid profiles, blood parameters, and immune response in swamp buffalo. Four male swamp buffalo with an initial body weight (BW) of 254 ± 10 kg and 26 months of age were used in this research. The experimental design was a 4  4 Latin squared design with RUSKEP supplementation at 0, 4, 6, and 8% of dry matter intake (DMI). Animals were fed concentrate at 1.0% BW, while rice straw was fed ad libitum. Supplementation with RUSKEP did not change DMI or nutrient digestibility (p>0.05), while ether extract (EE) digestibility increased cubically with the addition of RUSKEP (p<0.01). The ruminal pH, ammonia-nitrogen (NH3-N), and the proportion of acetate (C2) were similar among treatments (p>0.05). The proportion of propionate (C3) increased linearly (p≤0.04), leading to a decrease in the acetate to propionate ratio (C2:C3) (p≤0.04) with the addition of RUSKEP. Furthermore, the butyrate (C4) proportion decreased linearly with RUSKEP supplementation (p=0.03). The addition of RUSKEP did not affect on linoleic acid (LA; C18:2 cis-9,12 + trans-9,12), or α-linolenic acid (ALA; C18:3 cis-9,12,15) (p>0.05). With RUSKEP supplementation, the stearic acid (C18:0) content increased quadratically (p<0.01). The increasing level of RUSKEP was higher in cholesterol and eosinophils (p≤0.03). The immune function (IgA, IgM, and IgG) was similar among treatments (p>0.05). Supplementing RUSKEP with up to 8% of DMI could improve rumen fermentation efficiency without affecting feed utilization, rumen PUFA profile, or immune response in swamp buffalo.

Effects of Oregano on Lactation Performance, Nutrient Digestibility, Ruminal Fermentation Parameters, and Methane Emissions in Dairy Cows: A Meta-Analysis

Growing concerns regarding antibiotic use in livestock, due to antibiotic resistance and potential human transmission, have led to increased interest in herbs and their derivatives, including essential oils, which possess antimicrobial properties that may enhance overall productivity and serve as a strategy for methane mitigation. The objective of this meta-analysis was to investigate the effects of adding oregano to the diet in different forms (essential oils, plant materials, or leaves) on the dry matter intake (DMI), milk yield (MY), milk components, nutrient digestibility, ruminal fermentation parameters, and methane (CH4) emissions of dairy cows. A literature search was conducted to identify papers published from 2000 to 2023. Effect size for all outcomes was reported as a standardized means difference (SMD) and raw means difference with 95% confidence intervals. Heterogeneity was determined using the Q test and I2 statistic. The results of the meta-analysis indicated that adding oregano had no effect on DMI (SMD = 0.081; p = 0.507) and MY (SMD = 0.060; p = 0.665). Milk fat percentage, milk protein percentage, and milk lactose percentage were not affected by oregano. The addition of oregano to the diet significantly decreased dry matter digestibility (SMD = −0.502; p = 0.013), crude protein digestibility (SMD = −0.374; p = 0.040), and neutral detergent fiber digestibility (SMD = −0.505; p = 0.014). Ruminal pH (SMD = −0.122; p = 0.411), total volatile fatty acids concentration (SMD = −0.038; p = 0.798), acetate (SMD = −0.046; p = 0.757), propionate (SMD = 0.007; p = 0.960), and butyrate (SMD = 0.037; p = 0.801) proportion were not affected by oregano. The addition of oregano to the diet tended to decrease CH4/DMI (SMD = −0.275; p = 0.095) but did not affect CH4 production (SMD = −0.156; p = 0.282). Heterogeneity (Q and I2) was non-significant for all parameters. We conclude that the inclusion of oregano in various forms (essential oils, plant materials, or leaves) in the diet of dairy cows reduces nutrient digestibility but does not significantly affect DMI, MY, milk components, ruminal fermentation parameters, or CH4 production. Future research should focus on optimizing the dosage of oregano (both EOs and plant materials) and exploring the impact of its form on lactation, nutrient digestibility, ruminal fermentation, and CH4 emissions in dairy cows.

Effects of Chitosan-Based Additive on Rumen Fermentation and Microbial Community, Nutrients Digestibility and Lactation Performance in Goats.

Recently, the potential of using chitosan (CHI) as a feed additive to enhance ruminal fermentation and improve animal performance has gained increasing attention in ruminant nutrition. This study was undertaken to investigate the effect of dietary supplementation with increasing doses of CHI on rumen fermentation attributes and microbial composition, digestibility and milk performance in Dhofari goats. Twenty-four lactating goats (27 ± 1.8 kg of initial live body weight) were fed a control diet comprising of Rhodes grass hay plus a concentrate feed mixture. Goats were assigned to one of three experimental treatments (n = 8 per treatment) as: (1) control diet with no supplement (CTRL), (2) control diet with 0.300 g/day CHI (CHI0.3) and (3) control diet supplemented with 0.600 g/day CHI (CHI0.6) for a 45-day experimental period. Dietary supplementation with increasing doses of CHI decreased (p < 0.05) linearly ruminal pH (p = 0.023), total short chain fatty acids concentrations (p = 0.011), acetate (p = 0.013) and butyrate (p = 0.042) proportions, acetate to propionate ratio (p < 0.001), estimated methane (CH4) production (p < 0.001), ammonia nitrogen concentrations (p = 0.003) and protozoa abundance (p = 0.003). However, the ruminal propionate proportion augmented (p = 0.002) linearly with increasing doses of CHI in the diet. Increasing doses of CHI linearly increased the abundance of the ruminal propionate-producing bacteria, while diminished acetate and CH4-producing bacteria (p < 0.05). Serum total protein (p = 0.037) and glucose (p = 0.042) levels linearly increased as CHI doses increased in the diet. However, serum UREA levels decreased linearly (p = 0.002) by 21% with increasing CHI amounts in the diet. The digestibility of organic matter, crude protein and neutral detergent fibre increased linearly with the increasing CHI doses (p < 0.05). Neither linear nor quadratic responses (p > 0.05) were observed in daily milk yield and feed efficiency by supplementing the diet with CHI. In conclusion, supplementing the diet with CHI at a dose of 0.600 g/day as a feed additive for dairy goats reduced estimated CH4 generation and improved fibre and protein digestion, with no influence on feed intake, milk yield or composition.

Adding red propolis to the diet of Lacaune lambs: Effects on animal health, ruminal environment, performance, and meat quality

This study determined the influence of red propolis ethanolic extract in lambs' diets on the ruminal environment, animal health, and growth. Two experiments were carried out to achieve these objectives. Pilot study: Twenty-four female Lacaune lambs were divided into four groups, with three replicates and two animals per replicate (pen): T0 (Control), TP1.3, TP2.7, and TP5.3, representing 0, 1.3, 2.7, and 5.3 mL of propolis extract per animal/day, respectively. The highest daily weight gain was observed in lambs that consumed 2.7 mL of propolis extract per day, and they also had the lowest feed conversion rate compared to the control. Lower total leukocyte counts were observed in lambs that consumed propolis extract compared to control due to lower granulocyte and lymphocyte counts. Ceruloplasmin and C-reactive protein levels were lower in the serum of lambs that consumed propolis compared to the control. Lambs that consumed 1.3 and 2.7 mL of propolis extract had lower TBARS levels than the control. The effect of treatment was observed for ruminal pH, which was higher in lambs that consumed propolis extract than in control. A lower concentration of short-chain fatty acids was observed in lambs that consumed propolis than the control due to lower concentrations of acetic and butyric acid. In experiment II, 36 male Lacaune lambs were selected and divided into two groups: MONENSIN (23.45 ppm of monensin per kg/dry matter (DM)) and PROPOLIS (3.8 mL of propolis per animal/day). The animals that consumed propolis extract had greater body weight, weight gain, and average daily gain. These also had a shorter time to reduce methylene blue, thus demonstrating more significant bacterial activity in the rumen. Furthermore, they had lower counts of Escherichia coli, total coliforms, and Enterobacteria. The meat's fatty acid profile in animals fed the red propolis extract showed higher concentrations of monounsaturated fatty acids. In conclusion, adding red propolis extract to the concentrate increased weight gain, average daily gain, and oxidative balance with an antimicrobial and anti-inflammatory effect.

Marine microalgae meal (Schizochytrium sp.) influence on intake, in vivo fermentation parameters and in vitro gas production and digestibility in sheep diets is dose-dependent

The objective of this study was to evaluate the dry matter intake (DMI), intake of nutrients and in vivo ruminal fermentation in wethers fed diets without or with 2 or 4% of marine microalgae meal (Schizochytrium sp.) as a source of docosahexaenoic polyunsaturated fatty acid (DHA; C22:6 n-3), as well as the total gas production and digestibility of the experimental diets using in vitro techniques. Six Santa Inês wethers with a body weight of 55.6 ± 5.20kg and 18 months of age fitted with a ruminal cannula, were used and housed in individual stalls. The experimental design consisted of a double 3 ×3 Latin square (three treatments and three periods) with each experimental period lasting 21 days (14 days for adaptation to diets, 5 days for sample collection and 2 days of blank time between periods), for a total of 63 days. Animals fed 4% microalgae meal showed lower DMI (P<0.05; 1,14 vs. 0,86kg/d) and lower intake of nutrients (P<0.05), except for ether extract (EE; P=0.967), compared to animals not fed microalgae. Wethers that were not fed marine microalgae had lower ruminal pH just two hours after feeding (P=0.042) and lower concentrations of ammoniacal nitrogen (NH3-N) in the ruminal fluid at all sampling times (P=0.011) compared to wethers fed diets with 2 and 4% level inclusion. The addition of marine microalgae meal did not have an effect on heat production and in vitro gas production (P>0.05). The in vitro digestibility of non-fibrous carbohydrates (NFC) increased (P=0.033) with the inclusion of marine microalgae in the diet, being higher in the 4% treatment compared to the others. Additionally, marine microalgae meal significantly reduced (P=0.002; 0.55 to 0.47g/g of DM) the in vitro digestibility of neutral detergent fiber corrected for ash and protein (NDF). The inclusion of marine microalgae meal Schizochytrium sp. as a DHA source did not negatively affect ruminal fermentation. However, it compromised dry matter and nutrients intake, as well as NDF digestibility in animals fed 4% microalgae while a reduction on DMI as well as intake of nutrients at 2% inclusion was not significant. Therefore, it is recommended to use marine microalgae meal in the feeding of wethers under tropical conditions at a concentration of 2% of the diet.

Effect of replacing concentrates with cassava root-top silage on feed utilization, rumen fermentation, blood parameters and growth performance in beef cattle.

This experiment aimed to evaluate the effects of replacing concentrates with cassava root-top silage (CARTOS) on feed intake, digestibility, rumen fermentation, blood parameters, and growth performance of beef cattle. Twenty crossbred bulls with a body weight (BW) of 226±56 kg were randomly assigned to one of five treatments for 90 d in a randomized complete block design having four blocks based on BW. The concentrates were replaced by CARTOS at levels of 0%, 25%, 50%, 75%, and 100% dry matter (DM). Animals were fed dietary treatments at 1.8% BW, with rice straw offered ad libitum. The DM and crude protein (CP) intake were decreased (p<0.01, p = 0.04) when the diet's CARTOS level was increased. The digestibility of DM, OM, and CP were not different among treatments, while fiber digestibility was increased with the inclusion of CARTOS (p = 0.03). The addition of CARTOS to replace concentrates did not change ruminal pH or volatile fatty acid proportions except for acetic acid, which increased with the addition of CARTOS (p = 0.03). The ruminal ammonia-nitrogen (NH3-N) was decreased (p<0.01) with increasing levels of CARTOS. The blood glucose and blood urea nitrogen decreased (p = 0.01) with the addition of CARTOS at 100%, whereas total protein and hematological parameters did not change with increasing levels of CARTOS. The use of CARTOS to substitute concentrates at 75% and 100% decreased average daily gain (ADG) and gain to feed ratio (G:F) (p<0.01); therefore, the addition of CARTOS up to 50% maintained ADG and G:F in beef cattle. CARTOS can replace concentrates up to 50% in beef cattle diets without adversely affecting feed intake, nutrient digestibility, rumen fermentation characteristics, blood parameters, or growth performance of beef cattle.

Dietary macronutrient composition and partial soybean meal replacement with slow-release urea: Effects on performance, digestibility, rumen fermentation, and nitrogen metabolism in dairy cows

A 2 × 2 factorial arrangement of treatments was used to investigate the interactive effects of dietary macronutrient composition [high-starch, low-fat, low-fiber (HsLFF) than low-starch, high-fat, high-fiber (LsHFF)] and N source [soybean meal (SBM) or partially replaced by slow-release urea (SRU)] on lactation performance, rumen fermentation, N utilization efficiency, nutrient digestibility, blood metabolites, and feeding behavior in cows. A replicated 4 × 4 Latin square design was used involving 12 multiparous Holstein cows (milk yield of 40.5 ± 5.6 kg/d, BW of 590 ± 20 kg; 81 ± 12 d in milk). The HsLFF diet contained 300 g/kg starch, 31.3 g/kg fat, and 301 g/kg NDF, without straw or additional fat. In contrast, the LsHFF diet contained 195.5 g/kg starch, 60.8 g/kg fat, and 367.5 g/kg NDF, enriched with wheat straw (100 g/kg), and additional fat (34 g/kg). The diets were formulated to be iso-nitrogenous and isocaloric. Cows fed the HsLFF diet had greater DM intake, digestibility of DM and CP, milk yield and milk protein %, but lower intakes of NDF, and physically effective NDF, and milk fat % than cows fed the LsHFF diet. Replacing SBM with SRU significantly increased milk solids yield without affecting other lactation performance or BW. Cows fed the LsHFF diet had higher ruminal pH and branched-chain VFA proportions but lower total VFA concentrations compared with the HsLFF diet, while those on the LsHFF-SRU diet had the highest ruminal ammonia levels. Compared with the HsLFF diet, cows fed LsHFF had lower NE intake, milk energy output and energy requirement for maintenance, although energy balances were similar among groups. The HsLFF diet improved N utilization, resulting in higher N content in milk and lower N excretion in feces. Blood metabolite studies showed significant interactions between the main factors, particularly for blood glucose and creatinine, with the lowest levels in cows fed the LsHFF-SRU and LsHFF-SBM diets. In addition, alanine aminotransferase levels were higher in cows fed the LsHFF diet than in cows fed the HsLFF diet. This could indicate early-stage liver stress due to the metabolic imbalance caused by a high-fat, low-starch diet, which can alter energy metabolism. Cows on the HsLFF-SRU diet had the highest glucose levels, indicating possible changes in carbohydrate metabolism or a higher metabolic rate. The concentration of BUN increased steadily after feeding in the LsHFF diet and peaked after 4 h in the LsHFF-SRU diet, with no difference between N sources in the HsLFF diet. Partial replacement of SRU with SBM had no effect on BUN. The interaction between the main factors had a significant effect on MUN content, which was highest in LsHFF-SRU and lowest in HsLFF-SRU, with no difference between the N sources in the HsLFF diets. Overall, while diets with reduced starch and increased fiber and fat compromised lactation performance, partially substituting SRU with SBM helped maintain milk production and milk nitrogen efficiency. However, the LsHFF-SRU diet was less efficient in N utilization, as shown by higher levels of ruminal ammonia, BUN and MUN.

PSIX-19 Effect of protein and starch level on N balance and ruminal fermentation parameters in steers consuming low-quality forage: Bos taurus taurus

Abstract Globally cattle convert low-quality forage to beef and milk; therefore, understanding protein utilization in Bos taurus taurus is critical to enhancing sustainability as over and under-supplementation of protein are economically and environmentally costly. Low-quality forage lacks the N necessary for proper utilization and metabolic function. Supplemental protein improves low-quality forage utilization and is expected to increase N absorption and retention. Supplement starch can increase volatile fatty acid (VFA) production and energy supplied to the animal; however, too much starch decreases ruminally available N and pH potentially decreasing fibrolytic activity. Accordingly, our objective was to determine the effect starch supplementation on N balance and ruminal fermentation parameters in Bos taurus steers. Ruminally cannulated Angus steers [n = 5; body weight (BW) = 375 ± 45 kg] were used in a 4 × 4 Latin square to evaluate the effect of decreasing supplemental starch when consuming King Ranch Bluestem hay (3.5% CP, 73% NDF). Steers received four isonitrogenous (130 mg N/kg BW) supplements providing increasing levels of starch (2% starch = 100% soybean meal; 20% starch = 26.3% corn, 73% soybean meal, 0.7% urea; 38% starch = 51.6% corn, 47% soybean meal, 1.4% urea; 56% starch = 78.6% corn, 19% soybean meal, 2.4% urea). Five 14-d periods were conducted, consisting of 9 d adaptation and 4 d to measure intake and digestion, and 1 d for ruminal fermentation. Supplemental N intake decreased linearly (P &amp;lt; 0.01) with increasing starch as the crude protein content of the soybean was underestimated. Forage and total N intake were not affected by starch level (P ≥ 0.17). Fecal and total urinary N excretion were not different between starch levels (P ≥ 0.43). Urinary ammonia-N and urea-N averaged 6.6 and 16.8% of total urinary N excretion, respectively, but no differences between starch levels were observed (P ≥ 0.39). Level of starch supplementation had no effect on N retention and absorption (P ≥ 0.50). There was a treatment × time interaction observed for ruminal ammonia concentration (P &amp;lt; 0.01). All treatments, except 2% starch, peaked at 4 h post feeding, 20 and 38% treatments gradually decreased following four, but the concentration of ruminal ammonia decreased by 80% between 4 h and 8 h after feeding in the 56% starch treatment. Starch level had no effect total VFA concentration, VFA molar proportions, or ruminal pH (P ≥ 0.10). In conclusion, providing supplemental starch did not affect N balance or VFA production when fed to steers consuming low-quality forage. Nitrogen balance and VFA production likely were not affected because all supplements provided sufficient ruminally available N and, therefore, exerted minimal effects on forage utilization.

PSIII-7 Effects of Saccharomyces cerevisiae fermentation product on total tract digestibility, ruminal fermentation, and plasma metabolome of beef steers fed a finishing diet

Abstract Saccharomyces cerevisiae fermentation product (SCFP) has been widely studied; however, its mode of action on high-concentrate diets has not been fully elucidated. This study evaluated the impact of SCFP on total tract digestibility, fecal excretions of N, P, Zn, and Cu, rumen fermentation, and plasma metabolome of finishing beef steers. Ruminally cannulated Holstein steers [n = 8; body weight (BW) = 580 ± 29.2 kg] were enrolled in a crossover design study with 25-d treatment periods and a 24-d washout period. Steers were fed ad libitum a finishing diet consisting of 20% corn silage and 80% concentrate (on DM basis). Steers were blocked based on initial BW and randomly assigned to two treatments in period 1 and switched to the other treatment in period 2. The treatments were CON (Control, basal diet only) and SCFP (basal diet top-dressed with 12 gּ steer-1ּ ּ d-1 SCFP, NaturSafe, Diamond V, Cedar Rapids, IA). Feed and fecal samples were collected during d 22 to 24 for determination of digestibility. Blood was collected before morning feeding on d 25. Plasma samples were analyzed for metabolome with liquid chromatography-mass spectrometry (LC-MS). Rumen fluid was collected via the rumen cannula at 0, 4, 8, and 12 h post-morning feeding on d 25 and analyzed for pH, volatile fatty acids (VFA), and NH3-N. Performance and ruminal fermentation characteristics data were analyzed using the GLIMMIX procedure of SAS 9.4. Metabolomic data analysis was conducted with Metaboanalyst 6.0. Supplementing steers with SCFP reduced DMI (10.6 vs. 11.4 kg/d, P = 0.05) without affecting (P &amp;gt; 0.05) average daily gain, feed efficiency, and digestibility of organic matter, crude protein, and neutral detergent fiber. Treatment did not affect (P &amp;gt; 0.10) fecal excretions of N, P, Cu, and Zn. Feeding SCFP increased ruminal pH (6.29 vs. 6.01, P = 0.01), numerically reduced concentrations of NH3-N (5.01 vs 6.25 mM, P = 0.16), and total VFA (96.8 vs. 102.5 mM, P = 0.15). SCFP also reduced the ruminal molar proportion of butyrate (11.2 vs. 12.8 molar %, P = 0.01) and tended to increase those of isobutyrate (1.03 vs. 0.90, molar %, P = 0.06) and isovalerate (2.62 vs. 2.29, molar %, P = 0.10). Supplementation of SCFP enriched (P ≤ 0.05) purine metabolism, amino sugar and nucleotide sugar metabolism, and lysine degradation pathways in the plasma. Additionally, tryptophan metabolism and pyrimidine metabolism pathways tended to be enriched (0.05 &amp;lt; P ≤ 0.10) by SCFP. Our findings indicate that feeding SCFP improved the ruminal pH of finishing cattle, which may be beneficial for preventing subacute ruminal acidosis in feedlot cattle. Additionally, SCFP enriched several important plasma nitrogen metabolism pathways, potentially associated with microbial nitrogen metabolism in the rumen, warranting further research.

PSXIII-22 Intake, digestibility, and ruminal parameters of Nellore cattle fed with amylolytic and fibrolytic enzymes in feedlot

Abstract This study was carried out to evaluate the use of dietary exogenous enzyme (ENZ) products with amylolytic and fibrolytic activity on nutrient intake, digestibility, and ruminal volatile fatty acids production (VFA) of Nellore cattle in feedlot. Rumen-cannulated Nellore steers [n = 10; body weight (BW) = 543 kg ± 28.6 BW] were distributed in a replicated Latin-square design (5 × 5) in individual pens. The treatments consisted of a negative control (CON; without ENZ); Amylase (AML; Amaize, Alltech, 0.5 g/kg of DM); Xylanase (FBL, Fibrozyme, Alltech, 0.9 g/kg of DM); Half dose (HD; AML 0.25 g/kg of diet DM and FBL 0.45 g/kg of diet DM); and Full dose (FD; AML 0.5 g/kg of diet DM and FBL 0.90 g/kg of diet DM; Table 1). The experimental period lasted 19 d (14 d of adaptation and 5 d of collection). Between d 15 and 18, total fecal collection was performed and on d 19 rumen fluid was collected at 0, 4, 8, 12, and 16 h post-feeding for ammonia, VFA, and pH determination. The data were analyzed as orthogonal contrasts using SAS: (C1) CON vs. ENZ, (C2) AML vs. FBL, (C3) HD vs. FD, and (C4) AML + FBL vs. HD + FD. There were no C1 differences for nutrient digestibility, total VFA, or ruminal pH (P &amp;gt; 0.10). However, a tendency effect in neutral detergent fiber (NDF) intake (P = 0.065) was observed, where animals fed ENZ had reduced values compared with animals kept in CON group. In the same way, ENZ reduced ther extract (EE) intake (P = 0.023), ruminal ammonia (P &amp;lt; 0.001), and isovalerate proportion (P = 0.080) as well as increased proportion of acetate (P &amp;lt; 0.001), valerate (P &amp;lt; 0.001) and acetate:propionate ratio (P = 0.030). No differences were observed in nutrient intake between AML and FBL (P &amp;gt; 0.10), but AML had greater organic matter (OM) digestibility (P = 0.097) and ruminal valerate (P = 0.039) and decreased butyrate proportion (P = 0.068). Animals that received FD had greater values of dry matter (DM; P = 0.009) and OM (P &amp;lt; 0.001) digestibility than HD. The enzyme combination resulted in greater DM (P = 0.026), OM (P = 0.062), crude protein (P = 0.018), EE (P = 0.063) and NDF (P = 0.040) intake and reduced OM digestibility (P = 0.008) compared with AML and FBL alone. The addition of exogenous enzymes in feedlot diets affected nutrient utilization and ruminal fermentation of Nellore cattle fed a feedlot finishing diet.

PSXII-16 Effect of including sugar cane molasses on rumen fermentation characteristics in young beef finishing heifers

Abstract In ruminant animals, the use of molasses has benefits related to improved voluntary intake and increased production of short-chain fatty acids (SCFA) in the rumen, especially butyrate. Butyrate is closely related to gastrointestinal tract health, as it may contribute to the increase in the absorption area of the ruminal epithelium and improve the utilization of diet components, resulting in improved voluntary intake and immune response capacity in stressful situations, such as weaning. Hence, our objective was to assess the effect of sugar cane molasses on rumen fermentation characteristics in young beef finishing heifers. Newly weaned Nellore × Red Angus heifers (n = 12) averaging 238 ± 5.1 kg body weight (BW), were used. All heifers were housed in individual pens with concrete floors, covered feeders, and drinkers. The basal diet was 50 % concentrate, and consisted of corn silage, sorghum silage, ground corn, soybean meal, urea, and a mineral premix. The diet was provided twice daily at 0700 and 1600 h, allowing up to 10% in orts (as fed). The following treatments were evaluated: control (no addition of powdered molasses) or addition of 50 g/kg of diet [dry matter (DM) basis] of powdered molasses. The experiment lasted for a total of 80 d, including a 14-d adaptation period. On d 68 and 76, rumen fluid samples were collected both before and 4 h after the morning feeding using an oral probe coupled to a vacuum pump. The initial fluid samples were discarded to prevent saliva contamination. The rumen fluid was filtered through four layers of cheesecloth, and then pH was measured. Subsequently, samples were taken and stored in an ultra-freezer (-80°C) for subsequent SCFA analysis. The data were subjected to analysis of variance using the GLM procedure of SAS 9.4 (α = 0.05). Providing molasses increased ruminal pH compared with control heifers (P &amp;lt; 0.032). Adding molasses did not affect SCFA concentration (P &amp;gt; 0.90). Conversely, we detected an effect of molasses on SCFA molar proportion. The molar proportion of both acetate (P &amp;lt; 0.013) and butyrate (P &amp;lt; 0.012) were greater in heifers fed molasses than with controls. On the other hand, dietary molasses addition decreased (P &amp;lt; 0.001). the propionate molar proportion. This resulted in an increased (P &amp;lt; 0.002) acetate-to-propionate ratio in heifers fed diets containing molasses. In conclusion, providing sugar cane molasses enhances rumen fermentation characteristics in young beef finishing heifers.

287 Effects of crude glycerin supplementation of beef cattle grazing wheat pasture on forage intake and characteristics of rumen fermentation

Abstract Crude glycerin (CG), mainly composed of glycerin, is a by-product of biodiesel production. Glycerin can be utilized as a substrate of gluconeogenesis by either rapid fermentation to propionate in the rumen or can be directly absorbed through the rumen epithelial wall, resulting in the conversion to glucose in the liver. Therefore, CG supplementation may increase the energy intake of cattle grazing wheat pasture. Ruminally cannulated Angus-crossbred cows [n = 9; 564.4 ±101.6 kg initial body weight (BW)] grazing wheat pasture were utilized in a split-plot design with the objective of evaluating the effects of CG supplementation and forage maturity on forage intake and rumen fermentation characteristics. Treatment was the main plot, and stage of forage maturity was the subplot. Treatments were unsupplemented control (CON) and crude glycerin supplementation (SUP; 37.2% glycerin, DM basis) dosed at 0.11% BW (DM basis). Supplementation levels correspond to 5% of the diet, assuming forage intake of 2.2% of BW on a DM basis. The stages of wheat maturity pasture were March (MAR; vegetative stage) and April (APR; early reproductive stage). Cows grazed a single wheat pasture and were supplemented directly through the rumen cannula twice daily at 0700 and 1900 h. Forage intake in kg/d and as % of BW was greater (P = 0.04) for SUP than CON. Ruminal pH, ammonia, and VFA concentrations, as well as proportions of VFAs, were not affected by CG supplementation (P ≥ 0.34; Table 1). However, ruminal pH (5.77 and 5.99 ± 0.049) and ammonia concentration (0.67 and 3.37 ± 0.307 mM) were greater, while total VFA concentration (136.3 and 110.8 ± 5.23 mM) was less (P = 0.01) for APR compared with MAR. Acetate, propionate, and butyrate molar proportions, as well as acetate: propionate ratio, were not affected (P ≥ 0.27) by the stage of wheat pasture maturity. Results indicate that crude glycerin used as an ingredient in supplementation strategies for cattle grazing wheat pasture may increase cattle energy intake without negatively affecting forage intake and ruminal fermentation.

124 Effects of Saccharomyces cerevisiae and dietary type offered to beef cattle on intake, feeding behavior, nutrient digestibility, and ruminal fermentation

Abstract The effects of live yeast and diet type offered to beef steers on intake, feeding behavior, nutrient digestibility, and ruminal fermentation profile were evaluated. Ruminally cannulated beef steers [n = 8; body weight (BW) = 550 ± 20 kg] were used in a duplicated 4 × 4 Latin square design following a 2 × 2 factorial arrangement of treatments: A) presence of live-yeast [Saccharomyces cerevisiae (CNCM I-1077), at 1 × 1010 CFUּ animal-1ּ d-1]; and B) diet type [steam-flaked corn-based grower or finisher diets (ad libitum intake)]. Live yeast was delivered with gel-capsules (0.25 g, as is) twice daily via ruminal-cannula. Four, 35 d periods were used. Feed refusal was subtracted from offered (dry matter basis) to calculate feed intake (DMI). The 24 h feeding behavior assessment was conducted on d 31 by trained personnel (time spent eating, ruminating, chewing, drinking, resting, and meal size/number). A 5-d fecal collection (twice daily) was used for the digestibility assessment. Ruminal pH was continuously measured (7 d, intra-ruminal Dascor wireless data loggers). Ruminal ammonia-N and volatile fatty acids (VFA) were analyzed at 0, 2, 4, 8, 16, and 23 h on d 35. The GLIMMIX procedure of SAS was used with animals as the experimental unit. No live yeast × diet interactions (P ≥ 0.17) were observed. Intake was not affected (P = 0.83) by live yeast, while steers offered the grower diet consumed more (P ≤ 0.01) NDF, ADF, and hemicellulose compared with the finisher diet. Live yeast increased (P ≤ 0.02) the dietary NDF, ADF, and hemicellulose digestibility of the grower diet by 13.7, 12.8, and 14.6%, and on the finisher diet by 6.7, 9, and 6.4%, respectively. Live yeast did not affect (P ≥ 0.23) major feeding behavior activities measured. Steers offered grower diet spent more time (P ≤ 0.01) on each meal, ruminating, eating, and chewing and less time (P &amp;lt; 0.01) resting. Live yeast did not affect (P ≥ 0.81) ruminal pH variables measured. Steers offered the grower diet had a greater (P &amp;lt; 0.01) ruminal pH pattern compared with the finisher diet. The ruminal ammonia-N and volatile fatty acids were not affected (P ≥ 0.16) by live yeast, while steers offered the finisher diet had a greater (P ≤ 0.01) total VFA and propionate molar proportion, while a lower (P ≤ 0.01) ammonia-N and acetate molar proportion compared with the grower diet. Regardless of the diet type, live yeast improved digestibility of fiber fractions, while dry matter intake was unaffected. Grower diets were more prone to stimulate feeding behavior activities than finisher, while live yeast seemed to not affect such variables. Expected effects of diet type on ruminal fermentation were ratified, while live yeast inclusion did not affect the ruminal fermentation variables evaluated.

193 Evaluation of in-dwelling pH monitoring technologies

Abstract We compared ruminal pH measurements determined using smaXtec bolus (SMAX; smaXtec Inc., Graf, Austria), Moonsyst bolus (MOON; Moonsyst International, Kinsale, Republic of Ireland), and handheld pH meter (METER; PH8500 pH/mV Meter, Apera, Columbus, OH) over time and during an ex vivo acidosis challenge. Ruminally cannulated heifers (n = 8) were used for 6 consecutive 21-d periods. On d 0, SMAX and MOON were placed in the reticulum of each heifer and continuously measured ruminal pH. On d 20 of each period, ruminal digesta samples were collected prior to feeding and again 2, 4, 6, 8, 12, 18, and 24 h post-feeding pH was measured with METER. MOON yielder lower (P &amp;lt; 0.01) pH measurements compared with SMAX and METER at all time points. From h 0 to 2 post-feeding measurements from SMAX were similar compared with METER (P = 0.54); however, measurements from SMAX tended to be greater 4 h post-feeding (P &amp;lt; 0.07) and differed at all subsequent timepoints (P &amp;lt; 0.05) compared with METER. On d 21 of each period, boli were removed and placed in a pH 4 and pH 7 solution, each for 3 h. In pH 4 solution, MOON pH measurements did not differ (P &amp;gt; 0.39) from 4 from periods 1 to 5; however, pH measured by MOON in period 6 was less (P &amp;lt; 0.01) than 4. Smaxtec pH measurements did not differ (P ≥ 0.39) from 4 during periods 2 to 5 but was greater (P &amp;lt; 0.01) than 4 in period 6. In pH 7 solution, pH measures with MOON did not differ (P &amp;gt; 0.26) from 7 for period 1 and 2 but declined in period 3 and were less than 7 from periods 4 to 6 (P &amp;lt; 0.05). In pH 7 solution, SMAX measurements varied over time and yielded greater (P &amp;lt; 0.05) than 7 for periods 2, 3, and 6. Subsequently, boli were placed in a container of strained ruminal fluid (6.5 L), and pH was measured for 1 h using SMAX, MOON, and METER. Following, 500 mL of vinegar was added to the ruminal fluid to simulate an acidosis challenge, pH was measured and change in pH detected by SMAX and MOON, relative to METER was determined. With change in pH detect by METER considered the true response, MOON provided a better measurement of the pH decrease than did SMAX, particularly during periods 1 to 3 (P &amp;lt; 0.01). Overall, pH measurements differed between SMAX, MOON, and METER. MOON and SMAX pH measurements began to drift after approximately 100 d. MOON was more accurate than SMAX in detecting a change in ruminal pH, whereas pH measurements over time were more precise for SMAX than for MOON.

248 Impacts of sprouted barley on the performance and carcass traits in finishing Angus steers

Abstract The growing population, coupled with unpredictable weather patterns, demands that livestock producers think innovatively to improve sustainability. Producers are interested in innovative practices and technology, such as controlled environment farming to sprout cereal grains that can be fed to livestock. However, little research has determined the effects of giving these feeds to finishing beef steers. As such, Angus steers (n = 60) were stratified by body weight (BW; 385 kg ± 10.3) to receive two different diets (n = 30/diet). The control (CON) diet was a traditional finishing ration for the region, whereas the other included 20% (dry matter; DM) sprouted barley (SB) in place of corn silage. Animals were fed for 128 d in pens with Vytelle units to measure intake and feeding behavior. On d 0, 30, 60, 90, and 128 BW, ruminal fluid, and ultrasound measurements were taken. Liver score (LS) and typical carcass data were collected from a commercial harvest facility. Statistical analyses used the MIXED procedure of SAS to assess the main effect of diet for all measurements collected over time. Dry matter intake (DMI), feed efficiency (gain to feed; G:F), ruminal volatile fatty acid (VFA) composition, and feeding behavior were run as repeated measures. No differences (P = 0.37) in BW gain were found between steers receiving different diets, but steers receiving SB had decreased (P &amp;lt; 0.0001) DMI throughout the trial compared with CON. This decrease in DMI drove a diet × day effect (P = 0.004) for G:F such that SB had increased (P ≤ 0.04) G:F on d 0 and 60, but no effect (P ≥ 0.52) was observed at d 90 or 128. Steers receiving the CON diet spent more (P &amp;lt; 0.0001) time at the feed bunk than those receiving the SB diet, which supports the observation that steers receiving the CON had an increased DMI. Ruminal pH, total VFA concentration, acetate:propionate, percent propionate, and percent butyrate were each impacted by diet × day (P ≤ 0.007). The only carcass trait impacted by diet was yield grade (YG), where steers receiving the SB diet had an increased (P &amp;lt; 0.03) YG compared with CON. These results demonstrate that replacing corn silage with SB in the ration of finishing steers has some effect on ruminal VFA composition, DMI, G:F, and USDAYG. Due to decreased DMI, SB steers had increased feed efficiency which could potentially have a positive economic impact for producers. However, additional analysis is needed to further determine if these systems are economically viable in a production setting.

516 Effects of increasing hybrid rye silage as a replacement for barley silage for growing beef heifers

Abstract The objective of these studies was to evaluate effects of increasing hybrid rye silage (HRS; harvested at boot stage in Study 1 and soft-dough in Study 2) inclusion as a replacement for barley silage (BS; harvested at soft-dough stage) on dry matter intake (DMI), ruminal fermentation, and growth performance of growing beef cattle. In Study 1, ruminally cannulated Hereford × Simmental heifers (n = 8) with an initial body weight (BW) of 519 ± 25.8 kg were used in a replicated 4 × 4 Latin square design with 28-d periods including 21 d of dietary adaptation and 7 d of data and sample collection to assess DMI and ruminal fermentation. Treatments included a control diet (DM basis) that contained 59.62% BS, 38.60% barley grain, and 1.78% of a vitamin and mineral supplement. Hybrid rye silage replaced 33, 67, and 100% of the BS on a DM basis. In Study 2, steers (n = 384; BW = 343 ± 20.2 kg) were stratified by BW and allocated to 32 pens in a randomized complete block design over 2 yr (4 pens/treatment/yr) to evaluate DMI, growth, and gain:feed (G:F). Steers were fed similar diets as Study 1 for 84 d in both years. In Study 1, increasing HRS linearly (P &amp;lt; 0.01) decreased DMI from 12.0 to 9.2 kg/d, and linearly increased (P = 0.02) water intake from 18.6 to 22.5 L/d. Increasing HRS linearly increased mean (P &amp;lt; 0.01) and minimum ruminal pH (P &amp;lt; 0.01). There was no effect of HRS inclusion on total short-chain fatty acid concentration (P = 0.46) in ruminal fluid, but the molar proportion of acetate linearly (P &amp;lt; 0.01) increased while propionate and butyrate linearly decreased (P &amp;lt; 0.01, and &amp;lt; 0.01, respectively) with increasing HRS inclusion. Moreover, increasing HRS inclusion linearly increased the molar proportions of isobutyrate and valerate (P = 0.06, and &amp;lt; 0.01, respectively) while caproate decreased linearly (P = 0.02). The ammonia-N concentration linearly increased with increasing HRS inclusion. In Study 2, DMI was 9.23, 9.10, 8.82, 8.08 kg/d (quadratic, P = 0.02) for diets containing 0, 33, 67, and 100% HRS, respectively. Likewise, ADG decreased (1.45, 1.36, 1.30, 1.08 kg/d; quadratic P &amp;lt; 0.01) as HRS inclusion increased and G:F ratio decreased linearly (P &amp;lt; 0.01) from 0.158 with 0% HRS to 0.134 g/kg when diets contained 100% HRS. Final BW was 462, 456, 450, and 432 kg when HRS was included at 0, 33, 67, and 100% of the silage, respectively (quadratic, P = 0.04). In conclusion, replacing BS with increasing proportions of HRS reduced DMI resulting in greater ruminal pH, altered molar proportions of individual SCFA, and reduced growth performance and G:F during the growing phase.

433 Use of polyclonal antibodies to improve the efficiency of rumen function

Abstract Technologies such as polyclonal antibody preparations (PAP) have been investigated as a tool to improve rumen function, by targeting specific bacteria or molecules. While PAP can be sourced from the serum of immunized mammals, isolating targeted avian-derived antibodies (immunoglobulin Y; IgY) from egg yolk gained popularity due to its reduced impact on hens and greater IgY concentration in yolks. Advantages of avian-derived PAP utilization include cost-effectiveness and convenient production, high stability, and reduced cross-reactivity compared with other PAPs. Furthermore, IgY does not activate the host immune complement system, as observed with PAP derived from mammalian serum. Several proposed strategies explain how PAP might protect the host. It is suggested that PAP can agglutinate bacteria, inhibit bacterial adhesion, suppress bacterial virulence factors, and neutralize toxins. Avian-derived PAP, mainly administered as a direct-fed product in beef and dairy cattle diets, has been studied for its impact on specific rumen microbial populations, especially during high-grain feeding. Research confirms the effectiveness of PAP-IgY in inhibiting the growth of targeted bacteria. In beef steers, feeding PAP-IgY against Streptococcus bovis and Fusobacterium necrophorum resulted in growth inhibition, while IgY against cellulolytic rumen bacteria also showed efficacy in reducing the growth of the targeted strains in vitro. In other studies, PAP-IgY targeting S. bovis and F. necrophorum increased ruminal pH in beef steers and heifers and dairy cows, while also cattle-fed PAP-IgY against F. necrophorum had reduced severity of liver abscesses. When performance was evaluated, PAP-IgY against S. bovis improved feed efficiency of feedlot beef steers, and milk production increased when dairy cows were supplemented with PAP-IgY against lipopolysaccharides, with no observed impact on cow health status. However, not all studies have consistently demonstrated positive effects of PAP-IgY on nutrient digestibility or on mitigating systemic inflammation during high-grain feeding. A recent study revealed that supplementation with PAP-IgY against Methanobrevibacter ruminantium M1 decreased methane output ex-situ and tended to increase molar proportion of propionate in beef steers. In summary, polyclonal antibody preparations, particularly avian-derived IgY, offer a promising alternative to improve rumen function and animal performance. This is evidenced by increased ruminal pH during high grain feeding, inhibition of targeted bacterial growth, and, most recently, methane reduction. However, not all studies demonstrate consistent effects regarding nutrient digestibility. Further research is needed to refine recommendations, including dosage and antibody combinations, and to explore the broader impacts of PAP-IgY supplementation on ruminal and systemic variables to optimize livestock performance.