Ruminal Fluid Research Articles

Can dietary magnesium sources and buffer change the ruminal microbiota composition and fermentation of lactating dairy cows?

Magnesium oxide (MgO) is one of the most used Mg supplements in livestock. However, to avoid relying upon only one Mg source, it is important to have alternative Mg sources. Therefore, the objective of this study was to evaluate the effects of the interaction of two Mg sources with buffer use on the ruminal microbiota composition, ruminal fermentation, and nutrient digestibility in lactating dairy cows. Twenty lactating Holstein cows were blocked by parity and days in milk into five blocks with four cows each, in a 2 × 2 factorial design. Within blocks, cows were assigned to one of four treatments: 1) MgO; 2) MgO + Na sesquicarbonate (MgO+); 3) calcium-magnesium hydroxide (CaMgOH); 4) CaMgOH + Na sesquicarbonate (CaMgOH+). For 60 d, cows were individually fed a corn silage-based diet, and treatments were top-dressed. Ruminal fluid was collected via an orogastric tube, for analyses of the microbiota composition, volatile fatty acids (VFA), lactate, and ammonia nitrogen (NH3-N). The microbiota composition was analyzed using V4/16S rRNA gene sequencing, and taxonomy was assigned using the Silva database. Statistical analysis was carried out following the procedures of block design analysis, where block and cow were considered random variables. Effects of Mg source, buffer, and the interaction between Mg Source × Buffer were analyzed through orthogonal contrasts. There was no interaction effect of the two factors evaluated. There was a greater concentration of NH3-N, lactate, and butyrate in the ruminal fluid of cows fed with CaMg(OH)2, regardless of the buffer use. The increase in these fermentation intermediates/ end-products can be explained by an increase in abundance of micro-organisms of the genus Prevotella, Lactobacillus, and Butyrivibrio, which are micro-organisms mainly responsible for proteolysis, lactate-production, and butyrate-production in the rumen, respectively. Also, dietary buffer use did not affect the ruminal fermentation metabolites and pH; however, an improvement of the apparent total tract digestibility of dry matter (DM), organic matter (OM), neutral fiber detergent (NDF), and acid fiber detergent (ADF) were found for animals fed with dietary buffer. In summary, there was no interaction effect of buffer use and Mg source, whereas buffer improved total tract apparent digestibility of DM and OM through an increase in NDF and ADF digestibility and CaMg(OH)2 increased ruminal concentration of butyrate and abundance of butyrate-producing bacteria.

Effects of hempseed cake on ruminal fermentation parameters, nutrient digestibility, nutrient flow, and nitrogen balance in finishing steers.

Five ruminally and duodenally cannulated red angus steers (n = 5; initial body weight [BW] = 542 kg, SD = 40 kg) were used in a three-period Youden square design consisting of three 21-d periods, three treatments, and five steers (one or two steers per treatment within each period) to evaluate the effect of feeding hempseed cake on ruminal fermentation parameters, organic matter (OM) intake, total tract nutrient digestion, and nitrogen (N) balance in steers fed finishing diets. The control (CON) diet contained 75% dry-rolled corn, 20% corn silage, and 5% supplement (DM basis). The dried corn distillers grains plus solubles (DDGS) and hempseed cake (HEMP) diets contained 55% dry-rolled corn, 20% corn silage, 20% dried corn distillers grains plus solubles or hempseed cake, and 5% supplement (DM basis). Total ruminal volatile fatty acid concentration was greater (P < 0.01) in steers fed the HEMP diet than in steers fed the DDGS or CON diets. Ruminal fluid pH was not influenced (P = 0.93) by treatment. Organic matter intake tended (P = 0.07) to be greater and OM total tract digestibility was less (P = 0.03) in steers fed the HEMP diet compared with steers fed the DDGS or CON diets. Ruminal true and total tract apparent N digestibility was greater (P < 0.01) in steers fed the HEMP diet than steers fed the DDGS or CON diets. Duodenal flow of essential, nonessential, and total amino acids was not influenced (P ≥ 0.37) by dietary treatment, but the lack of response was likely because ruminally degradable protein (RDP) supply exceeded the RDP requirement. Steers fed the HEMP diet had greater (P < 0.01) N retention (g/d) than steers fed the DDGS diet, which was greater (P < 0.01) than steers fed the CON diet, suggesting that feeding hempseed cake improved utilization of N. Although inclusion of hempseed cake decreased total tract OM digestibility compared with dried corn distillers grains or corn, improvements in N utilization suggest that hempseed cake could be a useful alternative feed ingredient for finishing cattle diets.

Effect of a molasses-based liquid supplement on gastrointestinal tract barrier function, inflammation, and performance of newly received feedlot cattle before and after a transport stress.

The objective of this study was to determine the effect of a dry versus a molasses-based liquid supplement on ruminal butyrate concentration, gastrointestinal tract (GIT) barrier function, inflammatory status, and performance of newly received feedlot cattle. In experiment 1, 60 mixed breed steers (234 ± 2.1 kg) were weaned, held overnight at a sale barn, then transported 14 h to Purdue University. After arrival, steers were weighed, blocked by body weight, and allotted within block to treatments (six pens per treatment and five steers per pen). Diets consisted of 45% roughage and 55% concentrate (dry matter basis). Treatments differed in the supplement source as follows: DRY: 10% dry supplement or LIQUID: 10% liquid molasses-based supplement. Feed intake, average daily gain (ADG), and gain:feed were determined for the three 21-d periods and overall. In experiment 2, 16 crossbred heifers (246 ± 7.5 kg) were used (8 heifers per treatment). Diets were the same as in experiment 1 and were fed for 60 d. On d 56 ruminal fluid samples were collected at 0, 3, 6, and 9 h after feeding. To mimic a stress event, heifers were transported for 4 h on d 61, rested overnight, and transported 12 h on d 62. Blood was collected from heifers immediately prior to transport and immediately upon their return. Gut barrier function using a Cr-EDTA marker was determined after transportation. Data were analyzed using the GLIMMIX procedure of SAS. Steers fed the liquid supplement had greater (P ≤ 0.03) ADG through d 42 and overall compared to steers fed the dry supplement. Feed intake did not differ (P = 0.25) between treatments from d 0 to d 21. However, steers fed the liquid supplement showed greater (P < 0.001) dry matter intake after d 21 and overall compared to those fed the dry supplement. Steers fed the liquid supplement tended (P < 0.09) to have reduced serum haptoglobin and lipopolysaccharide-binding protein (LBP) compared to those fed the dry supplement. Heifers fed the liquid supplement had greater (P = 0.02) Cr in urine and tended (P = 0.07) to have lower serum LBP after transport compared to those fed the dry supplement. Heifers fed the liquid supplement had 72% lower serum haptoglobin before, but only a 19% lower serum haptoglobin after transport compared to animals fed the dry supplement (treatment × time; P = 0.07). Therefore, the liquid supplement altered GIT barrier function, and improved inflammatory status, resulting in increased growth of receiving cattle.

Effects in air-exposed corn silage of medium chain fatty acids on select spoilage microbes, zoonotic pathogens, and in vitro rumen fermentation

Medium chain fatty acid (MCFA) treatment (0.75% C6, hexanoic; C8, octanoic; C10, decanoic; or equal proportion mixtures of C6:C8:C10:C12 or C8:C10/g; C12 = dodecanoic acid) of aerobically-exposed corn silage on spoilage and pathogenic microbes and rumen fermentation were evaluated in vitro. After 24 h aerobic incubation (37 °C), microbial enumeration revealed 3 log10 colony-forming units (CFU)/g fewer (P = 0.03) wild-type yeast and molds in C8:C10-treated silage than controls. Compared with controls, wild-type enterococci decreased (P < 0.01) in all treatments except the C6:C8:C10:C12 mixture; lactic acid bacteria were decreased (P < 0.01) in all treatments except C6 and the C6:C8:C10:C12 mixture. Total aerobes and inoculated Staphylococcus aureus or Listeria monocytogenes were unaffected by treatment (P > 0.05). Anaerobic incubation (24 h at 39 °C) of ruminal fluid (10 mL) with 0.02 g overnight air-exposed MCFA-treated corn silage revealed higher hydrogen accumulations (P = 0.03) with the C8:C10 mixture than controls. Methane, acetate, propionate, butyrate, or estimates of fermented hexose were unaffected. Acetate:propionate ratios were higher (P < 0.01) and fermentation efficiencies were marginally lower (P < 0.01) with C8- or C8:C10-treated silage than controls. Further research is warranted to optimize treatments to target unwanted microbes without adversely affecting beneficial microbes.

Polyunsaturated fatty acids and rumen undegradable protein alter ruminal fermentation and milk fatty acid profiles in dairy cows

ABSTRACT The present study evaluated the effects of incorporating polyunsaturated fatty acid (PUFA)- and rumen undegradable protein (RUP)-enriched feeds on ruminal fermentation, methane production, milk yield and milk FA profiles in dairy cows. Experiment 1 was carried out on 12 multiparous HF dairy cows in mid-lactation (106 ± 18.6 days in milk, 13.1 ± 1.67 kg/d of milk). Environmental conditions throughout the experiment were 34.5 ± 1.9 8°C, 58.0 ± 2.65% relative humidity and 85.7 ± 2.71 temperature–humidity index. Cows (n = 6/group) were randomly allocated to a control diet (Ctrl) consisting of corn silage and concentrate (F:C 60:40) containing 27.2% RUP in the crude protein (CP) or a treatment diet (Trt) consisting of 58.3% corn silage, 29.6% concentrate, 3.24% roasted soybean meal, 5.82% corn dried distiller grains with solubles and 3% added oil, which contained linseed, sunflower and tuna crude oil (1:1:1, wt/wt). The Trt diet contained 35.0% RUP in the CP. Experiment 2 was conducted in vitro using ruminal fluid collected from three Holstein Friesian dairy cows. The experimental design and diets were the same as in Exp. 1. Dry matter intake (DMI) tended to be lower (P = 0.06) in the Trt group. No difference in milk yield was detected, but the lower (P < 0.01) milk fat was measured in the Trt group (2.82% vs. 3.81%). Feed efficiency (milk/DMI) tended to be greater (P = 0.06) in the Trt cows (1.08 vs. 0.88). Lower 18:0 (5.73% vs. 8.29%), but greater concentrations of c9,t11 CLA (1.88% vs. 0.34%), c9,c12 18:2 (1.55% and 0.69%) 18:3n-3 (0.30% vs. 0.12%) and 22:6n-3 (0.17% vs. 0%) were detected in milk fat of cows fed Trt (P < 0.01). Atherogenicity and thrombogenic indices were lower (P < 0.01) with Trt. Concentrations of ruminal total volatile fatty acids and methane, which was assessed by production of volatile fatty acids, were 10.2% and 11.7% lower P < 0.01) in the Trt group. In conclusion, incorporating PUFA- and RUP-high feeds in lactating cow diets in the tropics causes a reduction in concentrations of ruminal VFA, methane production and milk fat while improving aspects of milk quality without affecting milk production.

Inclusion ofYucca schidigeraextract into finishing diets: impacts on ruminal, physiological, and productive responses of feedlot cattle

AbstractThis experiment compared ruminal, physiological, and productive responses of feedlot cattle receiving Yucca schidigera extract to replace or fed in conjunction with monensin + tylosin. Angus-influenced steers (n = 120) were ranked by body weight (BW; 315 ± 3 kg) and allocated to 4 groups of 30 steers each. Groups were housed in 1 of 4 drylot pens (30 × 12 m) equipped with GrowSafe feeding systems (4 bunks/pen) during the experiment (day −14 to slaughter). On day 0, groups were randomly assigned to receive a diet containing (2 × 2 factorial): 1) no inclusion or inclusion of monensin + tylosin (360 mg and 90 mg/steer daily, respectively) and 2) no inclusion or inclusion of Y. schidigera extract (4 g/steer daily). Steers were slaughtered in 3 groups balanced by treatment combination (36 steers on day 114, 36 steers on day 142, and 48 steers on day 169). Blood was sampled on days 0, 28, 56, and 84, and the day before shipping to slaughter. On day 41, eight rumen-cannulated heifers (BW = 590 ± 15 kg) were housed with steers (1 pair/pen). Pairs rotated among groups every 21 d, resulting in a replicated 4 × 4 Latin square (n = 8/treatment combination) with 14-d washout intervals. Heifers were sampled for blood and rumen fluid at the beginning and end of each 21-d period. Monensin + tylosin inclusion decreased (P &amp;lt; 0.01) feed intake and improved (P = 0.02) feed efficiency of steers, but did not alter (P ≥ 0.17) steer BW gain or carcass merit traits. Inclusion of Y. schidigera extract did not impact (P ≥ 0.30) steer performance and carcass characteristics. Plasma glucose, insulin, insulin-like growth factor-I, and urea-N concentrations were not affected (P ≥ 0.16) by monensin + tylosin, nor by Y. schidigera extract inclusion in steers and heifers. Ruminal pH in heifers was increased (P = 0.04) by monensin + tylosin, and also by (P = 0.03) Y. schidigera extract inclusion. Rumen fluid viscosity was reduced (P = 0.04) by Y. schidigera extract, and rumen protozoa count was increased (P &amp;lt; 0.01) by monensin + tylosin inclusion. The proportion of propionate in the ruminal fluid was increased (P = 0.04) by monensin + tylosin, and tended (P = 0.07) to be increased by Y. schidigera extract inclusion. Hence, Y. schidigera extract yielded similar improvements in rumen fermentation compared with monensin + tylosin, but without increasing performance and carcass quality of finishing cattle. No complimentary effects were observed when combining all these additives into the finishing diet.

Using rose pulp silage instead of sugar beet pulp silage in lambs fed with total mixed ration

The aim of this study was to determine the effects of using rose pulp (Rosa damacena) silage instead of sugar beet pulp silage on fattening performance, carcass yield, and some ruminal fluid parameters in lambs fed with total mixed ration. For this purpose, a total of 16 (average 30 ± 5 kg) 6-month-old Pırlak lambs, 8 in each group, were randomly divided into two groups. Total mixed rations were formulated by using concentrate, wheat straw and rose pulp silage (RPS) (Group 1) or sugar beet pulp silage (SBPS) (Group 2) in the experiment. Due to the low dry matter content of rose pulp, 7% wheat bran was added to its silage (RPS). The physical and chemical properties of both silages were evaluated, and rations were formulated as isocaloric and isonitrogenic. The study lasted 8 weeks after 2 weeks of the animals' adaptation to the ration. Live weight, live weight gain, feed consumption, feed conversion ratio, hot-cold carcass yield and ruminal parameters such as volatile fatty acids, protozoan number, pH, and ammonia nitrogen concentration were measured in the experiment. It was determined that the acetic acid level (12.4% DM) of RPS was approximately 6 times higher than SBPS, and the butyric acid level (3.83% DM) was 3 times higher. At the end of the study, it was determined that the difference between the performance parameters of both groups was not significant. Apart from acetic and butyric acid, rumen fluid parameters were not affected by the usage of RPS in the ration. It was concluded that the rose pulp silage consisting of wheat bran (7%) can be used as an alternative silage source to feed small ruminants instead of sugar beet pulp silage without any adverse effects.

Sunflower husk processing technology for fodder production

The article considers the possibilities of environmental protection from agricultural waste - sunflower husks. A technology for processing this waste from the oil extraction industry into a feed product using ultrasonic treatment (cavitation) is proposed. The chemical changes of this product after processing, including nutritional value, were studied. The indicators of the use of this product under the conditions of incubation of an analogue of the rumen of ruminants were studied. Positive changes in the chemical composition of the processed product and its more active fermentation in the ruminal fluid of ruminants were revealed.

Ruminal microbiome and blood parameters in beef cattle fed with high-grain diets buffered with Lithothamnium calcareum

Context and aims DNA metabarcoding strategy was used to sequence the 16S rRNA region of ruminal fluid samples from Nellore cattle fed with concentrate-rich diets in response to modulatory effect of buffering additives calcarea seaweed (Lithothamnium calcareum) and sodium bicarbonate. Methods Besides characterising the richness and diversity indices of rumen bacterial community, the impact of potentially acidogenic diets on rumen pH, blood parameters, and short-chain fatty acid profile (SCFA) was investigated for which four male Nellore cattle were used, distributed in a 4 × 4 Latin square (treatments × periods). Treatments comprised the same highly concentrated basal diet, and were as follows: T1, without additive (CON); T2, inclusion of 90 g of sodium bicarbonate (BIC); T3, inclusion of 90 g of L. calcareum (L90); and T4, inclusion of 45 g of L. calcareum (L45). Data were analysed in R, in which diversity and abundance at gender level were analysed using Friedman’s test, with means being adjusted by False Discovery Rate (FDR) correction. The analyses of pH, biochemical parameters and SCFA were analysed using Scott–Knott test and means were evaluated with a significance level of 10% (P &lt; 0.10). Key results We identified 1474 operational taxonomic units (OTUs) belonging to 52 genera and 16 phyla of bacteria domain. The results showed that bacterial microbiota were dominated by Firmicutes (44.12%), Bacteroidetes (28.29%), and Proteobacteria (5.88%). Animals fed with L90 demonstrated greater abundance and ruminal diversity for the Prevotella genus (P &lt; 0.07% and P &lt; 0.09% respectively), whereas cattle supplemented with L45 demonstrated greater diversity of the Fibrobacter genus (P &lt; 0.05). There were differences in molar proportion for acetic (P &lt; 0.07%) and valeric (P &lt; 0.03%) acids in the period before feeding. Higher blood lactate concentrations were observed in animals supplemented with L45 (P &lt; 0.06%), while animals that received treatments L90 and BIC presented lower levels of blood lactate. This metabolite was lower in animals fed with 90 g of sodium bicarbonate and L. calcareum daily. These treatments also reduced the concentration of acetic acid and increased that of valeric acid, and improved ruminal diversity. Conclusions and implications Our results supported this choice to improve ruminal function, with a great prospective of better weight-gain performance in Nellore cattle.

Биохимический статус крови и рубца овец при использовании новой формы бетаина

The physiological effect of the «protected» form of betaine in a comparative aspect on the processes of ruminal digestion and biochemical parameters of the blood of sheep was studied and analyzed. The experiment was carried out on sheep with chronic scar fistulas. The experiment included 3 periods - control and 2 experimental. In the control period, the sheep received the main ration (hay and concentrates), in the 1st experimental period, betaine was added to the main ration at a dosage of 0,05 g/kg of live weight, in the 2nd experimental period, the «protected» form of betaine in the same dosage according to the current substance. A noticeable increase in the dry matter mass of ciliates and bacteria was noted as a result of the use of the «protected» form of betaine compared with the control. The decrease in the level of ammonium nitrogen in the ruminal fluid of sheep during the 2 experimental period, 3 hours after feeding, indicates the protection against the breakdown of betaine in the rumen. Compared with other groups, more noticeable changes occurred in the pH of the ruminal content when sheep were fed a «protected» form of betaine. The use of the native and «protected» form of betaine in the diets of sheep compared with the control contributed to an increase in total protein in the blood by 5,6 (p≤0,05) and 6,6 % (p≤0,05), albumin by 7,9 (p≤0,05) and 11,4 % (p≤0,05), creatinine by 5,5 and 23,1 % (p≤0,001), glucose by 1,7 and 12,2 %, triglycerides by 42,9 and 64,3 %, a decrease in the concentration of bilirubin by 39,46 (p≤0,001) and 42,86 % (p≤0,001), which indicates an improvement in carbohydrate-lipid metabolism and hepatoprotective function of the liver. The «protected» form of betaine in the diet of sheep contributed to positive changes in the antioxidant status of the animal organism. The use of the «protected» form causes more pronounced positive changes in the direction of the processes of digestion and metabolism in the body of ruminants.

Feeding incremental amounts of ground flaxseed: effects on diversity and relative abundance of ruminal microbiota and enteric methane emissions in lactating dairy cows.

We evaluated the effects of incremental amounts of ground flaxseed (GFX) on diversity and relative abundance of ruminal microbiota taxa, enteric methane (CH4) emissions, and urinary excretion of purine derivatives (PD) in lactating dairy cows in a replicated 4 × 4 Latin square design. Twenty mid-lactation Jersey cows were used in the study. Of these 20 cows, 12 were used for ruminal sampling, 16 for enteric CH4 measurements, and all for spot urine collection. Each period lasted 21 d with 14 d for diet adaptation and 7 d for data and sample collection. Diets were formulated by replacing corn meal and soybean meal with 0%, 5%, 10%, and 15% of GFX in the diet's dry matter. Ruminal fluid samples obtained via stomach tubing were used for DNA extraction. Enteric CH4 production was measured using the sulfur hexafluoride tracer technique. Diets had no effect on ruminal microbiota diversity. Similarly, the relative abundance of ruminal archaea genera was not affected by diets. In contrast, GFX decreased or increased linearly the relative abundance of Firmicutes (P < 0.01) and Bacteroidetes (P < 0.01), respectively. The relative abundance of the ruminal bacteria Ruminococcus (P < 0.01) and Clostridium (P < 0.01) decreased linearly, and that of Prevotella (P < 0.01) and Pseudobutyrivibrio (P < 0.01) increased linearly with feeding GFX. A tendency for a linear reduction (P = 0.055) in enteric CH4 production (from 304 to 256 g/d) was observed in cows fed increasing amounts of GFX. However, neither CH4 yield nor CH4 intensity was affected by treatments. Diets had no effect on the urinary excretion of uric acid, allantoin, and total PD. Overall, feeding GFX decreased linearly the relative abundance of the ruminal bacterial genera Ruminococcus and Clostridium and enteric CH4 production, but no change was seen for CH4 yield and CH4 intensity, or urinary excretion of total PD, suggesting no detrimental effect of GFX on microbial protein synthesis in the rumen.

Susceptibility to milk fat depression in dairy sheep and goats: Individual variation in ruminal fermentation and biohydrogenation.

Small ruminants are susceptible to milk fat depression (MFD) induced by marine lipid supplementation. However, as observed in dairy cows, there is wide individual variation in the response to MFD-inducing diets, which may be due to individual differences in ruminal processes. Therefore, we compared the ruminal responses of goats and sheep with varying degrees of MFD extent to improve our understanding of this complex syndrome. Our specific aims were to attempt to elucidate whether pre-existing variations in ruminal fermentation and biohydrogenation determine a higher tolerance or susceptibility to MFD, and whether the severity of MFD depends exclusively on the response to the diet. The trial was conducted with 25 does and 23 ewes fed a basal diet without lipid supplementation for 3 wk (control period). Then, 2% fish oil (FO) was added to the same diet for 5 additional weeks (MFD period). Based on the extent of the elicited MFD (i.e., the percentage variation between milk fat concentrations recorded at the end of the control and MFD periods), the 5 most responsive (RESPON+) and the 5 least responsive (RESPON-) animals were selected within each species. On the last day of each period, ruminal fluid samples were collected to examine fermentation parameters and fatty acid profiles. In general, the individual degree of MFD in sheep and goats did not seem to be predetermined by traits related to ruminal fermentation and biohydrogenation, including fatty acids that may serve as biomarkers of microorganisms. Regarding differences in the response to FO, the results suggest no link between MFD susceptibility and concentration of biohydrogenation intermediates such as trans-10-containing C18, C20, and C22 metabolites. The explanation for individual responses based on a shortage of ruminal acetate and 18:0 for mammary uptake also seems to be dismissed, based on the lack of variation in these compounds between RESPON+ and RESPON-. However, the concentration of unsaturated fatty acids provided by FO (e.g., cis-9 16:1, cis-11 18:1, and 20:5n-3) was higher in the rumen of RESPON+ than RESPON- ewes and does. Thus, although further research is needed, the extent of biohydrogenation of these fatty acids might be associated with tolerance or susceptibility to MFD.

Effects of intravenous lignocaine on anaesthetic parameters in cattle under dexmedetomidine-butorphanol-ketaminemidazolam- isofluraneanaesthesia

The present study was conducted for clinical evaluation of a multimodal anaesthetic protocol using butorphanol-dexmedetomidine-midazolam-ketamine-isoflurane and lignocaine continuous rate infusion (CRI) in six cross-bred female cattle. Preanaesthetics used were butorphanol and dexmedetomidine which were administered intravenously at dose rates of 0.05 mg/kg and 1 μg/ kg body weight, respectively. Ketamine and midazolam were intravenously administered at dose rates of 4.0 and 0.2 mg/kg body weight respectively, to induce anaesthesia. Isoflurane was used to maintain anaesthesia after endotracheal intubation, at a concentration of 1.05 ± 0.97 per cent concentration in 100 per cent oxygen using a large animal anaesthesia machine. Simultaneously, intravenous lignocaine was administered at a bolus dose of 2 mg/kg body weight followed by a CRI of 3 mg/kg body weight/hour using a volumetric infusion pump. Isoflurane sparing effect of intravenous lignocaine reduced the required concentration of isoflurane for maintenance. The third plane of surgical anaesthesia was maintained and various surgical procedures were done. Recovery was smooth. Other than the mild regurgitation of ruminal fluid in an animal, no anaesthetic complications were noticed.

Effect of Live Yeasts (Pichia guilliermondii) on In Vitro Fermentation of Corn Stover as a Fibrous Substrate

The objective of the present study was to examine the potential utilization of the yeast strain Pichia guilliermondii (Levica 27) on the ruminal fermentation of corn stover. Two in vitro treatments were evaluated: (A) filtered rumen liquid + powdered corn stover + yeast-free culture medium and (B) filtered rumen liquid + powdered corn stover + culture medium inoculated with yeast. Samples were collected at 0, 6, 12, and 24 h and examined for effects on culture pH, ammonia nitrogen (NH3-N), the fiber digestibility percentages of neutral detergent fiber and acid detergent fiber, the digestibility of dry matter, and the concentration of volatile fatty acids (VFAs). The results showed that the addition of Levica 27 had no effect on the ruminal pH, NH3-N or the digestibility indicators (p &gt; 0.05). However, at 12 h, the inclusion of Levica 27 increased (p &lt; 0.05) the molar concentrations of total VFAs and acetic and propionic acids in ruminal fluid and decreased (p &lt; 0.05) the C2:C3 ratio. It is concluded that Levica 27 seems to have a stimulating effect on ruminal fermentation over a range within 6 and 12 h, a result that should be taken into account when in vivo studies are performed with this yeast strain.

The microbiome shifts throughout the gastrointestinal tract of Bradford cattle in the Pampa biome.

A deep understanding of the cattle gastrointestinal microbiome is crucial to selective breeding high-efficiency animals that produce more and generate less environmental damage. Here we performed the taxonomic identification of Bacterial and Archaeal communities using high throughput 16SrRNA gene sequencing from critical compartments of the gastrointestinal tract of Bradford cattle raised in a natural grassland in the Pampa biome, Brazil. We analyzed 110 samples, including saliva, ruminal fluid, and feces from 36 months old Bradford heifers (weighing on average 343 ± 30 kg by the sampling time). To reduce unexpected variation and confounders, we selected the animals from the same breed, submitted them to the same food source, and collected the samples for three consecutive years from different animals in the same season. Our main goal was to analyze the microbial shifts throughout the gastrointestinal tract to reference future works proposing management strategies and interventions to improve animal nutrition and increase production in the Pampa Biome. To accomplish our objective, we accessed the microbial community differences in groups with a high and low weight gain controlling for food ingestion and quality of grazed pasture. Few taxa were shared among the samples. About 40% of the phyla and 60% of the genera were unique from saliva samples, and 12.4% of the microbial genera were uniquely found in feces. All samples shared only 36.1% of phyla and 7.5% of genera. Differences in microbial diversity and taxa counts were observed. The ruminal fluid presented the lowest microbial richness, while saliva and feces presented the highest microbial richness. On the other hand, saliva and feces also presented more distinct communities between themselves when compared with ruminal samples. Our data showed that the saliva microbiome is not representative of the rumen microbiome and should not be used as an easy-to-collect sample for studies about the rumen microbiome.

Potential of Agroindustrial By-Products to Modulate Ruminal Fermentation and Reduce Methane Production: In Vitro Studies.

The effects of including wine lees (WL), exhausted olive cake (EOC) and a 1:1 mixture of EOC and tomato pomace (EOCTP) in diets for fattening ruminants on in vitro fermentation parameters and CH4 production were analysed. Ten diets were studied, containing either none of the tested by-products (control), or 6.0, 12.0 or 18.0% of WL, EOC and ECOTP formulated to have similar protein and fiber content. Diets were incubated in vitro with sheep ruminal fluid to measure gas production kinetics and fermentation parameters. Increasing the level of WL, EOC and EOCTP decreased linearly (p ≤ 0.009) the potential gas production, but other gas production parameters were unaffected (p &gt; 0.05), excepting that EOCTP increased the gas production rate. No differences (p ≥ 0.0.05) among diets were observed in total volatile fatty acid (VFA) production at 24 h of incubation for EOC and EOCTP, but NH3-N concentration decreased (p ≤ 0.003). In contrast, WL at 12.0 and 18.0% decreased (p &lt; 0.05) total VFA production and increased the acetate/propionate ratio (p &lt; 0.05). None of the by-products had an effect on CH4 production (p ≥ 0.0.05). Results indicate that EOC and EOCTP could be included up to 18.0% in fattening diets, but lower levels of WL are recommended.

Production, physiological response, and calcium and magnesium balance of lactating Holstein cows fed different sources of supplemental magnesium with or without ruminal buffer

The objective of this study was to evaluate the effects of dietary replacement of magnesium oxide (MgO) with calcium-magnesium hydroxide [CaMg(OH)2] and its interaction with ruminal buffer (sodium sesquicarbonate) supplementation on production, Ca and Mg balance, and overall physiological response of mid-lactation Holstein dairy cows. Sixty cows averaging 40.5 ± 7.0 kg of milk/d were used. Treatments were assigned following a 2 × 2 factorial arrangement: (1) MgO, (2) MgO + buffer, (3) CaMg(OH)2, or (4) CaMg(OH)2 + buffer. Diets were formulated to have 16.5% of crude protein, 1.82 Mcal/kg of net energy for lactation, 0.67% Ca, 0.39% P, and 0.25% Mg, all on a dry matter (DM) basis. Treatments were individually top dressed. Milk production, composition, and DM intake were evaluated. A subsample of 20 cows were randomly selected for the evaluation of Ca and Mg balance, blood gases, and electrolytes. Ruminal fluid was also collected for evaluation of pH and Ca and Mg solubility. Effects of Mg source, buffer, and the interaction Mg source × buffer were analyzed through orthogonal contrasts. An interaction of Mg source × buffer was found for DM intake and feed efficiency, in which cows fed CaMg(OH)2 had a similar feed efficiency regardless of ruminal buffer inclusion; however, when cows were fed MgO, the inclusion of buffer reduced feed efficiency. No effects on body weight and milk yield were observed. Buffer addition tended to increase the concentrations of fat, protein, and solids-not-fat, without affecting the yields of these milk components. Magnesium source and buffer did not affect ruminal fluid, blood, urine, or fecal pH; however, buffer supplementation increased urinary pH. Treatment with CaMg(OH)2 increased blood concentration of HCO3-, total CO2, and base excess compared with cows fed MgO. No differences were observed in the ruminal solubility of Ca and Mg or on milk or urinary Ca and Mg excretion. Greater plasma Mg concentration was observed for animals fed MgO compared with cows fed CaMg(OH)2; however, both sources were above the threshold recommended in the literature for dairy cows. Also, a reduction in fecal Mg excretion was observed in animals fed CaMg(OH)2. In summary, we provide evidence that CaMg(OH)2 could replace MgO without affecting performance, overall physiological response, or Ca and Mg balance of mid-lactating dairy Holstein cows.

Reduction in Methane Productions from Sheep by Supplemented of Moringa oleifera Leaf Extract in The Ration

This study aimed to evaluate the decreasing methane gas production in sheep by supplementing Moringa oleifera extract in the ration. The study was conducted in a Completely Randomized Design with One Way Classification. The treatment of Moringa oleifera extract was offered at 0, 0.25 and 0.50% of DM ration, each with six replicates, which constitutes 18 treatment units. The materials included ruminal fluid of three freshly slaughtered thin-tailed sheep derived from an abattoir in Banyumas Central Java. Moringa oleifera leaves were oven-dried at 60ºC for 2 x 24 h, ground into powder, and extracted using ethanol. The ration consisted of concentrate and ammoniated rice straw with a ratio of 60:40 (DM basis). The concentrate was composed of 2:1 rice bran and coconut meal. The measured variables included total protozoa, methane gas production, total bacteria, N-NH3 concentration, and protein synthesis of ruminal fluid. The result indicated 0.50% Moringa oleifera extract (DM basis) produced the lowest total protozoa, the highest total bacteria and protein microbe synthesis, and the lowest methane gas production.

Effects of supplementation of sodium acetate on rumen fermentation and microbiota in postpartum dairy cows.

The primary product of rumen fermentation is acetic acid, and its sodium salt is an excellent energy source for post-partum cows to manage negative energy balance (NEB). However, it is unknown how adding sodium acetate (NAc) may affect the rumen bacterial population of post-partum cows. Using the identical nutritional total mixed ration (TMR), this research sought to characterize the impact of NAc supplementation on rumen fermentation and the composition of bacterial communities in post-partum cows. After calving, 24 cows were randomly assigned to two groups of 12 cows each: a control group (CON) and a NAc group (ACE). All cows were fed the same basal TMR with 468 g/d NaCl added to the TMR for the CON group and 656 g/d NAc added to the TMR for the ACE group for 21 days after calving. Ruminal fluid was collected before morning feeding on the last day of the feeding period and analyzed for rumen bacterial community composition by 16S rRNA gene sequencing. Under the identical TMR diet conditions, NAc supplementation did not change rumen pH but increased ammonia nitrogen (NH3-N) levels and microbial crude protein (MCP) concentrations. The administration of NAc to the feed upregulated rumen concentrations of total volatile fatty acids (TVFA), acetic, propionic, isovaleric and isobutyric acids without affecting the molar ratio of VFAs. In the two experimental groups, the Bacteroidota, Firmicutes, Patescibacteria and Proteobacteria were the dominant rumen phylum, and Prevotella was the dominant rumen genus. The administration of NAc had no significant influence on the α-diversity of the rumen bacterial community but upregulated the relative abundance of Prevotella and downregulated the relative abundance of RF39 and Clostridia_UCG_014. In conclusion, the NAc supplementation in the post-peripartum period altered rumen flora structure and thus improved rumen fermentation in dairy cows. Our findings provide a reference for the addition of sodium acetate to alleviate NEB in cows during the late perinatal period.

Comparative Accuracy of In Vitro Rumen Fermentation and Enzymatic Methodologies for Determination of Undigested Neutral Detergent Fiber in Forages and Development of Predictive Equations Using NIRS

Undigested neutral detergent fiber (uNDF) is becoming more widely recognized as an important fiber fraction in forage quality assessment because it explains a portion of NDF that is inaccessible to digestion in the ruminant digestive system and is, thus, important in modeling the digestion kinetics of the potentially degradable component of NDF. In experiment 1, uNDF was determined in several forage species in order to compare the accuracy of two reference methods: (1) a long-term in vitro ruminal fermentation (240 h) using an Ankom DaisyII incubator and (2) a multi-step enzymatic method without ruminal fluid. The objective of experiment 2 was to construct predictive equations for uNDF estimation using acid detergent lignin (ADL) and near-infrared reflectance spectroscopy (NIRS) in a pool (n = 264) of alfalfa hay, timothy hay, and tall fescue straw, using the most accurate reference method selected in experiment 1. Partial least squares regression analysis was used to calibrate the reference values against NIRS spectra. Several indicators were used to assess the performance of validation results, including standard error of cross-validation (SECrV), coefficient of determination of cross-validation (R2CrV), and ratio percentage deviation (RPD). The findings of experiment 1 suggested that, relative to the in vitro ruminal methodology, the enzymatic approach overestimated uNDF concentration of forages. Repeatability coefficient was also greater when uNDF was determined using the in vitro versus enzymatic procedure, potentially disqualifying the enzymatic method for the uNDF analysis in forages. In experiment 2, a poor relationship was established between ADL and uNDF (R2 &lt; 0.60), suggesting the inadequacy of ADL parameter to represent the uNDF pool size in these forages. The best predictive equation using NIRS was obtained for alfalfa hay (R2CrV = 0.92; SECrV = 1.16; RPD = 3.57), using the in vitro fermentation as a reference method. The predictive equations were moderately accurate for timothy hay (R2CrV = 0.80; SECrV = 1.31; RPD = 2.08) and tall fescue straw (R2CrV = 0.79; SECrV = 1.38; RPD = 2.18). Our findings suggested the inadequacy of the enzymatic procedure in accurately determining uNDF concentration of forages as compared with the in vitro rumen fermentation protocol. Although the NIRS equations developed using the alfalfa hay dataset were more accurate than that of timothy hay and tall fescue straw, the validation results verified applicability of the equations as a fast screening tool for qualitative prediction of uNDF in these forages, which is important in commercial settings.