Ruminal Fluid pH Research Articles

PSVI-5 Extruded blend of Nannochloropsis oculata microalgae and flaxseed and its effects on ruminal fermentation and nutrient digestion

Abstract Omega-3 fatty acids are essential nutrients for mammals, and are required for cellular growth and synthesis of numerous cellular signaling molecules. NBO3 Technologies, LLC (Manhattan, KS) has developed an omega-3 supplement consisting of an extruded blend of flaxseed and Nannochloropsis oculata microalgae (GreatOplus; GOP). Our objective was to evaluate effects of GOP on dry matter intake (DMI), water intake (WI), ruminal metabolism, and apparent total tract nutrient disappearance in cannulated Holstein steers (n = 11; initial body weight 586.4 ± 49.7 kg). Treatments consisted of backgrounding diets (40% roughage, 60% concentrate) containing 0% (CON) or 10% GOP (dry basis). Feed and water intake were recorded using an Insentec Roughage and Water monitoring system (Hokofarm Group; Emmeloord, The Netherlands). Steers were utilized in a cross-over design with two 19-d periods. Each period consisted of a 15-d adaptation phase and a 4-d collection phase. Ruminal contents, duodenal digesta, and feces were collected at 8-h intervals for 4 d starting at 1000 h on d 16. The sampling schedule was advanced by 2 h with each subsequent sampling day, thus generating a 24-h profile at 2-h intervals post-feeding over the 4-d sampling phase. Titanium dioxide (15 g) was dispensed directly into the rumen of each steer 15 min before feeding and to estimate apparent ruminal flow and fecal excretion of nutrients. There was a Treatment X Day interaction for DMI (P < 0.001); DMI was greater for steers fed GOP some of the days during the adaptation phase compared with steers fed the control diet, but intakes were similar during the collection phase. Ruminal fluid pH, ruminal ammonia concentration, and WI were not affected by treatment (P > 0.10). As expected, ruminal outflows of total fatty acids (195.6 vs 338.1 g/d for CON and GOP, respectively) and α-linolenic acid (ALA; 1.6 vs 6.3 g/d, respectively) were greater for steers fed GOP compared with steers fed CON (P < 0.05); however, ruminal disappearance (i.e., biohydrogenation) of ALA was extensive, with only 8% and 4.7% of ALA intake exiting the rumen for CON and GOP, respectively. Apparent total tract digestion of organic matter was not impacted by diet (P > 0.20; 78.1 and 76.8% for CON and GOP, respectively). Supplementing an extruded blend of flaxseed and microalgae can effectively increase the amount of α-linolenic acid available for absorption in the small intestine, but overall recovery of dietary α-linolenic acid is relatively low due to extensive biohydrogenation by microbes within the rumen.

Effects of yeast culture on in vitro ruminal fermentation and microbial community of high concentrate diet in sheep.

This research aimed to investigate effects of different yeast culture (YC) levels on in vitro fermentation characteristics and bacterial and fungal community under high concentrate diet. A total of 5 groups were included in the experiment: control group without YC (CON), YC1 (0.5% YC proportion of substrate dry matter), YC2 (1%), YC3 (1.5%) and YC4 (2%). After 48h of fermentation, the incubation fluids and residues were collected to analyze the ruminal fermentation parameters and bacterial and fungal community. Results showed that the ruminal fluid pH of YC2 and YC4 groups was higher (P < 0.05) than that of CON group. Compared with CON group, the microbial protein, propionate and butyrate concentrations and cumulative gas production at 48h of YC2 group were significantly increased (P < 0.05), whereas an opposite trend of ammonia nitrogen and lactate was observed between two groups. Microbial analysis showed that the Chao1 and Shannon indexes of YC2 group were higher (P < 0.05) than those of CON group. Additionally, YC supplementation significantly decreased (P < 0.05) Succinivibrionaceae_UCG-001, Streptococcus bovis and Neosetophoma relative abundances. An opposite tendency of Aspergillus abundance was found between CON and YC treatments. Compared with CON group, the relative abundances of Prevotella, Succiniclasticum, Butyrivibrio and Megasphaera elsdenii were significantly increased (P < 0.05) in YC2 group, while Apiotrichum and unclassified Clostridiales relative abundances were decreased (P < 0.05). In conclusion, high concentrate substrate supplemented with appropriate YC (1%) can improve ruminal fermentation and regulate bacterial and fungal composition.

Induced Ruminal Lactic Acidosis in Sheep Treated with Various Remedial Agents in Libo Kemkem Districts, Northwest Ethiopia.

Grain overload is a ruminant metabolic disorder associated with overingestion or a sudden change to rapidly fermentable concentrate feeds. A randomized clinical trial was carried out in Libo Kemkem districts to investigate vital signs, ruminal fluid, and hematological changes in sheep related to grain overload and to assess the treatment efficacy of various remedial agents in Farta sheep breeds. All sheep were selected by using the simple random process, and categorized into four groups of eight animals groups I, II, and III in which each sheep was given 80 g of wheat flour per kg of body weight then baking soda, Magnalax, and digestive powder were treated successively, but group IV was the negative control group. The current clinical trial explained that all acidotic sheep had statistically significant (p < 0.0002) lower body temperature, rumen motility, protozoa activity, and ruminal fluid pH with 38.48 ± 0.20, 0.5 ± 0.89, 6 (75%), and 5.37 ± 0.34 mean value successively. Nevertheless, there were significant (p < 0.0059) increments in hematological variables including total red blood cell, total white blood cell, packed cell volume, and hemoglobin estimation with 14.05 ± 1.27, 12.71 ± 0.99, 40.78 ± 5.24, and 14.78 ± 1.83 mean value, respectively, before treatment in acidotic sheep. There were also vital sign increments including pulse rate, respiratory rate, skin turgor, and capillary refill time with 123.5 ± 27.1, 73.75 ± 12.71, 3 ± 1.78, and 3.37 ± 1.77 mean values, respectively, before medical treatment in acidotic sheep. Digestive powder was the first drug of choice, followed by Magnalax, and baking soda was ranked at the end based on clinical recovery. The treatment effectiveness illustrated that all treatments could cure the grain overload. Nevertheless, digestive powder is the drug of choice based on the clinical and systemic recovery of the sheep. In addition to this, sheep should be introduced gradually to concentrate rations over 2-3 weeks with a mixture of concentrate in the milled feed containing roughage.

208 Impact of Feeding a Novel Probiotic on Ruminal Fermentation, Methane Production, and Nutrient Utilization in Beef Cattle

Abstract The search for alternatives to mitigate enteric methane emissions remains a top priority to ensure the continued sustainability of the livestock industry. Exploration of new direct-fed microbials with potential in ruminant nutrition is an active and promising area of research. This study aimed to evaluate the effects of feeding a novel probiotic on ruminal fermentation parameters, in vitro methane production, and nutrient utilization in beef steers. A total of 12 ruminally cannulated American Aberdeen steers (348 ± 37 kg BW) were used in a 4 × 4 Latin square design, with each period lasting for 35 d. The steers were fed a basal diet comprised of 82% corn silage, 12% cotton gin trash, 5% cottonseed meal, and 1% vitamin and mineral supplement on a dry matter (DM) basis. Four treatments were used in this study: CTL (no additive), B2 (probiotic at a dosage of 2 × 109 CFU/animal/d), B10 (probiotic at a dosage of 10 × 109 CFU/animal/d), and B30 (probiotic at a dosage of 30 × 109 CFU/animal/d). Steers were housed in two pens and were sorted daily to receive the treatments individually in a carrier of corn silage (250 g/d). The experiment consisted of 4 periods, with 21 d of adaptation to the treatments, 7 d of measurements, and 7 d of washout between periods. During the study, two in vitro batch culture incubations were performed in each period collecting ruminal fluid from each animal individually (experimental unit): one on d 0 before steers received the treatments, and one after 21 d of adaptation. The incubations on day 0 were used as a baseline. The use of this probiotic did not affect (P &amp;gt; 0.05) in vitro ruminal fluid pH, volatile fatty acids, or acetate to propionate ratio. However, there was a cubic effect (P &amp;lt; 0.05) on in vitro organic matter digestibility with the inclusion of probiotic, and the greatest digestibility was observed in the B2 treatment. The concentration of ammonia nitrogen linearly increased (P &amp;lt; 0.05) with the inclusion of probiotic with CTL and B2 treatments showing the least values. While there was no effect (P &amp;gt; 0.05) on total gas production among treatments, methane production (CH4) was decreased (P &amp;lt; 0.05), showing a quadratic effect where the B2 treatment showed the least values. These results suggest that adding this novel probiotic to beef steers fed a corn silage-based diet at a dose of 2× 109 CFU per day (B2) may have positive results in reducing CH4 and improving digestibility. However, confirmation of these results will be required by in vivo methane emissions data.

Can residual frying oil be an alternative to traditional sources of vegetable oils for sheep diets

This research aimed was to evaluate sources of vegetable oils in lamb diets regarding intake, digestibility, ruminal fermentation parameters, and microbial protein synthesis. Twelve mixed-breed, non-castrated lambs (45.00 ± 8 kg of body weight) were used and distributed in a triple 4 × 4 Latin square design. Each experimental period lasted 20 days, with 15 days of animal adaptation to the diets and 5 days of data collection. The evaluated treatments were as follows: a control diet without vegetable oils and diets containing 2% DM from one of the following oil sources: soybean, sunflower, or residual frying. The diets were balanced to be isonitrogenous with a roughage-to-concentrate ratio of 40:60. There was an 11 % reduction in DM intake when comparing the vegetable oil sources to the oil-free diet (1258 g animal-1 day-1). There was effect of the addition of vegetable oils on the digestibility of CP and NDF, where, on average, the oil sources reduced the digestibility by approximately 5 % and 8 %, respectively. Although the time spent on feeding and rumination did not change with the addition of oils, it was reflected in the pH and N-NH3 of ruminal fluid, which also did not show any effect. However, there was an effect on microbial protein synthesis, where diets with soybean oil, sunflower, and frying residue showed greater efficiency and synthesis of microbial protein. Based on the results, it is possible to conclude that vegetable oil sources can be used in diets for growing lambs without causing damage to the ruminal environment or interfering with microbial growth.

Inclusion of Red Macroalgae (Asparagopsis taxiformis) in Dairy Cow Diets Modulates Feed Intake, Chewing Activity and Estimated Saliva Secretion.

The current study assessed the effects of red macroalgae Asparagopsis taxiformis (AT)-included as an enteric methane inhibitor-in dairy cow diets on feed intake and eating-rumination behaviour. Fifteen early lactating Norwegian Red dairy cows were offered ad libitum access to drinking water and a total mixed ration (TMR) composed of 35% concentrate feed and 65% grass silage on a dry matter (DM) basis. The experiment lasted for 74 days with the first 22 days on a common diet used as the covariate period. At the end of the covariate period, the cows were randomly allocated into one of three dietary treatments: namely, 0% AT (control), 0.125% AT and 0.25% AT in the TMR. The TMR was offered in individual feed troughs with AT blended in a 400 g (w/w) water-molasses mixture. Eating-rumination behaviour was recorded for 11 days using RumiWatchSystem after feeding the experimental diets for 30 days. The 0.25% AT inclusion significantly reduced the DM intake (DMI). Time (min/d) spent on eating and eating in a head-down position increased with the increasing AT level in the diet, whereas rumination time was not affected. The greater time spent on eating head-down with the 0.25% AT group resulted in a significantly higher chewing index (min/kg DMI). Estimated saliva production per unit DMI (L/kg DMI, SE) increased from 10.9 (0.4) in the control to 11.3 (0.3) and 13.0 (0.3) in the 0.125% and 0.25% AT groups, respectively. This aligned with the measured ruminal fluid pH (6.09, 6.14, and 6.37 in the control, 0.125% AT and 0.25% AT groups, respectively). In conclusion, either the level of the water-molasses mixture used was not sufficient to mask the taste of AT, or the cows used it as a cue to sort out the AT. Studies with relatively larger numbers of animals and longer adaptation periods than what we used here, with varied modes of delivery of the seaweed may provide novel strategies for administering the additive in ruminant diets.

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.

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.

PSVII-2 Effects of Feeding a Starch or Pectin Supplement on Ruminal Parameters and gas Production of Grazing Young Bulls

Abstract The study aimed to investigate the effects of two feeding times and two sources of energy supplementation on pH, short-chain fatty acids (SCFA), and in vitro gas production (IVGP) of beef cattle reared in Urochloa brizantha cv. Marandu pastures. We used eight rumen-cannulated ½ Aberdeen Angus x ½ Nellore young bulls (280±7 kg) distributed in a double 4x4 Latin square design. Treatments consisted of supplementation at 0.3% of body weight with corn or citrus pulp, supplied at 0900 or 1700. Ruminal fluid pH was measured with a digital pH analyzer and SCFA was analyzed on a Shimadzu HPLC. The IVGP was determined using a transducer and a data logger for 48 h after incubation of samples combining forage and supplement in real intake proportion (88% forage, 12% supplement). Considering the rapid fermentation of sugars, animals supplemented with pectin maintained higher pH (P = 0.021) due to changes in bacterial populations to digest the pectic substances (Table 1). Lactate production after starch digestion caused lower pH. Despite the differences in evaluated energy substrates, there was no effect on the primary SCFA concentration (P &amp;gt; 0.05). Citrus pulp provided greater formic (P = 0.005) and valeric (P = 0.042) acids concentrations compared with corn, but there was no influence of formic acid in lactic acid production (Table 1). The greater IVGP by citrus pulp (P = 0.0140; Figure 1) may be related to its greater carbohydrate fraction A, soluble with a rapid rate of rumen degradation, and also because its ruminal fermentation results in greater acetic acid production, which provides more ruminal H2 and CO2, favoring the CH4 production. The citrus pulp can be used as an alternative source to corn because it might prevent acidosis, does not affect the main SCFA production, and is a non-human edible feed.

370 Effects of the Vasoactive Intestinal Polypeptide (VIP) for the Efficient Ruminant Product

Abstract Feeding high-grain diets can result in reduced ruminal pH, inflammation of ruminal and other tissues, and subacute ruminal acidosis. Vasoactive intestinal polypeptide (VIP), a gut hormone with anti-inflammatory and other functions, could have a beneficial role in ruminants fed high-concentrate diets. To determine the effects of VIP injection on dry matter intake, average daily gain, gain:feed, and ruminal pH, wether lambs (n=16; BW=68.5 ±1.8 kg) were blocked by body weight and randomly assigned to VIP treatment (n=8) or control (n=8). All lambs were housed in individual pens, adapted to the same high concentrate diet (75% whole corn and 25% supplemental pellet; DM basis), and feed intake and average daily gain were measured from day 1 to 21 when lambs were placed in metabolism crates. Lambs in the treatment group were injected intraperitoneally with VIP (1.3 nmol/kg BW in 0.9% NaCl), whereas lambs in the control group were injected with 0.9% NaCl every second day over 28 days. Nutrient balance was measured over the final seven days (data will be reported elsewhere), and lambs then were slaughtered and ruminal fluid and tissues collected. The average daily gain was greater (p = 0.04) in VIP treated lambs than in control lambs. However, no difference (p &amp;gt; 0.05) in daily feed intake was observed between treatments. Ruminal fluid pH was not significantly influenced by treatment (5.2±0.11 vs 5.0±0.11 for the control and VIP treatments, respectively). These data indicate that VIP injection may increase ADG and gain:feed in lambs fed high concentrate diets. Further research is needed to verify these results and to delineate the mechanisms responsible for the observed increases in ADG and gain:feed.

Invited review: Effect of subacute ruminal acidosis on gut health of dairy cows.

Subacute ruminal acidosis (SARA) is assumed to be a common disease in high-yielding dairy cows. Despite this, the epidemiological evidence is limited by the lack of survey data. The prevalence of SARA has mainly been determined by measuring the pH of ruminal fluid collected using rumenocentesis. This may not be sufficiently accurate, because the symptoms of SARA are not solely due to ruminal pH depression, and ruminal pH varies among sites in the rumen, throughout a 24-h period, and among days. The impact of SARA has mainly been studied by conducting SARA challenges in cows, sheep, and goats based on a combination of feed restriction and high-grain feeding. The methodologies of these challenges vary considerably among studies. Variations include differences in the duration and amount of grain feeding, type of grain, amount and duration of feed restriction, number of experimental cows, and sensitivity of cows to SARA challenges. Grain-based SARA challenges affect gut health. These effects include depressing the pH in, and increasing the toxin content of, digesta. They also include altering the taxonomic composition of microbiota, reducing the functionality of the epithelia throughout the gastrointestinal tract (GIT), and a moderate inflammatory response. The effects on the epithelia include a reduction in its barrier function. Effects on microbiota include reductions in their richness and diversity, which may reduce their functionality and reflect dysbiosis. Changes in the taxonomic composition of gut microbiota throughout the GIT are evident at the phylum level, but less evident and more variable at the genus level. Effects at the phylum level include an increase in the Firmicutes to Bacteroidetes ratio. More studies on the effects of a SARA challenge on the functionality of gut microbiota are needed. The inflammatory response resulting from grain-based SARA challenges is innate and moderate and mainly consists of an acute phase response. This response is likely a combination of systemic inflammation and inflammation of the epithelia of the GIT. The systemic inflammation is assumed to be caused by translocation of immunogenic compounds, including bacterial endotoxins and bioamines, through the epithelia into the interior circulation. This translocation is increased by the increase in concentrations of toxins in digesta and a reduction of the barrier function of epithelia. Severe SARA can cause rumenitis, but moderate SARA may activate an immune response in the epithelia of the GIT. Cows grazing highly fermentable pastures with high sugar contents can also have a low ruminal pH indicative of SARA. This is not accompanied by an inflammatory response but may affect milk production and gut microbiota. Grain-based SARA affects several aspects of gut health, but SARA resulting from grazing high-digestible pastures and insufficient coarse fiber less so. We need to determine which method for inducing SARA is the most representative of on-farm conditions.

The Use of Probiotic Megasphaera elsdenii as a Pre-Harvest Intervention to Reduce Salmonella in Finishing Beef Cattle: An In Vitro Model.

Reducing Salmonella in cattle may mitigate the risk of transmission through the food chain. Megasphaera elsdenii (ME) is a microorganism found naturally in the bovine rumen that can be administered as a probiotic to mitigate ruminal acidosis. Understanding the impact of feeding ME to Salmonella populations in cattle was the objective of this study. Bovine ruminal fluid (RF) and feces were inoculated with antibiotic susceptible or resistant Salmonella and treated with varying concentrations of ME. Salmonella was enumerated at 0, 24, 48, and 72 h using the most probable number (MPN). Volatile fatty acids (VFAs) and pH were recorded from non-inoculated samples. Treating RF with ME did not significantly impact Salmonella concentration or VFA production (p > 0.05). The pH of RF and feces decreased over time (p ≤ 0.05). Salmonella concentration declined in feces, with the largest reduction of 1.92 log MPN/g and 1.05 log MPN/g observed for antibiotic susceptible Salmonella between 0 and 72 h by the 2.5 × 105 CFU/g and control (0.0 CFU/g) concentration of ME, respectively. Treating RF with ME did not impact Salmonella concentration. Salmonella concentration in feces decreased, although ME must be further investigated before a conclusion regarding efficacy in vitro can be determined.

A high-concentrate diet provokes inflammatory responses by downregulating Forkhead box protein A2 (FOXA2) through epigenetic modifications in the liver of dairy cows

A high-concentrate diet has been reported to promote an inflammatory response in dairy cows. The purpose of this study was to clarify the effect of the high-concentrate (HC) diet on hepatic Forkhead box protein A2 (FOXA2) expression and uncover the molecular mechanisms in inflammatory responses in the liver. The results showed that the HC diet reduced the ruminal fluid pH and elevated the secretion of SAA3, IL-1α, and IL-8 and reduced that of IL-10 in peripheral blood plasma. Compared with the low-concentrate (LC) group, the concentration of myeloperoxidase (MPO) was higher in the liver of dairy cows in the HC group. In addition, the relative mRNA expression of acute phase proteins (HP, SAA3, and LBP), proinflammatory cytokines (TNFα, IL-1α, IL-1β, IL-8), TLR4, MyD88, TRAF6, TRIF, IκBα, p65, p38 and JNK1 was upregulated and that of IL-10 was downregulated in the liver of the HC group. Consistently, the protein abundance of TLR4, TNFα and phosphorylation of proteins involved in NF-κB (IκBα and p65) and MAPK (p38 and JNK) pathways were significantly increased in the HC group compared with the LC group. And both the mRNA and protein abundance of FOXA2 were downregulated in the HC group. Further epigenetic analysis results demonstrated that chromatin compaction and DNA hypermethylation contributed to inhibiting FOXA2 expression, in which the demethylase ten-eleven translocation 1 (TET1) and histone deacetylase 3 (HDAC3) might participate. Overall, these findings demonstrated that the high-concentrate diet triggered inflammatory cascades and downregulated FOXA2 by epigenetic modifications in the liver of dairy cows.

The effect of ruminal fluid pH on milk fatty acids composition in cattle

Abstract The present study aimed to evaluate the effects of ruminal fluid pH on the fatty acids (FA) profile of bovine milk. The experiment was performed on 250 Polish Holstein-Friesian cows reared in 11 commercial high-yielding dairy farms. Ruminal fluid samples were collected by rumenocentesis, and fat and FA concentrations in milk were analyzed by Fourier transform infrared spectroscopy. According to ruminal fluid pH, cows were categorized into three pH groups: high pH (pH &gt; 5.8), moderate pH (pH 5.8–5.6), and low pH (pH &lt; 5.6). Milk produced by low-rumen pH cows had a decreased fat content as compared to milk from moderate- and high-rumen pH cows (P≤0.05). Moreover, milk from low-rumen pH cows was characterized by the lowest level of short-chain FA (SCFA; P≤0.05), and consequently, the highest medium-chain FA to SCFA ratio (P≤0.01). The regression analysis showed that these traits explained a small proportion of rumen pH variance, which makes them unreliable indicators of subacute ruminal acidosis (SARA) in dairy cows. However, despite the extensive variability in milk fat composition observed in this study, the effect of ruminal pH on SCFA in all the analyzed herds showed the same trend. Future research aimed to identify SARA biomarkers should therefore be conducted using techniques that allow detection of more individual FA in milk, including SCFA.

The intraruminal redox potential is stabilised by opposing influences during fermentation.

An optimal fermentation process in the forestomach is pivotal for the wellbeing and performance of ruminants. Complex carbohydrates are broken down into short-chain fatty acids (SCFA) which form the major energy source for the animal. A strong interrelationship of this process with intraruminal pH and redox potential (Eh) exists. These parameters can be measured with intraruminal sensors, but the interpretation of the measurements, especially of Eh, and their meaning for intraruminal homeostasis is not completely clear. In this study, factors influencing intraruminal Eh were elucidated. We hypothesised that intraruminal Eh is influenced by the fermentation process as such, but not by its end products SCFA. We measured Eh and pH in ruminal fluid from fasting cannulated sheep after the addition of 0.06 m Na-acetate, -propionate, -butyrate or glucose in vitro. Furthermore, we assessed the interrelation of pH and Eh. Basal Eh and pH values were -120 ± 41 mV and 7.0 ± 0.3, respectively, in native ruminal fluid in vitro. While the addition of SCFA did not induce any changes, glucose addition caused a significant decrease in both pH and Eh compared to the values before the addition (paired Student's t-test, p < 0.05). We attribute the decrease in Eh to an increased production of H2 in the process of generating SCFA, predominantly acetate. By titrating both native and particle-free ruminal fluid to more acidic and basic pH values (4.5-8.5), we found a non-linear inverse correlation of pH and Eh, counteracting the H2 -driven decrease of Eh during fermentation. Thus, the intraruminal Eh is influenced by pH and H2 output during SCFA formation. The opposed character of these factors stabilises the intraruminal homeostasis which might help maintain symbiotic microbiota in the rumen. Understanding, monitoring, and supporting this system will be an essential part of modern cattle production.

Physiological Indicators and Production Performance of Dairy Cows With Tongue Rolling Stereotyped Behavior.

Non-nutritive oral behaviors, especially tongue rolling, are prevalent in the stabled cow population. These behaviors mean that the environment or management process might not suit the cows, suggesting low welfare. However, few researches have reported the physiological indicators or production performance of dairy cows with the stereotyped behavior. This study aimed to determine physical conditions, daily activity, rumen fermentation, and milk production of cows with tongue-rolling behavior. Three hundred and fifty nine Holstein cows in the same barn and lactation stage were subjected to scan sampling behavior observations 126 times for 7 days. Ten cows with high-frequency tongue-rolling behavior (TON) and 10 cows without abnormal oral behavior (CON) were selected for further study. Serum sample, ruminal fluid, milk sample, and behavior record video of TON and CON cows were collected. TON cows had more drinking behavior and more stable lying behavior than the CON cows during the daytime. The body condition score of the TON cows decreased, while the milk yield, yield of milk fat, protein, and lactose in the study period increased. The TON cows had lower ruminal fluid pH, acetate/propionate ratio, and total volatile acid. The bacterial diversity in the ruminal fluid was not different between the two groups. Compared to CON cows, the TON cows had a higher level of serum stress indicators, such as cortisol, thyroid hormone, and norepinephrine, which positively correlated to the frequency of tongue-rolling behavior. Meanwhile, the TON cows had a higher level of lactate dehydrogenase, serum glucose, total triglyceride, total cholesterol, and Interleukin 6. Overall, it means they suffer from higher levels of stress and have higher energy metabolism for a long time when cows show tongue-rolling behavior. TON cows had suffered a higher stress level and had higher energy metabolic status for a long time. The TON cows might have better heat tolerance to the thermal environment by more lying and drinking time. Our data revealed the changes in milk production, physiological stress indicators of dairy cows with high-frequency tongue rolling behavior, which will provide essential knowledge for the in-depth understanding of tongue rolling behavior in dairy cows.

Cyberlindnera jadinii yeast as a protein source in early- to mid-lactation dairy cow diets: Effects on feed intake, ruminal fermentation, and milk production

We examined the effects of substituting soybean meal with either yeast protein from Cyberlindnera jadinii or barley in concentrate feeds on feed intake, ruminal fermentation products, milk production, and milk composition in Norwegian Red (NRF) dairy cows. The concentrate feeds were prepared in pellet form as soy-based (SBM; where soybean meal is included as a protein ingredient), yeast-based (YEA; soybean meal replaced with yeast protein), or barley-based (BAR; soybean meal replaced with barley). The SBM contained 7.0% soybean meal on a dry matter (DM) basis. This was replaced with yeast protein and barley in the YEA and BAR concentrate feeds, respectively. A total of 48 early- to mid-lactation [days in milk ± standard deviation (SD): 103 ± 33.5 d] NRF cows in their first to fourth parity and with initial milk yield of 32.6 kg (SD = 7.7) were allocated into 3 groups, using a randomized block design, after feeding a common diet [SBM and good-quality grass silage: crude protein (CP) and neutral detergent fiber (NDF) content of 181 and 532 g/kg of DM, respectively] for 14 d (i.e., covariate period). The groups (n = 16) were then fed one of the dietary treatments (SBM, YEA, or BAR) for a period of 56 d (i.e., experimental period). The concentrate feeds were offered in split portions from 3 automatic feeders using electronic identification, with ad libitum access to the same grass silage. Dietary treatments had no effect on daily silage intake, total DM intake, or total NDF intake. Dietary CP intake was lower and starch intake was higher in the BAR group compared with the other groups. Ruminal fluid pH, short-chain volatile fatty acid (VFA) concentrations, acetate-to-propionate ratio, and non-glucogenic to glucogenic VFA ratio were not affected by dietary treatments. No effects of the dietary treatments were observed on body weight change, body condition score change, milk yield, energy-corrected milk yield, milk lactose and fat percentages, or their yields. In conclusion, yeast protein can substitute conventional soybean meal in dairy cow diets without adverse effect on milk production and milk composition, given free access to good-quality grass silage.

Analysis of pH and electrolytes in blood and ruminal fluid, including kidney function tests, in sheep undergoing long-term surgical procedures

BackgroundThe physiology of sheep as small ruminants is remarkably different from monogastric animals especially regarding the forestomach system. Using sheep for surgical procedures during scientific research thereby presents an exceptional setting for the anaesthetist. Long-term anaesthesia generally demands deprivation of food to reduce the risk of bloat in sheep. This might influence the energy and electrolyte balance. In horses and companion animals, close monitoring of mean arterial blood pressure, capnography and blood gas analysis are common procedures during long-term surgery. However, few data are available on reference ranges for blood gas in sheep and these cover only short periods of anaesthesia. To the authors’ knowledge, there is no study available that includes the monitoring of electrolytes and pH in ruminal fluid and kidney function tests in sheep undergoing long term anaesthesia. Thereby, the aim of the present study was to gather data on blood parameters, and data on ruminal fluid and kidney function during long-term anaesthesia in sheep. Data were obtained from eight sheep undergoing the invasive surgical procedure of left pneumonectomy and auto-transplantation or isolated left lung perfusion. After a 19-h fasting period, the animals were administered xylazine and ketamine and then intubated and maintained in general anaesthesia under artificial ventilation using isoflurane in oxygen. Blood samples were evaluated during 9 h of anaesthesia; ruminal fluid and kidney function tests were evaluated during 7 h of anaesthesia.ResultsBlood parameters such as electrolytes and partial pressure of carbon dioxide revealed few changes, yet blood glucose decreased and beta-hydroxybutyric acid increased significantly. All animals showed an elevated arterial pH and bicarbonate concentration despite artificial ventilation. In ruminal fluid, the pH significantly decreased and no significant changes in electrolytes occurred. Kidney function tests revealed no significant changes in any of the animals. However, fractional excretion of water and phosphate was slightly increased. One animal showed severe complications due to hypokalaemia.ConclusionInvasive surgery under long-term anaesthesia in sheep is possible without great imbalances of arterial pH and electrolytes. Nevertheless, potassium concentrations should be monitored carefully, as a deficiency can lead to life-threatening complications. The operated sheep tended not to develop metabolic acidosis and the mean kidney function could be maintained within the physiological range throughout anaesthesia. However, slight elevations in renal fractional water and phosphate excretion could suggest an early tubular reabsorption dysfunction. In ruminal fluid, acidification occurred, though no significant changes were observed in l- and d-lactate levels or in electrolyte concentrations. To our knowledge, the role of the rumen in storing fluids and balancing electrolytes in the blood has not yet been documented during anaesthesia. However, the importance of the rumen for fluid equilibrium in sheep indicates the necessity for routine monitoring and further research.

Prior Forage Type Influences Ruminal Responses to a Wheat Grain Challenge in Lactating Dairy Cows.

Simple SummaryHigh-producing dairy cows require more than just pasture to meet the energy demands of milk production. Wheat is an excellent energy source for milk production; however, cows require careful adaptation and monitoring to avoid ruminal upset when large amounts of wheat are introduced. The results of this study show that careful selection of the forage that precedes wheat could allow safer and more aggressive grain introduction strategies to be used in the dairy industry.To increase the dry matter and metabolisable energy intake of cows, dairy farmers often supplement pasture with concentrates and conserved fodder. Feeding large amounts of highly fermentable concentrates to cows can result in metabolic issues, such as ruminal acidosis, and thus safer but more efficient introduction strategies are desirable. We assessed the role that forages play in ruminal, behavioural and production responses to a wheat grain challenge in dairy cows with no previous wheat adaptation. Multiparous lactating Holstein dairy cows (n = 16) were fed a forage-only diet of either lucerne (Medicago sativa) hay, perennial ryegrass (Lolium perenne L.) hay or one of two cultivars of zero-grazing fresh perennial ryegrass herbage (Bealey or Base), for 3 weeks. The forage diet was then supplemented with crushed wheat grain at 8 kg dry matter/cow day−1, with no adaptation period. Wheat comprised between 32 and 43% of total dry matter intake. Cows fed hay maintained a higher mean ruminal fluid pH than those fed herbage, on both the forage-only diet (6.43 vs. 6.17) and the forage plus wheat diet (6.03 vs. 5.58). Following supplementation of wheat, cows fed herbage exhibited minimum ruminal fluid pH levels indicative of acute ruminal acidosis, at 5.15 and 5.06 for cultivars Bealey and Base, respectively. Furthermore, for both herbage cultivars, adding wheat resulted in a ruminal fluid pH under 6 for >20 h/day. The ruminal environment of cows fed lucerne hay remained most stable throughout the grain challenge, spending the least amount of time below pH 6.0 (9.0 h/day). Hay created a ruminal environment that was better able to cope with the accumulation of acid as wheat was digested. A combination of increased ruminating time and a slower rate of fermentation, due to higher neutral detergent fiber and lower metabolisable energy concentrations in the hays, is likely responsible for the higher ruminal fluid pH values. Forage plays a critical role in wheat introduction strategies; aggressive adaptation strategies could be implemented when a hay such as lucerne is used as the base forage.

286 Effects of Supplementation of Quebracho Extract Supplementation on Ruminal Ph of Growing Beef Steers

Abstract Rumen acidosis is a common metabolic disorder occurring when organic acid production exceeds clearance capacity, reducing ruminal pH. Acidosis occurrence has been directly correlated to the ratio of concentrate to forage in the diet. However, the rates of substrate fermentation and acid absorption vary at different locations in the rumen. The objective of this study was to determine the pH in different locations of the rumen using 16 rumenally- cannulated steers (309 ± 43 kg) receiving quebracho extract (QT; Schinopsis balansae) within a grower-type diet [25:75 forage-to-concentrate, dry matter (DM) % basis]. Animals were randomly assigned to one of four dietary treatments (n = 4): QT at 0, 1, 2, and 3% of DM (QT0, QT1, QT2, and QT3). Animals were adapted to the basal diet (QT0) for 12-d before being introduced to predetermined treatments for four weeks, with feed provided twice daily to allow ad libitum intake. Weekly measurements of ruminal fluid pH and redox potential (Eh) were taken four h post-feeding using a portable pH and redox meter probe in four locations of the rumen (cranial sac, ventral sac, dorsal sac, and reticulum). Data were analyzed using a random coefficients model with the pen as a random effect and week as repeated measures. The DM intake was included as a covariate. There was no interaction among diet, location, and week (P ≥ 0.925) on pH. Overall, ruminal pH was lower for QT0 and QT1 compared to QT3 (P &amp;lt; 0.001). Ruminal pH in the cranial sac and reticulum was greater than in the dorsal sac (5.98, 6.03, and 5.87, respectively; P = 0.001). Redox potential was lower for QT0 in week 1 than all other treatments (P = 0.042). This study indicated that pH differs among locations of the rumen regardless of QT supplementation level and days on feed.