Ruminal Acetate Concentrations Research Articles

Growth Performance, Rumen Fermentation, and Meat Quality of Finishing Lambs Supplemented with Calcium Propionate or Sodium Propionate.

This study aimed to evaluate the effect of dietary supplementation with calcium propionate (CaPr) or sodium propionate (NaPr) on growth performance, ruminal fermentation, and meat quality of finishing lambs. Twenty-seven non-castrated Creole male lambs (24.95 ± 2.15 kg body weight (BW); 4.5 ± 0.5 months old) were randomly assigned to three treatments: (a) CON: basal diet without the addition of CaPr or Na Pr; (b) basal diet + CaPr (10 g/kg DM); and (c) basal diet + NaPr (10 g/kg DM). The data were analyzed using a completely randomized experimental design, with each lamb considered an experimental unit (nine replicates/treatment). Dietary supplementation with CaPr or NaPr did not affect (p > 0.05) growth performance or dietary energetics. However, greater (p = 0.05) apparent dry matter digestibility was observed in the lambs that consumed the diet with NaPr10. Dietary supplementation with CaPr or NaPr did not affect (p > 0.05) ruminal pH or ruminal concentrations of ammonia nitrogen, acetate, propionate, butyrate, and total volatile fatty acids. However, ruminal lactate concentration increased (p = 0.01) in lambs consuming the NaPr diet. Hot carcass weight and yield, backfat thickness, meat pH, meat color (L*, a*, and b*), cooking loss, and water holding capacity were not affected by dietary supplementation with CaPr or NaPr. In conclusion, dietary supplementation with 10 g/kg DM of calcium propionate or sodium propionate does not affect growth performance, dietary energetics, ruminal fermentation, and the meat quality of finishing lambs.

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

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

22 Effects of trace mineral source and chromium propionate supplementation on rumen fermentation, growth performance, and carcass characteristics in finishing beef steers

Abstract Crossbred beef steers [n = 400; body weight (BW) = 370 ± 8 kg] were used to evaluate the effects of trace mineral (TM) source and chromium propionate (Cr) on rumen fermentation characteristics, plasma glucose and mineral concentrations, performance, and carcass characteristics in feedlot steers fed a steam-flaked corn-based finishing diet. Steers were blocked by initial BW and randomly assigned within block to 1 of 4 treatments (10 steers/pen) with 10 pens per treatment. The experimental design was a randomized complete block design with a 2 x 2 factorial arrangement of treatments. Factors included: 1) TM source [sulfate or hydroxychloride (IntelliBond] Cu, Mn, and Zn TM supplemented at 18, 40, and 90 mg/kg DM, respectively) and 2) with or without supplemental Cr (KemTRACE) at 0.0 or 0.25 mg/kg DM. Steers were individually weighed on d -1 and 0 and every 28 d throughout the experiment. Jugular blood samples and rumen contents were collected from 10 steers per treatment on d 28 and 84 of the experiment for plasma glucose and TM concentration and volatile fatty acid analysis, respectively. On d 154 of the experiment, steers were harvested at a commercial abattoir and carcass data was collected. Data were analyzed on a pen mean basis for a randomized complete block design using PROC MIXED of SAS. There was no TM source by Cr supplementation interactions for any of the response variables measured, therefore only main effects are reported. Overall ADG (P = 0.03) and gain:feed (P = 0.02) were greater in steers receiving supplemental Cr when compared with steers not supplemented with Cr. Hot carcass weight (P = 0.04), dressing percentage (P = 0.01), longissimus muscle area (P = 0.03), and USDA yield grades (P = 0.04) were greater in steers receiving hydroxychloride TM compared with steers receiving sulfate TM. Steers supplemented with Cr had a greater dressing percentage (P = 0.01) and longissimus muscle area (P = 0.04) compared with steers not supplemented with Cr. On d 28 of the experiment, ruminal acetate concentrations were lesser (P = 0.01) and ruminal propionate concentrations tended to be greater (P = 0.12) in steers receiving hydroxychloride TM compared with steers receiving sulfate TM. Steers supplemented with Cr had greater ruminal acetate concentrations (P = 0.04) and plasma glucose concentrations (P = 0.05) on d 28 of the experiment when compared with non-supplemented controls. These data indicate the Cr supplementation and TM source can influence feedlot steer performance, carcass characteristics, and rumen fermentation characteristics.

483 DMI, gastrointestinal tract fermentation and permeability, and white blood cell responses in beef heifers provided post-ruminal yeast cell wall extract following feed restriction

Abstract The objectives of this study were to 1) evaluate gastrointestinal fermentation characteristics and permeability, and white blood cell concentrations as beef heifers recovered from a feed restriction (FR) challenge, and 2) determine whether post-ruminal provision of a yeast cell wall extract (YCW) modulated responses. Ruminally cannulated beef heifers (n = 8) were used in a 2 × 2 crossover design. Treatments (TRT) included an abomasal infusion of a placebo (PLC; maltodextrin) or YCW derived from Saccharomyces cerevisiae (2 g/dose) infused at 0600 and 1800 h. Heifers were subject to 5-d of FR (offering 30% of ad libitum DMI) followed by five 5-d recovery phases (REC1, REC2, REC3, REC4, and REC5). Daily DMI, and rumen, fecal, and blood samples were collected on d 5 of FR, REC1, REC3, and REC5 with an additional collection on d 2 of REC1. Total gastrointestinal and post-ruminal permeability were measured using a ruminal dose of Cr-EDTA and an abomasal dose of Co-EDTA, respectively, during FR, REC1, REC3, and REC5 with concurrent urine collection. Data were analyzed to determine the effects of YCW provision, day, and the 2-way interaction. There were no TRT or TRT×day effects for any variables except DMI (interaction, P = 0.04), where DMI did not differ during the FR challenge; however, heifers provided YCW had a greater increase by REC1 compared with PLC heifers without any means differing. DMI progressively increased from FR, to REC1, REC2, and REC5. Ruminal acetate concentration increased (P &amp;lt; 0.01) from FR (45.4 mmol/L) to REC1 d5 (60.1 mmol/L) and increased further to REC3 (67.3 mmol/L) with no change thereafter (68.3 mmol/L in REC5). Ruminal propionate concentration increased (P &amp;lt; 0.01) from FR (14.5 mmol/L) to REC1 d2 (27.7 mmol/L) and was not different thereafter. Similarly, butyrate concentration increased (P &amp;lt; 0.01) from FR (7.9 mmol/L) to REC1 (d 5; 15.0 mmol/L) and was not different thereafter. Fecal acetate, propionate, and butyrate concentrations were not affected by day (P ≥ 0.12). Total gastrointestinal and post-ruminal permeability were greatest during FR (P &amp;lt; 0.01; 2.6% and 2.2% of the infused marker was excreted in urine, respectively) and decreased to 1.6% and 1.1%, respectively, in REC3 followed by an increase in REC5 for total (2.0% of infused) but not post-ruminal (1.0% of infused) permeability. The concentration of neutrophils (P &amp;lt; 0.01) was greatest on REC1 d2 (4.84 ×106 μmol/mL) and eosinophil concentration (P &amp;lt; 0.01) was greatest during FR (0.53 ×106 μmol/mL), least on d 2 of REC1 and increased on d 5 of REC1 but was not different thereafter. WBC (P &amp;lt; 0.01) gradually decreased (P = 0.02) from FR and REC1 d2 to REC3 and REC5. Post-ruminal provision of YCW may accelerate increases in DMI early in the recovery from FR, yet treatment did not modulate ruminal or fecal SCFA, blood concentrations, or gastrointestinal permeability.

Novel Perspective on Molecular and Cellular Adaptations of the Mammary Gland-Regulating Milk Constituents and Immunity of Heat-Stressed Dairy Cows.

Climate change with increasing ambient temperatures negatively influences the biology of dairy cows and their milk production in the mammary gland (MG). This study aimed to elucidate the MG proteome, differences in milk composition, and ruminal short-chain fatty acid concentrations of dairy cows experiencing 7 days of heat stress [HS, 28 °C, temperature humidity index (THI) = 76], pair-feeding (PF), or ad libitum feeding (CON) at thermoneutrality (16 °C, THI = 60). Ruminal acetate, acetate/propionate ratio, and milk urea concentrations were greater, whereas milk protein and lactose were lower in HS than in control cows. Proteome analysis revealed an induced bacterial invasion of epithelial cells, leukocyte transendothelial migration, reduction of the pyruvate and carbon metabolism, and platelet activation in the MG of HS compared to CON or PF cows. These results highlight adaptive metabolic and immune responses to mitigate the negative effects of ambient heat in the MG.

Early-life supplementation with mannan-rich fraction to regulate rumen microbiota, gut health, immunity, and growth performance in dairy goat kids

Enhancing gastrointestinal health, immunity, and digestion are key factors to support dairy goat kid performance. Several additives have been studied in relation to these actions. This study investigated the impact of mannan-rich fraction (MRF) inclusion in goat milk on the growth performance, gut health, rumen fermentation, and microbial profiles of Xinong Saanen dairy goat kids. A total of 80 kids aged 14 d and 4.72 ± 0.33 kg BW were randomly assigned into 2 groups: control and MRF (1 g/d MRF mixed into milk). Each group consisted of 40 kids with 10 kids per pen. All kids were given milk individually and fed a starter diet by pen, with the trial lasting 10 wk. Body weight and blood samples were collected on the seventh day at 2, 6, 10 and 12 wk of age, and feed intake was determined daily. From the first to seventh day at 12 wk of age, fecal samples were collected from 4 kids in each group to analyze nutrient digestibility. On the seventh day of 12 wk of age, 4 kids from each group were slaughtered for evaluation of rumen fermentation, rumen microbiota, and gut morphology. The results indicated that MRF supplementation led to greater overall BW, overall starter DMI, and overall ADG, along with a lower overall diarrhea rate. However, no difference in overall feed efficiency and apparent digestibility of nutrients was observed. Furthermore, MRF supplementation resulted in increased ileal villus height; higher RNA expression of claudin-1 and occludin in the duodenum; higher expression of ZO-1, JAM-2, and occludin in the jejunum; and higher expression of claudin-1, JAM-2, and occludin in the ileum. Additionally, the concentrations of overall IgA, overall IgM, and overall IgG were higher in the MRF group. The concentrations of ruminal acetate and total volatile fatty acid were higher with MRF supplementation (P < 0.05). Meanwhile, supplementation with MRF resulted in higher abundance of Bacteroidetes and Succinivibrio and lower abundance of Firmicutes and Succiniclasticum in the rumen. Overall, the growth performance, gut health, immunity, and ruminal microbial structure of dairy goat kids benefited from MRF supplementation.

Effects of bulk tank milk, waste milk, and pasteurized waste milk on the nutrient utilization, gastrointestinal tract development, and antimicrobial resistance to Escherichia coli in preweaning dairy calves

This study aimed to assess the effect of bulk tank milk (BTM), waste milk (WM), and pasteurized waste milk (PWM) on nutrient digestibility, ruminal and cecal fermentation, gastrointestinal tract (GIT) development, and antimicrobial resistance of fecal Escherichia coli from dairy calves at 2 periods (30 and 60 d of age). Calves were grouped according to BW, serum protein levels, and breed composition. Three treatments were included: BTM (n = 21), WM from cows under antibiotic treatment (n = 21), and PWM (WM submitted to HTST pasteurization; n = 21). A total of 63 calves were used, of which 18 animals (n = 6 per treatment) were evaluated in the period of 4 to 30 d, and 45 (n = 15 per treatment) from 4 to 60 d. During the experimental period, a daily intake of 6 L of milk was divided into 2 equal meals, with ad libitum access to water and starter. Milk and feed intakes were recorded daily. Apparent total-tract digestibility and nitrogen balance were conducted from 25 to 29 d of age (n = 6) and from 53 to 57 d of age (n = 15). Animals were slaughtered at 30 ± 1 and 60 ± 1 d of age for the assessment of ruminal and cecal fermentation and GIT development. Antimicrobial susceptibility testing was conducted at 1, 30, and 60 d of age (n = 15/treatment). Statistical analysis used a linear mixed-effects model for continuous outcomes and generalized linear models for single measurements (R software). Treatments WM and PWM had lower rumen pH, higher ruminal acetate concentration, larger reticulorumen and liver, and a higher prevalence of fecal-resistant E. coli compared with BTM at both 30 and 60 d. Up to 60 d, both BTM and WM treatments exhibited higher digestibility of ether extract and gross energy compared with the PWM, whereas WM and PWM treatments showed increased nitrogen intake and retention compared with the BTM treatment. These findings suggest that pasteurization of WM negatively affects nutrient digestibility and calf performance, while also affecting rumen development. Additionally, the use of milk containing antibiotic residue leads to the selection of resistant E. coli in the GIT over time.

Capsaicin as a Dietary Additive for Dairy Cows: A Meta-Analysis on Performance, Milk Composition, Digestibility, Rumen Fermentation, and Serum Metabolites.

This study aimed to evaluate the effects of dietary supplementation with capsaicin (CAP) on productive performance, milk composition, nutrient digestibility, ruminal fermentation, and serum metabolites of dairy cows using a meta-analytical approach. The database included 13 studies, from which the response variables of interest were obtained. Data were analyzed using a random effects model, and results were expressed as weighted mean differences between treatments supplemented with and without CAP. Dietary supplementation with CAP increased (p < 0.05) dry matter intake, milk yield, feed efficiency, milk fat yield, and milk fat content. However, CAP supplementation did not affect (p > 0.05) milk protein and lactose yield, milk urea nitrogen, or milk somatic cell count. Greater (p < 0.05) apparent digestibility of dry matter and crude protein was observed in response to the dietary inclusion of CAP. Likewise, supplementation with CAP increased (p < 0.05) the rumen concentration of total volatile fatty acids. In contrast, CAP supplementation did not affect (p > 0.05) ruminal pH or the ruminal concentration of ammonia nitrogen, acetate, propionate, and butyrate. In blood serum, CAP supplementation increased (p < 0.05) the glucose concentration and decreased (p < 0.05) the concentration of non-esterified fatty acids. However, CAP supplementation did not affect (p > 0.05) the serum concentration of urea and beta-hydroxybutyrate. In conclusion, capsaicin can be used as a dietary additive to improve the productive performance, milk composition, and nutrient digestibility in dairy cows and, at the same time, improve the ruminal concentration of total volatile fatty acids and serum levels of glucose and non-esterified fatty acids.

Effects of low-quality forage and starter protein content in starter diet of young calves on growth performance, rumen fermentation, and urinary purine derivatives.

Feeding low-quality forage (LQF) has been evaluated in mature ruminants and results show that it has been improved nitrogen utilization efficiency. The present study evaluated the interaction effect of feeding wheat straw as LQF (0 and 7.5%, DM basis) and starter protein level (20 vs. 24%, DM basis) on growth performance, ruminal fermentation, and microbial protein synthesis in Holstein dairy calves raised under moderate heat stress condition. Forty-eight 3-day old dairy calves (averaging 40.6 kg) were assigned in four experimental treatments as follow; 1) no LQF with 20% CP (NLQF-20CP), 2) no LQF with 24% CP (NLQF-24CP), 3) 7.5% LQF with 20% CP (LQF-20CP) and 4) 7.5% LQF and 24% CP (LQF-24CP). The calves were weaned on d 53 of age but the experiment extended until d 73 of age. Feeding LQF increased starter intake, average daily gain (tendency), ruminal acetate concentration, and improved fecal score of calves. The average daily gains before and after weaning were positively influenced with greater starter protein content. Hence, weaning and final BWs were improved when calves received greater CP content. In addition, greater starter CP content increased total ruminal volatile fatty acid concentration. With respect to the interaction effect between LQF feeding and starter protein content, the lower nitrogen excretion through urine was obtained for LQF-20CP diet among experimental treatments. The results of the current study showed that feeding LQF improved ruminal fermentation pattern and improved growth performance through increased starter intake. In addition, greater starter protein content is advisable during pre-weaning period for calves raised under mild heat stress condition. In conclusion, based on the results found in the current study, it can be suggested that feeding LQF for calves under heat stress condition can improve nitrogen utilization when dietary protein content is low. This can be opportunity to formulate starter diets with greater nitrogen utilization efficiency which is critical for accelerated growth programs at early stages of growth for young calves while calves raised under hot season condition.

Feeding live or inactive yeast to primiparous Jersey cows: nutrient digestibility, rumen fermentation, and milk fatty acid profile

ABSTRACT The aim of this study was to evaluate the effects of live yeast (LY) or inactive yeast (IY) on intake and apparent total-tract digestibility of nutrients, ruminal fermentation, milk yield and composition, milk fatty acid profile, N utilisation, and microbial protein synthesis of primiparous Jersey cows. Twelve primiparous Jersey cows were employed, with an average body weight of 403 kg, a lactation period of 100 days, and average daily milk output of 14.7 kg. The experimental diets were: 1 – CON (no additives); 2 – LY (inclusion of 40 g/day of live yeast); 3 – IY (inclusion of 40 g/day of inactivated yeast wall). Cows fed LY exhibited the greatest DM intake. Cows’ intake IY had the greatest digestibility of DM, OM, and NDF. Feeding IY reduced ruminal concentrations of acetate, isobutyrate, and branched-chain fatty acids. Cows fed either LY or IY increased the production of milk and FCM. Cows under the LY treatment had greater milk fat content. Cows fed LY had the greatest N intake. Yeast treatments also increased the absorbable purine estimation. Supplementing primiparous dairy cows with yeast products, especially live yeast, improved dry matter intake by positively influencing digestibility, particularly for starch and NDF.

Effects of dietary D-lactate levels on rumen fermentation, microflora and metabolomics of beef cattle.

Excessive intake of lactate caused by improper use of silage in animal husbandry has adverse effects on rumen fermentation, such as rumen acidosis. The speed of absorption and metabolism of D-lactate in rumen epithelial cells was slower than that of L-lactate, making D-lactate more prone to accumulate and induce rumen acidosis. Therefore, this study was conducted to explore the effects of dietary D-lactate levels on rumen fermentation of beef cattle and its mechanism in an in vitro system. This experiment was adopted in single-factor random trial design, with 5 days for adaptation and 3 days for sample collection. Three treatments (n = 8/treatment) were used: (1) D-LA (0.3%), basal fermentation substrate with 0.3% (dry matter, DM basis) D-lactate; (2) D-LA (0.75%), basal fermentation substrate with 0.75% (DM basis) D-lactate; and (3) D-LA (1.2%), basal fermentation substrate with 1.2% (DM basis) D-lactate. With the dietary D-lactate levels increased, the daily production of total gas, hydrogen and methane, as well as the ruminal concentrations of acetate, propionate, butyrate, isobutyrate, valerate, isovalerate, total volatile fatty acid and D-lactate increased (p < 0.05), but the ruminal pH and acetate/propionate ratios decreased (p < 0.05). Principle coordinate analysis based on Bray-Curtis distance showed that increasing dietary D-lactate levels could significantly affect the structure of rumen bacterial community (p < 0.05), but had no significant effect on the structure of rumen eukaryotic community (p > 0.05). NK4A214_group, Ruminococcus_gauvreauii_group, Eubacterium_oxidoreducens_group, Escherichia-Shigella, Marvinbryantia and Entodinium were enriched in D-LA (1.2%) group (p < 0.05), as well as WCHB1-41, vadinBE97, Clostridium_sensu_stricto_1, Anaeroplasma and Ruminococcus were enriched in D-LA (0.3%) group (p < 0.05). Changes in the composition of ruminal microorganisms affected rumen metabolism, mainly focus on the biosynthesis of glycosaminoglycans (p < 0.05). Overall, feeding whole-plant corn silage with high D-lactate content could not induce rumen acidosis, and the metabolization of dietary D-lactate into volatile fatty acids increased the energy supply of beef cattle. However, it also increased the ruminal CH4 emissions and the relative abundance of opportunistic pathogen Escherichia-Shigella in beef cattle. The relative abundance of Verrucomicrobiota and Escherichia-Shigella may be influenced by glycosaminoglycans, reflecting the interaction between rumen microorganisms and metabolites.

Trace mineral source and chromium propionate supplementation affect performance and carcass characteristics in feedlot steers.

Angus-crossbred steers (n = 400; 369.7 ± 7.6kg) were used to determine the influence of trace mineral (TM) source and chromium propionate (Cr Prop) supplementation on performance, carcass characteristics, and ruminal and plasma variables in finishing steers. Steers were blocked by body weight (BW) and randomly assigned within block to treatments in a 2 × 2 factorial arrangement, with factors being: 1) TM source (STM or HTM) and 2) Cr supplementation (0 or 0.25mg Cr/kg DM, -Cr or + Cr, respectively). Treatments consisted of the addition of: 1) sulfate TM (STM; 90, 40, and 18mg/kg DM of Zn, Mn, and Cu, respectively), 2) STM and 0.25mg Cr/kg DM from Cr Prop, 3) hydroxychloride TM (HTM; 90, 40, and 18mg/kg DM of Zn, Mn, and Cu, respectively), and 4) HTM and 0.25mg Cr/kg DM from Cr Prop. Each treatment consisted of 10 replicate pens with 10 steers per pen. Body weights were obtained on consecutive days at the initiation and termination of the 154-d study. Steers were fed a steam-flaked corn-based finishing diet. Ractopamine hydrochloride was fed for the last 31 d of the study. Ruminal fluid and blood samples were obtained from one steer per pen on days 28 and 84 for ruminal volatile fatty acids (VFA) and plasma TM and glucose analysis. Steers were slaughtered at the end of the study and individual carcass data were collected. No Cr × TM source interactions (P = 0.48)were detected. Steers supplemented with HTM had greater (P = 0.04) hot carcass weight (HCW), dressing percentage (DP), longissimus muscle (LM) area, and USDA yield grade (YG), and tended (P = 0.12) to have greater average daily gain (ADG) than those receiving STM. Average daily gain, gain:feed, dressing percentage, and longissimus muscle area were greater (P = 0.04) for + Cr steers compared to-Cr steers. Hot carcass weight tended (P = 0.06) to be greater for + Cr steers. Ruminal acetate concentrations at 28 d were lesser (P = 0.01) for HTM vs. STM steers, and greater (P = 0.04) for + Cr steers compared to-Cr steers. Plasma concentrations of Zn, Cu, and Mn were not affected by TM source or Cr supplementation. Steers supplemented with Cr had greater (P = 0.05) plasma glucose concentrations than-Cr steers at 28 but not at 84 d. Results of this study indicate replacing STM with HTM improved carcass characteristics in finishing steers, and Cr Prop supplementation improved steer performance and carcass characteristics.

Growth performance and ruminal fermentation of lambs supplemented with calcium propionate: A meta-analysis

This study aimed to evaluate the effects of dietary calcium propionate (CaPr) supplementation on growth performance and ruminal fermentation of lambs using a meta-analytic method. The data used were obtained from 10 peer-reviewed publications. The effect size was assessed using weighted mean differences (WMD) between CaPr supplementation and control treatments. Dietary supplementation with CaPr did not affect (P > 0.05) dry matter intake, hot carcass yield, Longissimus dorsi muscle area, rumen pH, and butyrate concentration, but it increased average daily gain (WMD = 0.012 kg/d; P = 0.022), and ruminal concentration of total volatile fatty acids (WMD = 6.633 mM; P = 0.022) and propionate (WMD = 4.443 mol /100 mol; P < 0.001). In contrast, a lower feed conversion ratio (WMD = −0.288 kg/kg; P = 0.029) and ruminal acetate concentration (WMD = −3.319 mol/100 mol; P < 0.001) were observed in response to CaPr supplementation. In conclusion, the dietary inclusion of calcium propionate can be used as a nutritional strategy to improve growth rate and ruminal fermentation in fattening lambs.

A comparison of average daily gain, apparent digestibilities, energy balance, rumen fermentation parameters, and serum metabolites between yaks (Bos grunniens) and Qaidam cattle (Bos taurus) consuming diets differing in energy level.

Yaks (Bos grunniens), indigenous to the harsh Qinghai-Tibetan Plateau, are well adapted to the severe conditions, and graze natural pasture without supplements all year round. Qaidam cattle (Bos taurus), introduced to the Qinghai-Tibetan Plateau 1,700 years ago, are raised at a lower altitude than yaks, provided with shelter at night and offered supplements in winter. Based on their different backgrounds, we hypothesized that yaks have lower energy requirements for maintenance than cattle. To test this hypothesis, we measured average daily gain (ADG), apparent digestibilities, energy balance, rumen fermentation parameters, and serum metabolites in growing yaks and cattle offered diets differing in metabolizable energy (ME) levels (6.62, 8.02, 9.42 and 10.80MJ/kg), but with the same crude protein concentration. Six castrated yaks (155±5.8kg) and 6 castrated Qaidam cattle (154±8.0kg), all 2.5 years old, were used in 2 concurrent 4×4 Latin square designs. Neutral and acid detergent fiber digestibilities were greater (P<0.05) in yaks than in cattle, and decreased linearly (P<0.05) with increasing dietary energy level; whereas, digestibilities of dry matter, organic matter, crude protein and ether extract increased (P<0.05) linearly with increasing energy level. The ADG was greater (P<0.001) in yaks than in cattle, and increased (P<0.05) linearly with increasing energy levels. From the regressions of ADG on ME intake, the estimated ME requirement for maintenance was lower (P<0.05) in yaks than in cattle (0.43 vs. 0.57MJ/kg BW0.75). The ratios of digestible energy (DE):gross energy and ME:DE were higher (P<0.05) in yaks than in cattle, and increased (P<0.05) linearly with increasing dietary energy level. Ruminal pH decreased (P<0.05), whereas concentrations of total volatile fatty acids (VFAs) and ammonia increased (P<0.01) with increasing dietary energy level, and all were greater (P<0.05) in yaks than in cattle. Concentrations of ruminal acetate and iso-VFAs were greater (P<0.05), whereas propionate was lower (P<0.05) in yaks than in cattle; acetate decreased (P<0.001), whereas butyrate and propionate increased (P<0.001) linearly with increasing dietary energy level. Serum concentrations of β-hydroxybutyrate were lower (interaction, P<0.001) in yaks than in cattle fed diets of 9.42 and 10.80MJ/kg, whereas non-esterified fatty acids were greater (interaction, P<0.01) in yaks than in cattle fed diets of 6.62 and 8.02MJ/kg. Concentrations of serum leptin and growth hormone were greater in yaks than in cattle and serum insulin and growth hormone increased (P<0.01) linearly with increasing dietary energy level. Our hypothesis that yaks have lower energy requirements for maintenance than cattle was supported. This lower requirement confers an advantage to yaks over Qaidam cattle in consuming low energy diets during the long winter on the Qinghai-Tibetan Plateau.

Probiotic effect of ferulic acid esterase-producing Lactobacillus plantarum inoculated alfalfa silage on digestion, antioxidant, and immunity status of lactating dairy goats.

A feeding experiment was conducted to determine the effects of inoculating alfalfa silage with a ferulic acid esterase-producing inoculum on feed digestibility, rumen fermentation, antioxidant, and immunity status of lactating dairy goats. Twenty dairy goats were distributed into 2 experimental groups consisting of control diet (Lp MTD/1, including Lactobacillus plantarum MTD/1 inoculated silage) against diet containing silage treated with ferulic acid esterase-producing L. plantarum A1 (Lp A1). Alfalfa silage inoculated with a ferulic acid esterase-producing Lp A1 had better fermentation quality than the Lp MTD/1 inoculation. The application of Lp A1 improved silage antioxidant capacity as indicated by greater total antioxidant capacity (T-AOC), superoxide dismutase (SOD) and glutathion peroxidase (GSH-Px) activities in Lp A1 treated silage versus Lp MTD/1 treatment. Compared with Lp MTD/1 treated group, inoculation of silage with Lp A1 increased apparent total tract digestibility of dietary dry matter, organic matter and crude protein, and ruminal concentrations of total volatile fatty acids, acetate, propionate and isobutyrate as well. The results of current study also demonstrated improved antioxidant capacity and immune performance of dairy goats with Lp A1 inoculation. Feeding Lp A1-treated silage increased dairy goats' serum antioxidase activity, such as T-AOC, SOD, GSH-Px and catalase, and the serum concentration of immunoglobulin A, while decreased tumor necrosis factor α, interleukin (IL)-2 and IL-6. In addition, compared with Lp MTD/1, diet containing alfalfa silage inoculated with Lp A1 endowed dairy goats' milk with greater fat and protein contents, improved dairy goat milk quality without affecting feed efficiency.

A Meta-Analysis of Essential Oils Use for Beef Cattle Feed: Rumen Fermentation, Blood Metabolites, Meat Quality, Performance and, Environmental and Economic Impact

The objective of this study was to see how dietary supplementation with essential oils (EOs) affected rumen fermentation, blood metabolites, growth performance and meat quality of beef cattle through a meta-analysis. In addition, a simulation analysis was conducted to evaluate the effects of EOs on the economic and environmental impact of beef production. Data were extracted from 34 peer-reviewed studies and analyzed using random-effects statistical models to assess the weighted mean difference (WMD) between control and EOs treatments. Dietary supplementation of EOs increased (p &lt; 0.01) dry matter intake (WMD = 0.209 kg/d), final body weight (WMD = 12.843 kg), daily weight gain (WMD = 0.087 kg/d), feed efficiency (WMD = 0.004 kg/kg), hot carcass weight (WMD = 5.45 kg), and Longissimus dorsi muscle area (WMD = 3.48 cm2). Lower (p &lt; 0.05) ruminal concentration of ammonia nitrogen (WMD = −1.18 mg/dL), acetate (WMD = −4.37 mol/100 mol) and total protozoa (WMD = −2.17 × 105/mL), and higher concentration of propionate (WMD = 0.878 mol/100 mol, p &lt; 0.001) were observed in response to EOs supplementation. Serum urea concentration (WMD = −1.35 mg/dL, p = 0.026) and haptoglobin (WMD = −39.67 μg/mL, p = 0.031) were lower in cattle supplemented with EOs. In meat, EOs supplementation reduced (p &lt; 0.001) cooking loss (WMD = −61.765 g/kg), shear force (WMD = −0.211 kgf/cm2), and malondialdehyde content (WMD = −0.040 mg/kg), but did not affect pH, color (L* a* and b*), or chemical composition (p &gt; 0.05). Simulation analysis showed that EOs increased economic income by 1.44% and reduced the environmental footprint by 0.83%. In conclusion, dietary supplementation of EOs improves productive performance and rumen fermentation, while increasing the economic profitability and reducing the environmental impact of beef cattle. In addition, supplementation with EOs improves beef tenderness and oxidative stability.

Responses of Lactation, Rumen Fermentation and Blood Biochemical Parameters with Increasing Dietary Inulin Supplementation in Mid-Lactation Dairy Cows

Effects of dietary supplementation of inulin in dairy cows were investigated in this study. Thirty-six mid-lactation Holstein dairy cows were randomly divided into six groups with six cows per group and offered a total mixed ration supplemented with 0 (control), 50, 150, 200, 250 and 350 g/d inulin per head, respectively. The animals were pre-fed for 2 weeks before rumen fluid, milk and blood samples were collected weekly for 3 weeks. With increasing inulin doses, milk yield (p &lt; 0.01) and milk fat concentration (p = 0.04) were linearly increased, while milk urea nitrogen (p &lt; 0.01) and somatic cell count (p = 0.04) were linearly decreased. Linear increases were also detected in the proportions of milk saturated fatty acids (p &lt; 0.01) and polyunsaturated fatty acids (p = 0.04); however, milk monounsaturated fatty acids were linearly decreased (p = 0.04). The ruminal concentrations of acetate, propionate and butyrate increased, while the ruminal pH and the concentration of NH3-N reduced at a decreasing rate with increasing inulin doses (p &lt; 0.01). Moreover, the concentrations of lactic acid (p = 0.03) and total volatile fatty acids (p &lt; 0.01) were linearly upregulated. There were linear increases in the serum concentrations of superoxide dismutase (p = 0.02), immunoglobin G (p &lt; 0.01), immunoglobin M (p = 0.04), interleukin-2 (p &lt; 0.01) and interleukin-10 (p = 0.04); quadratic increases in serum total protein (p &lt; 0.01) and albumin (p = 0.02) and linear decreases in serum total cholesterol (p = 0.02), triglyceride (p &lt; 0.01) and malondialdehyde (p &lt; 0.01). The results indicated that inulin increased milk production, shifted milk fatty acid profile, upregulated rumen volatile fatty acid concentration, and enhanced antioxidant and immunity function in dairy cows in a dose-dependent manner.

Impacts of added roughage on growth performance, digestibility, ruminal fermentation, and ruminal pH of feedlot steers fed wheat-based feedlot diets containing 30% modified distillers grains with solubles.

Two experiments were conducted to evaluate the inclusion rate roughage in wheat-based diets containing modified distillers grains with solubles (MDGS) on feedlot performance (Feedlot Experiment), as well as digestibility, ruminal pH, and ruminal fermentation characteristics (Digestibility Experiment). The feedlot experiment utilized 72 Angus steers (392 ± 46.3 kg initial body weight) which were randomly assigned to 1 of 12 pens, 3 pens per treatment, to evaluate feedlot performance and carcass characteristics. Dietary treatments were 1) control; 10% roughage, 2) 12% roughage, 3) 14% roughage, and 4) 16% roughage. The digestibility experiment used four ruminally and duodenally cannulated steers (393 ± 33.0 kg) in a 4 × 4 Latin Square with either 10%, 12%, 14%, or 16% roughage as in the feedlot experiment. However, dietary roughage source was different between these two experiments and included a combination of grass hay and wheat straw (Feedlot Experiment), and corn silage (Digestibility Experiment). All data were analyzed with the Mixed Procedures of SAS. Feed intake was recorded, with duodenal and fecal output calculated using chromic oxide. Ruminal pH and fermentation were assessed. Growth performance and most carcass characteristics were not affected by increasing roughage (P ≥ 0.11). Marbling tended to decrease linearly (P = 0.10) with increasing roughage inclusion. Increasing dietary roughage content had no effect on organic matter intake (P = 0.60) in the digestibility experiment. Intake, duodenal flow, and digestibility of neutral detergent fiber and acid detergent fiber were not affected by treatment (P ≥ 0.16). Ruminal pH increased linearly (P < 0.01) as rate of roughage inclusion increased. Ruminal concentrations of acetate and butyrate increased, and propionate decreased in a linear fashion (P < 0.01) thereby increasing (P < 0.01) acetate and butyrate to propionate ratio with increasing dietary roughage. Our data indicate that increasing roughage inclusion in wheat-based diets including 30% MDGS increased ruminal pH and shifted ruminal fermentation patterns. Additionally, increasing roughage inclusion did not affect feedlot performance in steers fed wheat at 36% to 42% of dietary dry matter in combination with 30% MDGS.

Nitrate supplementation at two forage levels in dairy cows feeding: milk production and composition, fatty acid profiles, blood metabolites, ruminal fermentation, and hydrogen sink

Abstract Nitrate may reduce the ruminal methane emission by competing methanogenesis to achieve more hydrogen. For this purpose, twenty Holstein lactating cows were examined using a 2×2 factorial design in 4 groups for 60 days with two forage levels (40% and 60%) and supplemental nitrate 0% (F40 and F60) and 3.5% (F40N and F60N) of diet dry matter (DM). Then, the effect of nitrate and forage levels on cow performance, ruminal fermentation, methane emission, and metabolic hydrogen sink were evaluated. The nitrate supplementation did not significantly affect milk yield and ECM/DMI, while milk urea nitrogen was increased. Lowest quantity of milk vitamins (A and E) was observed in nitrate groups. The nitrate supplementation increased c9-C18:1, unsaturated fatty acids, and n-6/n-3 contents of the milk. Blood parameters were affected by nitrate supplementation. Blood met-Hb concentration was increased, while blood glucose was decreased in nitrate groups. High forage and nitrate fed animals (F60N) had higher ruminal acetate and lower propionate concentration, and higher acetate+butyrate to propionate ratio than other groups. Nitrite and NH3-N concentrations were higher in the rumen of nitrate fed animals. Nitrate supplementation inhibited gas volume and methane emission without affecting volatile fatty acids at 12 and 24 h of incubation. The H2 balance, H2 production and consumption, and recovery percentage were significantly lower in F60N group. In conclusion, nitrate supplementation can be employed as an alternative strategy for improving ruminal fermentation, milk quality and methane inhibition.

Intake, digestibility rumen fermentation and nitrogen balance in lambs offered alfalfa and tall fescue-mixtures harvested and ensiled after a frost

The objective of this study was to determine the effect of harvesting alfalfa (Medicago sativa L.) and tall fescue [Schedonorus arundinaceus (Schreb.) Dumort] after frost and ensiling mixtures of these forages on silage fermentation characteristics, intake, digestibility and ruminal fermentation by ewe lambs. Forages were harvested in October of 2017, wilted, and blended as either alfalfa alone, 67% alfalfa + 33% novel endophyte-infected tall fescue, 33% alfalfa + 67% fescue, or 100% fescue. Twenty bins were lined with 2 plastic bags, packed (n = 5/trt) with the respective forages, stored for 3 months, and then assigned randomly to Dorper ewe lambs (n = 20; mean BW = 34.7 ± 6.65 kg) and offered for ad libitum consumption. Lambs were allowed 14 d of adaptation followed by 5 d of total feces and urine collection. Data were analyzed using PROC-MIXED of SAS and orthogonal polynomial contrasts were used to identify trends associated with different proportions of fescue to alfalfa. Silage total acids, lactate, and acetate concentrations increased linearly (P < 0.01), while silage ammonia decreased linearly and quadratically (P < 0.01) with increasing proportions of fescue in the silage. The proportions of lactate to total acids (g/kg total acids) increased linearly (P < 0.01) and quadratically (P = 0.02) with increasing fescue-to-alfalfa ratio. Dry matter (DM) and organic matter (OM) intake (g/kg BW), digestibility, and intake of digestible DM and OM (g/kg BW) decreased linearly (P < 0.01) as fescue proportion increased in the silages. Total ruminal volatile fatty acids (VFA), as well as concentrations of isovalerate and total branched-chain VFA decreased (P < 0.05) linearly and quadratically, butyrate and valerate decreased linearly (P < 0.01), and ruminal acetate concentrations increased (P < 0.01) linearly with increasing fescue concentration in the silage. All N utilization measurements (intake, absorption and retention) decreased with increasing fescue concentration in the silage (P < 0.01). Ensiling alfalfa with fescue that was harvested after a frost may improve forage fermentation characteristics, but may reduce intake and digestibility by lambs compared to feeding undiluted alfalfa silage.