Ruminal Variables Research Articles

Effects of Acacia mearnsii De Wild. extract and monensin on intake, digestibility, and ruminal variables of lambs

Effects of Acacia mearnsii De Wild. extract and monensin on intake, digestibility, and ruminal variables of lambs

Immunity, rumen metagenomics, ruminal variables, and growth performance of calves fed milk with sage (Salvia officinalis) essential oil.

The study aimed to determine the effect of sage (Salvia officinalis) essential oil (EO) to the drinking milk until the weaning stage of Holstein calves on the growth performance, body measurements, ruminal fermentation, rumen metagenomic profile, proinflammatory cytokines [interleukin-6 (IL-6), tumor necrosis factor (TNF-α), and IL-1β], immune globulins (IgG, IgM, and IgE), and acute phase proteins (serum amyloid-A, SAA). In the study, 24 Holstein calves were divided into three groups as 0 μL (SAG0; control group), 100 μL (SAG100), or 200 μL (SAG200) of sage EO to the milk per calf per day. The addition of sage EO to the milk linearly increased the live weight, feed intake, and daily body weight gain (P < 0.05). The addition of sage EO to the milk in calves linearly increased serum IgG titter dose dependently (P < 0.05), but serum IgM and IgE titters did not change (P > 0.05). The concentrations of serum TNF-α, IL-1β, and IL-6 in the weaned calves linearly decreased by the sage aromatic oil addition to the milk (P < 0.05). The serum SAA concentrations of calves did not differ among the control and treatment groups (P > 0.05). Probiotic Bifidobacterium and Acidaminococcus genusin calf rumen fluid canincrease bysage EO addition to milk. The relative abundance of genus Prevotella, Prevotellaceae_NK3B31_group, and Prevotella_9 increase with sage EO. The ruminal ammonia-nitrogen (NH3-N) concentration and total short chain fatty acid (T-SCFA) molarity decreased by sage EO addition to the drinking milk (P < 0.05). Themolarities of iso butyric (IBA) and iso valeric acids (IVA) in rumen fluid of the weaned calves linearly reduced by the increasing sage EO dose to the milk (P < 0.05). The butyric acid (BA) and iso caproic acid (ICA) molarities in rumen fluid did not change by the sage EO addition (P > 0.05). Consequently, it has been observed that sage EO addition to the milk of calves positively affected the immune system variables and performance parameters.Sage EO additionof calves before weaning may support the immune system in the eventual immunosuppression at the weaning stage.

CHEMICAL ANALYSIS AND in situ DEGRADATION OF DIETS PREPARED WITH AND WITHOUT FRUIT OF Parmentiera aculeata (Kunth) L.O. Williams IN SHEEP

During the drought period in cattle pastures, the fruits of chote (Parmentiera aculeata (Kunth) L.O.) Williams are available, which are satisfactorily consumed by grazing ruminants. However, the nutritional value and ruminal availability of the dry matter of this fruit, to which nutritional properties are attributed, are unknown. The objective was to evaluate the degradation of chote fruit for inclusion in sheep diets using in situ degradation and to identify some physiological variables in the rumen. Six rumen fistulated lambs with a live weight of 30 ± 2 kg were adapted for 11 days to the following experimental diets: T 0: 0 % chote fruit; T 15: 15 % chote fruit, and T 30: 30 % chote fruit. In situ degradation of chote fruit was determined and experimental diets were analyzed with a 3 × 3 crossover design. The results show that after 3 and 6 h, chote fruit at T 30 presented greater degradation (p ≤ 0.05). After 24, 48, and 72 h, pH and ammonia nitrogen (N-NH3) showed no statistical differences (p &gt; 0.05). The yields of acetic, propionic, and butyric acids were not different (p &gt; 0.05) at T 15 (acetic acid = 77.81 mM L-1; propionic = 14.39 mM L-1; butyric = 0. 67 mM L-1) and T 30 (acetic acid = 77.21 mM L-1; propionic = 18.52 mM L-1; butyric = 8.97 mM L-1), but both were greater than T 0 (acetic = 62.03 mM L-1, propionic = 18.52 mM L-1, butyric = 9.27 mM L-1). In conclusion, the addition of 30 % chote to sheep diets increases degradation without affecting ruminal variables.

DIGESTIBILITY, RUMEN FERMENTATION, RUMEN MICROBIOTA, AND LIPID PEROXIDATION IN SHEEP SUPPLEMENTED WITH LIPOIC ACID

Lipoic acid (LA) reduces oxidative stress and stimulates the immune system. However, data on its use in ruminants is limited. The objective of this study was to determine the effects of LA supplementation on free radical production, rumen variables, and feed digestibility in sheep fed high-grain diets. Nine rumen-cannulated Suffolk sheep were randomly assigned to three treatments: control (LA0 ), no LA inclusion; supplementation of 10 (LA10) mg LA kg-1 body weight (BW); and supplementation of 20 (LA20) mg LA kg-1 BW. In situ (ISDMD) and in vitro (IVDMD) degradation of dry matter and ruminal variables were evaluated. Total bacteria (TB), cellulolytic bacteria (CB), and protozoa (P) were also determined. Thiobarbituric acid reactive substances (TBARS) were evaluated in blood samples at the beginning and end of each experimental period. The ruminal variables and IVADDM were analyzed using a PROC GLM model with a repeated 3 × 3 latin square design, while means were compared using pairwise Tukey tests. LA supplementation did not affect (p 0.05) the ruminal variables under study. LA modified (p 0.05) ISDMD at 4 h in LA10, while no differences were found in terms of IVDMD among the treatments. The LA dose of 10 mg kg-1 BW increased CB (p 0.05) and decreased TB (p 0.05). TBARS differed (p 0.01) among the treatments and evaluation periods and were higher (p 0.05) 15 d after administration. In conclusion, LA supplementation in sheep had an antioxidant effect, reducing oxidative stress 15 d after administration, with slight differences in the ruminal variables evaluated.

The effects of a nutritional packet (live yeast, vitamins C and B1, and electrolytes) offered to steers in a calf-fed system on growth performance, nutrient digestion, feeding behavior, carcass characteristics, and ruminal variables.

Effects of a nutritional packet strategically offered to calf-fed system steers on growth performance, nutrient digestibility, feeding behavior, ruminal variables, and carcass characteristics were evaluated. Angus crossbred steer-calves (N = 60; body weight [BW] = 234 ± 4 kg) were used in a randomized complete block design (block = BW) and stratified into two treatments: 1) control; and 2) 30 g/steer-daily (dry matter [DM] basis) of a nutritional packet containing (steer-daily basis): Live yeast (Saccharomyces cerevisiae; 1.7 × 1010 CFU), vitamin C (Ascorbic acid, 162 mg), vitamin B1 (thiamin hydrochloride, 400 mg), sodium chloride (2.4 g), and potassium chloride (2.4 g). Animals were offered (electronic feed-bunks [SmartFeed, C-Lock Inc., Rapid City, SD]), a steam-flaked corn-based finishing diet to ad libitum (individual intake), once daily for 233 d. Treatments were offered during the first and last 60 days on feed (DOF). The GLIMMIX procedure of SAS was used, with steer as the experimental unit, treatment and phase (for feeding behavior and digestibility) as fixed effects, and BW-block as a random effect. Steers offered the nutritional packet had 14% less (P < 0.01) intake and 18% greater (P = 0.01) feed efficiency during the initial 30 DOF. Intake (days 0 to 233) was 6% greater (P = 0.02) for steers offered the nutritional packet, while BW gain was not different (P ≥ 0.44). Greater (P = 0.02) dressing percent (61.1% vs. 62%) for steers offered the packet was observed, while other carcass variables were not different (P ≥ 0.33). Digestibility of DM, organic matter, and fiber were greater (P < 0.01) for steers offered the packet. Steers offered the packet spent 13% less time eating during the first 60 DOF, while during the last 60 DOF a 14% greater meal frequency and 12.3% smaller mean meal size (treatment × phase interaction, P < 0.02) were observed. Steers offered the packet had a reduced (P ≤ 0.01) mean meal duration during both phases. Regardless of treatment, a decreased rumination (P ≤ 0.03) and chewing (P ≤ 0.01) activities were observed for the last 60 DOF compared to the first 60 DOF. Ruminal papillae area was 30% greater (P = 0.02) and the total volatile fatty acid (VFA) tended (P = 0.09) to be greater for steers offered the nutritional packet. The nutritional packet offered to calf-fed steers improved feed efficiency during the initial 30 d after arrival, while inducing superior overall intake, nutrient digestibility, dressing percentage, ruminal papillae area, and total ruminal VFA.

342 Effects of Direct fed Microbial Mixtures on Beef Cattle Ruminal Fermentation Characteristics, Intake, and Nutrient Digestibility

Abstract Direct fed microbials (DFM) dietary mixture effects on beef cattle ruminal variables, intake, and apparent total tract digestibility were evaluated. Six ruminally cannulated beef steers (BW = 520 ± 30 kg) were used in a duplicated 3 × 3 Latin square design and offered a steam-flaked corn-based finishing diet ad libitum for three 28-d periods (21-d adaptation and 7-d collection). Treatments assigned were: 1) Control (no DFM mixture; lactose only); 2 and 3) DFM mixtures at distinct concentrations [Mixture A and B, at 2 g/animal-daily (lactose used as carrier)]. Ruminal pH and temperature were measured every 6 min (wireless probes). Ruminal samples were collected at 0, 2, 4, 8, 16, and 23 h post-feeding on d28. Feed and fecal samples (collected once and twice daily, respectively) were composited by period and analyzed. Fecal output was estimated with a dietary internal marker (288-h indigestible-NDF). Data were analyzed using the GLIMMIX procedure of SAS. No treatment × time interactions (P ≥ 0.20) were observed. Steers offered mixture-A experienced 300 min/d less (P = 0.04) time under the ruminal pH 5.6, tended (P = 0.13) for a lesser area under the curve of ruminal pH 5.6, while showing a greater (P = 0.04) ruminal pH average (5.67 vs. 5.50), and tended (P = 0.06) for a lesser ruminal temperature (39.2 vs. 39.4°C) compared to control. The ruminal concentration of NH3-N was greater (P = 0.02) for mixture-A compared with control (10.78 vs. 4.35 mg/dL), while animals offered mixture-B tended (P = 0.07) to be greater (9.11 mg/dL) than control. Steers offered DFM mixture-A increased (P = 0.04) ADF digestibility compared with control (39.8 vs. 54.0%), while not affecting DM intake (P = 0.61). The DFM mixture-A induced a safer ruminal pH environment and encouraging fiber degradation and NH3-N release, while not affecting animal intake

Effect of Oregano (Lippia graveolens) Essential Oil as a Phytogenic Feed Additive on Productive Performance, Ruminal Fermentation, and Antioxidant Activity in Lamb Meat

The objective of this study was to evaluate the inclusion of oregano essential oil (OEO) as a phytogenic feed additive in the diet of lambs on the productive performance, ruminal pH, ammoniacal nitrogen production, volatile fatty acids, nitrogen balance, carcass yield, backfat thickness, loin eye (Longissimus dorsi) area, shelf life, and antioxidant activity of the meat. Thirty-nine Suffolk × Hampshire lambs (19 ± 3.7 kg live weight) were used in a completely randomized design with three treatments (n = 13) consisting of 0, 0.02, and 0.04% OEO in the diet. The inclusion of OEO in the diet did not affect (p &gt; 0.05) the productive performance due to the treatments; similarly, no differences (p &gt; 0.05) were observed in the ruminal variables and nitrogen balance. Backfat thickness and loin eye area had similar results (p &gt; 0.05), and the antioxidant activity in meat was improved (p &lt; 0.05) with the inclusion of OEO. Shelf life and crude protein content increased (p &lt; 0.05) with the inclusion of OEO in the diet and with the passing of storage days. Dry matter was affected (p &lt; 0.05) by the storage time, with a decrease observed on day 24. pH, ether extract, and ash were not affected (p &gt; 0.05). It is concluded that the productive performance, ruminal variables, nitrogen balance, loin eye area, backfat thickness, and carcass yield were not affected by the inclusion of OEO. However, crude protein remained stable and antioxidant activity improved, increasing the shelf life of lamb meat.

Use of Fecal Indices as a Non-Invasive Tool for Ruminal Activity Evaluation in Extensive Grazing Sheep.

For a simple, non-invasive evaluation of nutritional status of sheep kept under extensive grazing conditions on annual rangeland, fecal indices (2,6 diaminopimelic acid, nitrogen, and phosphorus) obtained during the vegetative, reproductive, and dry grassland phenological stages, were correlated with ruminal physiological biomarkers (volatile fatty acids and ruminal ammonia). Through correlation analysis and linear regressions, the degree of association between the variables studied was established. The fecal indices that presented the highest degree of association with ruminal variables were FN and FP, being highly correlated with the production of branched-chain volatile fatty acids (isobutyrate and isovalerate) and with ruminal ammonia (r ≥ 0.65), establishing simple linear regression equations of high significance (p ≤ 0.05). Therefore, fecal indices, especially fecal concentrations of N and P, could reflect the metabolism at the ruminal level and with it the availability of compounds for microbial growth, which would help to establish the nutritional status of sheep herds under extensive grazing conditions.

Selected ruminal variables and purine urinary excretion rate of steers subjected to feeding, fasting, and re-feeding conditions

The effects of feeding, fasting, and re-feeding on the ruminal profile of growing cattle were studied. Ruminal fluid and urine samples were obtained from 12 crossbred steers weighing approximately 300 kg during the following periods: 11 h of normal feeding (postprandial period), 48 consecutive hours of fasting, and followed by 48 h of re-feeding. Fasting promotes changes in the ruminal profile, such as an increase in ruminal pH, reduction in the number of rumen protozoa and bacteria, and decrease in the urinary excretion of allantoin; however, it does not change the urinary uric acid excretion rate. The overall mean ruminal pH was higher during fasting (7.53±0.27) in comparison to those at normal feeding (6.72±0.25) and re-feeding (6.62±0.31) (p⟨0.05). During re-feeding, the ruminal profile returned to normal, except for the protozoa count, which despite a slight increase only after 48 h of re-feeding, did not recover to baseline values.

Efeitos de antibióticos promotores de crescimento e do concentrado sobre o consumo, digestibilidade, degradabilidade e variáveis ruminais de novilhos de corte

ABSTRACT The objective of this study was to evaluate the addition of antibiotic growth promoters to concentrate on intake, digestibility, in situ degradability and ruminal variables in steers. Four steers in a Latin square design were fed hay (ad libitum), concentrate [10g kg-1 of body weight (BW)] and mineral mix (0.272g kg-1 of BW). The additives (0.75mg kg-1 of BW) were incorporated in the mineral mix as follows: Control (no antibiotics), lasalocid (LASA), salinomycin (SALI) or virginiamycin (VIRG). Antibiotic did not affect intake, pH, volatile fatty acids (VFA) and digestibility of dry matter (DM), organic matter, crude protein, ethereal extract, and non-fibrous carbohydrates. The LASA and SALI tended (P=0.09) to reduce the digestibility of neutral detergent fiber (NDF). The SALI and VIRG tended (P=0.09) to reduce the DM disappearance, and VIRG tended (P=0.06) to reduce the NDF disappearance in the rumen. The SALI and VIRG reduced the effective degradation and only SALI reduced the concentration of N-NH3 in the rumen. Thus, the antibiotics did not affect intake, pH, VFA and digestibility, but decreased the degradation of fiber and only SALI reduced the concentration of ammonia nitrogen (N-NH3) in the rumen.

Nutritive value of sorghum silage for sheep.

This study compared ensiled sorghum (ES) from two varieties (first and second cuts) with corn silage (CS) for chemical analysis, total-tract nutrient digestibility, ruminal variables and blood biochemistry metabolites in sheep. Five experimental silages representing first cut ES var. Pegah (PS1), second cut ES var. Pegah (PS2), first cut ES var. Speedfeed (SS1), second cut ES var. Speedfeed (SS2) and CS were assessed for chemical analysis, silage fermentation and anti-quality compounds. Diets consisted of lucerne hay, silage and a premix (at the ratio of 53.5:46:0.5 on a dry matter [DM] basis). Feed consumption, total-tract nutrient digestibility, microbial nitrogen supply (MNS), ruminal variables and blood biochemistry metabolites were determined in a Latin square design of five periods with five male sheep. Compared to sorghum, CS had lower (p<0.01) concentrations of ash, water-soluble carbohydrates and crude protein, but higher starch, lignin (sa), non-structural carbohydrates and apparent nutrient digestibility. The measurements of pH, lactic acid, NH3 -N and volatile fatty acids (VFA) confirmed that all silages were well-preserved. The anti-quality compound levels in the silages were below the safe limits for ruminants. No differences were observed in feed consumption (p>0.05) and total-tract digestibility of DM and nutrients (p>0.05). Rumen pH, NH3 -N, VFA concentrations and acetate to propionate ratio showed no difference among treatments (p>0.05). Sheep fed on sorghum silage showed a decrease (p<0.01) in total protozoa, and particularly in the Entodiniae population. There were no differences in cellulolytic bacteria counts (p>0.05) among treatments. Urinary N, MNS and blood biochemistry metabolites showed no difference among treatments (p>0.05). Silages from both cuts of sorghum had comparable total-tract nutrient digestibility to CS, therefore, these varieties could be used as a more drought resilient silage source in the feeding of sheep.

Variation in urea kinetics associated with ruminant species, dietary characteristics, and ruminal fermentation: A meta-analysis

The objective of this meta-analysis was to quantitatively summarize variations in urea kinetics related to ruminant species, diet composition, and ruminal fermentation. A database of 31 studies measuring urea recycling kinetics were used to derive 2 sets of linear mixed-effects regression models. Study was used as a random intercept and regressions were weighted by 1 divided by the standard error of the mean observation. Models were compared, when appropriated, using the concordance correlation coefficient, root estimated variance associated with study (σˆs) and error (σˆe) and corrected Akaike information criterion values. From a dietary standpoint, most response variables were affected by measures reflecting dietary crude protein [(CP; e.g., N-NH3 or rumen-degradable protein (RDP)] and by variables reflecting dietary energy content [e.g., total digestible nutrients (TDN), dietary starch, or ruminal pH]. Dietary CP, N-NH3, and TDN typically had positive slopes on urea N entry rate (UER; g/d and g/kg0.75), whereas starch and TDN/RDP had negative slopes on UER (g/kg0.75). On the other hand, increasing TDN increased gastrointestinal entry rate (GER; g/kg0.75), whereas an opposite effect was observed for RDP. Increasing diet RDP content reduced the urea N returned to ornithine cycle (ROC; g/kg0.75) in most models. Ruminal variables also reflected the importance of N and energy supplies. Ruminal ammonia concentration significantly affected ROC (g/d and g/kg0.75), used for anabolism (UUA; g/kg0.75), ROC:GER, UUA:GER, and the incorporation of recycled urea N into microbial N relative to gastrointestinal entry rate of urea. Ruminal pH significantly affected GER:UER and ROC:GER ratios. Total digestible nutrients had a positive slope on UUA (g/kg0.75). Increasing the ratio of energy to protein (TDN:RDP) increased the GER:UER ratio, decreased the ROC:GER ratio, and increased the UUA:GER ratio and the incorporation of recycled urea N into microbial N relative to gastrointestinal entry rate of urea N. Comparison among models revealed that species was an important explanatory variable affecting most response variables. However, whether these differences are related to the intrinsic N metabolism of each species or due to the diet variation remains unclear. Understanding these differences could lead to improvements in N use efficiency in ruminant diets by formulating more precise low-N diets considering the particularities for each species.

Effects of diet fermentability and supplementation of 2-hydroxy-4-(methylthio)-butanoic acid and isoacids on milk fat depression: 2. Ruminal fermentation, fatty acid, and bacterial community structure

The experiment was conducted to understand ruminal effects of diet modification during moderate milk fat depression (MFD) and ruminal effects of 2-hydroxy-4-(methylthio)-butanoic acid (HMTBa) and isoacids on alleviating MFD. Five ruminally cannulated cows were used in a 5 × 5 Latin square design with the following 5 dietary treatments (dry matter basis): a high-forage and low-starch control diet with 1.5% safflower oil (HF-C); a low-forage and high-starch control diet with 1.5% safflower oil (LF-C); the LF-C diet supplemented with HMTBa (0.11%; 28 g/d; LF-HMTBa); the LF-C diet supplemented with isoacids [(IA) 0.24%; 60 g/d; LF-IA]; and the LF-C diet supplemented with HMTBa and IA (LF-COMB). The experiment consisted of 5 periods with 21 d per period (14-d diet adaptation and 7-d sampling). Ruminal samples were collected to determine fermentation characteristics (0, 1, 3, and 6 h after feeding), long-chain fatty acid (FA) profile (6 h after feeding), and bacterial community structure by analyzing 16S gene amplicon sequences (3 h after feeding). Data were analyzed using the MIXED procedure of SAS (SAS Institute Inc., Cary, NC) in a Latin square design. Preplanned comparisons between HF-C and LF-C were conducted, and the main effects of HMTBa and IA and their interaction within the LF diets were examined. The LF-C diet decreased ruminal pH and the ratio of acetate to propionate, with no major changes detected in ruminal FA profile compared with HF-C. The α-diversity for LF-C was lower compared with HF-C, and β-diversity also differed between LF-C and HF-C. The relative abundance of bacterial phyla and genera associated indirectly with fiber degradation was influenced by LF-C versus HF-C. As the main effect of HMTBa within the LF diets, HMTBa increased the ratio of acetate to propionate and butyrate molar proportion. Ruminal saturated FA were increased and unsaturated FA concentration were decreased by HMTBa, with minimal changes detected in ruminal bacterial diversity and community. As the main effect of IA, IA supplementation increased ruminal concentration of all branched-chain volatile FA and valerate and increased the percentage of trans-10 C18 isomers in total FA. In addition, α-diversity and the number of functional features were increased for IA. Changes in the abundances of bacterial phyla and genera were minimal for IA. Interactions between HMTBa and IA were observed for ruminal variables and some bacterial taxa abundances. In conclusion, increasing diet fermentability (LF-C vs. HF-C) influenced rumen fermentation and bacterial community structure without major changes in FA profile. Supplementation of HMTBa increased biohydrogenation capacity, and supplemental IA increased bacterial diversity, possibly alleviating MFD. The combination of HMTBa and IA had no associative effects in the rumen and need further studies to understand the interactive mechanism.

Inclusion of concentrate and growth promoters additives in sheep diets on intake, digestibility, degradability, ruminal variables and nitrogen balance

This study evaluated the inclusion of concentrate and monensin, salinomycin and flavomycin in sheep diets on intake, digestibility, in situ degradability, ruminal variables and nitrogen balance. Five sheep in a latin square received the treatments: HAY (hay only), CONT (hay + concentrate), MON (hay + concentrate + monensin), SALI (hay + concentrate + salinomycin), and FLAV (hay + concentrate + flavomycin). Hay was offered ad libitum , concentrate, 20 g kg -1 of body weight (BW), and additives, 0.75 mg kg -1 of BW. The treatments with the concentrate (CONT, MON, SALI and FLAV) showed increased ( P ≤0.05) on intake, digestibility, total VFA, propionate and butyrate proportions, N-NH 3 , and nitrogen balance, and decreased ( P ≤0.05) DM and NDF degradability, acetate proportion, acetate:propionate ratio, and rumen pH compared to the HAY. The comparison between the outcome effects from additives with the CONT showed that the acetate proportion and acetate:propionate ratio was only reduced by MON ( P ≤0.05). MON and SALI increased ( P ≤0.05) the propionate proportion. The proportion of butyrate was increased with the inclusion of FLAV and reduced with MON and SALI. Only MON reduced the production of N-NH 3 ( P ≤0.05). Other variables showed no effects from additives ( P >0.05) in relation to the CONT. The inclusion of the concentrate in sheep diets caused alterations on intake, digestibility, ruminal variables (VFA, pH, and N-NH 3 ) and nitrogen balance. However, the additives only altered the ruminal variables (VFA and N-NH 3 ) and the greatest effects were observed with MON.

Protein-energy supplementation frequency on ruminal variables, intake and digestibility in steers receiving low quality hay

Abstract The aim was evaluated the effect of reduce in protein-energy supplementation frequency on nutrients intake, forage digestibility and degradability, as well as, ruminal pH and ammonia nitrogen (N-NH3) concentration in beef cattle receiving low-quality hay. A 4 x 4 Latin square design were used. Four steers were fed with low-quality hay and subjected to four treatments: no supplementation (control); protein-energy supplementation with 0.82% of body weight (BW) offered three times per week (3WK); 0.49% of BW offered five times a week (5 WK), and 0.35% of BW offered seven times per week (7 WK). The use of protein-energy supplementation increased intake of dry matter (DM), crude protein (CP), neutral detergent fiber (NDF), ether extract (EE), non-fibrous carbohydrates (NFC) and the digestibility coefficients of CP, EE, and NFC. However, no differences in DM and NDF degradation visit the website to get the how were observed between treatments in the evaluated hay. Supplementation did not alter ruminal pH, but the N-NH3 concentration was highest in treatment 7WK. Reduction in protein-energy supplementation frequency of daily to 3WK or 5WK does not negatively affect intake, digestibility and degradability of nutrients in beef cattle receiving low quality hay.

Effects of lactic acid bacteria inoculants and fibrolytic enzymes on the fermentation quality, in vitro degradability, ruminal variables and microbial communities of high‐moisture alfalfa silage

AbstractThe silage additives not only influence the fermentation quality of silages, but may have positive effects on animal performance by affecting the ruminal fermentation. This study was conducted to determine the effect of lactic acid bacteria (LAB) inoculants, either alone or in combination with fibrolytic enzymes on the fermentation quality, and ruminal nutrients degradability, fermentation profile and microbial communities of high‐moisture alfalfa silage. Alfalfa (206 g dry matter [DM]/kg fresh matter) was ensiled in laboratory‐scale silos with four experimental variants: (a) deionized water (Control); (b) LAB inoculants (Lactobacillus plantarum and Pediococcus pentosaceus combination; I); (c) fibrolytic enzymes (cellulase and hemicellulase enzymes combination; E); (d) a mixture of I and E (IE). All silos were opened after 45 days for determining the silage quality. Further, the four experimental silages were used to measure in vitro rumen degradability, fermentation profile and bacterial populations by fermenting with buffered rumen fluid. The addition of I stimulated a more efficient homofermentation of high‐moisture alfalfa silage than in the variants without I, as evidenced by higher lactic‐to‐acetic acid ratios and lower DM losses, and IE addition further enhanced the homofermentation. Compared to the Control, the addition of E increased the proteolysis, and decreased in vitro degradability of DM (IVDMD) and crude protein of DM (IVCPD) as well as in vitro gas production of 48 hr (GP48). The addition of I reduced the proteolysis and methane production, and increased the IVDMD, IVCPD, GP48, ruminal short‐chain fatty acids concentrations and microbial protein production. The populations of Genus Prevotella were higher in silages produced with I, but lower with E than the Control. The data suggested that the addition of LAB inoculants alone or together with fibrolytic enzymes could improve the fermentation quality and nutritive value of high‐moisture alfalfa silage.

Meta-analysis of postruminal microbial nitrogen flows in dairy cattle. I. Derivation of equations.

The objective was to summarize the literature and derive equations that relate the chemical composition of diet and rumen characteristics to the intestinal supply of microbial nitrogen (MicN), efficiency of microbial protein synthesis (EMPS), and flow of nonammonia nonmicrobial N (NANMN). In this study, 619 treatment means from 183 trials were assembled for dairy cattle sampled from the duodenum or omasum. Backward elimination multiple regression was used to derive equations to estimate flow of nitrogenous components over a large range of dietary conditions. An intercept shift for sample location revealed that omasal sampling estimated greater MicN flow relative to duodenal sampling, but sample location did not interact with any other variables tested. The ruminal outflow of MicN was positively associated with dry matter intake (DMI) and with dietary starch percentage at a decreasing rate (quadratic response). Also, MicN was associated with DMI and rumen-degraded starch and neutral detergent fiber (NDF). When rumen measurements were included, ruminal pH and ammonia-N were negatively related to MicN flow along with a strong positive association with ruminal isovalerate molar proportion. When evaluating these variables with EMPS, isovalerate interacted with ammonia such that the slope for EMPS with increasing isovalerate increased as ammonia-N concentration decreased. A similar equation with isobutyrate confirms the importance of branched-chain volatile fatty acids to increase growth rate and therefore assimilation of ammonia-N into microbial protein. The ruminal outflow of NANMN could be predicted by dietary NDF and crude protein percentages, which also interacted. This result is probably associated with neutral detergent insoluble N contamination of NDF in certain rumen-undegradable protein sources. Because NANMN is calculated by subtracting MicN, sample location was inversely related compared with the MicN equation, and omasal sampling underestimated NANMN relative to duodenal sampling. As in the MicN equation, sampling location did not interact with any other variables tested for NANMN. Equations derived from dietary nutrient composition are robust across dietary conditions and could be used for prediction in protein supply-requirement models. These empirical equations were supported by more mechanistic equations based on the ruminal carbohydrate degradation and ruminal variables related to dietary rumen degradable protein.

Influences of growth stage and nitrogen fertilizer on chemical composition, phenolics, in situ degradability and in vitro ruminal variables in amaranth forage

This study was carried out to assess the influences of growth stage (early flowering or milk stage of kernels) and nitrogen (N) fertilizer level (120, 180 or 240kg of N/ha) on the chemical composition, phenolic compounds, in situ degradability and in vitro ruminal fermentation variables in amaranth forage (Amaranthus hypochondriacus). The study was conducted as split plot arrangement based on randomized complete block design with four replicates of two samples each. Chemical composition, in situ degradability of dry matter (DM) and crude protein (CP), gas production (GP) and in vitro ruminal fermentation variables were determined. Data were analyzed using GLM procedure of SAS. The concentrations of DM, CP, ash-free neutral detergent fiber (NDFom), total phenolics (TP), and effective degradability (ED) of DM and CP were respectively 159g/kg fresh weight, 224, 346 and 13.4g/kg DM, and 767g/kg DM and 810g/kg CP for the amaranth harvested at early flowering and fertilized with 120kgN/ha (treatment 1). In vitro organic matter (OM) disappearance (OMD), 24-h partitioning factor (PF24), microbial CP (MCP), methane production, pH, ammonia-N, volatile fatty acids (VFA), protozoa and cellulolytic bacteria were 686g/kg OM, 4.36mg/mL, 201mg/g DM, 35.5mL/g degraded DM, 10.2mg/dL, 68.3mmol/L, 6.82×105/mL and 8.09 log10/g digesta, respectively, for treatment 1. With advancing the amaranth growth stage, the concentrations of DM, OM, NDFom, EE and TP increased, but CP, soluble and very rapidly degradable fraction (fraction ‘A’) and ED reduced (P<0.05). Rising N fertilization caused a linear increase of the DM, CP, fraction ‘A’ and ED (P<0.05). With increasing the plant age, the in vitro ruminal GP, OMD, PF24, MCP, ammonia-N, VFA and cellulolytic bacteria decreased (P<0.05), but methane production, per g degraded DM, increased (P<0.05). The values of in vitro GP, OMD, VFA and cellulolytic bacteria increased linearly as N fertilization enhanced (P<0.05). In vitro ruminal pH, ammonia-N and protozoa were not affected by fertilization. Overall, increasing amaranth age decreased CP, degradability, in vitro ruminal VFA and MCP, but increased lignin(sa), phenolics and methane production per g of degraded substrate. Increasing N fertilization enhanced the forage quality at both growth stages. Thus, the decrease of amaranth quality in second growth stage can be reduced by increasing N fertilization. Though, the effect of growth stage on the forage quality was more pronounced than the effect of N fertilization.

Effect of abomasal infusion of oligofructose on portal-drained visceral ammonia and urea-nitrogen fluxes in lactating Holstein cows

The effects of abomasal infusion of oligofructose in lactating dairy cows on the relationship between hindgut fermentation and N metabolism, and its effects on NH3 absorption and transfer of blood urea-N across the portal-drained viscera versus ruminal epithelia were investigated. Nine lactating Holstein cows fitted with ruminal cannulas and permanent indwelling catheters in major splanchnic blood vessels were used in an unbalanced crossover design with 14-d periods. Treatments were continuous abomasal infusion of water or 1,500g/d of oligofructose. The same basal diet was fed with both treatments. Eight sample sets of arterial, portal, hepatic, and ruminal vein blood, ruminal fluid, and urine were obtained at 0.5h before the morning feeding and at 0.5, 1.5, 2.5, 3.5, 4.5, 5.5, and 6.5h after feeding. It was hypothesized that an increased supply of fermentable substrate to the hindgut would increase the uptake of urea-N from blood to the hindgut at the expense of urea-N uptake to the forestomach. The study showed that abomasal oligofructose infusion decreased the total amount of urea-N transferred from the blood to the gut, NH3 absorption, and arterial blood urea-N concentration. Subsequently, hepatic NH3 uptake and urea-N production also decreased with oligofructose infusion. Additionally, urea-N concentration in milk and urinary N excretion decreased with oligofructose treatment. The oligofructose infusion did not affect ruminal NH3 concentrations or any other ruminal variables, nor did it affect ruminal venous − arterial concentration differences for urea-N and NH3. The oligofructose treatment did not affect milk yield, but did decrease apparent digestibility of OM, N, and starch. Nitrogen excreted in the feces was greater with the oligofructose infusion. In conclusion, the present data suggest that increased hindgut fermentation did not upregulate urea-N transfer to the hindgut at the expense of urea-N uptake by the rumen, and the observed reduction in arterial blood urea-N concentration appeared not to be due to increased urea-N transport, but rather could be explained by reduced NH3 input to hepatic urea-N synthesis caused by increased sequestration of NH3 in the hindgut and excretion in feces. Increasing the hindgut fermentation in lactating dairy cows by abomasal infusion of 1,500g/d of oligofructose shifted some N excretion from the urine to feces and possibly reduced manure NH3 volatilization without impairing rumen fermentation.

Effect of calcium propionate and sorghum level on lamb performance

The objective of this experiment was to evaluate the effect of calcium propionate and grain level on performance and ruminal variables in 32 finishing Criollo lambs (28.14±2.34kg initial BW) over 42 days. A completely randomized design was used with a factorial arrangement of treatments with either 550 or 650g grain and 0 or 10g calcium propionate per kg diet. All diets contained corn grain 200 and molasses 100g/kg diet. Sorghum grain levels were 350 or 450g/kg diet, replacing corn stover. No differences were observed in intake, gain or feed conversion among treatments. Rib eye area increased with 650g/kg grain (P<0.05). Ruminal pH was not affected by treatments. Ruminal acetate concentration decreased with more grain (P<0.005). It was concluded that Ca propionate could be used to partially replace the energy usually supplied by grain in diets for finishing lambs.