Rumen Volatile Fatty Acid Concentrations Research Articles

Digestion, nitrogen excretion and rumen microbial communities in beef cattle, and in vitro methane output, of fresh temperate grass with or without citrus pulp supplementation

The effects of supplementing grass with a high-energy, low-protein concentrate on intake, rumen fermentation, rumen microbial communities, apparent total tract digestibility and N-balance in beef cattle, and rumen fermentation and methane output in vitro, were studied. Sixteen Charolais steers (mean live weight (s.d.) 564 (24.3) kg)), were used in a completely randomised block design experiment, and offered either zero-grazed perennial ryegrass (Lolium perenne L.) ad libitum (GO), or the same grass with 2.25 kg citrus pulp dry matter (DM) daily (GCP). During the measurement phase, DM intake was restricted at 0.85 of their pre-determined intake. The same diets were incubated in an eight-vessel RUSITEC system. Supplementation decreased grass DM intake (6.59 vs. 7.54 kg/d) but increased total DM intake by 0.95 kg/d (P < 0.01). Rumen pH (P = 0.05) and NH3 concentration (P < 0.05) decreased, and total volatile fatty acid (VFA) concentrations (P < 0.01), molar proportions of propionate (P = 0.08) and butyrate (P < 0.05) increased for GCP compared to GO. Supplementation significantly altered the overall rumen microbial community structure compared to GO, driven principally by changes in relative abundance of Prevotella, Methoanobrevibacter and Lachnospiraceae genera. Plasma urea concentration was lower (P < 0.05) for GCP than GO. There was no effect (P > 0.10) of supplementation on apparent total tract digestibility of DM, OM and ADFom, but aNDFom digestibility tended to be lower (P = 0.07) and crude protein (N × 6.25) digestibility was lower (P < 0.01) for GCP compared to GO. Nitrogen intake (200 g/d) did not differ (P > 0.05) between treatments. Faeces N loss was 9 g/d greater (P < 0.01), and urine (P < 0.01) and total (P < 0.05) N losses were 22 and 13 g/d lower, respectively, for GCP compared to GO. In terms of N-balance (g/kg N intake), faecal N excretion was greater and urinary N excretion was lower (P < 0.01) resulting in a greater N use efficiency (P = 0.06) for GCP than GO. In vitro rumen NH3 concentrations were lower (P < 0.01) for GCP compared to GO, whereas in vitro rumen pH, lactic acid, VFA concentrations and molar proportions, and methane and total gas output did not differ (P > 0.05) between treatments. Supplementing grass with a low-protein, high-energy feed may be a strategy to reduce urinary and total N excretion in beef cattle grazing temperate grass pasture.

Evaluation of the nutritive value of fermented corn grain for ruminants

ABSTRACT The study aimed to evaluate the nutritive value of fermented corn grain (FCG) for ruminants by in vitro and in vivo methods. Free-toxin FCG was evaluated alone or as an ingredient of feedlot diets replacing standard corn grain (SCG) by in vitro gas production technique and by nutritional and performance study using lamb as the animal model. FCG presented similar contents of dry matter (DM), crude protein (CP), neutral detergent fibre (NDF) and starch, but presented higher ash and lower density than SCG. When evaluated in vitro alone, FCG presented higher lag time and lower in vitro dry matter digestibility (IVDMD) than SCG, but as an ingredient of feedlot diets, FCG levels linearly decreased digestion rate and lag time, but linearly increased IVDMD. In an in vivo study, FCG levels had quadratic effects on the intake and digestibility of crude fat, increased feeding time, and decreased resting time of lambs. FCG levels did not affect rumen volatile fatty acid concentration and its profile but trended to linearly increase final body weight, average daily gain and carcase weight. Thus, mycotoxin-free fermented corn grain can be fed to feedlot lambs without negatively affecting the intake and digestibility of nutrients or animal performance.

Effects of Chromium Propionate and Calcium Propionate on Lactation Performance and Rumen Microbiota in Postpartum Heat-Stressed Holstein Dairy Cows.

Chromium propionate (Cr-Pro) and calcium propionate (Ca-Pro) are widely applied in dairy production, especially in the alleviation of heat stress (HS). HS can reduce the abundance of rumen microbiota and the lactation performance of dairy cows. The present work mainly focused on evaluating the effects of Cr-Pro and Ca-Pro on the performance, ruminal bacterial community, and stress of postpartum HS dairy cows as well as identifying the differences in their mechanisms. Fifteen multiparous postpartum Holstein cows with equivalent weights (694 ± 28 kg) and milk yields (41.2 ± 1.21 kg/day) were randomly divided into three groups: control (CON), Cr-Pro (CRPR), and Ca-Pro (CAPR). The control cows received the basal total mixed ration (TMR) diet, while the CRPR group received TMR with 3.13 g/day of Cr-Pro, and the CAPR group received TMR with 200 g/day of Ca-Pro. The rumen microbial 16S rRNA was sequenced using the Illumina NovaSeq platform along with the measurement of ruminal volatile fatty acids (VFAs) and milking performance. Cr-Pro and Ca-Pro improved lactation performance, increased the rumen VFA concentration, and altered the rumen microbiota of the HS dairy cows. Cr-Pro significantly improved the milk yield (p < 0.01). The richness and diversity of the microbial species significantly increased after feeding on Ca-Pro (p < 0.05). Gene function prediction revealed increased metabolic pathways and biological-synthesis-related function in the groups supplemented with Cr-Pro and Ca-Pro. Our results indicate that the application of Cr-Pro or Ca-Pro can provide relief for heat stress in dairy cows through different mechanisms, and a combination of both is recommended for optimal results in production.

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.

505 Late-Breaking: Ruminal Microbiota, Inflammation Cytokines, and Performance of High-yield Dairy Cows Supplemented with Saccharomyces Cerevisiae Culture

Abstract Dramatic increases in milk yields in recent decades have created challenges in terms of rumen pH and microbial health which ultimately impact dairy cow health. The objective of this study was to assess the effects on ruminal pH, Volatile Fatty Acid (VFA), microbiota, inflammation, and performance of high-yield dairy cows by supplementing Saccharomyces cerevisiae culture (SC). Forty Holstein cows were divided into two groups based on their milk yield, days of milk, and parity fed the same basal ration diet that did or did not contain 100 g of SC /cow per day. Individual dry matter intake (DMI) and milk yield were recorded each day. Rumen fluid and milk samples were collected after 2 hours of morning feeding at intervals of 15 days during the experiment period. The data showed that rumen pH was increased by 0.19 (P = 0.09) when SC was supplemented than no SC was provided. SC-supplemented cow consumed 0.28 kg (P &amp;lt; 0.05) extra DM/d. Those supplemented with SC produced 1.36 kg (P &amp;lt; 0.05) more milk/cow per day than did non-supplemented cows. Milk fat percentage was higher (4.11 vs. 3.96%) for cows receiving SC. There were no differences in milk protein percentage. Rumen fluid VFA concentration was not statistically affected by SC but was numerically higher acetic and lower propionic for supplemented cows. The blood of the SC group with lower inflammation cytokines and somatic cell count (SCC). SC-supplemented cows had a greater relative abundance of Prevotellaceae, Succinivibrionaceae, Fibrobacteraceae, Lactobacillaceae, and lower relative abundance of Spirochaetaceae, Methanobacteriaceae, Enterobacteriaceae than the unsupplemented cows. It had greater functions on xylanolysis, fermentation, cellulolysis in the rumen in terms of the KEGG function prediction analysis. This study demonstrated that high-yield lactation cows receiving supplemental SC produced more milk and potentially reduced the inflammation and enhanced rumen cellulolysis bacteria growth.

Changes in the In Vitro Ruminal Fermentation of Diets for Dairy Cows Based on Selected Sorghum Cultivars Compared to Maize, Rye and Grass Silage

An in vitro experiment was conducted to determine the impact of silage produced from selected varieties of sorghum on the microbial fermentation profile of cows’ ruminal fluid. To determine the main microbial fermentation products, ruminal fluid samples were obtained from Polish Holstein–Friesian cows. Serum bottles were filled with 80 mL of ruminal samples, and 1 g of one of the following substrates was added: corn silage (CS), grass silage (GS), rye silage (RS), sorghum silage (sweet) (SS1), sorghum silage (grain) (SS2) or sorghum silage (dual-purpose) (SS3). The serum bottles were flushed with CO2 and fermented for 8 and 24 h at 39 °C. After incubation, the obtained gas and rumen fluid were then analysed to determine the methane and volatile fatty acid (VFA) contents using gas chromatography. The use of sorghum silage (SS) resulted in a decrease in the total concentration VFA concentration in the ruminal fluid compared with the use of other silages, especially GS. Moreover, the ruminal fluid contained a lower molar proportion of propionic and butyric acids when SS was used compared with CS. The butyric acid proportion was higher in SS samples than in RS samples. The differences in chemical composition between sorghum varieties did not influence the rumen VFA concentration or profile. A decrease in gas production, but without effects on methanogenesis, was observed when SS was used compared with GS and CS. The analysis demonstrates the physiological processes of fermentation in the rumen, as evidenced by the products of microbial fermentation. The main advantage is that the addition of SS, irrespective of the plant variety, reduced fermentation gas production in the ruminal fluid compared with CS. The silage of the analyzed sorghum varieties may be used in the diets of dairy cows as a substitute for corn and grass silages.

Rumen volatile fatty acid molar proportions, rumen epithelial gene expression, and blood metabolite concentration responses to ruminally degradable starch and fiber supplies

The objective of this work was to characterize rumen volatile fatty acid (VFA) concentrations, rumen epithelial gene expression, and blood metabolite responses to diets with different starch and fiber sources. Six ruminally cannulated yearling Holstein heifers (body weight = 330 ± 11.3 kg) were arranged in a partially replicated Latin square experiment with 4 treatments consisting of different starch [barley (BAR) or corn (CRN)] and fiber [timothy hay (TH) or beet pulp (BP)] sources. Treatments were arranged as a 2 × 2 factorial. Beet pulp and TH were used to create relative changes in apparent ruminal fiber disappearance, whereas CRN and BAR were used to create relative changes in apparent ruminal starch disappearance. Each period consisted of 3 d of diet adaptation and 15 d of dietary treatment. In situ disappearance of fiber and starch were estimated from bags incubated in the rumen from d 10 to 14. From d 15 to 17, rumen fluid was collected every hour from 0500 to 2300 h. Rumen fluid samples were pooled by animal/period and analyzed for pH and VFA concentrations. On d 18, 60 to 80 papillae were biopsied from the epithelium and preserved for gene expression analysis. On d 18, one blood sample per heifer was collected from the coccygeal vessel. In situ ruminal starch disappearance rate (7.30 to 8.72%/h for BAR vs. 7.61 to 10.5%/h for CRN) and the extent of fiber disappearance (22.2 to 33.4% of DM for TH vs. 34.4 to 38.7% of DM for BP) were affected by starch and fiber source, respectively. Analysis of VFA molar proportions showed a shift from propionate to acetate, and valerate to isovalerate on TH diets compared with BP. Corn diets favored propionate over butyrate in comparison to BAR diets. Corn diets also had higher molar proportions of valerate. Expression of 1 gene (SLC9A3) were increased in BP diets and 2 genes (BDH1 and SLC16A4) tended to be increased in TH diets. Plasma acetate demonstrated a tendency for a starch by fiber interaction with BAR-BP diets having the highest plasma acetate, but other metabolites measured were not significant. These results suggest that TH has the greatest effect on shifts in VFA molar proportions and epithelial transporters, but does not demonstrate shifts in blood metabolite concentrations.

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.

Weaning Age Affects the Development of the Ruminal Bacterial and Archaeal Community in Hu Lambs During Early Life.

Weaning plays an important role in many animal processes, including the development of the rumen microbiota in ruminants. Attaining a better understanding of the development of the rumen microbial community at different weaning stages can aid the identification of the optimal weaning age. We investigated the effects of weaning age on ruminal bacterial and archaeal communities in Hu lambs. Thirty male Hu lambs were randomly assigned to two weaning-age groups: a group weaned at 30 days of age (W30) and a group weaned at 45 days of age (W45), with each group having five replicate pens. On the weaning day (day 30 for W30 and day 45 for W45) and at 5 days postweaning [day 35 for W30 (PW30) and day 50 for W45 (PW45)], one lamb from each replicate was randomly selected and sacrificed. Rumen contents were collected to examine the ruminal microbiota. Compared to W30, PW30 had a decreased relative abundance of Bacteroidetes. At genus level, the extended milk replacer feeding (W45 vs. W30) increased the relative abundance of Ruminococcus while decreased that of Prevotella and Dialister. Compared to W30, PW30 exhibited decreased relative abundances of Prevotella, Dialister and Bacteroides but an increased unclassified Coriobacteriaceae. No significant difference was noted in the detected archaeal taxa among the animals. The function “biosynthesis of secondary metabolites” was less predominant in PW30 than in W30, whereas the opposite held true for “metabolism of cofactors and vitamins.” Some bacterial genera were significantly correlated with rumen volatile fatty acid (VFA) concentration or other animal measures, including negative correlations between ruminal VFA concentration and unclassified Mogibacteriaceae and unclassified Veillonellaceae; positive correlations of ruminal papillae length with Fibrobacter and unclassified Lachnospiraceae, but negative correlations with Mitsuokella and Succiniclasticum; and negative correlations between plasma D-lactate concentration and Prevotella, unclassified Paraprevotellaceae, and Desulfovibrio. Our results revealed that the ruminal bacterial community underwent larger changes over time in lambs weaned at 30 days of age than in lambs weaned half a month later. Thus, extending milk replacer feeding to 45 days weaning was recommended from the perspective of the rumen microbial community in the Hu lamb industry.

Meat goat diet supplementation with crude glycerine: Ruminal fermentation metabolism, blood chemistry profile, animal performance and carcass traits.

The objective of this experiment was to determine the effects of feeding varying levels of crude glycerine (CG) on dry matter intake (DMI), animal performance, carcass traits and rumen volatile fatty acids (VFA) concentration in meat goats. Twenty-four intact male Boer goats (23.9±1.0kg initial BW and 4-5months of age) were randomly assigned to one of four experimental diets (n=6) containing 30% bermudagrass hay plus 70% concentrate mix with 0, 5, 10 or 15% CG in the diet on an as-fed basis, substituted for the corn portion of the concentrate. Feed offered and refusals were monitored daily for 84days. Goats were weighed at 28-days interval. Blood and rumen samples were collected on day 84. At the end of the 84-days feeding period, goats were harvested, and carcass characteristics measured. Feed intake, average daily gain (ADG), gain-to-feed ratio (G:F), carcass traits and VFA concentrations were analysed as a completely randomized design. The CG did not influence animal body weight (BW) changes, ADG and G:F ratio but tended to (p=0.06) decrease DMI. Molar per cent propionic acid increased linearly (p<0.05) with increasing CG. The acetate: propionate (A:P) ratio decreased (p<0.05) with increasing amounts of CG in the diet. The CG addition tended to increase (p=0.09) the longissimus muscle (LM area) in meat goats. In conclusion, CG can replace corn in diet for growing meat goats when fed up to 15% of diet, improving ruminal propionate concentration, but decreasing A:P ratio without affecting animal performance and carcass traits.

Differing planes of pre- and postweaning phase nutrition in Holstein heifers: I. Effects on feed intake, growth efficiency, and metabolic and development indicators

The objectives of this study were to determine the effects of pre- and postweaning planes of nutrition on feed and metabolizable energy (ME) intake, growth, concentrations of glucose, insulin, insulin-like growth factor 1 (IGF-1), and β-hydroxybutyrate (BHB) in blood and rumen volatile fatty acids (VFA) from birth to 25 wk of age in Holstein heifers. Heifer calves (n = 36) were randomly assigned to receive either a low (5 L/d of whole milk) or high (10 L/d of whole milk) preweaning plane of nutrition from 1 to 7 wk of age, and either a low (70% concentrate dry total mixed ration) or high (85% concentrate dry total mixed ration) postweaning plane of nutrition from 11 to 25 wk of age. From birth to 25 wk of age, feed intake was recorded daily, and body measures were obtained weekly. Circulating hormone and metabolite concentrations were measured biweekly and total ruminal VFA, fecal starch, and body condition were assessed monthly. Overall, average daily gain and body weight were greater for heifers offered increased planes of nutrition during both the pre- and postweaning phases. Heifers offered the high preweaning plane had greater milk intake (7.7 ± 0.1 vs. 4.5 ± 0.1 L/d) but lower starter intake (0.3 ± 0.04 vs. 0.7 ± 0.04 kg/d) during the preweaning phase than those offered the low plane. High preweaning plane heifers also had greater ME intake from wk 1 to 7, but less ME intake at wk 9 (5.3 ± 0.3 vs. 6.6 ± 0.2 Mcal/kg) than those offered the low plane. Furthermore, overall glucose (118.8 ± 2.9 vs. 110.1 ± 2.9 mg/dL) and IGF-1 (101.6 ± 3.6 vs. 75.9 ± 3.6 ng/mL) concentrations were greater for high versus low preweaning plane heifers, although circulating insulin and BHB did not differ between preweaning plane groups. However, heifers offered the high preweaning plane had reduced total rumen VFA concentrations compared with heifers offered the low plane in the preweaning phase (47.3 ± 2.0 vs. 55.6 ± 2.1 mM). During the postweaning phase, dry matter intake and ME were consistently greater in heifers offered the high postweaning plane. Overall insulin (2.0 ± 0.1 vs. 1.8 ± 0.1 ng/mL), glucose (97.1 ± 0.6 vs. 92.1 ± 0.6 ng/mL), IGF-1 (178.0 ± 4.8 vs. 155.8 ± 4.8 ng/mL), and BHB concentrations (8.8 ± 0.2 vs. 8.1 ± 0.2 ng/mL) were greater in heifers offered the high than the low postweaning plane. In addition, heifers offered the high postweaning plane had increased VFA concentrations in the postweaning phase (73.4 ± 1.3 vs. 63.9 ± 1.3 mM) compared with heifers offered the low postweaning plane. The results indicated that increasing the pre- and postweaning planes of nutrition along with energy levels positively influenced several indicators associated with heifer development before 25 wk of age. Nevertheless, there was limited interaction in growth and development indicators between the 2 phases.

Effects of fertiliser nitrogen rate to spring grass on apparent digestibility, nitrogen balance, ruminal fermentation and microbial nitrogen production in beef cattle and in vitro rumen fermentation and methane output

The effects of two fertiliser nitrogen (N) application rates - 15 (LN) or 80 (HN) kg N/ha - to Lolium perenne dominant swards in spring, on grass dry matter (DM) intake, digestion, rumen fermentation, microbial N production and N-balance in beef cattle, and in vitro fermentation and methane production were studied. Sixteen Charolais steers with a mean live weight (s.d.) of 475 (18.4) kg, were used in a completely randomised block design experiment and offered zero-grazed grass harvested 21-d post N application. The same grass was incubated in an eight-vessel RUSITEC in a completely randomised block design experiment. The HN treatment had a 540 kg/ha higher grass DM yield, and a 20 g/kg DM higher crude protein (CP) concentration compared to LN. There was no difference (P > 0.05) in DM intake, or in vivo DM, organic matter (OM) and N digestibility between treatments. Rumen fermentation variables pH, lactic acid, ammonia (NH3) and total volatile fatty acid (VFA) concentration were similar (P > 0.05) for both treatments. Nitrogen intake was 19 g/d higher (P < 0.05) for HN compared to LN. Total and urine N loss was 16 and 14 g/d greater (P < 0.05), respectively, for HN compared to LN, but faecal N loss did not differ (P > 0.05) between treatments. The quantity of N retained and N-use efficiency did not differ (P > 0.05) between LN and HN. Plasma urea concentration was 1 mmol/L greater (P < 0.05) for HN compared to LN. Estimated microbial N production was greater (P < 0.05) for HN compared to LN. In vitro NH3 concentrations were higher (P < 0.05) for HN compared to LN, whereas in vitro rumen pH, lactic acid and VFA concentrations and molar proportions did not differ (P > 0.05) between HN and LN. In vitro methane and total gas output were not different (P > 0.05) between treatments. Reducing fertiliser N application rate to grass in spring reduced total and urinary N excretion, which has environmental benefits, with no effects on in vitro methane output.

Molecular hydrogen produced by elemental magnesium inhibits rumen fermentation and enhances methanogenesis in dairy cows

Hydrogen is a key metabolite that connects microbial fermentation and methanogenesis in the rumen. This study was to investigate the effects of elevated H2 produced by elemental Mg on rumen fermentation and methanogenesis in dairy cows. Four nonlactating Chinese Holstein dairy cows were employed for this experiment in a replicated crossover design. The 2 dietary treatments included a basal diet supplemented with Mg(OH)2 (14.5 g/kg of feed dry matter) or elemental Mg (6.00 g/kg of feed dry matter). When compared with Mg(OH)2 treatment, cows fed diet with elemental Mg had similar rumen Mg2+ concentration, but higher rumen dissolved H2 and methane concentrations at 2.5 h after morning feeding. Also, elemental Mg supplementation decreased feed digestibility, rumen volatile fatty acid concentration, and relative abundance of group Ruminococcaceae_UCG-014, genus Bifidobacterium, and group Mollicutes_RF9, increased acetate to propionate ratio, succinate concentration, and abundance of family Christensenellaceae. Elemental Mg supplementation increased enteric CH4 emission, altered methanogen community with increased abundance of order Methanomassiliicoccales, 16S ribosomal RNA gene copies of methanogens, and order Methanobacteriales. In summary, the pulse of elevated dissolved H2 after feeding produced by elemental Mg inhibited rumen fermentation and feed digestibility by decreasing the abundance of carbohydrate-degrading bacteria, promoted H2 incorporation into succinate by increasing family Christensenellaceae and genus Bacteroidales_BS11, and increased H2 utilization for methanogenesis by favoring growth of methanogens.

Response of lactating Zaraibi goats fed with berseem and/or triticale forage on milk production, feed utilization and economic efficiency

Twenty eight female Zaraibi goats in 2nd, 3rd and 4th season of lactation with average body weight of 33.0 kg were divided randomly into 4 groups (7 does in each) to study the effect of substitution of berseem forage by triticale forage in diets of lactating Zaraibi goats on their performances for milk yield and composition. In addition, twelve Rahmani rams average body weight of 50 kg were used to evaluate the feeding value of tested diets. Half the crude protein (CP) requirements of lactating goats were covered from concentrate feed mixture (CFM) while other 50% of CP was covered from triticale forage in the first group (G1), mixture forage (50% triticale- 50% berseem) in the second group (G2), mixture forage (70% triticale- 30% berseem) in the third group (G3), and berseem forage in (G4). The obtained results showed that the dry matter (DM) percent of triticale was higher than berseem (16.50 vs. 13.98). Moreover, the ether extract (EE) and nitrogen free extract (NFE) were higher while CP and ash were lower in triticale forage than berseem. But, crude fiber (CF) was nearly similar in both forages. The daily dray mater intake (DMI) as g/ kg w0.75 and body weight (BW) tended to increase with mixture forage G2 (99.10 and 4.07, respectively) compared with G3(98.75 and 4.06, respectively) and G4 (95.27 and 3.91, respectively) and G1 (91.79 and 3.77, respectively). Ammonia-N (NH3-N) level and pH values tended to decrease in the rumen of Rahmani sheep fed triticale forage (G1) compared with other forages (G2, G3, and G4). Rumen volatile fatty acids (TVFA's) concentrations as well as microbial protein (MP) were higher with 50% triticale - 50% berseem than with other rations. The digestion coefficients of OM, CF and NFE were significantly improved with G2 and G3 compared with G1 and G4. The CP, DM and OM digestibility recorded the lowest values (P<0.05) with triticale forage. The total digestible nutrients (TDN) showed the higher estimates (P<0.05) with the mixture rations (G2 and G3), while digestible crude protein (DCP) was significantly higher with increasing berseem in the rations. Whereas, serum protein, albumin, globulin, urea-N and glucose did not significantly differed among the tested diets. Concerning milk production, the obtained data indicated that milk yield of Zaraibi goats was significantly (P<0.05) higher with mixture forage (1.350 kg/ h/ d) G2 and (1.310 kg/h/d) G3 compared with the other groups (1.230 and 1.260 for G1 and G4, respectively). The effect of experimental treatments on milk fat percentage was significant (P<0.05). While, other milk contain and milk quality parameters (such as pH value and acidity %) were not significant. Accordingly, it could be concluded that using mixture forage (triticale and berseem) in feeding Zaraibi goats has positive effect on feeding value, milk yield and milk composition as well as feed utilization efficiency. Triticale forage could be safety use in feeding Zaraibi goats as it is or mixed with berseem.

Lactation performance and rumen fermentation in dairy cows fed a diet with alfalfa hay replaced by corn stover and supplemented with molasses.

ObjectiveThe objective of current study was to investigate the lactation performance and rumen fermentation characteristics of dairy cows fed a diet with alfalfa hay replaced by corn stover but supplemented with molasses.MethodsSixteen Holstein cows in mid-lactation were randomly assigned to 1 of 2 dietary treatments: i) alfalfa based diet (AH), and ii) corn stover based diet supplemented with molasses (CSM). The experiment was conducted according to a 2×2 crossover design with 22-d each period, consisting of 17 d for adaptation and 5 d for data and samples collection.ResultsDry matter intake and milk yield were higher for cows fed AH than CSM (p<0.01). Milk protein content and nitrogen conversion were higher (p<0.05), while milk urea nitrogen was lower (p<0.01) for cows fed AH than CSM-fed cows. Contents of milk total solids, fat and lactose were not different between two groups (p>0.10). Total rumen volatile fatty acid concentration tended to be higher (p = 0.06) for cows fed AH than CSM-fed cows. Molar proportion of acetate was lower (p = 0.04), but valerate was higher (p = 0.02) in cows fed AH than CSM-fed cows. Rumen concentration of propionate, and isobutyrate, and ratio of acetate to propionate tended to be different (p<0.10) between two groups. The feed cost per kilogram of milk was lower in CSM than AH (p<0.01). No differences were found in feed efficiency and most plasma parameters tested (p>0.10).ConclusionIn comparison with AH diet, CSM diet could be fed to dairy cows without negative effect on feed efficiency, ruminal fermentation, but economically beneficial, indicating that CSM could be an alternative choice for dairy farms instead of AH to feed mid-lactation dairy cows.

Feeding processed soybean to mid-lactation Holstein cows: ingestive behaviour and rumen fermentation characteristics

The objective of this study was to evaluate the effects of roasted soybean (RSB), extruded soybean (ESB) and their equal blend (RSB + ESB) compared with soybean meal (SBM) on nutrient intake, feed preference, meal and rumination patterns, feeding and chewing behaviour and rumen fermentation characteristics of mid-lactation dairy cows. Eight Holstein dairy cows were used in a replicated 4 × 4 Latin square design with four 28-d periods. Cows received one of the four following experimental diets: (1) 13.88% of diet dry matter (DM) as SBM; (2) 15.22% of diet DM as RSB, (3) 15.55% of diet DM as ESB and (4) 7.69% RSB plus 7.69% ESB (RSB + ESB). Each experimental period consisted of a 21-d diet adaptation period and a 7-d data collection period. Meal patterns, including meal size and inter-meal interval, were not affected by the experimental diets and thereby DM intake was not different among diets. Sorting index was not different across dietary treatments but intake of particles retained on 1.18-mm sieve and on pan increased and decreased in both SBM and ESB as compared with RSB and RSB + ESM, respectively. Total time spent eating and ruminating and rumen volatile fatty acid concentrations were unaffected by dietary treatments. Feeding processed soybean instead of SBM had minimal effects on sorting behaviour and meal patterns and thereby no changes in feed intake occurred. Finally, RSB and ESB and their equal blend had a similar effect on feed intake and chewing behaviour of mid-lactation Holstein cows.HighlightsFeeding processed soybean products had the minor effect on feed intake and can be considered as alternative feedstuffs when the price is competitive.

Investigation of rumen fermentation parameters and some blood metabolites of dromedary camels fed with C3 and C4 forages.

The aim of this experiment was to investigate rumen fermentation and some blood parameters of dromedary camels fed with C3 and C4 forage. Four fistulated dromedary adult camels were fed with diets as a changeover design, 30 days for each period. The diets included alfalfa hay + wheat straw (C3 forage) and atriplex+ suaeda + seidlitzia (C4 forage). At the end of the experiment, rumen and blood parameters, gas production of wheat straw and atriplex as a 2 × 2 factorial experiment were determined. The highest blood glucose and urea nitrogen levels were found for camels fed with C3 forage, 2 hr after feeding (p < 0.05). The maximum NH3-N concentration in the rumen was for diets C3 and C4, 2 and 4 hr after feeding (p < 0.05). The lowest rumen pH was observed for C3 diet at 2 and 4 hr and for C4 diet at 4 and 8 hr after feeding. The activity of rumen carboxymethylcellulase (CMCase) and microcrystalline cellulase (MCCase) enzymes was the highest for C3 and C4 diets, 8 hr after feeding, however, during feeding the enzyme activity in C4 was higher than that of 2 hr (p < 0.05). The rumen volatile fatty acid (VFA) concentrations were significantly higher in camels fed C3 forage in comparison with C4 (p < 0.05). The results showed that the gas production potential was significantly higher in treatments containing atriplex, however, the gas production rate was higher in treatment containing wheat straw (p < 0.05). The results suggested that for camels maintained in closed systems, the replacement of C3 forages instead of C4 could be possible and useful.

Composition of Rumen Bacterial Community in Dairy Cows With Different Levels of Somatic Cell Counts.

Mastitis is an inflammatory disease, affects the dairy industry and has a severe economic impact. During subclinical mastitis, milk production and milk quality deteriorates. Recently, rumen microbial composition has been linked to rumen health, but few studies have investigated the effect of rumen microbiota on mammary health in cows. This study was undertaken to identify the rumen microbial composition and associated microbial fermentation in cows with different somatic cell counts (SCC), with the speculation that cows with different health statuses of the mammary gland have different rumen bacterial composition and diversity. A total of 319 Holstein dairy cows fed the same diet and under the same management were selected and divided into four groups as SCC1 (N = 175), SCC2 (N = 49), SCC3 (N = 49), and SCC4 (N = 46) with < 200,000, 200,001–500,000, 500,001–1,000,000, and >1,000,000 somatic cells/mL, respectively. Further, 20 cows with the lowest SCC and 20 cows with the highest SCC were identified. The rumen microbial composition was profiled using 16S rRNA sequencing, along with measurement of rumen fermentation parameters and milking performance. Compared to low SCC, cows with high SCC showed poorer milk yield, milk composition, and rumen volatile fatty acids concentration, but higher rumen bacterial diversity. Although the predominant rumen bacterial taxa did not vary among the SCC groups, the relative abundance of phyla SR1 and Actinobacteria, unclassified family Clostridiales and genus Butyrivibrio were significantly different. In addition, Proteobacteria and family Succinivibrionaceae were enriched in cows with low SCC. Our results suggest that specific rumen microbes are altered in cows with high SCC.

Effects of field pea supplementation on digestibility and rumen volatile fatty acid concentrations of beef-cattle diets containing high and low quality forages

ABSTRACT Field peas (Pisum sativum) are increasingly available with limited data on the effects on forage digestibility. Two experiments were conducted to determine the effects of field pea supplementation in forage-based diets on total-tract digestibility and RUP digestibility in growing beef cattle. In Exp. 1, 5 ruminally fistulated steers (202 kg) were used in a 2 × 3 factorial. The first factor was high quality forage (50% alfalfa, 50% sorghum silage) or low quality forage (50% bromegrass hay, 50% wheat straw). The second factor was supplement type: a nonsupplemented control (CON), dry-rolled corn (DRC), or ground field peas (FP), supplemented at 0.43% of BW. Each diet was fed for 14 d. There were no interactions between forage quality and supplement type for digestibility estimates (P ≥ 0.25). Intake and digestibility of OM were greater with high quality forage (4.96 kg/d and 64.2%, respectively) than with low quality forage (3.60 kg/d and 50.1%, respectively; P

Effect of supplemental dietary slow-release urea on growth performance and physiological status of dairy heifers.

We examined the effect of supplemental dietary slow-release urea on the growth performance and physiological status of 16 dairy Holstein heifers (10months of age, 322±10kg). The heifers were offered a formulated isocaloric and isonitrogenous 70:30 roughage:concentrate ration and were assigned randomly to one of four levels of slow-release urea supplementation (0% [U0 ], 1% [U1 ], 1.5% [U1.5 ] and 2% [U2 ] dry matter [DM]). The total study lasted 95days, which included a 20days adaptation period. Dry matter intake (DMI) of U2 was lower than the intakes of U0 and U1 (p<.05), while average daily gains (ADG) of U1 and U1.5 were higher than U0 and U2 (p<.05). Rumen volatile fatty acids concentration did not differ among the four treatments, while ammonia nitrogen concentration increased with an increase in urea level (p<.05). Serum blood urea nitrogen concentration was lower in U1.5 than in U0 and U2 while serum free fatty acids concentration in U2 was higher than in the other three treatments (p<.05). We concluded that the addition of urea at a level of 1.5 to 2.0% DM resulted in a reduction in DMI but the addition of 1.0%-1.5% urea resulted in the highest ADG, with no negative effects on rumen fermentation and health status of the calves.