Ruminal Volatile Fatty Acids Research Articles

Ruminal and Intermediary Metabolism of Propylene Glycol in Lactating Holstein Cows

Four lactating Holstein cows fitted with ruminal cannulas and permanent indwelling catheters in the mesenteric artery, mesenteric vein, hepatic portal vein, and hepatic vein were used in a cross-over design to study the metabolism of propylene glycol (PG). Each cow received 2 treatments: control (no infusion) and infusion of 650g of PG into the rumen at the time of the morning feeding. Propylene glycol was infused on the day of sampling only. Samples of arterial, portal, and hepatic blood as well as ruminal fluid were obtained at 0.5h before feeding and at 0.5, 1.5, 2.5, 3.5, 5, 7, 9, and 11h after feeding. Infusion of PG did not affect ruminal pH or the total concentration of ruminal volatile fatty acids, but did decrease the molar proportion of ruminal acetate. The ruminal concentrations of PG, propanol, and propanal as well as the molar proportion of propionate increased with PG infusion. The plasma concentrations of PG, ethanol, propanol, propanal, glucose, l-lactate, propionate, and insulin increased with PG and the plasma concentrations of acetate and β-hydroxybutyrate decreased. The net portal flux of PG, propanol, and propanal increased with PG. The hepatic uptake of PG was equivalent to 19% of the intraruminal dose. When cows were dosed with PG, the hepatic extraction of PG was between 0 and 10% depending on the plasma concentration of PG, explaining the slow decrease in arterial PG. The increased net hepatic flux of l-lactate with PG could account for the entire hepatic uptake of PG, which suggests that the primary hepatic pathway for PG is oxidation to l-lactate. The hepatic uptake of propanol increased with PG, but no effects of PG on the net hepatic and net splanchnic flux of glucose were observed. Despite no effect of PG on net portal flux and net hepatic flux of propionate, the net splanchnic flux of propionate increased and the data suggest that propionate produced from hepatic metabolism of propanol is partly released to the blood. The data suggest that PG affects metabolism of the cows by 2 modes of action: 1) increased supply of l-lactate and propionate to gluconeogenesis and 2) insulin resistance of peripheral tissues induced by increased concentrations of PG and propanol as well as a decreased ratio of ketogenic to glucogenic metabolites in arterial blood plasma.

Establishment and Development of Ruminal Hydrogenotrophs in Methanogen-Free Lambs

The aim of this work was to determine whether reductive acetogenesis can provide an alternative to methanogenesis in the rumen. Gnotobiotic lambs were inoculated with a functional rumen microbiota lacking methanogens and reared to maturity on a fibrous diet. Lambs with a methanogen-free rumen grew well, and the feed intake and ruminal volatile fatty acid concentrations for lambs lacking ruminal methanogens were lower but not markedly dissimilar from those for conventional lambs reared on the same diet. A high population density (10(7) to 10(8) cells g(-1)) of ruminal acetogens slowly developed in methanogen-free lambs. Sulfate- and fumarate-reducing bacteria were present, but their population densities were highly variable. In methanogen-free lambs, the hydrogen capture from fermentation was low (28 to 46%) in comparison with that in lambs containing ruminal methanogens (>90%). Reductive acetogenesis was not a significant part of ruminal fermentation in conventional lambs but contributed 21 to 25% to the fermentation in methanogen-free meroxenic animals. Ruminal H(2) utilization was lower in lambs lacking ruminal methanogens, but when a methanogen-free lamb was inoculated with a methanogen, the ruminal H(2) utilization was similar to that in conventional lambs. H(2) utilization in lambs containing a normal ruminal microflora was age dependent and increased with the animal age. The animal age effect was less marked in lambs lacking ruminal methanogens. Addition of fumarate to rumen contents from methanogen-free lambs increased H(2) utilization. These findings provide the first evidence from animal studies that reductive acetogens can sustain a functional rumen and replace methanogens as a sink for H(2) in the rumen.

Use of compartmental analysis to study ruminal volatile fatty acid metabolism under steady state conditions in Holstein heifers

Four rumen-cannulated Holstein heifers were used to quantify volatile fatty acid (VFA) kinetics in the rumen using 13C stable isotopes. Heifers were fed either a low (L) or high (H) concentrate diet with level of concentrate of 250 or 700 g/kg dry matter, respectively. Isotopic tracers, Na-1- 13C-acetate (Ac), -propionate (Pr), or -butyrate (Bu) were infused as a bolus into the rumen. Three days prior to sampling, cows were fed equal meals every 4 h for 2 days followed by 2 h feeding intervals 1 day prior to and on the day of sampling. The rumen was sampled 26 times (3 times prior to tracer infusion; background samples and 23 times during 8 h after tracer infusion). Isotopic enrichment was expressed as Tracer/(Tracee + Tracer) or F value. F values were corrected for skewness and graphed against time. A three-compartment model was adequate to describe VFA kinetics in the rumen. It was estimated that there was a flux of Ac to the Pr pool [0.05 g/min (L) versus 0.03 g/min (H)], resulting in an average conversion fraction of Ac to Pr of 0.051 in both groups. The model predicted that the fraction of Ac which contributed to the Pr pool was 0.198 (L) versus 0.145 (H). Although the fraction of the Ac conversion to Bu ranged from 0.367 (L) to 0.448 (H), only a small fraction [0.0137 (L) and 0.0160 (H)] of the Bu was converted to Ac. A major portion of the Bu was coming from Ac in both diet groups. The portion of Bu coming from Ac in the rumen varied between 0.95 and 0.65 in (L) and (H) diets, respectively. Turnover time of all VFA was calculated to be longer in H. Results indicate that Ac and Bu exchange, and that Ac contributes to the Pr pool. However, Pr does not contribute to the Ac or Bu pools. This study demonstrates the usefulness of 13C isotopes to study VFA kinetics and metabolism in cattle.

Effects of Different Protein Supplements on Milk Production and Nutrient Utilization in Lactating Dairy Cows

Sixteen (8 ruminally cannulated) multiparous and 8 primiparous lactating Holstein cows were used in 6 replicated 4×4 Latin squares to test the effects of feeding supplemental protein as urea, solvent soybean meal (SSBM), cottonseed meal (CSM), or canola meal (CM) on milk production, nutrient utilization, and ruminal metabolism. All diets contained (% of DM) 21% alfalfa silage and 35% corn silage plus 1) 2% urea plus 41% high-moisture shelled corn (HMSC), 2) 12% SSBM plus 31% HMSC, 3) 14% CSM plus 29% HMSC, or 4) 16% CM plus 27% HMSC. Crude protein was equal across diets, averaging 16.6%. Intake and production were substantially reduced, and milk urea, blood urea, and ruminal ammonia were increased on urea vs. the diets supplemented with true protein. Although intake was lower in cows fed SSBM compared with CM, no differences were observed for milk yield among SSBM, CSM, and CM. Yields of fat and protein both were lower on CSM than on CM, whereas SSBM was intermediate. Milk urea and milk protein contents also decreased when CSM replaced SSBM or CM. Diet did not affect ruminal volatile fatty acids except that isobutyrate concentration was lowest on urea, intermediate on CSM, and greatest on SSBM and CM. Urinary excretion of urea N and total N was greatest on urea, intermediate on SSBM and CM, and lowest on CSM. Apparent N efficiency (milk N/N intake) was lower on the CSM diet than on the SSBM diet. Overall, production and N utilization were compromised when the diets of high-yielding dairy cows were supplemented with urea rather than true protein and the value of the true proteins, from most to least effective, was in the order CM > SSBM > CSM.

Dynamic model of the lactating dairy cow metabolism

The whole-animal model described in this paper is intended to be a research model with an intermediary structure between sophisticated and simple cow models. The mechanistic model structure integrates the main metabolic pathways of the lactating dairy cow. Milk yield and related feed intake for varying production potentials were considered to be the driving forces and were empirically defined. The model was designed to explain the main metabolic flows and variations in body reserves associated with the push of nutrients from dry matter intake and their pull by the mammary gland to synthesise milk components throughout lactation. The digestive part of the model uses either known feed unit systems (e.g. PDI system for protein) or published empirical equations for the prediction of digestive flows of organic matter, starch and fatty acids and ruminal volatile fatty acid production. The metabolic sub-system is made up of four tissue compartments (body protein, body lipid, protein in the uterus and triglycerides in the liver) and five circulating metabolites (glucose, amino acids, acetate + butyrate, propionate, and triglycerides and non-esterified fatty acids). A major original aspect of the model is its homeorhetic control system. It was assumed that flows relating to adipose and protein tissue anabolism and catabolism were driven by a couple of linked theoretical hormones controlling mobilisation and anabolism. The evolution in body composition and body weight were outcomes of this control. Another originality of the model is its suitability for milk yields varying from 10 to 50 kg at peak production. This was achieved by homeorhetic control of milk potential acting on several key metabolic flows. Homeostatic regulation was also introduced in order to confine the behaviour of the model within realistic physiological values. For some basic aspects (e.g. Uterine involution, standard kinetics of body protein and fat), it was necessary to build specific databases from the literature and interpret these by meta-analysis. Fairly realistic simulated kinetics were obtained for body composition, liver triglycerides, blood plasma metabolite concentrations, milk protein and fat contents, and also for major groups of milk fatty acids.

Dose effect of live yeasts on rumen microbial communities and fermentations during butyric latent acidosis in sheep: new type of interaction

AbstractSix ruminal cannulated Texel sheep were used to assess the dose response and the effect of live yeasts (Levucell® SC, Saccharomyces cerevisiae CNCM I-1077) on the prevention of induced ruminal latent acidosis. The sheep received, in a replicated 3×3 Latin-square design, an acidotic diet (wheat +lucerne hay, 60:40 (dry matter (DM) basis); starch: 410 g/kg DM) without yeast (control group; L0 treatment), supplemented with 0·2 g/day yeast (4×109colony-forming units (c.f.u.) per day corresponding to producer recommendations; L1 treatment) or with 2 g/day yeast (4×1010c.f.u. per day; L10 treatment). The following measurements were carried out: food intake, ruminal pH, ruminal volatile fatty acids (VFA), lactate and ammonia (NH3) concentrations, protozoal and lactate-utilizing bacterial counts, relative proportions of two main bacteria implicated in lactate metabolism (a lactate-producing species, Streptococcus bovis, and a lactate-utilizing species, Megasphaera elsdenii) using specific 16S-rRNA-targeting oligonucleotide probes, activities of lactate dehydrogenase (LDH) and of polysaccharidases involved in plant cell wall (xylanase, carboxymethylcellulase) and starch (amylase) degradation. The acidotic diet (L0) induced a butyric (12 mol per 100 mol total VFA) rather than lactic (<4 mmol/l) ruminal latent acidosis. Ruminal pH, fermentative patterns, lactate-metabolizing bacteria (concentration, LDH activity) and polysaccharidase activities were similar between treatments (P>0·1). Yeast supplementation tended to increase ruminal protozoal population (P<0·1) and intake of animals (P<0·1). The recommended yeast concentration (L1) was sufficient to ensure these effects. The yeast's action may differ according to the nature and function of the micro-organisms involved and the type of fermentative pattern favoured (protozoa/butyrate v. lactate-metabolizing bacteria/lactate and propionate) during ruminal acidosis in sheep.

A revised CNCPS feed carbohydrate fractionation scheme for formulating rations for ruminants

Balancing ruminant diets for appropriate levels and types of dietary carbohydrates (CHO) is necessary to maximize production while assuring the health of the animals. Several feed fractions ( i.e., volatile fatty acids (VFA), lactate, sugars, starch) are now being measured in some commercial feed laboratories and this information may assist in better formulating diets. A CHO fractionation scheme based on ruminal degradation characteristics needed for nutritional models is described and its impact on predictions with the Cornell Net Carbohydrate and Protein System (CNCPS) is assessed. Dietary CHO are divided into eight fractions: the CA1 is volatile fatty acids (VFA), CA2 is lactic acid, CA3 is other organic acids, CA4 is sugars, CB1 is starch, CB2 is soluble fiber, CB3 is available neutral detergent fiber (NDF), and CC is unavailable NDF. A Monte Carlo analysis was conducted with an example lactating dairy cow ration to compare the original CNCPS CHO scheme (CA = sugars and organic acids, CB1 = starch and soluble fiber, CB2 = available NDF, CC = unavailable NDF) with the developed CHO scheme. A database was used to obtain distributions and correlations of the feed inputs used in the schemes for the ingredients of the ration (corn and grass silages, high moisture corn, soybean meal, and distillers’ grains). The CHO fractions varied in a decreasing order as VFAs, soluble fiber, lactic acid, sugar, NDF, starch, and total non-fiber carbohydrates (NFC). Use of the expanded scheme in the CNCPS decreased the microbial CP production, which was sensitive (standard regression coefficient in parenthesis) to corn silage starch (0.55), grass silage NDF rate (0.46), high moisture corn grain starch rate (0.44), and corn silage NDF rate (0.33). Predicted ruminal NFC digestibility remained similar. The expanded CHO scheme provides a more appropriate feed description to account for variation in changes in silage quality and diet NFC composition. However, to fully account for differences in feed CHO utilization, further improvements in the methodology used to estimate the fractions and their corresponding degradation rates, inclusion of dietary factors in dry matter intake predictions, and prediction of ruminal VFA production and pH are necessary.

Influence of Corn Steep Liquor on Feeding Value of Urea Treated Wheat Straw in Buffaloes Fed at Restricted Diets

Influence of different levels of corn steep liquor (CSL) on chemical composition of urea treated wheat straw (UTWS), ruminal characteristics, digestion kinetics, nitrogen (N) utilization, and nutrient digestibility by ruminally-cannulated buffalo bulls was studied in a 4×4 Latin Square Design. The CSL was used to ensile 5% UTWS at the rate of 0, 3, 6, and 9% on a dry matter (DM) basis. Total N and neutral detergent fibre (NDF) were increased with increasing level of CSL. Increased NDF content was attributable to increased neutral detergent insoluble nitrogen. Four diets were formulated to contain 20% concentrate and 80% UTWS ensiled with 0, (control), 3 (CSL3), 6 (CSL6), and 9% CSL (CSL9). All diets were mixed daily and fed at 1.5% of body weight twice daily. Ruminal NH3 concentration decreased with level of CSL used to ensile UTWS at 3 and 6 h post prandial, however, at 9 h post parandial it was similar across all diets and at 12 h post prandial was higher with diets containing UTWS ensiled with CSL. Concentrations of total ruminal volatile fatty acid and acetate were increased with the CSL level used to ensile UTWS. Increased rate of disappearance and reduction in lag time of DM and NDF was recorded with diets containing UTWS ensiled with CSL. Dry matter and NDF digestibilities were higher with CSL diets than on the control diet. Buffalo bulls retained more N with diets containing UTWS ensiled with CSL. The present results indicated that UTWS could be ensiled with CSL to improve its nutritive value and N utilization by ruminants. (Key Words : Urea, Corn Steep Liquor, Wheat Straw, Digestibility, Digestion Kinetics, Nitrogen Balance, Buffalo)

Effects of Weaning and Ionophore Supplementation on Selected Blood Metabolites and Growth in Dairy Calves

Dairy calf weaning results in blood ketone concentrations in excess of mature rates of use and can result in excretion of ketones in urine representing a loss of energy. Lasalocid is frequently supplemented as an anticoccidial agent in calf starters; however, in mature ruminants it is known to alter molar ratios of ruminal volatile fatty acids (VFA). Effects of weaning transition and postweaning ionophore supplementation on body weight, dry matter (DM) intake, average daily gain (ADG), and blood concentrations of glucose, acetoacetate, β-hydroxybutyrate (BHBA), lactate, pyruvate, nonesterified fatty acids (NEFA), VFA, insulin, and glucagon were examined using Jersey bull calves (n=24) over 16 wk. Calves were blocked into groups of 2 according to birth date and weight and randomly assigned to receive either a commercial pelleted starter (control), or the same diet containing lasalocid (TRT; 83mg/kg of DM). Calves were fed milk replacer from d 3 to 34 (d 3 to 20=454g/d at 12% solids; d 21 to 34=568g/d at 15% solids), from d 35 to 48 calves received both replacer (d 35 to 41=454g/d; d 42 to 38=227g/d) and free access to control or TRT starter, and from d 49 to 112 received ad libitum control or TRT. Body weight and jugular blood metabolite concentrations were measured and recorded weekly. Postweaning DM intake, average daily gain, and feed:gain did not differ between control and TRT calves. Glucose and NEFA concentrations did not differ between control and TRT, but declined with age. Insulin and glucagon concentrations did not differ between control and TRT, but glucagon concentrations increased with weaning. Total VFA significantly increased following introduction of solid feed at d 35 in both groups with an apparent 1-wk lag in TRT VFA increases compared with control. Jugular acetate and butyrate concentrations were greater in control calves than TRT calves during wk 7. Propionate concentrations did not differ between control and TRT at any time following weaning. Blood BHBA concentrations were greater in control than TRT during wk 8 and 9. Thus, consumption of starter supplemented with lasalocid delayed peak acetate and butyrate and lowered peak BHBA concentrations. However, supplementation at concentrations currently recommended for control of coccidiosis did not appear to be sufficient to enhance growth or efficiency during the wk 7 to 16 postweaning interval for this sample size.

Comparison of Techniques to Determine the Clearance of Ruminal Volatile Fatty Acids

The objective of this experiment was to compare measurements of fractional clearance rates obtained by using an unlabeled valerate-CoEDTA technique with measurements obtained by using a 13C-labeled volatile fatty acids (VFA) technique. The exponential decay rate of the 13C/12C ratio after pulse-dosing 13C-acetate, 13C-propionate, or 13C-butyrate into the rumen was compared with the decay rate of rumen valerate concentration following a simultaneous pulse dose. The unlabeled valerate, CoEDTA, and each labeled VFA, one at a time, were concurrently mixed with the evacuated ruminal content of 6 lactating cows in two 3×3 Latin squares. The clearance of VFA by passage to the omasum was assumed to be equivalent to the decay in ruminal Co concentration and was around 50% of the total clearance. Acetate, propionate, and butyrate had similar fractional clearance rates (31.2, 33.4, 30.4%/h, respectively), but propionate had a higher absorption rate (19.2%/h) than butyrate (14.2%/h). Linear regression determination coefficients using the valerate clearance rate as an estimator for acetate, propionate, and butyrate rumen clearance were 0.51, 0.56, and 0.99, respectively. In a second experiment, the 13C-valerate fractional clearance rate estimate (33.7%/h) was similar to the estimate obtained with unlabeled valerate (35.0%/h) by the valerate-Co technique. No 13C enrichment of rumen microbes was noted 4h after the intraruminal infusion of 13C-valerate. Fractional VFA absorption rate estimates obtained in both techniques were similar, although both were lower than estimates reported in the literature by other methods.

랜드레이스, 요크셔, 듀록 및 교잡종에 대한 도체 및 육질특성

본 실험은 alcohol 사료 처리에 따른 in vitro 발효 pattern의 변화를 검토하여 alcohol 사료 처리가 반추위내 발효 pattern에 미치는 영향을 규명코자 실시하였다. 시험구 처리는 배합사료를 첨가하는 대조구(control), 배합사료와 1, 3 및 5%의 alcohol 사료(Alcoholic feed; AF)를 첨가하는 처리구를 각각 AF-1구, AF-3구 및 AF-5구로 나누어 실시하였다. 배양 12시간 동안 ammonia 농도는 AF-1, AF-5구에서 대조구에 비해 낮았다(p<0.05). 배양액의 alcohol 농도는 alcohol 첨가 수준이 증가할수록 높았다(p<0.05). 배양 12시간에 TVFA 농도는 AF-1, AF-3 및 AF-5에서 대조구에 비해 현저히 높았다(p<0.05). 배양 8～12시간 사이에 acetate 비율은 대조구에서 빠른 속도로 감소하였으며, AF-1, AF-3 및 AF-5구에서는 일정한 수준을 유지하는 것으로 나타났다. Propionate 비율은 배양 8～12시간 사이에 AF-1, AF-3 및 AF-5에 비해 대조구에서 빠른 속도로 증가하였다(p<0.05). Butyrate 및 valerate 비율은 AF-1, AF-3 및 AF-5에서 대조구에 비해 높았다(p<0.05). Caproate 비율은 배양 8시간에 AF-1구, AF-3구 및 AF-5구에서 각각 0.05, 0.58 및 0.47M%로 나타났으나, 대조구에서는 검출되지 않았다. 본 실험의 결과에서 alcohol 사료의 처리는 in vitro 반추위액의 ammonia, alcohol 및 휘발성지방산 농도와 pH에 긍정적인 영향을 미치는 것으로 판단된다. 또한 본 실험의 결과에서는 5%의 alcohol 첨가 수준이 여타 alcohol 첨가 수준에 비해 반추위 발효에 보다 효과적인 것으로 사료된다. In this study, changes of ammonia, alcohol and volatile fatty acid(VFA) concentrations or pH in in vitro ruminal fluid were studied to determine the effects of alcoholic feeds on in vitro ruminal fermentation characteristics. To formulate the alcoholic feeds, alcohol was added to commercial formulated feed at the levels of 1, 3, and 5 %. Experiments were done with four treatment groups, control(commercial feed), AF-1(commercial feed+1% alcohol), AF-3(commercial feed+3% alcohol), and AF-5(commercial feed+5% alcohol). Ammonia concentrations of AF-1 and AF-5 were significantly lower than that of control for the 12h incubation(p<0.05). Ruminal alcohol concentration was increased with the addition level of alcohol increased(p<0.05). TVFA concentrations of AF-1, AF-3 and AF-5 were significantly higher than those of control at 12h(p<0.05). Significant decrease of molar percentage of acetate was observed in control from 8 to 12h incubation, but molar percentage of acetate for AF-1, AF-3 and AF-5 was constant. Molar percentage of propionate was increased in control compared with AF-1, AF-3 and AF-5 from 8 to 12h incubation(p<0.05). Molar percentages of butyrate and valerate were higher in AF-1, AF-3 and AF-5 than in control(p<0.05). Molar percentage of caproate for AF-1, AF-3 and AF-5 was 0.05, 0.58 and 0.47M% at 8h, respectively, but that was not detected for control. Present results may indicate that the alcoholic feeds show positive effects on in vitro ruminal ammonia, alcohol and VFA concentrations or pH. Furthermore, the results of this study implies that the addition level of 5% could be more effective to ruminal fermentation than other addition levels.

Alcohol 사료가 In vitro 반추위내 pH, Ammonia, Alcohol 및 Volatile Fatty Acids 농도에 미치는 영향

본 실험은 alcohol 사료 처리에 따른 in vitro 발효 pattern의 변화를 검토하여 alcohol 사료 처리가 반추위내 발효 pattern에 미치는 영향을 규명코자 실시하였다. 시험구 처리는 배합사료를 첨가하는 대조구(control), 배합사료와 1, 3 및 5%의 alcohol 사료(Alcoholic feed; AF)를 첨가하는 처리구를 각각 AF-1구, AF-3구 및 AF-5구로 나누어 실시하였다. 배양 12시간 동안 ammonia 농도는 AF-1, AF-5구에서 대조구에 비해 낮았다(p<0.05). 배양액의 alcohol 농도는 alcohol 첨가 수준이 증가할수록 높았다(p<0.05). 배양 12시간에 TVFA 농도는 AF-1, AF-3 및 AF-5에서 대조구에 비해 현저히 높았다(p<0.05). 배양 8～12시간 사이에 acetate 비율은 대조구에서 빠른 속도로 감소하였으며, AF-1, AF-3 및 AF-5구에서는 일정한 수준을 유지하는 것으로 나타났다. Propionate 비율은 배양 8～12시간 사이에 AF-1, AF-3 및 AF-5에 비해 대조구에서 빠른 속도로 증가하였다(p<0.05). Butyrate 및 valerate 비율은 AF-1, AF-3 및 AF-5에서 대조구에 비해 높았다(p<0.05). Caproate 비율은 배양 8시간에 AF-1구, AF-3구 및 AF-5구에서 각각 0.05, 0.58 및 0.47M%로 나타났으나, 대조구에서는 검출되지 않았다. 본 실험의 결과에서 alcohol 사료의 처리는 in vitro 반추위액의 ammonia, alcohol 및 휘발성지방산 농도와 pH에 긍정적인 영향을 미치는 것으로 판단된다. 또한 본 실험의 결과에서는 5%의 alcohol 첨가 수준이 여타 alcohol 첨가 수준에 비해 반추위 발효에 보다 효과적인 것으로 사료된다. In this study, changes of ammonia, alcohol and volatile fatty acid(VFA) concentrations or pH in in vitro ruminal fluid were studied to determine the effects of alcoholic feeds on in vitro ruminal fermentation characteristics. To formulate the alcoholic feeds, alcohol was added to commercial formulated feed at the levels of 1, 3, and 5 %. Experiments were done with four treatment groups, control(commercial feed), AF-1(commercial feed+1% alcohol), AF-3(commercial feed+3% alcohol), and AF-5(commercial feed+5% alcohol). Ammonia concentrations of AF-1 and AF-5 were significantly lower than that of control for the 12h incubation(p<0.05). Ruminal alcohol concentration was increased with the addition level of alcohol increased(p<0.05). TVFA concentrations of AF-1, AF-3 and AF-5 were significantly higher than those of control at 12h(p<0.05). Significant decrease of molar percentage of acetate was observed in control from 8 to 12h incubation, but molar percentage of acetate for AF-1, AF-3 and AF-5 was constant. Molar percentage of propionate was increased in control compared with AF-1, AF-3 and AF-5 from 8 to 12h incubation(p<0.05). Molar percentages of butyrate and valerate were higher in AF-1, AF-3 and AF-5 than in control(p<0.05). Molar percentage of caproate for AF-1, AF-3 and AF-5 was 0.05, 0.58 and 0.47M% at 8h, respectively, but that was not detected for control. Present results may indicate that the alcoholic feeds show positive effects on in vitro ruminal ammonia, alcohol and VFA concentrations or pH. Furthermore, the results of this study implies that the addition level of 5% could be more effective to ruminal fermentation than other addition levels.

Effects of dietary whole cottonseed and crude protein level on rumen protozoal population and fermentation parameters

In this investigation in vitro and in vivo trials were performed to determine the efficacy of a cottonseed to limit protozoal population and fermentation parameters. The composition of diets given to the different treatments were as follow: (1) control (without whole cottonseed), 16% crude protein (CP), 3.2% ether extract (E.E.); (2) 20% whole cottonseed, 16% CP, 6.5% E.E.; (3) 20% whole cottonseed, 13% CP, 6.4% E.E. and (4) 20% crushed whole cottonseed, 13% CP, 6.4% E.E. DM disappearance (DMD) and fermentation characteristics of the treatments were determined by in vitro incubation studies. In the in vivo trial, ruminal fluid was taken by rumenocentesis (3 h after feeding) on days 1, 3, 5, 7, 9, 11, 14, 21 and 28 from four sheep fed about treatment diets. The pH and protozoal counts were determined in each sample, while ammonia nitrogen and volatile fatty acid (VFA) were determined in samples taken on days 7, 14, 21 and 28. The in vitro DMD after 24 h incubation decreased ( p < 0.01) with the addition of cottonseed in diets 3 and 4 and DMD after 72 h incubation was highest ( p < 0.01) for the control diet. The fractional rate of gas production ( c) for the control and diet 2 was higher ( p < 0.05) than for the diets 3 and 4. Feeding crushed whole cottonseed decreased molar proportion of propionate ( p < 0.05) and increased molar proportion of butyrate ( p < 0.01). Low crude protein level increased the molar proportion of propionate ( p < 0.05) and decreased molar proportion of butyrate ( p < 0.05) and cellolytic protozoa population ( p < 0.05). Feeding cottonseed decreased ( p < 0.05) the total protozoa population from approximately 500,000 to 250,000 ml −1 and Holotrich and cellulolytic protozoa disappeared from the rumen of sheep and only Entodinium sp., remained. This was associated with lower concentration of ammonia nitrogen in rumen fluid of sheep fed diets 4 ( p < 0.05) and 2 ( p < 0.01). It was concluded that cottonseed reduced rumen fauna and ammonia nitrogen, but had no effect on ruminal VFA while the crushed whole cottonseed decreased molar proportion of isovalerate only. In vivo molar proportion of propionate and butyrate and valerate were increase and decrease, respectively, by decreasing CP percentage in treatment diets.

Effects of synchronizing starch and protein degradation in rumen on fermentation, nutrient utilization and total tract digestibility in sheep

The objective of this experiment was to investigate the effects of synchronizing the dietary starch and crude protein (CP) degradation in the rumen on nutrient utilization, fermentation, and total tract digestibility in sheep. The four diets were formulated with different rates of starch and CP release in the rumen but with similar metabolic energy, starch, and CP. The diets were slowly degradable starch, slowly degradable protein; slowly degradable starch, rapidly degradable protein; rapidly degradable starch, rapidly degradable protein; and rapidly degradable starch, slowly degradable protein. The diets were fed to four cannulated sheep ad libitum in two equal portions, using a 4x4 Latin square design.Dry matter intake (DM) was not influenced by either the rate of starch or protein degradation. There was no significant effect of dietary treatment on the digestibility of DM, organic matter, starch, CP, neutral detergent fiber or acid detergent fiber in the rumen and total tract. Ruminal pH was greater for sheep fed slowly degradable starch diets than rapidly degradable starch (P< 0.05). Ruminal total volatile fatty acid concentrations were not affected by treatments but the molar proportions of propionic acid were greater for sheep fed rapidly degradable starch diets than slowly degradable starch diets (P< 0.05). The ratios of acetic acid (A) to propionic acid (P) were higher for sheep fed slowly degradable starch diets than rapidly degradable starch diets (P< 0.05). Ruminal ammonia-N concentrations were not affected from the degradability characteristics of protein. Rumen pH and A:P were higher in diets containing slowly degradable starch than in diets rapidly degradable starch. Propionic acid was higher in diets containing rapidly degradable starch than in diets containing slowly degradable starch. Rumen fermentation and utilization of nutrients in the rumen affected starch degradability more than protein degradability. Synchronizing starch and protein degradation in rumen had no effect on the intake, digestibility of nutrients in sheep.

Fontes de lipídio e monensina sódica na fermentação, cinética e degradabilidade ruminal de bovinos

O objetivo deste trabalho foi avaliar a degradabilidade, a fermentação e a cinética ruminal de dietas com caroço de algodão ou sal de cálcio de ácidos graxos, como fontes de gordura, acrescidos de monensina sódica, e verificar o efeito da última em dietas com caroço de algodão. Quatro novilhos Nelore, canulados no rúmen, foram submetidos a um experimento em delineamento quadrado latino 4x4. Os tratamentos consistiram de três dietas com monensina (sal de cálcio graxo, caroço de algodão e controle) e uma dieta com caroço de algodão sem monensina. Os períodos de incubação foram de 0, 3, 6, 12, 24, 48, 72 e 96 horas, e o líquido ruminal foi colhido nos horários 0, 1,5, 2, 3, 4, 6, 8, 12 e 24 horas depois da alimentação. As dietas com caroço de algodão apresentaram maior degradabilidade da fibra em detergente neutro e maior teor de proteína bruta. A dieta com caroço de algodão e monensina apresentou maior taxa de passagem líquida e turnover ruminal. Não houve diferença entre as dietas quanto ao pH, amônia ruminal e ácidos graxos voláteis. As fontes de gordura, sal de cálcio de ácidos graxos e caroço de algodão não apresentaram efeito deletério no rúmen. A utilização de monensina afeta a degradabilidade, a cinética e a fermentação ruminal, quando se utiliza caroço de algodão na dieta.

Treated Extruded Soybean Meal as a Source of Fat and Protein for Dairy Cows

The influence of treated, extruded, partially expelled soybean meals as undegradable protein and bypass fat sources on lactation performance and ruminal fermentation of dairy cows was studied. Experiment 1: nine cows were used in a replicated 33 Latin square design with each period being 3 wk in duration. Cows were fed 440 g/kg forage and 560 g/kg grain diet with one of three extruded soybean meals fed at 110 g/kg of the diet. The 3 soybean meals were 1) twice-extruded soybean meal (ESM; as a control); 2) lignosulfonate-treated, twice-extruded soybean meal (LSM); and 3) calcium oxide plus lignosulfonate-treated, twice extruded soybean meal (CLSM). Experiment 2: 3 ruminally cannulated cows were used in a 33 Latin square to study the treatment influence on ruminal fermentation characteristics. Feeding treated soybean meal to cows in LSM and CLSM treatments did not improve feed intake, milk yield, or milk composition except that cows fed the LSM and CLSM treatments produced less milk protein compared with the ESM treatment. The proportion of was greater in milk fat of cows fed CLSM compared with that of cows fed the ESM or LSM treatments. Ruminal pH, ammonia, and total volatile fatty acids were not affected by treatment. An increased proportion of in milk fat suggests that there is a potential use of calcium salts of fatty acids in protecting the lipid portion of extruded soybean meal and further research is needed to explore this potential with full-fat extruded soybeans not with extruded and partially oil expelled soybeans.

Wet Corn Gluten Feed Fed Fresh or Stored and Supplemented with Rumen Undegradable Protein in the Diets of Lactating Dairy Cows

The main objective was to evaluate replacing fresh with long-term stored wet corn gluten feed (WCGF) in lactating cow diets and to evaluate added levels of rumen undegradable protein (RUP) to diets with WCGF. Twenty-four multiparous Holstein cows averaging 558 ± 45kg of BW and 57 ± 35 d in lactation were stratified by age, days in milk, and milk yield and assigned to one of four treatments: 1) fresh WCGF, 5.4% RUP DM; 2) stored WCGF, 5.4% RUP DM; 3) stored WCGF, 6.3% RUP DM, and 4) stored WCGF, 7.2% RUP DM. Total mixed rations containing 19% dietary DM as WCGF were formulated to be isonitrogenous (17.2% CP) and isoenergetic (7.20MJ NEl/kg of DM). The substitution of fresh WCGF as stored WCGF did not affect (P>0.10) milk yield or composition. Supplementing stored WCGF with RUP did not alter (P>0.10) actual or adjusted milk yield, but milk casein (P=0.03), fat (P=0.04), and total solids (P=0.03) increased in a linear fashion with increasing RUP supplementation. Ruminal ammonia concentration increased linearly (P<0.05), and total ruminal volatile fatty acid concentrations were similar among treatments; acetate increased (P<0.05), and butyrate decreased (P<0.05) with increasing levels of supplemental RUP. The WCGF may be stored for extended periods in an oxygen-limiting environment without reducing palatability or nutrient availability. Adding RUP may increase milk components when used in diets balanced for the nutrient demands of high producing dairy cows.

Nutrient Digestibility of Diets with Different Fiber to Starch Ratios when Fed to Lactating Dairy Cows

The objective of this experiment was to determine whether increasing the dietary neutral detergent fiber (NDF):starch ratio affected NDF digestibility when diets were formulated to have equal in situ NDF digestibility. Six lactating Holstein cows were fed 1 of 3 diets in a replicated 3×3 Latin square. All diets had 41.5% of the dry matter (DM) as corn silage but the concentration of corn grain varied from 23.3 to 34.8% and the NDF:starch ratios were 0.74, 0.95, and 1.27. As corn grain increased, the concentration of a mixture of 54% soyhulls and 46% cottonseed hulls decreased. The soyhull:cottonseed hull mixture had the same in situ NDF digestibility as the corn silage. All diets had 18% forage NDF but starch concentration varied from 25.4 to 33.3% and NDF varied from 24.7 to 32.2%. Intake tended to increase as the NDF:starch ratio increased. Total tract digestibility (measured by total collection of feces and urine) of dry matter and energy decreased linearly as the NDF:starch ratio increased, but NDF digestibility was not affected by treatment. Retention of N increased linearly as the NDF:starch ratio increased. As dietary NDF:starch ratio increased, ruminal pH was not affected, but the concentration of total volatile fatty acids (VFA) decreased and the VFA profile was altered by diet. Consistent with the observed changes in ruminal VFA, milk fat percentage increased with increasing dietary NDF:starch. Intake of digestible energy and output of energy in milk and body weight change was not affected by treatment.

Effect of Different Dietary Geometric Mean Particle Length and Particle Size Distribution of Oat Silage on Feeding Behavior and Productive Performance of Dairy Cattle

Twenty lactating Holstein cows (5 primiparous and 15 multiparous) were used in a 5×5 Latin Square design, with 5 treatments and 3 periods of 21 d each. Diets contained 25% corn silage, 25% oat silage, and 50% concentrate (dry matter basis). The 5 treatments tested in the experiment were long oat silage (LOS), medium oat silage (MOS), fine from long oat silage (FLOS), fine from medium oat silage (FMOS), and half LOS plus half FLOS (LFLOS). The geometric mean particle length (GMPL) of the diets was 6.68, 5.19, 4.46, 4.35, and 5.39mm for LOS, MOS, FLOS, FMOS, and LFLOS, respectively. The LFLOS was designed to provide dietary GMPL similar to MOS, but with a more bimodal particle size distribution (PSD). Linear and quadratic effects of GMPL were tested, based on the mean GMPL of the feed actually consumed (cGMPL). Contrasts were used to test for the effect of different PSD (MOS vs. LFLOS) and to test for differences between FMOS and FLOS, which would indicate unequal fermentations in the MOS and LOS silos. No differences were detected between FMOS and FLOS in most of the variables measured. Increasing cGMPL linearly decreased dry matter intake, milk production, and milk protein percentage and yield without affecting milk fat percentage, milk fat yield, ruminal pH, and ruminal volatile fatty acid concentration. Although cows fed diets with increasing cGMPL spent more time eating and chewing per day and per kilogram of dry matter intake, there was no effect of cGMPL on rumen pH. Feeding medium oat silage increased milk fat percentage and yield compared with feeding a mixture of long and fine oat silage.

Bioavailability of zinc from zinc sulfate and different organic zinc sources and their effects on ruminal volatile fatty acid proportions

Twenty-four Angus steers were used to determine the effects of dietary zinc (Zn) level and source on Zn metabolism and ruminal volatile fatty acid (VFA) patterns. All steers were fed a low Zn diet (18.8 mg Zn per kg) for 42 days prior to assignment to dietary treatments. Treatments consisted of: (1) control (low Zn diet), (2) Zn sulfate (ZnSO 4), (3) Zn methionine complex (ZnMet) and (4) Zn glycine complex (ZnGly). The Zn sources were added to provide 20 mg of supplemental Zn per kg diet. A 5-day total collection of feces and urine was conducted beginning on day 14 of the study. Liver biopsy samples were obtained on days 0 and 42 for Zn analysis, and ruminal fluid was collected on day 42 for VFA and ruminal soluble Zn determination. Plasma samples were obtained on days 0, 2, 19, 21, and 42 for determination of plasma Zn and alkaline phosphatase activity. Urinary excretion of Zn was higher ( P<0.05) in steers supplemented with ZnMet or ZnGly than in controls. Apparent absorption and retention of Zn were not significantly affected by treatment, but tended to be higher in steers receiving ZnGly. Liver Zn concentrations were higher ( P<0.05) on day 42 in steers supplemented with ZnGly, compared to steers receiving control, ZnMet or ZnSO 4 treatments. Plasma Zn concentrations were higher ( P<0.05) for the ZnGly and ZnMet treatments compared to the control on day 42. Plasma alkaline phosphatase was not affected by treatment. Ruminal soluble Zn concentrations were higher ( P<0.05) in steers fed ZnMet compared to those fed the control or ZnSO 4 diets. Total VFA concentrations were higher ( P<0.05) in steers fed the control and ZnSO 4 treatments than in those receiving ZnGly or ZnMet. Steers supplemented with ZnMet had a higher ( P<0.05) molar proportion of propionate and lower ( P<0.05) molar proportions of butyrate and valerate than controls. Compared to the control treatment, valerate was the only VFA affected by ZnSO 4 or ZnGly supplementation. Results suggest that Zn from ZnGly was more bioavailable than ZnSO 4 or ZnMet. However, ZnMet supplementation resulted in the highest ruminal soluble Zn concentrations and altered ruminal VFA proportions to the greatest extent of the Zn sources evaluated.