Ruminal Cannulas Research Articles

A comparison of post-ruminal provision of Ca-gluconate and Ca-butyrate on growth performance, gastrointestinal barrier function, short-chain fatty acid absorption, intestinal histology, and brush-border enzyme activity in beef heifers.

The objective of this study was to compare the effects of post-ruminal provision of Ca-butyrate (CaB) when delivered via abomasal dosing, and Ca-gluconate (CaG) when provided ruminally using a rumen protected form or using an unprotected form via abomasal dosing on short-chain fatty acid (SCFA) concentration throughout the GIT, nutrient digestibility, GIT barrier function, ruminal SCFA absorption, ruminal morphometrics, intestinal brush border enzyme activity, and blood parameters for beef heifers. Thirty-two beef heifers fitted with ruminal cannulas were used in a randomized complete block design and assigned to one of four treatments: 1) negative control (ruminal infusion of double-distilled water; CON); 2) abomasal infusion of CaB (AB; 0.0029% of BW); 3) abomasal infusion of CaG (AG; 0.0077% of BW); and 4) ruminal infusion of a hydrogenated fat-embedded CaG (RG; 0.0192% of BW) to provide ruminal protection. Excluding CON, treatments were designed to deliver the same amount of butyrate in the small intestine. Heifers were housed in individual pens and DMI was limited to 95% of voluntary intake to minimize a potential confounding effect of DMI on treatment responses. Total GIT barrier function was assessed on day 17 and SCFA disappearance was evaluated on day 21 using the temporarily isolated and washed reticulo-rumen technique. On day 28, heifers were slaughtered, and ruminal and colonic digesta were collected to assess SCFA concentration. Additionally, ruminal, jejunal, and colonic tissues were collected to assess SCFA fluxes and regional barrier function ex vivo using the Ussing chamber technique. For colonic digesta, both AB and CaG treatments reduced the proportion of acetate (P < 0.05) and increased the proportion on propionate (P < 0.05) compared to CON. Relative to CON, AB but not CaG treatments increased in vivo ruminal disappearance of total SCFA (P = 0.01), acetate (P = 0.03), propionate (P = 0.01), and butyrate (P > 0.01). Treatments did not affect (P ≥ 0.10) acetate and butyrate fluxes in the ruminal and colonic tissues when measured ex vivo; however, when compared with CON, AB tended to decrease (P = 0.09) mannitol flux across ruminal tissue. In addition, mannitol flux was affected (P < 0.01) by region, with greater mannitol flux across the jejunum than rumen and colon. We conclude that while both abomasal infusion of CaB and CaG affect the molar proportion of acetate and propionate in the colon, only abomasal CaB stimulated ruminal SCFA absorption for growing beef heifers.

Influence of supplemental flavomycin on growth performance, carcass characteristics, and nutrient digestibility in calf-fed Holstein steers.

The objective of this study was to evaluate the influence of supplemental flavomycin on cattle growth performance, carcass characteristics, diet digestibility, and ruminal fermentation characteristics of calf-fed Holstein steers. One hundred Holstein steers (123 ± 7 kg) were balanced by weight and assigned to 20 pens. Dietary treatments consisted of a steam flaked corn-based diet supplemented with (dry matter basis): 1) control, no feed additive; 2) 6.6 mg/kg flavomycin; 3) 13.2 mg/kg flavomycin, and 4) 30 mg/kg monensin (MON). There were no treatment effects (P ≥ 0.17) on live weight, average daily gain (ADG), and gain efficiency. Flavomycin did not affect dry matter intake (DMI; P ≥ 0.24). Flavomycin supplementation did not affect (P ≥ 0.37) the ratio of observed vs. expected DMI. However, MON decreased (P = 0.02) observed vs. expected DMI by 3.7%. There were no treatment effects (P ≥ 0.44) on ruminal pH or temperature. Flavomycin did not affect (P ≥ 0.13) carcass characteristics and liver abscess among steers. Four Holstein steers (463 ± 20 kg) with ruminal cannulas were used in 4 × 4 Latin square experiment to study treatment effects on site and extent of digestion, ruminal pH, and volatile fatty acid (VFA) molar proportions. Dietary treatments were the same as experiment 1. Flavomycin tended to increase (linear effect, P = 0.07) ruminal organic matter (OM) digestion, associated with increased (linear effect, P < 0.01) ruminal starch digestion. Supplementing flavomycin at 13.2 mg/kg decreased net microbial N synthesis (quadratic effect, P = 0.03). Compared with control, MON tended to increase (P = 0.10) ruminal neutral detergent fiber (NDF) digestion and increased (P < 0.01) ruminal starch digestion. Monensin did not affect (P = 0.39) net microbial N synthesis, but decreased (P = 0.01) ruminal degradation of feed nitrogen (N). There were no treatment effects (P > 0.10) on total tract apparent digestion of DM, OM, NDF, and starch. Flavomycin decreased ruminal pH (quadratic effect, P < 0.01) measured 4 h postprandial. Compared with control, MON increased ruminal pH (P = 0.03). Flavomycin increased (linear effect, P = 0.03) ruminal propionate molar proportion and decreased (linear effect, P ≤ 0.04) ruminal molar proportions of acetate and butyrate, and decreased (linear effect, P = 0.02) acetate:propionate molar ratio and estimated methane production. We conclude that supplementing flavomycin at 6.6 or 13.2 mg/kg had no major effects on cattle growth performance, carcass characteristics, diet digestibility, and ruminal fermentation characteristics.

Rumen Fermentation Profile and Greenhouse Gas Mitigation of Three Forage Species from Agroforestry Systems in Dry and Rainy Seasons

The variability of climatic conditions throughout the year and the physiological maturity of plant material can have effects on the nutritional value of plants and the productive performance of animals. The aim was to determine the effect of three tropical forage species (Tithonia diversifolia, Erythrina poeppigiana and Cratylia argentea) harvested at four cutting ages (30, 45, 60 and 75 days), during the dry and rainy seasons on in vitro gas production, rumen pH, volatile fatty acids (VFA) and CH4 production. A completely randomized design in a factorial arrangement (three forage species, four cutting ages and two seasons) was used. Four Brahman bulls of 250.0 ± 20.5 kg of live weight were used, provided with a ruminal cannula for the extraction of ruminal fluid. The animals were kept separately in individual pens, where they were fed with P. maximum and water was provided ad libitum. Gas production among forage species was lower (p = 0.0001) in T. diversifolia and E. poeppigiana in the dry season. The cutting age had an influence on gas production, showing lower production (p = 0.0164) at 30 and 45 days in the dry season. The VFA production showed differences for the effect between forages in the rainy season, with higher values (p &lt; 0.05) for acetic, propionic and butyric acid in the species E. poeppigiana, C. argéntea and T. diversifolia respectively. CH4 production showed differences between forage species, showing the lowest (p = 0.0001) production of CH4 in T. diversifolia for the dry and rainy seasons. It is concluded that the use of shrubby species (T. diversifolia, E. poeppigiana and C. argéntea) in ruminant production systems in the rainy and dry seasons, with an early regrowth age (30 and 45 days), present a promising alternative on the reduction of CH4.

Rumen effects of monensin in dry cow diets varying in energy density.

Controversy has existed as to whether monensin will provide equal or differential benefits in a higher-energy, lower-roughage close-up diet versus a higher-roughage, lower-energy diet. Our objective was to determine the rumen effects of a controlled-energy, high-fiber diet balanced to meet but not greatly exceed energy requirements during the dry period or a traditional 2-group approach of higher-energy close-up diet. The effects of added monensin in each diet type were determined. Multiparous Holstein cows (n = 17) were fitted surgically with ruminal cannulas. During the first 4 wk of the dry period, all cows were fed a controlled-energy, high-fiber diet (CE) as a total mixed ration for ad libitum intake. During the last 3 wk before calving, half of the cows were switched to a higher-energy, close-up diet until calving (CU), whereas the other half continued to receive the CE diet. Within each dietary group, half of the cows received monensin (MON) supplementation in the diet (24.2 g/t of total dry matter) and half did not (CON). After calving, all cows received the same lactation diet containing monensin (15.4 g/t of dietary dry matter). At 14 d prepartum, dry matter intake was not different across treatments. The weight of rumen contents was greater for cows fed CE. Rumen liquid dilution rate, solids passage rate, pH, total volatile fatty acid (VFA) concentrations, molar proportions of acetate and propionate, and papillae length did not differ among diets. Butyrate percentage tended to be greater for cows fed CE. Postpartum, dry matter intake, mass of rumen contents, solids passage rate, pH, total VFA concentration, molar percentages of propionate and butyrate, and papillae length did not differ among treatments. Liquid dilution rate (16.6, 10.7, 16.0, and 18.2%/h for CE + CON, CE + MON, CU + CON, and CU + MON, respectively) was affected by a diet × monensin interaction. Cows on the CE + CON diet had a greater ruminal proportion of acetate than did cows fed CU + CON, whereas cows fed monensin on either diet were intermediate (diet × monensin interaction). Addition of MON to the CU diet decreased the proportion of propionate (diet × monensin interaction). Cows fed CE had greater mass of rumen contents before parturtition but the high inclusion of wheat straw in the CE diet did not negatively affect rumen papillae length. Monensin inclusion differentially affected liquid passage rate and VFA concentrations.

PSVII-13 Evaluation of Ginkgo Leaf as a Feed for Ruminants by Using in Vitro gas Production Technique

Abstract The objective of this study was to examine the fermentation characteristics of ginkgo leaf compared with traditional feeds, rice straw, alfalfa and soybean meal, by using in vitro gas production technique. Three ruminal cannulated Chinese Holstein dairy cows were fed a total mixed ration. Rumen fluid was collected via from a ruminal cannula before feeding and then filtered through four layers of cheesecloth. Samples (220 mg air-dried) of rice straw, alfalfa, soybean meal and ginkgo leaf were placed in each glass bottle (150 mL), and 30 mL mixed solution with rumen fluid and a buffer solution (1:2 v/v). Three replicates of each sample were incubated in shaking bath at 39 °C for 48 h. The gas production was measured at 0, 3, 6, 9, 12, 24 and 48 h, respectively. The gas production data were fitted to the non-linear model Y = A + B (1 – e-CT). The results demonstrated that the ginkgo leaf had significantly greater in vitro gas production compared with the other feeds at each observation time. The amount of gas production from the immediately soluble fraction (A) of the four test feeds were all positive. The gas production from the insoluble fraction (B) of alfalfa was least at 43.82 mL and ginkgo leaf showed significantly greater B values than alfalfa. The gas production rate (C) was significantly greater for ginkgo leaf than those C values for rice straw and soybean meal. The in vitro dry matter and crude protein digestibility (%) of ginkgo leaf were 99.6 and 98.7, respectively, which were significantly greater than those of soybean meal. The total volatile fatty acid production of ginkgo leaf was significantly greater than that of rice straw, and the ammonia concentration of ginkgo leaf decreased significantly. It indicated that ginkgo leaf could be used as a protein source feed for ruminants.

Ruminal alkalizing potential of brucite and sodium bicarbonate in feedlot cattle diets

The effects of brucite (BR; magnesium hydroxide) and sodium bicarbonate (SB) on ruminal fermentation characteristics were evaluated following a ruminal glucose challenge. Four Holstein steers were used in a 4 × 4 Latin square design with 4 dietary treatments: (1) control (CTL; no buffer), (2) 0.5% BR, (3) 1% BR, or (4) 1% SB. The basal diet contained 70% steam-flaked wheat. On the collection day, 500 g of glucose was introduced through a ruminal cannula 1 h after the morning feeding. Time required for 50% reactivity at pH 6.0 of BR and SB was 450 and 0.5 min, respectively. Ruminal pH tended to decrease (P < 0.09) 1 h after feeding (just before the glucose challenge), but ruminal fluid buffer capacity was greater (P = 0.01) 1 h before feeding for CTL than buffer-supplemented diets. Average pH was not influenced by buffer supplementation. Buffers tended (P = 0.07) to reduce average ruminal buffer capacity. Ruminal pH and lactate had an inverse relationship (r = −0.59). Average ruminal VFA concentration tended to be lower (P = 0.06) for SB than BR. Compared with CTL, buffers decreased (P = 0.03) ruminal protozoa. Supplemental BR had lower (P < 0.05) average ruminal glucose concentration than SB. Buffer supplementation decreased average ruminal osmolality (P = 0.02). Ruminal alkalizing equivalence of BR and SB were similar. Neither appreciably altered ruminal buffering capacity. Although, both reduced ruminal lactate during the first few hours following a glucose challenge. Buffer supplementation may depress ruminal protozoa.

PRODUCCIÓN DE BIOGÁS Y CARACTERÍSTICAS FERMENTATIVAS in vitro DE CONSORCIOS BACTERIANOS CELULOLÍTICOS RUMINALES OBTENIDOS DE DIFERENTES FIBRAS

&lt;p&gt;&lt;strong&gt;Background&lt;/strong&gt;. Cellulolytic bacterial consortia (CBC) serve as additives to improve fiber degradation in ruminants, since they improve biogas production and &lt;em&gt;in vitro&lt;/em&gt; fermentation characteristics. &lt;strong&gt;Objective&lt;/strong&gt;. To evaluate the biogas production and fermentative characteristics &lt;em&gt;in vitro &lt;/em&gt;of mulato grass inoculated with ruminal CBC obtained from ground sawdust, ground mulato grass or whole stem as substrates in the selective culture medium. &lt;strong&gt;Methodology&lt;/strong&gt;. The CBC were obtained from ruminal fluid from a Suiz-Bu cow fitted with a ruminal cannula, which was transferred six times in a selective anaerobic medium. The test consisted of preparing sterile biodigesters with 0.5 g of mulatto grass with 63 d of regrowth, 45 mL of culture medium. The inoculation was with 5 mL of a type of CBC. The biodigesters were incubated 72 h at 39 °C. Biogas production was measured at 3, 6, 9, 12, 24, 48 and 72 h. In the culture media, ammonia nitrogen (N-NH&lt;sub&gt;3&lt;/sub&gt;), total bacterial count, cellulase activity, pH, dry matter degradation (DMD) and neutral detergent fiber degradation (NDFD) were determined at 12, 24, 48 y 72 h. In the biogas production a completely random design was used; while in the rest of the variables a completely randomized design was carried out with a 3x4 factorial arrangement, with fiber source and incubation time as factors. &lt;strong&gt;Results&lt;/strong&gt;. The biogas production of the CBC obtained from the ground grass showed higher (p&amp;lt;0.05) accumulated production in all the evaluated times. The CBC obtained from sawdust increased the biogas production by 175% from 24 to 48 h and by 313% from 48 to 72 h. There was an interaction effect (p &amp;lt;0.05) on DMD, NDFD, N-NH&lt;sub&gt;3&lt;/sub&gt;, total bacterial count and cellulase enzymatic activity. The CBC obtained from ground mulatto grass at 72 h increased (p &amp;lt;0.05) the DMD and NDFD. The CBC obtained from sawdust increased DMD by 19.1% and NDFD by 33% from 48 to 72 h. The concentration of bacteria in the observed interactions is within the range of the ruminal ecosystem. The highest (p&amp;lt;0.05) content of N-NH&lt;sub&gt;3&lt;/sub&gt; was determined when the CBC obtained from grass stem with 12, 24 and 72 h of incubation were used. &lt;strong&gt;Implications&lt;/strong&gt;. Using the same fiber source to obtain the CBCs improves the degradation of said fiber. &lt;strong&gt;Conclusion&lt;/strong&gt;. The size and source of fiber are decisive in the type of bacteria that make up the cellulolytic bacterial consortia of ruminal origin under the conditions of this &lt;em&gt;in vitro&lt;/em&gt; test.&lt;/p&gt;

Effect of supplementation strategies and the use of exogenous xylanase enzyme on ruminal fermentation, digestibility, animal performance, and carcass characteristics of Nellore bulls grazing during dry season

Two experiments were conducted to assess the effects of two different supplementation strategies and the use of xylanase enzyme (Enz) on ruminal fermentation, total tract digestibility, animal performance, and carcass characteristics of Nellore bulls grazing during the dry season. In the experiment 1, animal performance was evaluated in a 2-yr study, 28 Nellore bulls (442 ± 39 kg of body weight (BW); 24 ± 4 months old; yr 1) and 48 Nellore bulls (447 ± 37 kg BW; 24 ± 4 months old; yr 2) were allotted to a randomized block design in a 2 × 2 factorial arrangement. The factor 1 was supplementation strategy of a concentrated feed: constant rate (10 g/kg BW/d) or stair-step strategy (4, 8, 12, and 16 g/kg BW/d) with increases every 35 days in yr 1 and every 28 days in yr 2. The factor 2 was xylanase enzyme inclusion: with or without exogenous xylanase enzyme (Supplied at 15 mg/kg BW/d). The following parameters were measured: nutrient intake, apparent digestibility, animal performance, and carcass characteristics. The experiment 2 was conducted only in year 1, the same treatments of the experiment 1 were applied to assess the pH and the ruminal fermentation profile using 8 Nellore bulls with ruminal cannula (622 ± 13.7 kg) in a completely randomized design. Experiment 1, no difference was observed among treatments on the total DM intake, apparent digestibility of DM, OM, NDF and CP, and animal performance based on live weight (ADG, feed efficiency of supplement intake, and final BW). Animals receiving the stair-step supplementation strategy had higher (P < 0.01) proportion of forage in their diet and the daily supplement intake was slightly lower (P = 0.01) than the constant supplementation. The supplementation strategy factor did not affect carcass ADG, final HCW, nor carcass adjusted final BW, while the use of enzyme increase (P < 0.01) carcass ADG, adjusted final body weight, and carcass dressing percentage and there is a tendency for greater final hot carcass weight (P = 0.08). Experiment 2, the average ruminal pH was higher in the animals receiving Enz in the stair-step supplementation, and lower in cattle on the same supplementation strategy without Enz (P < 0.01). The use of Enz generate lower total quantification of ruminal VFA and increased the acetate: propionate ratio (P = 0.02). In summary, the stair-step supplementation strategy did not present any benefit to animal performance and carcass characteristics. The use of xylanase enzyme, independent of the supplementation strategy, can improve animal performance based on carcass gain.

Effect of dietary concentrate level on digestibility of nutrients in each region of the gastrointestinal tract and rumen fermentation in goats

This study evaluated the effects of high concentrate diets (HCD) on the rumen fermentation and the digestibility of nutrients in different sites of the gastrointestinal tract (GIT) in goats. Four goats were used in a crossover design. The goats were fitted with a ruminal cannula and flexible T-cannulae proximal duodenum and terminal ileum. Treatments were as follows: low concentrate group (LCG) and high concentrate group (HCG). Duodenal flow and forestomach digestibility of starch were significantly higher in the HCG than those in the LCG (p < 0.05); There was no significant difference in ileum flow and digestibility of starch in the small intestine, large intestine and total GIT (p > 0.05). The digestibility of crude protein (CP) in the forestomach was significantly higher in the HCG than in the LCG (p < 0.05); the flow of the duodenum and ileum of CP, and the CP digestibility of the small intestine, large intestine and total GIT were not significantly different between groups (p > 0.05). The duodenal and ileal flow of neutral detergent fiber (NDF), the NDF digestibility of the different segments and total GIT were not significantly different between groups (p > 0.05). Compared to the LCG, the ruminal pH of the HCG was significantly lower (p < 0.05). The HCG concentrations of microbial crude protein, ammonia nitrogen and isovaleric acid were significantly higher (p < 0.05) than the LCG. The foam strength, foam production and viscosity of the rumen fluid in the HCG were higher than the LCG (p < 0.01). These results showed that when the goats were fed with HCD, the digestibility of nutrients was not significantly impaired, but the risk of frothy rumen bloat increased. Implications Due to a serious shortage of high-quality roughage in China, producers commonly used a high-concentrate diet in ruminants, which can improve animal production performance. Gastrointestinal digestive function plays a vital role in the absorption of nutrients and the healthy growth of animals. Therefore, this research evaluated the digestibility of various nutrients in different segments of the gastrointestinal tract (GIT) under HCD feeding by using three-site cannula goats as experimental animals. The results indicated that the GIT of goats could fully digest nutrients such as starch and protein under HCD feeding conditions.

Increasing doses of biocholine on apparent digestibility, ruminal fermentation, and performance in dairy cows

Biocholine is an herbal feed additive considered a natural alternative to synthetic choline, with relatively low rumen degradability composed of cellulose and choline conjugates, namely phosphatidylcholine. Rumen-protected choline has been largely evaluated during the peripartum period, but few studies evaluated the effects of choline supplementation after the transition period. The objective of this study was to determine the effects of increasing doses of biocholine on feed intake, feed particle sorting, total apparent digestibility, ruminal fermentation, milk yield and composition, purine derivative excretion, and nitrogen balance. Twenty-four Holstein cows (163 ± 98 days in milk, 27.6 ± 7.14 kg/d milk yield), 4 of which were ruminally cannulated, were enrolled to this study. Cows were blocked according to milk yield, days in milk, and presence of ruminal cannulas, then all cows were randomly assigned to a treatment sequence in a replicated 4 × 4 Latin square experiment design. The experimental treatments were a control (CON) diet, and biocholine (BC; Biocholine FC®, Nutriquest Technofeed Nutrição Animal Ltda., Campinas, Brazil) fed at 7, 14, and 21 g/d. Cows were allowed 14 d of adaptation to treatments and the last 7 days of each period were used for sampling. The forage to concentrate ratio of the basal diet was 48:52 (on a dry matter basis) with corn silage as the single forage source, and diet was provided in the form of total mixed ration. No treatment effects were detected on feed intake, but BC quadratically affected (P = 0.010) sorting for feed particles >19 mm and linearly increased (P = 0.037) ether extract digestibility (840, 834, 843, and 853 g/kg for cows fed BC at 0, 7, 14, and 21 g/d, respectively). Biocholine supplementation tended to quadratically decrease ruminal pH (6.17, 6.04, 6.11, and 6.11 for cows fed BC at 0, 7, 14, and 21 g/d, respectively) but had no effect on concentrations of total volatile fatty acids and NH3-N. Biocholine had a positive quadratic effect (P ≤ 0.042) on milk yield (29.5, 30.5, 30.0, and 29.8 kg/d for cows fed BC at 0, 7, 14, and 21 g/d, respectively) and feed efficiency (1.20, 1.25, 1.21, and 1.21 kg milk/kg DM intake for cows fed BC at 0, 7, 14, and 21 g/d, respectively). Biocholine tended to quadratically affect (P = 0.058) N excretion through milk (157, 162, 160, and 159 g/d for cows fed BC at 0, 7, 14, and 21 g/d, respectively). There was no evidence for treatment effects on purine derivatives excretion. In conclusion, feeding BC may improve milk yield and feed efficiency of dairy cows. Predicted maxima response in milk yield and feed efficiency were observed at 10 g/d of BC.

Trace mineral source influences digestion, ruminal fermentation, and ruminal copper, zinc, and manganese distribution in steers fed a diet suitable for lactating dairy cows

High solubility of certain trace minerals (TM) in the rumen can alter nutrient digestibility and fermentation. The objectives of the present studies were to determine the effects of TM source on 1) nutrient digestibility and ruminal fermentation, 2) concentrations of soluble Cu, Zn, and Mn in the rumen following a pulse dose of TM, and 3) Cu, Zn, and Mn binding strength on ruminal digesta using dialysis against a chelating agent in steers fed a diet formulated to meet the requirements of a high producing dairy cow. Twelve Angus steers fitted with ruminal cannulae were adapted to a diet balanced with nutrient concentrations similar to a diet for a high producing lactating dairy cow for 21 d. Steers were then randomly assigned to dietary treatments consisting of 10 mg Cu, 40 mg Mn, and 60 mg Zn/kg DM from either sulfate (STM), hydroxychloride (HTM) or complexed trace minerals (CTM). The experimental design did not include a negative control (no supplemental Cu, Mn, or Zn) because the basal diet did not meet the National Research Council requirement for Cu and Zn. Copper, Mn, and Zn are also generally supplemented to lactating dairy cow diets at concentrations approximating those supplied in the present study. Following a 14-d adaptation period, total fecal output was collected for 5-d. Following the fecal collection period, rumen fluid was collected for Volatile fatty acid (VFA) parameters. On the following day, the same diet was provided for 14 d, without supplemental Cu, Zn, and Mn. This period served as a wash-out period. A pulse dose of 100, 400, and 600 mg of Cu, Zn, Mn, respectively, from either STM, HTM, or CTM, was administered via ruminal cannulae to the steers on day 15. Over a 24-h period ruminal samples were obtained every 2-h. Following centrifugation, the supernatant was analyzed for Cu, Mn, and Zn. Ruminal solid digesta samples from times 0, 12, and 24 h after bolus dosing were exposed to dialysis against Tris-EDTA. Digestibility of NDF and ADF were lesser in STM vs. HTM and vs. CTM supplemented steers. Steers receiving HTM and CTM had greater total VFA concentrations than STM, and molar proportions of individual VFA were not affected by treatment. Ruminal soluble Cu and Zn concentrations were greater post dosing in STM and CTM supplemented steers at 2, 4, and 6 h for Cu and 4, 6, 8, 10 and 12 h for Zn when compared to HTM supplemented steers. The release of Cu and Zn from ruminal solid digesta following dialysis against Tris-EDTA at 12 and 24 h postdosing was greater for steers receiving HTM compared to those receiving STM or CTM. Results indicate trace mineral source impacts: 1) how tightly bound Cu and Zn are to ruminal solid digesta; 2) fiber digestion; 3) and ruminal total VFA concentrations.

Performance, Digestibility, Nitrogen Balance and Ingestive Behavior of Young Feedlot Bulls Supplemented with Palm Kernel Oil.

Simple SummaryVegetable oil can be used to increase energy density in diets; manipulate ruminal fermentation; alter nutrient degradation, digestion and absorption; and improve carcass characteristics and quality. Palm kernel oil (PKO) is extracted from the fruit of the oil palm (Elaeis guineenses), a plant of African origin adapted to tropical regions. The aim of this study was to evaluate PKO as a supplementary fat source in ruminant diets. Thus, two studies were developed to understand the effects of PKO inclusion on performance, ingestive behavior, nutrient digestibility, fermentation parameters and carcass characteristics. The results showed a reduction in dry matter intake with consequent negative effects on digestibility, performance and carcass characteristics due to the dietary inclusion of PKO. However, the addition of the lipid source reduced protozoa counts and the acetate/propionate ratio, important characteristics for reducing ruminal methanogenesis, in further studies.Vegetable oils can be used to increase energy density in diets; manipulate rumen fermentation; and alter the capacity for degradation, digestion and absorption of nutrients. Two experiments were conducted to evaluate palm kernel oil (PKO) in the diet of confined bulls with the inclusion of 0.0, 11.5, 23.0 and 34.6 g PKO/kg dry matter (DM). The first experiment evaluated nutrient intake, performance, ingestive behavior and carcass characteristics. In the second experiment, steers crossbred with a ruminal cannula were used to evaluate digestibility, nitrogen balance, microbial protein synthesis, short-chain fatty acid levels and protozoal counts. The results showed that the inclusion of PKO linearly reduced intake in kg/day (DM, crude protein—CP, neutral detergent fiber—NDFap, nonfibrous carbohydrates—NFC and total digestible nutrient—TDN) and digestibility (DM, NDFap and TDN). Ether extract intake increased quadratically with the predicted maximum intake of 15.4 g/kg DM. Regarding ingestive behavior, there was a quadratic increase in rumination time and a quadratic reduction in idle time. Nitrogen balance, nitrogen intake, nitrogen retention, microbial protein production, acetate, butyrate, acetate/propionate ratio and protozoa count showed linear decreases due to dietary PKO inclusion. Regarding the carcass characteristics, linear decreases were observed for the final weight, average daily gain, hot carcass weight, cold carcass weight, hot carcass yield, cold carcass yield, loin eye area and subcutaneous fat thickness. The inclusion of PKO at up to 34.6 g/kg DM in diets for confined bulls reduces intake, negatively affecting digestibility, performance and carcass characteristics.

Effect of Diet Supplementation with the Mycotoxin Binder Montmorillonite on the Bioavailability of Vitamins in Dairy Cows.

The objective of this study was to determine the effect of the mycotoxin binder montmorillonite (MMT) supplemented in the diet of dairy cows on the bioavailability of vitamins A, D, E, B1 and B6. Six multiparous Holstein-Friesian cows were used in a crossover design with two periods. Treatments were a control diet with or without MMT. Vitamins were infused individually into the abomasum through the ruminal cannula. Blood samples were collected from the jugular vein at 0, 1, 2, 3, 4, 6, 9, 12, 24 and 48 h after the administration of each vitamin. Results showed that vitamin A reached maximal concentration (Tmax) at 5.3 h after dosing, the maximal concentration (Cmax) was 1.2 times higher than the basal concentration (Cbasal), and the area under the curve (AUC) was 739 arbitrary units. Vitamin B6 reached the Tmax at 13 h after dosing, the Cmax was 1.4 times higher than the Cbasal, and the AUC was 222 arbitrary units. No differences were observed in Cbasal, Tmax, Cmax and AUC of vitamin A and B6 between control vs. MMT-supplemented cows. Plasma concentrations of vitamins D, E and B1 had no concentration peaks, and were not affected by MMT addition. The lack of a response suggests that their plasma concentration may be tightly regulated. Results of this study do not show evidence that MMT affects the bioavailability of vitamins A and B6 in vivo.

The Effect of Horn Fly (Diptera: Muscidae) Infestation on Behavior, Water, and Feed Intake, and Digestion Characteristics of Beef Cattle.

Seven mature Angus × Hereford crossbreed cows (544 ± 23.2 kg of body weight) fitted with duodenal and ruminal cannulas were used in a crossover design to evaluate the effects of horn fly (Haematobia irritans) (L.) infestation on horn fly-induced defensive behaviors, feed and water intake, as well as digestion characteristics of beef cows. Cows were randomly assigned to one of two treatment groups: 1) a horn fly infested (1,000 flies per cow) or 2) a noninfested control group. All cows were housed in individual screened pens. Fly counts and infestations were performed daily to maintain consistent populations throughout the study. Sudan hay (11.4 % crude protein, dry matter basis) was selected to mimic forage quality that range cattle frequently graze in the southwest region. Horn fly-induced host defensive behaviors were greater (P ≤ 0.0002) for horn fly infested cattle. Intake of water, dry matter, organic matter, crude protein, and neutral detergent fiber were similar (P ≥ 0.4765) among infested and noninfested cows. However, total volatile fatty acid concentration tended to increase (P = 0.0967) when horn flies were present. Dry matter fecal excretion and total tract digestion were not affected (P ≥ 0.2602) by horn fly infestation. These data indicate that horn fly infestations do not affect forage intake or digestion characteristics of beef cattle (Bos taurus) in confinement settings.

Kinetics of In Vitro Gas Production and Fitting Mathematical Models of Corn Silage

This study aimed at examining the effects of rumen inoculum of steers receiving different combinations of ionophore and probiotics in their diets on in vitro gas production of corn silage. The fitting of gas production was performed with five mathematical models and its kinetics was evaluated. Four crossbred steers (403.0 ± 75.5 kg body weight) with ruminal cannula were assigned to a 4 × 4 Latin square design. The additives used were Monensin sodium (Rumensin® 100, 3 g/day), Bacillus toyonensis (Micro-Cell Platinum® 109, 1 g/day) and Saccharomyces cerevisiae boulardii (ProTernative®20, 0.5 g/day). Additives were arranged into the following treatments, supplied daily into total mixed diet: (1) Monensin; (2) Monensin + B. toyonensis; (3) Monensin + S. boulardii; and (4) B. toyonensis + S. boulardii. The gas production data were fitted into the models of Gompertz, Groot, Ørskov, Brody, Richards, and Dual-pool Logistic. A perfect agreement between observed and predicted values in curves of accumulated in vitro gas production was observed in the Groot and Richards models, with higher coefficient of determination (R2 = 0.770 and 0.771, respectively), concordance correlation coefficient (CCC = 0.871 and 0.870, respectively), and root mean square error of prediction (RMSEP = 1.14 and 1.15, respectively). Evaluating the feed additives throughout the Groot model, the B. toyonensis + S. boulardii treatment presented higher VF (12.08 mL/100 mg of DM; p = 0.0022) than Monensin and Monensin + S. boulardii (9.16 and 9.22 mL/100 mg of DM, respectively). In addition, the fractional rate of gas production (k) was higher (p = 0.0193) in B. toyonensis + S. boulardii than in Monensin, not presenting a statistical difference (p &gt; 0.05) from the other two treatments. Additionally, with the time of beginning to gas production, the lag time (λ), was greater (p &lt; 0.001) with Monensin and Monensin + B. toyonensis than with Monensin + S. boulardii and B. toyonensis + S. boulardii. The combination of Monensin and probiotics (B. toyonensis + S. boulardii) resulted in better kinetics of degradation of corn silage, being that the Groot and Richards models had the best fit for estimates of the in vitro gas production data of corn silage tested with different feed additive combinations.

Bromatological composition and ruminal degradability of Xaraés palisade grass under grazing in integrated systems

To evaluate the bromatological composition and ruminal degradability of dry matter (DM), crude protein (CP), neutral detergent fiber (NDF) and acid detergent fiber (ADF) of Xaraés palisade grass (Urochloa brizantha ‘Xaraes’ syn Brachiaria brizantha) under grazing in integrated crop, livestock (ICL), and forest (ICLF) systems, we conducted an in situ degradability trial in randomized blocks with three non-lactating 3/4 Gyr × 1/4 Holstein cows, provided with ruminal cannula. The management of Xaraés palisade grass was similar in both systems, differing only regarding shading in the ICLF system provided by eucalyptus trees (average 65% crown cover). Grass samples were incubated for 0, 3, 6, 9, 12, 24, 36, 48, 72, and 96 hours. Considering the passage rate 2% h-1, the Xaraés palisade grass of ICL system had greater NDF effective degradability in relation to ICLF (46.38% vs 44.98%). However, the palisade grass CP potential degradability was greater in the ICLF than in the ICL system (68.92% vs. 65.40%). The presence of trees in the pasture has effect on nutritional traits of the Xaraés palisade grass, increasing its protein content and degradability and reducing its fiber degradability.

PSXVI-23 The influence of trace mineral source on digestion, ruminal fermentation characteristics, and mineral solubility in beef cattle fed a high concentrate feedlot diet

Abstract Twelve Angus steers (BW 530.9 ± 22.7kg) fitted with ruminal cannulae were used to determine the impact of trace mineral (TM) source on digestibility and ruminal VFA and soluble concentrations of Cu, Mn, and Zn. Steers were fed a high concentrate diet balanced to meet the requirement of finishing feedlot steers for 21d. Treatments consisted of Cu, Mn, and Zn supplemented at 18, 40, and 90 mg/kg DM, respectively, from either sulfate (STM) or hydroxy trace mineral (HTM) sources (n = 6 steers/treatment; experimental unit = steer). Following a 21-d adaptation period total fecal output was collected for 5 d. Trace mineral sources had no impact on nutrient digestibility. On d 6, rumen fluid was collected at 0, 2, and 4 h post-feeding for VFA analysis. There were no treatment x time interactions for any VFA measured. However, HTM steers had greater (P &amp;lt; 0.05) ruminal molar proportions of propionate and tended (P &amp;lt; 0.07) to have greater molar proportions of valerate compared to STM steers. Steers fed STM had greater (P &amp;lt; 0.05) molar proportions of butyrate compared to HTM steers. Steers were then fed the same high concentrate diet without supplemental Cu, Zn, or Mn for 14 d. On d 15 steers received a pulse dose (via rumen cannula) from either STM or HTM. Ruminal samples were obtained at 2 h intervals starting at -4 and ending at 24 h relative to dosing. There was a treatment x time interaction (P &amp;lt; 0.05) for ruminal soluble Cu concentrations. Ruminal soluble mineral concentrations were greater (P &amp;lt; 0.05) for Cu at 4, 6, 8, and 16 h post-dosing in STM compared to HTM supplemented steers. Results indicate that ruminal solubility of Cu differs between STM and HTM sources and may impact rumen fermentation characteristics.

PSX-A-12 Late-Breaking: Effects of Renergy™ on ruminal fermentation in steers fed a high-grain diet

Abstract Renergy™ is a proprietary blend of organic acids with a proposed mode of action of increasing ruminal propionate production. Little is known about the efficacy of Renergy™ supplementation in modifying ruminal fermentation in beef cattle consuming high-grain diets. Therefore, eight Angus steers (BW 531.7 ± 20.4 kg) fitted with ruminal cannulae were used to determine the effects of Renergy™ on ruminal fermentation characteristics. Steers were fed a high concentrate diet (DM basis: 13.6% CP, 1.38 Mcal/kg NEg, and 2.02 Mcal/kg NEm) with no monensin sodium or tylosin phosphate added to the diet for 30 d prior to the initiation of the experiment. Treatments consisted of control (CON; no supplemental Renergy™) and Renergy (REN) fed at 27.6 g.animal-1.d-1 (n = 4 steers/treatment; experimental unit = animal). Following the 30 d diet adaptation period, dietary treatments were initiated for 28-d. On day 28, rumen fluid was collected at 3 h post feeding and analyzed for VFA, pH, and NH3. Ruminal pH (P = 0.62) and NH3 (P = 0.56) were unaffected by treatment. However, total VFA (P = 0.05) and propionate (P = 0.03) production were increased by Renergy, 13.3% and 25.7% respectively. There was a tendency (P = 0.14) for acetate production to be increased 10.9% in steers supplemented with Renergy™. Butyrate was unaffected (P = 0.51) by treatment. However, isobutyrate production was lower (P &amp;lt; 0.01) in steers receiving Renergy™. Feeding Renergy™ also resulted in 25% less (P = 0.07) L-lactate production. Under conditions of this experiment, results indicate that supplementing Renergy™ for 28d to beef cattle consuming high concentrate diets impacts ruminal fermentation 3 h post feeding.

PSIX-7 Differences in rumen degradability according to the degree of corn gelatinization

Abstract This study was conducted to evaluate the difference in ruminal degradability by the degree of gelatinization of corn grain. The treatments were Control (whole corn grain), T1 (70% gelatinized corn grain steam flake), and T2 (30% gelatinized corn grain steam flake). Corn grain steam flaked for T1 was produced by a pressurized steam chamber for a longer time than T2. For this reason, the thickness of T1 and T2 was 1.5 and 2.5mm on average, respectively. Two Holstein cows (BW.405±15.4kg, 26.5±12 months) fitted with ruminal cannula were fed 4 kg of tall fescue and 3 kg of a formulated concentrate mix. Immediately after morning feeding, the nylon bags containing the sample from all treatments were incubated in the ruminal ventral sac for 0, 2, 4, 8, 12, 18, 24, 36, and 48h. At 0h of incubation, the DM degradability of T1 (16.70%) was higher (P&amp;lt; 0.05) than Control (9.74%) and T2 (12.00%). The degradability of both Control and T2 slightly increased from 4 (23.08 and 27.57%) to 18h (36.65 and 35.52%), exponentially increased from 18 to 48h. On the other hand, the degradability for T1 exponentially increased from 2 (28.74%) to 18h (77.31%), only slightly increased thereafter. The final degradability (48h) of Control, T1, and T2 were 78.07, 89.20, and 84.86%, respectively (P&amp;lt; 0.05). The fraction a of DM degradability for T1 (24.29%) was higher than Control (2.26%) and T2 (6.26%) (P&amp;lt; 0.05). The effective degradability (ED) of T1 (75.31%) was higher (P&amp;lt; 0.05) than Control (57.42%) and T2 (60.86%). Therefore, this study demonstrated that 70% gelatinized corn grain steam flake showed a higher rate of ruminal degradability than other treatments. Thus, it is necessary to determine how these differences affect ruminant productivity through additional feeding experiments.

PSXVI-22 The influence of Propionibacteria on in vivo rumen fermentation characteristics and in vitro lactic acid clearance rate in fistulated steers fed moderately high concentrate diets

Abstract Six steers fitted with ruminal cannulae were used in a crossover design to examine the impact of direct fed microbial (DFM) supplementation on in vivo rumen fermentation characteristics and in vitro lactic acid clearance. Steers were fed a moderately high concentrate -1∙day-1 of 4.45x 1010 CFU/g of Propionibacteria acidipropionici). Treatments were administered daily, directly into the rumen via the cannula as a single bolus dose at the time of feeding. Rumen contents were sampled two h post-feeding daily and analyzed for short chain fatty acids (SCFA). On d 7 and 14, rumen fluid was collected from all steers and subjected to an in vitro lactic acid clearance challenge. Lactic acid and SCFA concentrations were determined at 3, 6 and 9 h post incubation. After d 14, all cattle received the basal diet for 21 d. On d 22, treatment crossover was implemented and the experiment repeated. Animal was considered the experimental unit and data were analyzed as a crossover design using Proc Mixed in SAS. In vivo propionic acid concentrations were greater (P &amp;lt; 0.05) and total SCFA tended (P &amp;lt; 0.06) to be greater in rumen fluid from steers receiving DFM. D- and total lactic acid concentrations were lesser (P &amp;lt; 0.05) at 3 h post in vitro incubation for steers receiving DFM. D-, L+, and total lactic acid concentrations were similar between treatments at all other timepoints. In vitro propionic acid and total SCFA concentrations were greater (P &amp;lt; 0.05) and acetic acid concentrations lesser (P &amp;lt; 0.05) in steers receiving DFM. These data indicate that the DFM Propionibacteria acidipropionici, alters in vivo and in vitro rumen fermentation characteristics.