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An experiment was conducted to determine the effect of feeding finishing pigs a corn-soybean (CSBM) diet or a CSBM diet supplemented with 30% dried distillers grains with solubles (DDGS), in combination with or without a growth-promoting ionophore (0 or 30 mg narasin/kg of diet), has on manure composition, microbial ecology, and gas emissions. Two separate groups of 24 gilts (initial BW = 145.1 kg, SD = 7.8 kg) were allotted to individual metabolism crates that allowed for total but separate collection of feces and urine during the 48-d collection period. After each of the twice-daily feedings, feces and urine from each crate was collected and added to its assigned enclosed manure storage tank. Each tank contained an individual fan system that pulled a constant stream of air over the manure surface for 2 wk prior to air (day 52) and manure sampling (day 53). After manure sampling, the manure in the tanks was dumped and the tanks cleaned for the second group of pigs. Except for total manure Ca and P output as a percent of intake and for manure methane product rate and biochemical methane potential (P ≤ 0.08), there were no interactions between diet composition and narasin supplementation. Narasin supplementation resulted in increased manure C (P = 0.05), increased manure DM, C, S, Ca, and phosphorus as a percent of animal intake (P ≤0.07), and increased manure volatile solids and foaming capacity (P ≤ 0.09). No effect of narasin supplementation was noted on manure VFA concentrations or any of the gas emission parameters measured (P ≥ 0.29). In contrast, feeding finishing pigs a diet containing DDGS dramatically affected manure composition as indicated by increased concentration of DM, C, ammonia, N, and total and volatile solids (P = 0.01), increased manure DM, N, and C as a percent of animal intake (P = 0.01), increased manure total VFA and phenols (P ≤ 0.05), decreased gas emissions of ammonia and volatile sulfur compounds (VSC; P = 0.01), increased emissions of phenols and indoles (P ≤0.06), decreased methane production rate (P = 0.01), and slight differences in microbial ecology (R ≤0.47). In conclusion, feeding a diet which contains an elevated level of indigestible fiber (i.e., DDGS) resulted in more fiber in the manure which therefore dramatically affected manure composition, gas emissions, and microbial ecology, while narasin supplementation to the diet did not exhibit a significant effect on any of these parameters in the resultant swine manure. [ABSTRACT FROM AUTHOR]

Our hypothesis was that increasing the inclusion level of dried distiller's grains with solubles (DDGS) to feedlot lambs would increase growth and the inclusion of lasalocid (LAS; Bovatec, Alpharma, LLC, Bridgewater, NJ) would increase ADG and G:F, while not affecting digestibility, ruminal VFA concentration, and ruminal pH. Furthermore, we hypothesized that rations containing LAS and higher levels of DDGS would cause increased ruminal hydrogen sulfide gas (H2S) concentrations. Two hundred forty crossbred (Suffolk x Rambouillet) lambs (31.9 ± 5.87 kg BW; approximately 90 d of age) were allocated to 6 treatments in a completely randomized design with a 3 x 2 factorial arrangement of treatments. Lambs were placed into 24 feedlot pens (4 pens/treatment; 10 lambs/pen) for a 111 d finishing study. Main effects included concentration of DDGS (0, 15, or 30% DM basis) and inclusion of LAS (0 or 22.05 g/metric ton LAS) resulting in treatments of: 1) 0% DDGS without LAS (0DDGS-NL), 2) 0% DDGS with LAS (0DDGS-L), 3) 15% DDGS without LAS (15DDGS-NL), 4) 15% DDGS with LAS (15DDGS-L), 5) 30% DDGS without LAS (30DDGS-NL), and 6) 30% DDGS with LAS (30DDGS-L). Two-day weights were taken at the beginning and end of the experiment. Two-hundred-eighteen lambs (64.8 ± 7.99 kg BW) were slaughtered on d 112 at a commercial abattoir and carcass data collected. The inclusion of LAS increased (P ≤ 0.02) final BW, ADG, G:F, and HCW. As DDGS in the ration increased to 30%, DMI decreased linearly (P = 0.03) while G:F increased linearly (P = 0.03). A second study was conducted utilizing the same treatments to evaluate N and S balance, ruminal VFA and H2S concentration, and ruminal pH in 24 crossbred wethers (Suffolk x Rambouillet; 41.2 ± 12.23 kg BW). Daily urinary sulfur excretion and ruminal H2S concentration were linearly increased (P < 0.001) as DDGS increased in the ration. Total ruminal VFA concentration linearly decreased (P = 0.002) as DDGS increased in the ration. The inclusion of LAS increased (P = 0.02) ruminal pH. The results confirm our hypothesis that LAS increased overall growth and increasing DDGS increased ruminal H2S concentration but did not influence growth. We reject the hypothesis that the combined effects of LAS and DDGS would have no effect on rumen pH and VFA concentrations. [ABSTRACT FROM AUTHOR]

Effects of monensin withdrawal and cattle subspecies on the utilization of bermudagrass hay (14.3% CP, 72.3% NDF, and 36.9% ADF) were evaluated using ruminally cannulated steers (5 Bos taurus indicus [BI] and 5 Bos taurus taurus [BT]). Subspecies were concurrently subjected to a 2-period, 2-treatment crossover design. Treatments consisted of either 0 mg·steer−1·d−1 monensin with no previous monensin feeding (CON) or withdrawal from 200 mg·steer−1·d−1 monensin (MON) fed individually in 0.91 kg dried distillers’ grains with solubles for 42 d. Withdrawal was evaluated for a 28-d period. Ruminal fluid was collected 2 h after feeding on d 0, 1, 4, 7, 14, and 21 after withdrawal for determination of pH, VFA, ruminal NH3–N (RAN), rate of NH3 production, and CH4 production rate. Hay, ort, and fecal grab samples were collected d 23 through 28 after withdrawal for determination of intake and digestion. No subspecies × monensin, subspecies × day, or subspecies × monensin × day interactions were observed (P ≥ 0.11). An effect of day after monensin withdrawal was observed (P < 0.01) for total VFA concentration, with an increase following withdrawal followed by a decrease and then stabilization. Monensin × day after monensin withdrawal interactions (P ≤ 0.01) were observed for the acetate:propionate (A:P) ratio and molar percent of acetate and propionate. There was a decrease in molar percent of propionate between d 1 and 4 from 19.1 to 18.0; however, it remained greater (P ≤ 0.10) for MON than CON through d 7. Withdrawal increased molar percent of acetate from 68.3 to 69.8 between d 0 and 4 for MON steers. The A:P ratio was less (P ≤ 0.01) on d 0 for MON than for CON (3.4 vs. 4.0), but by d 4, it increased to 3.8 and was not different (P = 0.14) from CON. By d 14, no differences (P ≥ 0.88) remained for acetate, propionate, or the A:P ratio. After monensin withdrawal, monensin reduced (P < 0.01) RAN by 12.3% (2.09 vs. 1.83 mM for CON and MON, respectively). Monensin withdrawal and cattle subspecies had no effect (P ≥ 0.23) on rate of NH3 production or CH4 production rate. Monensin withdrawal had no effect (P ≥ 0.45) on intake or digestibility parameters. Greater forage OM intake (P = 0.09; 21.2 vs. 19.2 g/kg BW) and OM digestibility (P < 0.01; 72.4 vs. 63.0%) resulted in greater (P < 0.01) total digestible OM intake (16.8 vs. 13.2 g/kg BW) in BT steers than in BI steers. These results suggest that BT steers are better able to utilize bermudagrass hay than BI steers. Upon monensin withdrawal, steers previously fed monensin continue to have a reduced A:P ratio for at least 7 d. [ABSTRACT FROM AUTHOR]

Effects of monensin inclusion and cattle subspecies on utilization of bermudagrass hay (13.7% CP, 77.3% NDF, and 38.8% ADF) were evaluated using ruminally cannulated steers (5 Bos taurus indicus [BI] and 5 Bos taurus taurus [BT]; 398 kg BW). Subspecies were concurrently subjected to a 2-period, 2-treatment crossover design. Treatments were 0 (CON) or 200 mg·steer−1·d−1 monensin (MON) in 0.91 kg dried distillers’ grains with solubles. Periods were 70 d in length: 20 d of adaptation, 22 d of sample collection, and 28 d for withdrawal of treatment. Steers were group housed during adaptation and moved to individual covered pens for sampling. Hay, ort, and fecal grab samples were collected d 21 through 25 for determination of intake and digestion. Ruminal fluid was collected with a suction strainer 0, 2, 4, 8, and 12 h after feeding on d 42 for pH, VFA, and ruminal NH3–N (RAN) analysis. Additionally, at h 2, ruminal fluid and contents were collected for determination of rate of NH3 production and CH4 production rate. No subspecies × monensin interactions were observed (P ≥ 0.12). Monensin had no effect (P ≥ 0.16) on intake or digestibility parameters. No subspecies effect (P ≥ 0.11) was observed for forage OM intake, total OM intake, or OM digestion. Total digestible OM intake tended to be greater (P = 0.06) for BT steers than for BI steers (14.0 vs. 12.2 g/kg BW). There was an effect of hour after feeding (P ≤ 0.01) on pH, total VFA, acetate:propionate ratio, and molar percent acetate and propionate. Total VFA concentration was greater (P = 0.01) in CON steers than in MON steers (66.5 vs. 62.0 mM). Monensin decreased molar percent acetate (P = 0.02) from 72.5 to 71.2% and increased molar percent propionate (P < 0.01) from 16.9 to 18.7%, resulting in a reduced (P < 0.01) acetate:propionate ratio (from 4.34 to 3.85). Although not significantly (P = 0.19), monensin numerically reduced the CH4 production rate by 15.8%. Greater (P = 0.07) CH4 production rate tended to be observed in BI steers than in BT steers (21.4 vs. 16.6 μmol CH4·mL−1·h−1, respectively). Monensin had no effect (P ≥ 0.32) on pH, RAN, or rate of NH3 production. A subspecies × hour after feeding interaction was observed for RAN, with BT having greater RAN at h 0 and 4, whereas BI had greater RAN at h 2, 8, and 12. Overall, monensin decreased the acetate:propionate ratio and total VFA concentration but had no effect on forage utilization. Bos taurus indicus steers consumed less digestible OM and had a greater CH4 production rate compared with BT steers, suggesting BT were better able to utilize the available forage resource than BI. [ABSTRACT FROM AUTHOR]

The use of antibiotics in animal feed, commonly used as a strategy to achieve greater daily weight gains and recently as way to reduce methane emission, might result in the selection of resistant microorganisms and certain bacterial strains isolated from cattle are resistant to multiple antibiotics and could be human health hazards. To evaluate methane production in ruminant diet without roughage containing ionized amino acids as antibiotic alternative, twentyfour Nellore young bulls were allotted into two groups. The first group was fed with high-grain diet without roughage and without antibiotics diet, containing 82 mg/kg of ionized amino acids mixture (L-lysine and L-taurine HCl 99%, pH 9.74) manufactured by MJ Animal Nutrition. The second group was fed with high-grain diet containing Brachiaria brizantha hay (15% dry matter) and sodium monensin (120 mg animal -1 day-1). It was not used a negative control group to avoid metabolic disturbances. The feedlot time was 100 days. The weight measurements were performed at the beginning of the trial period and monthly, always with water restriction and fasting for 18 hours, even before slaughter. A completely randomized design was used. Methane emission was measured using the sulfur hexafluoride technique and daily dry matter intake were measured in GrowSafe system. There was no detection of lameness or laminitis in any groups and there were no changes in feed conversion ratio (FCR). The total methane emission (-77.11%) and the methane emission per dry matter intake (DMI; -57.12 %), per average daily weight gain (ADG; -71.11%) and per kilogram of carcass (-70.07%) were different between treatments (P < 0.0001), resulting in decreased emission intensities for group fed without roughage with diet containing ionized amino acids. We conclude that fed without roughage with diet containing ionized amino acids was an effective strategy as an antibiotic alternative, mitigate GHG emissions and facilitate feedlot diets management. In field conditions, the roughagelacking diets represent advantage, especially regarding its administration to a large amount of the animals just once a week or less, no need area, infra-structure and expertise to produce, preserve and feeding roughage. [ABSTRACT FROM AUTHOR]

One hundred ninety-two steers (BW = 354 ± 23.5 kg) were used in a randomized block design to evaluate the effects of ionophore and ractopamine hydrochloride (RH) supplementation strategies on performance and carcass characteristics. Twelve pens of 4 steers were assigned to each of the following treatments: unsupplemented control (CON), laidlomycin propionate (12.1 mg/kg DM) with or without RH (LPRH and LP, respectively), and monensin sodium (36.4 mg/kg DM) with RH (MSRH). Steers were fed for 151 d, of which respective treatments received RH (Actogain; Zoetis, Florham Park, NJ) at a rate of 300 mg/(animal · d) for the final 32 d. Laidlomycin was removed from the LPRH treatment during this period, as no combination feeding has been approved. Upon harvest, carcass data were collected by trained personnel, and subsequent analysis of the LM was conducted to estimate tenderness using Warner-Bratzler shear force (WBSF). Prior to RH supplementation, both LP and LPRH had greater ADG (P ≤ 0.02) and G:F (P < 0.01) than CON, whereas MSRH was intermediate. During the final 32 d, MSRH improved G:F (P ≤ 0.02) compared to all other treatments and tended to increase ADG over unsupplemented controls (P = 0.05). Cattle receiving LP without RH had significantly greater BW at d 151 than CON (P = 0.02), whereas both RH treatments tended to improve final BW (P ≤ 0.09). Ionophores improved ADG (P ≤ 0.03) and G:F (P < 0.01) for the entire feeding period, and although LP-supplemented cattle had greater DMI for the final 32 d than both RH treatments (P ≤ 0.01), intakes for the 151-d trial were similar among treatments. Carcass weights were greater (P = 0.04) in cattle fed LP with no RH than CON, where cattle yielded an average of 12 kg more HCW. Ractopamine increased LM area in MSRH-supplemented cattle (P = 0.03) and tended to increase LM area for steers receiving LPRH (P = 0.07). Longissimus steaks of MSRH-supplemented cattle had greater WBSF values than CON (P = 0.04) after 7 d of postmortem aging and greater WBSF values than LPRH steaks after 28 d (P = 0.03). All other carcass and WBSF measurements were similar among treatments. The results of this study indicate that LP supplementation without RH may yield a performance similar to and carcass responses associated with the administration of a β-agonist. These results also suggest that performance and carcass characteristics for cattle fed LP are similar to those of cattle fed monensin throughout the feeding period. [ABSTRACT FROM AUTHOR]

A total of 90 young crossbreed bulls (initial weight=228.04±7.06 kg) were used in a 171-day feeding trial in order to evaluate the combination of supplemental blend of essential oils (Crina® Ruminants; DSM Nutritional Products) plus 25-hydroxy-vitamin-D3 (HyD®, DSM Nutritional Products; EO+HyD) on growth performance and carcass characteristics in cattle finishing under tropical conditions. Cattle were blocked by weight into 2 blocks and randomly allocated to 2 treatments (9 pens/treatment, 5 bulls/pen). Cattle were fed with a steam-flaked corn-based diets (average diet NEm= 1.95 Mcal/kg during first 84-d, and 2.15 Mcal/kg during the remaining 87-d). Treatments consisted of: 1) EO+HyD supplementation along fattening period (171-d), or 2) supplementation with monensin (Rumensin®, Elanco Animal Health; 20 mg/kg diet) during the first 84-d and monensin (20 mg/kg diet) plus virginiamycin (Stafac®, Phibro Animal Health; 20 mg/kg diet) during remaining time (87-d). The average THI during course of the experiment was 76.67±2.7 with a maximum of 85.46±2.2 and minimum of 68.29±2.6. There were no statistical differences (P > 0.10) between EO+HyD and ionophores/antibiotic supplemented cattle on DM intake (7.575 vs 7.534 kg/d), average daily gain (1.433 vs 1.406 kg), or gain-to-feed ratio (0.189 vs 0.187). However, cattle fed with EO+HyD tended (P = 0.07) to have heavier carcass weight in 5.2 kg (304.9 vs 299.7 kg), showed greater LM area (89.89 vs. 82.77 cm², P < 0.01) and greater estimated retail yield (1.6%, P = 0.02) than cattle receiving ionophores/antibiotic mixture. Cattle receiving EO+HyD showed more percentage of carcass classified as Choice (14.28 vs 13.33%) and "Select" (59.52 vs 44.44%) and lower percentage of carcass classified as "Standard" (26.20 vs 42.23%). The combination of a blend of essential oils plus 25-hydroxy-Vit-D3 (EO+HyD) in finishing phase improve carcass characteristics. Supplemental EO+HyD is a viable alternative to supplemental monensin, or monensin plus virginiamycin used in growing-finishing diets for feedlot cattle. [ABSTRACT FROM AUTHOR]

Degree of unsaturation of fatty acids, which is influenced by lipid source and level of metabolism in the rumen, is a major determinant in how dietary lipids affect genes that regulate beef marbling. A total of 28 Red Norte bulls with an initial live weight of 361 ± 32 kg (P > 0.05) were used in a completely randomized experimental design to analyze the expression of genes that are involved in lipid metabolism in the longissimus dorsi (LD) when diets contained soybean grain or rumenprotected fat, with or without monensin. Treatments were arranged as a 2 x 2 factorial, with 4 treatments and 7 replicates per treatment. Half of the animals that received soybean or rumen-protected fat were supplemented with 230 mg head-1 d-1 of monensin. Gene expression was analyzed by reverse-transcription quantitative PCR (RTqPCR). Expression of sterol regulatory element-binding protein-lc (SREBP-lc) in the LD muscle was not affected by lipid source or monensin (P > 0.05). There was an interaction effect (P < 0.05) between lipid source and monensin for peroxisome proliferator-activated receptor a {PPAR-α) and stearoyl-CoA desaturase (SCD) expression, where greater gene expression was found in animals fed soybean plus monensin and the lower gene expression was found in animals fed mmen-protected fat plus monensin. Expression of lipoprotein lipase {LPL) and fatty acid-binding protein 4 {FABP4) were greater (P < 0.05) in the LD muscle of animals fed soybean. Monensin had no effect on LPL and FABP4 expression when soybean without monensin was fed, but when mmen-protected fat was fed, monensin increased LPL expression and decreased FABP4 expression {P < 0.05). Linoleic and arachidonic acids had negative correlations (P < 0.05) with the expression of PPAR-α, SCD, FABP4, and LPL genes. PPAR-α gene expression was not correlated with SREBPlc but was positively correlated with SCD, FABP4, LPL, and glutathione peroxidase {GPX1) gene expression (P < 0.001). Lipid sources and monensin interact and alter the expression of PPAR-α, SCD, acetyl CoA carboxylase a {A CA CA), LPL, FABP4, and GPX1. These changes in gene expression were most associated with arachidonic and a-linolenic acids and the ability of lipid sources and monensin to increase these fatty acids in tissues. [ABSTRACT FROM AUTHOR]

This research was designed to evaluate the effect of monensin (Elanco Animal Health, Greenfield, IN) supplementation via mineral or pressed protein block with or without a growth-promoting implant on performance of steers grazing wheat pasture in Arkansas over 2 yr. Preconditioned steers (n = 360, BW = 238 ± 5.1 kg) grazed 15 1.6-ha wheat pastures in the fall (n = 60 steers each fall, stocking rate of 2.5 steers/ha) or 30 0.8-ha wheat pastures in the spring (n = 120 steers each spring, stocking rate of 5 steers/ha). Steers in each pasture were given freechoice access to nonmedicated mineral (CNTRL; Moor-Man's Weather Master Range Minerals A 646AAA; ADM Alliance Nutrition, Inc., Quincy, IL), or were supplemented with monensin (Elanco Animal Health, Greenfield, IN) via mineral containing 1.78 g monensin/kg (RMIN; Moor-Man's Grower Mineral RU-1620 590AR; ADM Alliance Nutrition, Inc.), or pressed protein block containing 0.33 g monensin/kg (RBLCK; MoorMan's Mintrate Blonde Block RU; ADM Alliance Nutrition, Inc.). Additionally, one-half of the steers in each pasture were implanted (IMPL) with 40 mg trenbolone acetate and 8 mg estradiol (Component TE-G with Tylan; Elanco Animal Health). There was no interaction (P >0.71) between supplement treatment and growth-promoting implants, and ADG for RMIN and RBLCK were increased (P< 0.01 )over CNTRL by 0.07 to 0.09 kg/d, respectively. Implanting steers with Component TE-G increased (P< 0.01) ADG by 0.14 kg/d. The combination of these growth-promoting technologies are a cost-effective means of increasing beef production by 22% without increasing level of supplementation or pasture acreage. Utilizing ionophores and implants together for wheat pasture stocker cattle decreased cost of gain by 26%. Utilizing both IMPL and monensin increased net return by $30 to $54/steer for RMIN or $18 to $43/steer for RBLCK compared with UN IMPL CNTRL at Low and High values of BW gain, respectively. [ABSTRACT FROM AUTHOR]

Increased animal productivity has the potential to reduce the environmental impact per unit of consumable product and is believed to be the most promis-ing and sustainable mitigation technique to meet increasing demand for high quality protein. The feedlot industry uses ionophores, antibiotics, growth implants, and ß2-adrener-gic agonists to improve health and growth performance of cattle. These technologies not only increase productivity but also alter microbes in the rumen and increase nitro-gen retention in the animal, which may lead to changes in greenhouse gas (GHG), volatile organic compound (VOC), and ammonia (NH3) emissions from feedlot cattle. The present study investigated GHG, VOC, and NH3 emissions from 160 Angus crossbred steers. Steers were blocked by weight in a randomized block design and assigned to 16 pens of 10 animals each. Treatments applied were 1) control (CON; no technology applica-tion), 2) monensin and tylosin phosphate (MON), 3) monensin, tylosin phosphate, and growth implant (IMP), and 4) monensin, tylosin phosphate, growth implant, and zilpaterol hydrochloride (fed during the last 20 d of the feeding period; BAA). Cattle were on feed for an aver- age of 107 d. Performance variables (DMI, BW, ADG, and G:F) and carcass traits (HCW, dressing percent, KPH, LM area, fat thickness, marbling score, yield grade, and quality grade) were measured. Gaseous emissions were measured during the last 10 d of the feeding period when animals were housed in 4 totally enclosed identical cattle pen enclosures. To quantify gaseous emissions a 4 x 4 Latin square design (n = 4) was used. Gaseous emissions were analyzed using Proc Mixed in SAS and reported in grams per kilogram HCW per day and grams per kilo-gram per animal per hour. Treatment with IMP and BAA increased (P < 0.05) ADG, final BW, and HCW. Cattle on BAA had greater HCW and LM area (P < 0.05) and had lower (P < 0.05) CH4, methanol, and NH3 emissions per kilogram HCW than cattle on the remaining treatments. Methane emissions were similar for CON and IMP treat-ed cattle. Nitrous oxide emissions were similar across CON, MON, and IMP treated cattle and were higher in BAA treated cattle (P < 0.05). The present study provides a better understanding of how application of growth pro-moting technologies to feedlot steers affects GHG, VOC, and NH3 emissions per kilogram of product. [ABSTRACT FROM AUTHOR]

Use of coproducts such as corn and sorghum distillers grain (DG) and corn gluten feed (CGF) in beef cattle finishing diets has increased significantly in recent years, but research to evaluate the efficacy of traditional feeding practices and feed additives when coproducts are fed has not kept pace. Grain processing methods that increase starch availability seem equally effective in traditional diets and diets with wet CGF; however, in wet DG diets, some studies have shown decreased efficacy of grain processing, whereas others have shown no evidence of an interaction. Limited data are available on the physical and nutritional value of the fiber in wet DG and CGF; however, CGF at concentrations ≥25% of the dietary DM seems to have some degree of "roughage value," whereas fiber in wet DG seems to have less potential to replace traditional roughage sources. There is little evidence that efficacy of ionophores and antibiotics is changed with diets based on wet CGF or that they interact when wet DG is added to finishing diets. In vitro data from our laboratory suggest no loss of monensin efficacy in substrates with 15% (DM basis) corn DG in terms of changes in VFA and gas production. Moreover, efficacy of ionophores was not affected in our data by diet substrates with increasing concentrations of S, and in vitro H2S production in substrates containing wet DG seems predictable from substrate S concentrations. Nonetheless, limited in vivo data indicate decreased ruminal acetate-to-propionate ratios in diets with increased wet DG, which may minimize the potential for ionophores to alter propionate. Likewise, in vivo results indicate that feeding wet DG may decrease ruminal pH; thus, to maximize DMI and minimize digestive upsets, optimal concentrations of roughage need to be evaluated in diets containing wet DG. Research is needed on other potential technology interactions with coproducts of biofuel production such as glycerol and condensed distillers solubles. The effects of yeast products and live microbial cultures in diets with coproduct feeds have generally not been determined. Because of the elevated fiber concentrations in CGF and DG, effects of exogenous enzyme preparations on ruminal fermentation and fiber digestion of diets containing these coproducts should be evaluated. [ABSTRACT FROM AUTHOR]

ABSTRACT: Effects of 3 ionophores and 2 antibiotics on in vitro H[sub2]S production, IVDMD, total gas production, and VFA profile with or without added S were examined. In Exp. 1, ruminal fluid from 2 ruminally cannulated steers fed a steam-flaked corn-based diet (75% concentrate) without ionophore and antibiotics for 28 d before collection was usedto inoculate in vitro cultures. Treatments were control (no ionophore or antibiotic), 3 ionophores (lasalocid sodium and monensin sodium at 5 mg/L or laidlomycin propionate at 1.65 mg/L), and 2 antibiotics (chlortetracycline hydrochloride at 5 mg/L and tylosin tartarate at 1.25 mg/L). Cultures also had 0 or 1.75 mg of S/L (from sodium sulfate). No S x ionophore-antibiotic treatment interactions were noted (P> 0.53) for IVDMD, total gas production, and H[sub2]S production. Hydrogen sulfide (μmol/g of fermentable DM) was increased (P < 0.001), and total gas production tended (P = 0.09) to be increased with additional S; however, IVDMD was not affected by added S (P = 0.90). Production of H[sub2]S was not affected by ionophores or antibiotics (P> 0.18). On average, IVDMD (P = 0.05) was greater for ionophores than for antibiotics, whereas total gas production was less for ionophores than for control (P < 0.001) and antibiotics (P <0.001). Molar proportions of acetate (P < 0.01) and acetate:propionate (P < 0.01) were decreased and propionate was increased (P < 0.001) in ionophore treatments when no S was added, but when S was added there were no differences (P > 0.20) in acetate, propionate, or acetate:propionate between ionophores and control (S x treatment interaction, P = 0.03). In Exp. 2, the effects of ionophore-antibiotic combinations with added S were examined using the same procedures as in Exp. 1. Treatments were control, monensin plus tylosin (MT), and lasalocid plus chlortetracycline (LCTC), with concentrations of the ionophores and antibiotics as in Exp. 1. No differences were observed among treatments for H[sub2]S production (P> 0.55). Treatments MT and LCTC tended (P = 0.06) to increase IVDMD and decreased (P = 0.02) gas production vs. control. Proportion of acetate (P 0.01) and acetate:propionate (P < 0.01) were decreased and propionate increased (P = 0.01) for both MT and LCTC compared with control. These data suggest that when S is approximately 0.42% of substrate DM, the 3 ionophores and 2 antibiotics we evaluated did not affect production of H[sub2]S gas in an in vitro rumen culture system. [ABSTRACT FROM AUTHOR]

Acute and subacute ruminal acidosis, bloat, liver abscesses, and polioencephalomalacia (PEM) were reviewed with respect to contributions published in the Journal of Animal Science (JAS) regarding these metabolic and digestive disorders in beef cattle. Increased grain feeding and expansion of the feedlot industry in the 1960s led to considerable research on acidosis, and. early publications defined ruminal changes with acute acidosis. The concept of subacute acidosis was developed in the 1970s. Significant research was published during the 1980s and 1990s on adaptation to high-grain diets, effects of ionophores, and the development of model systems to study ruminal and metabolic changes in acidosis. Since 2000, JAS publications on acidosis have largely focused on individual animal variability in response to acid loads and the role of management strategies in controlling acidosis. Increased grain feeding also was associated with an increase in the incidence of liver abscesses, which were quickly linked to insults to the ruminal epithelium associated with acidosis. The role of antibiotics, particularly tylosin, in decreasing the incidence and severity of liver abscesses was a significant contribution of JAS publications during the 1970s and 1980s. Papers on bloat were among the earliest published in JAS related to metabolic and digestive disorders in cattle. Noteworthy accomplishments in bloat research chronicled in JAS include the nature of ruminal contents in legume and feedlot bloat, the role of plant fractions and microbial populations in the development of bloat, and the efficacy of poloxalene, ionophores, and, more recently, condensed tannins in decreasing the incidence and severity of bloat. Although less research has been published on PEM in JAS, early publications highlighting the association between PEM and ruminal acidity and the role of thiaminase in certain forms of the disorder, as well as more recent publications related to the role of sulfur in the development of PEM, are noteworthy contributions. Since the 1940s, outstanding and often-cited review articles have made JAS a highly visible source of information on these disorders. Thus, JAS has played a significant role as a repository for information pertaining to metabolic and digestive disorders in cattle and other ruminants, and it will no doubt continue to be a premier resource for information on these conditions during the second century of the American Society of Animal Science. [ABSTRACT FROM AUTHOR]

Three experiments with factorial arrangements of treatments were designed to test the efficacy of avian-derived polyclonal antibody preparations (PAP) against Streptococcus bovis (PAP-Sb) or Fusobacterium necrophorum (PAP-Fn) in reducing ruminal counts of target bacteria in beef steers supplemented or not with feed additives (300 mg of monensin/ d and 90 mg of tylosin/d; MT). Feeding increasing doses of PAP-Sb in Exp. 1 or a single dose in Exp. 2 reduced S. bovis counts in a cubic fashion (P = 0.014). In Exp. 1 and 2, inclusion of MT in the diet had no effect (P > 0.05) on ruminal S. bovis counts. In Exp. 2, ruminal pH was increased (P < 0.05) by feeding PAP-Sb, MT, and PAP-Sb plus MT. Ruminal F. necrophorum counts were reduced by feeding PAP-Fn (P = 0.002) and MT (P < 0.001). Reduction in ruminal F. necrophorum counts was greater (P = 0.008) when feeding MT alone than when feeding PAP-Fn and MT together. In Exp. 3, ruminal S. bovis counts were not affected (P = 0.64) by PAP-Fn. Ruminal pH was not affected (P = 0.61) by feeding PAP-Fn, and the total anaerobic bacterial count was not affected (P > 0.05) by either PAP-Sb or PAP-Fn in Exp. 1 or Exp. 3. In conclusion, PAP of avian origin and against S. bovis or F. necrophorum were effective in reducing target ruminal bacterial populations. These PAP could be effective in preventing the deleterious effects associated with these bacteria, and possibly in enhancing animal performance. [ABSTRACT FROM AUTHOR]

Use of ionophores in cattle diets has been proposed as a strategy for mitigation of enteric CH4 emissions. Short- and long-term effects of feeding a single ionophore (monensin) or rotation of 2 ionophores (monensin and lasalocid) on enteric CH4 emissions were evaluated in 36 Angus yearling steers (328 ± 24.9 kg of BW) over a 16-wk period. Steers were randomly assigned to 6 dietary treatments of 6 steers each. The 6 diets were low-concentrate without ionophore supplementation, low-concentrate with monensin supplemenration, low-concentrate with a 2-wk rotation of monen- sin and lasalocid supplementation, high-concentrate without ionophore supplementation, high-concentrate with monensin supplementation, and high-concentrate with a 2-wk rotation of monensin and lasalocid supplementation. Daily enteric CH4 emissions, as measured using the SF6 tracer gas technique, ranged from 54.7 to 369.3 L/steer daily. Supplementing ionophores decreased (P < 0.05) enteric CH4 emissions, expressed as liters per kilogram of DMI or percentage of GE intake, by 30% for the first 2 wk and by 27% for the first 4 wk, for cattle receiving the high-concentrate and low-concentrate diets, respectively. Cattle fed a rotation of ionophores did not (P > 0.05) exhibit a greater decrease and did not (P > 0.05) have a longer period of depressed enteric CH4 emissions compared with cattle receiving monensin only. Ionophore supplementation did not (P > 0.05) alter total ruminal fluid VFA concentration; however, the acetate:propionate ratio and ammonia-N concentration in ruminal fluid were decreased (P < 0.001) from the time that ionophores were introduced to the time they were removed from the diets. Both monensin and the rotation of monensin and lasalocid decreased (P < 0.001) total ciliate protozoal populations by 82.5% in the first 2 wk and by 76.8% in the first 4 wk during which they were supplemented in the high-concentrate and low-concentrate diets, respectively. Original ciliate protozoal populations were restored by the fourth and sixth week of supplementation when cattle were fed the high- or low-concentrate diets, respectively. No significant change was observed thereafter. These data suggest that the effects of ionophores on enteric CH4 production are related to ciliate protozoal populations and that ciliate protozoal populations can adapt to the ionophores present in either low- or high-concentrate diets. Rotation of monensin and lasalocid did not (P > 0.05) prevent ciliate protozoal adaptation to ionophores. [ABSTRACT FROM AUTHOR]

Presents abstracts of several studies on dairy animal growth and development. "Effects of Weaning and Ionophore on Selected Blood Metabolites and Growth in Dairy Calves," by J. L. Klotz and R. N. Heitmann; "The Effects of Feeding Chlortetracycline on the Performance of Breeding Age Dairy Heifers," by E. D. Reid and P. S. Erickson; "Analysis of In Vitro Body Composition of New Born Calves Using Dual Energy X-Ray Absorptiometry (DXA)," by J. Hampe, S. Nueske, A. M. Scholz and M. Foerster.

Presents abstracts of several articles on ruminant nutrition for animals. "Monensin or Decoquinate in High Concentrate Diets Fed to Santa Ines Lambs," by I. Susin, C. Q. Mendes, A. V. Pires and I. U. Packer; "Rate and Extent of In Situ DM Disappearance of Feedstuffs in Cows Fed Different Strains of Yeast," by J. C, Silva and L. W. Greene; "Fermentable and Nutritional Characteristics of Fermented Feedstuffs Added Aspergillus Oryzae and Saccharomyces Cerevisiae," by P. Byung Ki, R. Chang Six and S. Jong Suh; "Effect of Supplemental Chromium on Tissue Chromium Concentrations in Cattle," by J. W. Spears, K. E. Lloyd, M. E. Tiffany and M. T. Socha.

Two taste preference studies were conducted using six Holstein heifers in each experiment to determine preferences for no ionophore, lasalocid, or monensin in the diet. En Exp. 1, individually penned (approx. 5 mo old; 220 ± 14 kg BW) heifers were fed a basal total mixed ration containing 46% corn silage, 46% grass haylage, and 8% soybean meal (DM basis). There were five treatments (mg/kg BW-1·d-1): 0 ionophore (control), lasalocid (IL), 2 lasalocid (2L), 1 monensin (1M), or 2 monensin (2M). Jonophores were provided as part of the mineral mix that had been added to the control diet and through an ionophore grain by-product mix to make the 2L and 2M treatments. All five diets were offered for 7 d, with the first 2 d for adaptation and the last 5 d for measurement of feed intake. The most preferred diet was then removed and the study continued with the four remaining diets. The most preferred diets were again eliminated sequentially, so that only two diets remained on d 13 and 14. Each feeding segment ranking of treatment preferences was determined based on the weight of feed refused at the end of each feeding segment. In Exp. 2, six 6-wk-old heifers (75 ± 5 kg of BW) were individually fed either 0, 1L, or 1M in a study similar to Exp. 1, except that the most preferred diet was removed after 4 d, with the first day for adaptation and the last 3 d for measurement of feed intake. In Exp. 1, orthogonal contrasts indicated that heifers preferred the 1L and 2L diets over the IM and 2M diets. Preferences between diet concentrations of ionophores (1 and 2 mg/kg of BW; Exp. 1) and the control and ionophore treatments did not differ, nor was there an interaction between ionophores and their concentration. Dairy heifers previously fed lasalocid prefer lasalocid over monensin when given a choice; however, heifers without previous exposure to an ionophore did not indicate a preference (Exp. 2). [ABSTRACT FROM AUTHOR]

Two experiments, Trial 1 (in vitro) and Trial 2 (in vivo), were conducted to examine the effects of ionophores, monensin, laidlomycin, and laidlomycin propionate on whole-animal O[sub 2] consumption, organ weights, jejunal glucose absorption, and O[sub 2] utilization, as well as growth, feed and water consumption, and feed efficiency. In Trial 1, 30 male Swiss-Webster mice, 8 wk old, were used to measure the in vitro effects of each of the ionophores at concentrations of 1.62 or 16.2 mM. Six combinations of three ionophores at two concentrations resulted in a total of eight treatments. All eight treatments were exposed to jejunal rings from a single mouse for a total of 30 observations per treatment. Jejunal rings were exposed to each ionophore treatment for 15 min. Laidlomycin propionate (16.2 mM) decreased (P < 0.02) glucose absorption, as estimated by H³-3-O-methyl glucose uptake compared with all other treatments, whereas laidlomycin propionate (1.62 mM) increased (P = 0.032) jejunal DM content compared with 16.2 mM laidlomycin propionate. In Trial 2, 40 5-wk-old mice were allotted into four treatments—control and 16.2 mM each of monensin, laidlomycin, and laidlomycin propionate—for a total of 10 observations per treatment. Ionophores were administered via the drinking water for 14 d. No ionophore treatment had any effect on whole-mouse O[sub 2] consumption. Monensin increased (P = 0.004) stomach size and decreased (P = 0.049) the efficiency of BW gain compared with controls. Laidlomycin propionate decreased (P = 0.032) the percentage of whole jejunum oxygen consumption due to oubain-sensitive respiration compared with control. The efficiency of intestinal glucose absorption was not changed due to treatment in either trial. Under the conditions of these studies, monensin, laidlomycin, and laidlomycin propionate had minimal and inconsistent effects on jejunal function and energy utilization in mice. This investigation suggests that changes... [ABSTRACT FROM AUTHOR]

Escherichia coli O157:H7 and Salmonella are widely recognized as important agents of foodborne disease with worldwide distribution. The use of ionophores in feeding growing ruminants is widespread in the United States and has attracted recent interest due to the apparent temporal relationship between initial ionophore use and the increase in human E. coli O157:H7 cases. Two experiments were conducted to evaluate the effects of short-term feeding of ionophores on fecal shedding, intestinal concentrations, and antimicrobial susceptibility of E. coli O157:H7 andS. typhimurium in growing lambs. Sixteen lambs were used in each experiment, four lambs per treatment group: monensin, laidlomycin propionate, bambermycin, and a control treatment. Lambs were fed a grain and hay (50:50) diet with their respective ionophore for 12 d before experimental inoculation with E. coli O157:H7 or S. typhimurium. Animals were maintained on their respective diets an additional 12 d, and fecal shedding of inoculated pathogens was monitored daily. Lambs were killed and tissues and contents were sampled from the rumen, cecum, and rectum. No differences (P > 0.05) in fecal shedding of Salmonella or E. coli O157:H7 were observed due to treatment. Occurrence of Salmonella or E. coli in luminal contents and tissue samples from the rumen, cecum, and rectum did not differ (P > 0.05) among treatments. Feeding monensin decreased (P < 0.05) the incidence of scours in sheep infected with Salmonella compared with the other treatments. No differences in antimicrobial susceptibility were found in any of Salmonella or E. coli O157:H7 isolates. Results from these studies indicate that short-term ionophore feeding had very limited effects on E. coli and Salmonella shedding or on antimicrobial susceptibility in experimentally infected lambs. [ABSTRACT FROM AUTHOR]

Presents information on an experiment which evaluated the effect of the ionophore laidlomycin propionate on steer performance and ruminal nitrogen metabolism. Ruminal characteristics; Experimental procedure; Results and discussion.

The major focus of animal nutrition studies is the efficient production of meat, milk, and eggs. Much has changed in animal nutrition over the past forty years that have facilitated these improvements in efficiencies. While advances in technologies have been quantum and research methodologies have improved yet there remains a need for traditional methodologies. Feed intake, growth rate, and feed efficiency still define success. Nutrient balance and digestibility studies, which originated in the 1800s, provide much-needed information regarding the value of feedstuffs. Bioassays are still needed to ascertain the requirements of each nutrient as these are ever-changing because animals are ever-changing. Genetic improvement dictates that requirements be continually reassessed and refined. Technologies that impact animal production, e.g. growth promotants, ionophores, repartitioning agents, hormones, nutraceuticals, etc. may all impact these requirements and should be considered. The challenge for the next generation of researchers will be to interface the technologies, genomic tools, and traditional approaches to provide targeted nutritional strategies tailored for individual genetic potential. Researchers must have a broader grasp of all the available tools if we ever hope to fully implement technologies and interface these with new knowledge to provide optimal nutrition. Changes in consumer preferences will continue to provide new challenges that must be met by research from a continually decreasing pool of researchers. This too will necessitate broader skill sets and increased multi-disciplinary support. The next 40 years will bring even greater changes and challenges. Animal agriculture must continue to improve. A goal of increased efficiency will not be enough. We must improve on every aspect of health, well-being, and perception. Nutrition research will be a component of these improvements but improving technologies will permit the evaluation of much more. Consumers will demand an optimum existence be demonstrated for each animal. [ABSTRACT FROM AUTHOR]

Presents information on a study which investigated the effects of energy source and ionophore supplementation on lamb performance, visceral organ mass and carcass characteristics. Experimental procedures; Results and discussion; Implications.

Provides information on a study which compared the effects of laidlomycin propionate and monensin on cell growth, glucose fermentation and glucose uptake in Streptoccocus bovis strain JB1 and Selenomonas ruminantium strain HD4. Theoretical background; Materials and methods; Results and discussion.

Investigates the effect of narasin on apparent nitrogen and dry matter digestibilities and large intestine in finishing swines. Materials and methods used; What is narasin; Previous studies which identified the microbial environment of the swine; Results and discussion.

The article discusses a study conducted to substantiate the hastening of puberty due to ionophore supplementation in spring-born beef heifers. It also intends to determine whether control of subclinical internal parasitism by anthelmintic administration will have direct effect on age and weight at puberty of bef heifers. It is noted that total weight gain in beef heifers was similar for all treatments.

The article discusses a report on the efficacy of laidlomycin propionate to reduce ruminal acidosis in cattle. It states that rate of gain fermentation in the rumen has a major influence on incidence of acidosis and on subsequent cattle performance. It adds that the donor steers were fed the diet containing no laidlomycin throughout the trial. Analysis of variance procedures for a replicated Latin square were reportedly performed.

The article discusses a report on ruminal microbiology, biotechnology, and ruminant nutrition. It notes that toxicity of ionophores stems from their ability to translocate ions across biological membranes and consequently to disrupt transmembrane ion gradients. It adds that the cloned genes can be readily detected using chromogenic substrates, and the enzymes are relatively stable.

The article reports on a study which examined ionophore binding with radiolabeled monensin and lasalocid. It was concluded that monensin binding was reduced by a large amount when the mixed ruminal lasalocid bacteria were pretreated using Tris+EDTA. Addition to monensin to animal feed is also discussed.

The article focuses on an experiment which investigates the impact of lasalocid and monensin plus tylosin on metabolic hormones of crossbred beef steers who were given a 90 percent of concentrate diet. Topics discussed include change in serum minerals in beef cattle due to lasalocid and monensin, no impact of ionophores on serum metabolic hormones and no impact of treatments on blood composition of cattle.

The article looks at a study regarding effect of monensin supplementation on ruminal ammonia accumulation in vivo and the numbers of amino acid-fermenting bacteria. It mentions addition of monensin to the diets caused in ruminal ammonia at all levels of soybean supplementation in specific activity of ammonia production. It also mentions ruminal amino acid deamination and ammonia production and concentration of bacterial protein in ruminal fluid.

The article offers a review on the nutritional management of replacement beef heifers. Topics discussed include the process of developing heifers as replacements which must begin during the cowcalf production phase; and discusses several management techniques that can be used both pre and post weaning, including using anthelmintics, anabolic growth implants, and ionophore. Article concludes management aspect involved with the raising of beef replacement heifers such as breed composition.

The article offers information on a study regarding Supplemental Fat and Ionophores in Finishing Diets, Feedlot Performance and Ruminal Digesta Kinetics in Steers. It mentions that supplemental fat and ionophores are often used concurrently in beef cattle finishing diets, in the study showed no interactive effects between monensin and fat supplementation, interactions between fat and ionophores have been noted in other studies when lasalocid or monensin were included in the diet.

The article looks at a study regarding effect of influence of addition of monensin to an alfalfa hay diet on net portal and hepatic nutrient flux in steers. It mentions addition of monensin increased the molar percentage of ruminal propionate and decreased ruminal isobutyrate and isovalerate. It also mentions absorption from feeding monensin were not consistent with its role in increasing ruminal propionate production and net portal energy flux did not change.

The article looks at a study by net carbohydrate and protein system for evaluating cattle diets which has a kinetic submodel that predicts ruminal fermentation. It mentions ruminal microbial population is divided into bacteria that ferment structural carbohydrate (SC) and those that ferment nonstructural carbohydrate (NSC). It also mentions protein-sparing effect of ionophores is accommodated by decreasing the rate of peptide uptake.

The article examines the impact of ionophore lysocellin on ruminal fermentation as well as populations of microbes. In vitro batch cultures with combined ruminal microorganisms were created from steers who were given soybean and alfalfa diet. It was observed that lysocellin tended to increase OM digestion in corn-based diets and reduced OM digestion in barley-based diets.

Two experiments were conducted to evaluate corn dried distiller's grains with solubles (DDGS) and corn gluten feed (CGF) as replacements for soybean meal (SBM) and determine the impact of an ionophore on Boer goat growth performance and carcass characteristics. In Exp. 1, 75 Boer-goat kids (initial BW 26.9 ± kg) were allotted to one of 5 dietary treatments: 1) Negative control (100% SBM, 0% DDGS and 0% CGF; 100SBM); 2) Positive control (100% DDGS, 0% CGF and 0% SBM; 100DDGS); 3) 66% DDGS, 33% CGF and 0% SBM (66DDGS/33CGF); 4) 66% CGF, 33% DDGS and 0% SBM (33DDGS/66 CGF); and 5) 100% CGF, 0% DDGS and 0% SBM (0DDGS/100CGF). Dietary treatment did not impact (P = 0.21) growth. In Exp. 2, 72 Boer-goat kids (initial BW 21.7 ± kg) were allotted to one of 4 dietary treatments in a 2 X 2 factorial with 2 protein sources and 2 ionophore inclusions: 1) SBM/no ionophore (SBM-NI); Diet 2) SBM with ionophore (SBM-I); Diet 3) DDGS/no ionophore (DDGS-NI); and Diet 4) DDGS with ionophore (DDGS-I). On d 21, goats were split into 2 groups according to their protein source and fed an additional d 10 (Group 1: DDGS-I; Group 2: SBM-I). The 15 heaviest goats from each group were harvested and carcass data collected. The protein source X ionophore interaction was not significant (P = 0.15) for any measured response criteria. Goats fed a diet with SBM had significantly increased (P = 0.04) ADG compared to goats fed DDGS. No evidence of difference was observed (P = 0.10) for ADFI or G:F. Dietary treatment did not impact (P > 0.05) carcass characteristics. In summary, these data suggest that corn co-products can be economically included in Boer-goat diets, however their impact on growth performance is variable compared to that of soybean meal. [ABSTRACT FROM AUTHOR]

Presents abstracts of studies about dairy production. "Leptin: What Is Its Role in the Dairy Cow," by D. C. Barbour and E.H. Jaster; "Factors Affecting Fertility Rates in Embryo Transfers," by J. Hockney; "Efects of Pasteurization on Colostrum Quality," by M.L. Moody.

The objective with this trial was to evaluate the potential of ionophore (33 mg of monensin/kg DM) and condensed tannins (offered at 3% of DMI) to mitigate enteric methane production by beef steers fed corn dried distiller's grain (DDG) in finishing diets. Eight British-cross steers, 12 ± 2 mo old weighing 212 ± 11.7 kg, were assigned to two replicated Latin rectangle design (LRD, n = 32) to evaluate four treatments: control (no DDG or feed additive), DDG (40% DDG inclusion), DDGI (40% DDG inclusion + ionophore), and DDGCT (40% DDG inclusion + condensed tannins). Animals were randomly assigned to the diets fed at an intake of 2.5% of BW (DM basis). Animals were adapted to the diets for 14 d prior to collection periods. Enteric methane measurements were collected in two open circuit respiration, pull mode chambers in which animals were fed twice daily 0800 and 1600 h. The data acquisition consisted of a 48-h period of measurements (runs). The statistical analysis was performed using random coefficients model methodology in SAS 9.4 (SAS Inst., Cary, NC) assuming fixed effects of treatment (diet) and random effects of animals and runs. An effect of diet was observed (P < 0.001) for CH4 (L/d) production at 12h, 24h and 36h, but not at 48h. The addition of DDG significantly decreased CH4 (L/d; P < 0.001) at 12h, 24h, 36h, and 48h when compared to the control diet. Additionally, the inclusion of ionophore and condensed tannins decreased CH4 production (L/d; P < 0.001) at 12h, 24h and 36h, but only DDGCT decreased CH4 production (L/d; P < 0.001) at 48h when compared to the control diet, suggesting a more prolonged effect of condensed tannins over enteric CH4 mitigation. At 24h DDG, DDGI, and DDGCT diets were not different for CH4 production (L/d; P < 0.001), but at 36h DDGI and DDGCT had a significant effect on CH4 mitigation when compared to the control or DDG. Our results indicated that DDGCT was a prominent CH4 reducer over 48h followed by the DDGI treatment. The inclusion of ionophore and condensed tannins to DDG-based diets significantly affected enteric CH4 production (L/d; P < 0.001). [ABSTRACT FROM AUTHOR]