Feedlot Cattle Diets Research Articles

153 Use of probiotics in feedlot diets

Abstract The Food and Agricultural Organization of the United Nations and World Health Organization classifies probiotics as live microorganisms that have health benefits when fed to animals. While the original purpose of probiotic use in beef cattle was to enhance rumen health and to establish a healthy gastrointestinal tract microflora in young calves, probiotic use in finishing cattle has been steadily increasing. The reason for this increase in use of probiotics in feedlot cattle diets is primarily due to public health concern with antimicrobial resistance from the use of antimicrobial technologies in feedlot cattle diets to improve performance and reduce the incidence of disease. Feedlot cattle consuming high concentrate diets for extended periods of time can experience shifts in rumen microflora that may be detrimental to rumen health which can impact overall animal performance. There are several different strains of probiotics (e.g., lactic acid producing, lactic acid utilizing bacteria,) that can function to optimize the microbial populations within the gastrointestinal tract to improve gut health. With improved gut health, improvements in nutrient digestion, absorption, immune function, and barrier function are possible. Several recent experiments supplementing feedlot cattle with probiotics have reported improved ADF digestibility, increased ruminal pH, improved ruminal lactic acid clearance, inhibited C. perfringens Types A and C growth in vitro, increased red blood cell superoxide dismutase activity, and improved average daily gains during certain portions of the feeding period. However, other probiotic supplementation experiments have not observed improvements in growth and health responses in feedlot cattle. The reason for the discrepancies between the experiments may be due to differences in animal production scenarios, the ingredient and nutrient composition of the basal diet, dosage of the probiotic, and the bacterial composition of the probiotic. Future research investigating the impact of individual strains of probiotics and combinations of different probiotic bacteria is warranted.

PSVI-1 Backgrounding and finishing systems for cattle fed corn silages and corn grains differing in amylase expression

Abstract Amylase is a key enzyme involved in the hydrolysis of starch, which typically constitutes the predominant source of energy in feedlot cattle diets. Performance of cattle during the backgrounding phase can influence performance during the subsequent finishing phase. Our objective was to assess growth performance of backgrounding steers fed diets that contained combinations of corn silage (S) and steam-flaked corn (G) from hybrids with high amylase expression (Enogen corn; E; Syngenta Seeds, LLC) or common corn hybrid (C), as well as subsequent finishing performance, carcass characteristics, and liver abscess incidence when fed G produced from the same hybrids. Crossbred steers (n = 911; 306 ± 8 kg initial body weight) were assigned randomly to one of four backgrounding treatments with 12 replicates in a randomized complete block experiment using a factorial treatment arrangement. Factor 1 consisted of two corn silage hybrids (ES or CS), and factor 2 consisted of two SFC hybrids (EG or CG). In the subsequent finishing phase, animals were assigned to one of two treatments consisting of two grain hybrids (EG or CG) with 24 replicates per treatment. Backgrounding diets (dry basis) contained 20.1% flaked corn and 41.6% corn silage, and finishing diets contained 81.5% flaked corn with triticale silage as a common roughage source. There was no three-way interaction for measures of interest, and no differences among treatment combinations with respect to average daily gain (ADG) or incidence of abscessed livers (P > 0.10). Steers fed CG during the backgrounding phase ate more than steers fed EG (P = 0.04), thus leading to improved overall efficiency of steers fed EG in the backgrounding phase compared with their counterparts fed CG (P < 0.01; Table 1). Overall efficiency tended to be greater for cattle fed CG during the finishing phase (P = 0.06) compared with cattle fed EG during the finishing phase. There was a tendency for interaction between G fed in the backgrounding and G fed in the finishing phase for hot carcass weight (P = 0.07), such that steers fed the same hybrid in both phases had greater carcass weight compared with those fed different hybrids in the backgrounding and finishing phases. Type of grain fed in the backgrounding and finishing phases, but not silage, impacted overall system efficiency.

296 Effects of dietary antimicrobials on the ruminant gastrointestinal tract microbiome

Abstract Monensin, tylosin, and chlortetracycline (CTC) are antimicrobials frequently employed in high grain feedlot cattle diets to inhibit liver abscesses and enhance growth. However, increased public concerns regarding antibiotic resistance have created a pressing need to develop alternative strategies. A more mechanistic understanding of how antimicrobial drugs effect the microbiome in the ruminant gastrointestinal tract (GIT) may help develop effective alternatives. Therefore, the objective of this study was to determine changes in the GIT microbiome of grain-fed feedlot steers after antimicrobial drug administration. Thirty individually housed Angus x Simmental steers [body weight (BW) = 355 ± 16.8 kg] previously fed a 56% forage diet were immediately transitioned to a 93% concentrate diet and assigned to one of three treatments (10 steers/treatment): 1) control, without antibiotics, 2) 75 mg of tylosin and 200 mg of monensin per animal per day (TYLMON), and 3) 70 mg of CTC per animal per day. Fecal samples were collected on d 0, 7, 14, 28, 56, 112, and at slaughter and digesta were obtained from the rumen, jejunum, and cecum at slaughter. DNA was extracted from samples, amplified via 16S PCR, and sequenced. Jejunal samples had the least alpha diversity compared with ruminal, cecal, or fecal samples (P < 0.001). There were no differences in measures of alpha diversity in the ruminal, jejunal, or cecal digesta at slaughter (P ≥ 0.10). However, overall measures of alpha diversity (Shannon entropy, observed features) in feces were greater in CTC-fed steers (P ≤ 0.009) as well as in TYLMON-fed steers (P ≤ 0.04) compared with control steers. Measures of alpha diversity for all treatments decreased in feces from d 0 to 7, then increased from d 7 to slaughter (time effect, (P ≤ 0.001). There were no differences in fecal alpha diversity between treatment groups on d 0 (P ≥ 0.50), but by d 28 both TYLMON and CTC treated steers had greater fecal alpha diversity compared with the control steers (P ≤ 0.05). With regard to differential abundance, Phascolarctobacterium and Prevotellaceae UCG-003 were more abundant in feces of control steers relative to antimicrobial treated steers (P < 0.05). Bifidobacterium, Dorea, CAG-56, and Erysipelotrichaceae UCG-003, were the 4 genera found to be in the greatest abundance in the feces of TYLMON-fed relative to control steers (P < 0.05). Akkermansia, Succinivibrio, and Turicbacter were the 3 genera found to be in the greatest abundance in the feces of CTC-fed compared with control steers (P < 0.05). Taken together, these data suggest that differences in the microbiome associated with dietary antimicrobial treatment occur to a greater extent in the lower sections of the GIT, and that these changes in the microbiome occur after 28 d of feeding.

Effects of feeding α-amylase-expressed corn silage and grain on performance, enteric methane production, and carcass characteristics in beef steers.

An experiment was conducted to evaluate the effects of feeding Enogen feed corn (EFC) silage or EFC grain with different grain processing (dry-rolled corn vs. whole-shelled corn) in feedlot cattle diets. Total 68 Angus cross-bred steers were blocked by body weight and the treatments (diets) were randomly assigned to steers in each block: a basal diet with isoline corn silage and isoline dry-rolled corn grain (IIR); the basal diet with EFC silage and isoline dry-rolled corn grain (EIR); the basal diet with EFC silage and EFC dry-rolled grain (EER); and the basal diet with EFC silage and EFC whole-shelled grain (EEW). Isoline refers to the isogenic counterpart of Enogen corn silage or grain. Steers received the assigned treatment over 32wk of the entire experiment (backgrounding and finishing) until harvested. Part of the steers (eight blocks) in each treatment were used to measure CH4 production (g/d) using the GreenFeed and CH4 production per unit of DMI. All data were analyzed using a mixed procedure of SAS in a randomized complete block design, considering diet as a fixed effect and block as a random effect. Steers fed the EIR diet increased (P = 0.03) DMI compared to IIR during the backgrounding phase. However, feeding EFC silage or grain did not affect body weight, average daily gain, and feed efficiency during backgrounding and finishing phases. Feeding EEW decreased (P ≤ 0.05) body weight, average daily gain, feed efficiency, and tended to decrease (P = 0.06) hot carcass weight compared to EER during the finishing phase. Methane production per unit of DMI decreased (P = 0.02) for steers fed EIR compared with steers fed IIR only during the backgrounding phase. Feeding EFC grain had no effect on CH4 production (g/d) in both phases. In conclusion, feeding EFC silage or grain did not improve the performance of beef steers during the backgrounding and finishing phases in the current experiment condition. Methane production per unit of DMI was reduced for steers fed EFC silage compared with isoline corn silage only during the backgrounding phase.

Inclusion of exogenous enzymes in feedlot cattle diets: Impacts on physiology, rumen fermentation, digestibility and fatty acid profile in rumen and meat

The objective of this study was to evaluate if the inclusion of a blend composed of exogenous enzymes (amylase, protease, cellulase, xylanase and beta glucanase) in the individual and combined form in the feedlot steers diet has benefits on the physiology, rumen fermentation, digestibility and fatty acid profile in rumen and meat. The experiment used 24 animals, divided into 4 treatments, described as: T1-CON, T2-BLEND (0.5 g mixture of enzyme), T3-AMIL (0.5 g alpha-amylase), T4-BLEND+AMIL (0.5 g enzyme blend+ 0.5 g amylase). The concentration of mineral matter was higher in the meat of cattle of T4-BLEND+AMIL. A higher proportion of monounsaturated fatty acids was observed in the T3-AMIL group when compared to the others. The percentage of polyunsaturated fatty acids was higher in the T2-BLEND and T4-BLEND+AMIL compared to the T1-CON. The combination of exogenous enzymes in the diet positively modulate nutritional biomarkers, in addition to benefits in the lipid and oxidative profile meat.

426 Forages Containing Plant Secondary Compounds Can Improve Digestibility, Rumen Ammonia and Rumen Metabolites of Pasture: an in Vitro Continuous Culture Case Study

Abstract Forages containing plant secondary metabolites (PSM) have been investigated for use in reducing nitrogen waste in feedlot and dairy cattle diets but use as supplements to grazing beef cattle to capture the positive effects of PSM is unclear. Here we investigate potential improvement in rumen digestibility and metabolome, rumen ammonia production and flow from feed protein due to PSM bioactivity in forages used to supplement pasture grass using in vitro methods. Can PSM-containing forages offer a practical way to improve range nutrition and provide delivery of phytochemical benefits? Phytochemical- containing forages birdsfoot trefoil (BFT), sainfoin (SAN), small burnet (SMB) and cicer milkvetch (CMV) supplemented grass pasture diets (200 g/kg of DM). In vitro true dry matter digestibility was determined using 2-stage in vitro methods. Randomly assigned diets of PAS supplemented with one of the PSM-containing forage diets (PAS+X) or not supplemented (PAS) were randomly applied to in vitro dual flow continuous culture (CC) vessels inoculated with grazing beef cow rumen fluid as a metabolic host. For 2-stage digestibility, SMB digestibility exceeded that of CMV, followed by BFT and SAN. The grass diet (PAS) was the least digestible (Table 1). Saponin was detected in CMV samples, which is a new finding. For CC, compared with PAS, minimum culture pH for PAS+CMV was highest (P < 0.02) but no differences were observed in pH between PAS, and PAS+BFT and PAS+SAN. Compared with PAS, the molar proportion of the fatty acid propionate increased with PAS+CMV(P = 0.03) in contrast to the acetate- to- propionate ratio found highest for PAS and decreased for all diets with supplementation of PSM forages. Concentration of rumen NH3–N flow to rumen fluid per gram of protein intake was lower (P < 0.01) with PAS+CMV and PAS+SMB, compared with grass only. Feeding CMV and SMB to grazing cattle may improve nutrient utilization, metabolome, and environmental sustainability of beef cattle production by improving diet digestibility and reducing ammonia waste.

Effects of molasses supplementation on animal performance and carcass parameters of beef cattle: a meta-analysis.

Molasses must be one of the most used foods in the diet of ruminant animals; however, there is no consensus on the effect of including molasses on carcass parameters. In this context, the objective was to evaluate the effect of including molasses in the diet of feedlot cattle on performance and carcass parameters. Thirteen peer-reviewed publications with 45 treatment means were included in the dataset. The effect of molasses in beef cattle diets was evaluated by examining the weighted mean differences (WMD) between molasses treatment (diet with molasses) and control diet (diet without molasses). Heterogeneity was explored by meta-regression and subgroup analysis using genetic type and experimental period, molasses in diet (g/kg dry matter (DM)), molasses type, concentrate in diet (g/kg DM), and forage type. The inclusion of molasses in the diet increased dry matter digestibility, but reduced NDF digestibility, carcass weight, subcutaneous, and visceral fat. The main sources of variation for the responses with molasses inclusion on intake, digestibility, performance, and carcass parameters were the level of molasses inclusion and the experimental period. In general context, the inclusion of molasses in the diet between 100 to 150g/kg of DM did not affect performance and carcass parameters. However, the inclusion of molasses above 200g/kg reduces the average daily gain and carcass weight.

Automated Quantification of the Behaviour of Beef Cattle Exposed to Heat Load Conditions.

Cattle change their behaviour in response to hot temperatures, including by engaging in stepping that indicates agitation. The automated recording of these responses would be helpful in the timely diagnosis of animals experiencing heat loading. Behavioural responses of beef cattle to hot environmental conditions were studied to investigate whether it was possible to assess behavioural responses by video-digitised image analysis. Open-source automated behavioural quantification software was used to record pixel changes in 13 beef cattle videorecorded in a climate-controlled chamber during exposure to a simulated typical heat event in Queensland, Australia. Increased digitised movement was observed during the heat event, which was related to stepping and grooming/scratching activities in standing animals. The 13 cattle were exposed in two cohorts, in which the first group of cattle (n = 6) was fed a standard finisher diet based on a high percentage of cereal grains, and the second group of cattle (n = 7) received a substituted diet in which 8% of the grains were replaced by lucerne hay. The second group displayed a smaller increase in digitised movements on exposure to heat than the first, suggesting less discomfort under hot conditions. The results suggest that cattle exposed to heat display increased movement that can be detected automatically by video digitisation software, and that replacing some cereal grain with forage in the diet of feedlot cattle may reduce the measured activity responses to the heat.

Practical parameters for assessing starch digestion and feeding value of steam-flaked corn in finishing diets for feedlot cattle

ABSTRACT Six Holstein steers (153 kg ± 11) with cannulas in the rumen and proximal duodenum were used in a 6 × 6 Latin square design experiment to compare flake density (FD, kg/L), flake thickness (FT, mm), amyloglucosidase reactivity (AGR, % DM) and faecal starch (FS, % DM) as predictors of ruminal (RSD, %) and total tract (TSD, %) starch digestion. Dietary treatments consisted of a finishing diet containing 77% corn. The six corn processing treatments consisted of dry-rolled corn (DRC) with a density of 0.54 kg/L, and steam-flaked corn (SFC) processed to obtain densities of 0.46, 0.41, 0.36, 0.31 and 0.26 kg/L. Compared with DRC, steam flaking enhanced postruminal (34.2%, P < 0.01) and TSD (7.8%, P < 0.01). Measures of FS were the best single predictor of both ruminal (r 2 = 0.97) and TSD (r 2 = 0.98). Whereas AGR was a good predictor of RSD (r 2 = 0.94), it was less effective than FS for estimation of TSD (r 2 = 0.91). We conclude that compared with dry rolling, stream flaking markedly enhances the feeding value of corn. To evaluate the consistency of the flaking process, we recommend in addition to the determinations of FD, measurements of FT, starch enzymatic reactivity and FS are useful indicators.

Effect of increasing concentration of ergot alkaloids in the diet of feedlot cattle: performance, welfare, and health parameters.

This study was designed to evaluate the effects of feeding increasing dietary concentrations of ergot alkaloids from cereal grains (EA; 0, 0.75, 1.5, 3.0 mg/kg of dietary DM) to feedlot cattle over backgrounding (BG) and finishing (FS) phases on health, welfare, and growth performance. Two hundred and forty commercial steers (280 ± 32 kg BW) were stratified by weight and randomly allocated to 16 pens (15 steers/pen), 4 of which were equipped with the GrowSafe system (1 pen/treatment) to measure individual feed intake. Each pen was randomly assigned to a treatment (n = 4/treatment). Treatments included 1) control (CTRL), no added EA; 2) CTRL + 0.75 mg/kg EA (EA075); 3) CTRL + 1.5 mg/kg EA (EA150); and 4) CTRL + 3.0 mg/kg EA (EA300). Steers were fed barley-based BG diets containing 40% concentrate: 60% silage (DM basis) for 84 d. Steers were then transitioned over 28 d to an FS diet (90% concentrate: 10% silage DM basis) and fed for 119 d before slaughter. The diet fed to EA300 steers was replaced with the CTRL diet after 190 d on feed (DOF), due to EA-induced hyperthermia starting at 165 DOF. In the BG phase, average meal length (P = 0.01) and size (P = 0.02), daily feeding duration (P = 0.03), final body weight (BW; P = 0.03), and total BW gain (P = 0.02) linearly decreased with increasing EA levels, while gain to feed (G:F) responded quadratically (P = 0.04), with EA150 having the poorest value. Increasing concentrations of EA in the diet linearly increased rectal temperature (P < 0.01) throughout the trial. Over the full FS phase, a quadratic response was observed for ADG (P = 0.05), final BW (P = 0.05), total BW gain (P = 0.02), and carcass weight (P = 0.05) with steers fed EA150 having the lowest performance, as EA300 steers were transferred to CTRL diet after 190 DOF. Dressing percentage (P = 0.02) also responded quadratically, with the lowest values observed for EA300. Thus, EA reduced ADG during BG and FS phases, although more prominently in FS, likely due to increased ambient temperatures and high-energy diet in FS triggering hyperthermia. When EA300 steers were transferred to the CTRL diet, compensatory gain promoted higher hot carcass weight (HCW) when compared with steers fed EA150. In conclusion, feeding feedlot steers diets with > 0.75 mg/kg EA caused reductions in performance and welfare concerns, although this breakpoint may be affected by duration of feeding, environmental temperatures, and EA profiles in the feed.

Granulated Cane Sugar as a Partial Replacement for Steam-Flaked Corn in Diets for Feedlot Cattle: Ruminal Fermentation and Microbial Protein Synthesis

The aim of this study was to evaluate the influence of supplemental granulated cane sugar (GCS) levels (0, 13.3, 26.6, and 39.9% on a dry matter basis) in a steam-flaked corn-based finishing diet on measures of ruminal fermentation and the site and extent of nutrient digestion. Four Holstein steers (251 ± 3.6 kg live weight) with “T” type cannulas in the rumen and proximal duodenum were used in a 4 × 4 Latin square experiment to evaluate the treatments. The experiment lasted 84 d. Replacing steam-flaked corn (SFC) with GCS linearly decreased the flow of ammonia-N (NH3-N) to the small intestine, increasing the flow of microbial nitrogen (MN; quadratic effect, p = 0.02), ruminal N efficiency (linear effect, p = 0.03) and MN efficiency (quadratic effect, p = 0.04). The ruminal digestion of starch and neutral detergent fiber (NDF) decreased (linear effect, p ≤ 0.02) as the level of GCS increased. The postruminal digestion of organic matter (OM), neutral detergent fiber (NDF), and starch were not affected by the GCS inclusion. However, postruminal N digestion decreased (linear effect, p = 0.02) as the level of GCS increased. There were no treatment effects on total tract OM digestion. However, total tract NDF and N digestion decreased (linear effect, p ≤ 0.02) as the level of GCS increased. The ruminal pH decreased (linear effect, p &lt; 0.01) as the GCS increased in the diet. The ruminal acetate molar proportion decreased (linear effect, p = 0.02) and the ruminal valerate molar proportion tended to increase (linear effect, p = 0.08) as the level of GCS increased. It is concluded that replacing as much as 13% of SFC with GCS in a finishing diet will enhance the efficiency of N utilization (g non-ammonia-N entering the small intestine/g N intake) without detrimental effects on total tract OM digestion. The inclusion of GCS decreased the ruminal proportion of acetate linearly without an effect on the acetate-to-propionate ratio or estimated methane production. Some of the effects on N utilization at a high level of GCS inclusion (27 and 40%) can be magnified by the differences in the CP content between diets. A higher level of GCS supplementation in the diet decreased the ruminal pH below 5.5, increasing the risk of ruminal acidosis.

156 Effect of Increasing Levels of Ergot Alkaloids in the Diet of Feedlot Cattle

Abstract This study evaluated the effects of feeding ergot alkaloids (EA) at increasing levels (0, 0.75, 1.5, and 3.0 ppm) to feedlot beef cattle over backgrounding (BG) and finishing (FS) phases on growth performance and carcass quality. Steers (n=240; 280±32 kg) were blocked by weight and randomly allocated to 16 pens (4 pens/treatment; 15 steers/pen). Treatments included: no added EA (CTL); or EA added at 0.75 (EA075); 1.50 (EA150); and 3.0 ppm (EA300). Steers were fed barley-based BG diets containing 40% concentrate:60% silage (DM basis) for 84 d, then stepped up over 28 d to a 90% concentrate:10% silage (DM basis) FS diet for 119 d. Steers fed EA300 received CTL in FS after 77 days on feed (DOF). In the BG phase, a quadratic decrease (P=0.05) in ADG and a linear decrease in final BW (P=0.03) and total BW gain (P=0.02) were observed with increasing EA. In the FS phase, up to 77 DOF, there was a linear decrease in steers DMI (P=0.04), ADG (P=0.01), and total BW gain (P=0.01) with increasing levels of EA. Over the full FS phase (119 DOF), a quadratic response was observed for ADG (P=0.05), final BW (P=0.05), total BW gain (P=0.02) and carcass weight (P=0.05) with steers fed EA150 showing the lowest performance. Gain:feed was not affected (P&amp;gt;0.20) by EA in the BG or FS phase. Dressing percentage (P=0.02) showed a quadratic effect with EA300 being the lowest. Additionally, a linear increase in lean meat yield (P&amp;lt; 0.001) was observed with increasing EA. Including EA in the diet promoted a linear increase in rectal temperature (P&amp;lt; 0.01). In conclusion, increasing levels of EA in the diet reduced growth performance, but when EA was removed, steers showed compensatory weight gain.

PSII-B-13 Bacterial Composition of the Rumen Microbiome with a Bacillus Probiotic Added to the Diet of Feedlot Cattle

Abstract The threat of the development of an antibiotic resistant bacterium necessitates investigation for alternative feed additives. Probiotics are known to confer a health benefit to the animal and affect the production of the animal through increased nutrient digestibility. The aim of this study was to investigate the bacterial composition of the rumen of South African feedlot cattle when supplemented with a Bacillus probiotic. Twenty-four Bonsmara cattle were randomly divided into two groups: a basal diet (control, CTR) and the basal diet supplemented with Bacillus-based probiotic (B. licheniformis and B. subtilis; Bovacillus, Chr. Hansen A/S; BOV). The animals were fed for 120-days divided by starter, grower, and finisher diets. Four animals from each group were selected for rumen content collection via stomach tube during each phase. DNA extraction was performed and submitted for 16S rRNA sequencing (V3-V4). Approximately 41 300 ASVs were identified from 87 genera using DADA2, phyloseq and the RDP database. ANOSIM was used to determine different microbial profiles and Wilcoxon Rank Sum test to determine significant differences in the relative abundance of the microbes between the treatment groups. Microbial profiles in the starter (ANOSIM=0.0416) and grower (ANOSIM=0.1771) phases were similar between CTR and BOV. Most bacteria had greater abundance in CON compared with BOV in the starter phase. In the grower, BOV had a significantly greater abundance of Prevotella (p=0.028) and Lachnobacterium (p=0.042) compared to CTR. The microbial profiles between CTR and BOV differed in the finisher phase (ANOSIM=0.3229) with most of the bacteria having a significantly greater abundance in BOV compared with CTR including Roseburia (p=0.028), Fibrobacter (p=0.057) and Ruminococcus (p=0.028). These microbes as well as Prevotella are known fiber-degraders in the rumen microbiome. The results indicate a tendency in BOV for increased abundance of fibre-degrading microbes, however further studies are needed to validate these findings.

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.

Whole or coarsely broken açai seed as a source of roughage in the diet of feedlot cattle: intake, digestibility, and ruminal parameters.

This study was conducted to evaluate the effects of two methods of provision of açai seed (AS) as a fiber source (coarsely broken or whole) for feedlot beef cattle on the intake, digestibility, and ruminal parameters. Four bulls (male, non-castrated, and rumen fistulated), with an average body weight of 340 ± 31kg, distributed in two simultaneous 2 × 2 Latin squares, were used. The treatments were two methods of processing of the açai seed, as follows: whole açai seed (WAS), and coarsely broken açai seed (CBAS). The dry matter (DM), crude protein (CP), and neutral detergent fiber (NDF) intake were higher (P < 0.10) with the use of CBAS. The digestibility of DM and nutrients was not affected (P > 0.10) by AS processing. Acetate and total volatile fatty acids concentrations, and acetate:propionate ratio were higher with the CBAS diet, whereasthe pH was higher with the WAS diet. The concentrations of propionate, butyrate, and ruminal ammonia nitrogen (NH3) did not change with AS processing. Thus, coarsely broken açai seed increases the intake of DM and nutrients without altering the digestibility. Furthermore, it increases the concentrations of total fatty acids and acetate.

Feedlot diets containing different starch levels and additives change the cecal proteome involved in cattle\u2019s energy metabolism and inflammatory response

Diets for feedlot cattle must be a higher energy density, entailing high fermentable carbohydrate content. Feed additives are needed to reduce possible metabolic disorders. This study aimed to analyze the post-rumen effects of different levels of starch (25%, 35%, and 45%) and additives (monensin or a blend of essential oils and exogenous α-amylase) in diets for Nellore feedlot cattle. The cecum tissue proteome was analyzed via two-dimensional polyacrylamide gel electrophoresis (2D-PAGE) and then differentially expressed protein spots were identified with liquid chromatography–tandem mass spectrometry (LC–MS/MS). The use of blends of essential oils associated with α-amylase as a feed additive promoted the upregulation of enzymes such as triosephosphate isomerase, phosphoglycerate mutase, alpha-enolase, beta-enolase, fructose-bisphosphate aldolase, pyruvate kinase, glyceraldehyde-3-phosphate dehydrogenase (GAPDH), l-lactate dehydrogenase B, l-lactate dehydrogenase A chain, l-lactate dehydrogenase, and ATP synthase subunit beta, which promote the degradation of carbohydrates in the glycolysis and gluconeogenesis pathways and oxidative phosphorylation, support pyruvate metabolism through the synthesis of lactate from pyruvate, and participate in the electron transport chain, producing ATP from ADP in the presence of a proton gradient across the membrane. The absence of proteins related to inflammation processes (leukocyte elastase inhibitors) in the cecum tissues of animals fed essential oils and amylase may be because feed enzymes can remain active in the intestine and aid in the digestion of nutrients that escape rumen fermentation; conversely, the effect of monensin is more evident in the rumen and less than 10% results in post-ruminal action, corroborating the hypothesis that ionophore antibiotics have a limited effect on the microbiota and intestinal fermentation of ruminants. However, the increase in starch in these diets promoted a downregulation of enzymes linked to carbohydrate degradation, probably caused by damage to the cecum epithelium due to increased responses linked to inflammatory injuries.

Comparison of feeding value, ruminal fermentation and bacterial community of a diet comprised of various corn silages or combination with wheat straw in finishing beef cattle

Corn silage is an important feedstuff for cattle because of the joint provision of starch and physical effective fiber and its palatability. However, the whole plant corn silage is underproduced in some regions until today and could not be popularized in beef cattle raising. The objective of this study was to compare the feeding value, ruminal fermentation and bacterial community of a diet comprised of various corn silages or combination with wheat straw in finishing beef cattle. One hundred eighty Simmental crossbred steers were blocked (60 steers/block) on the basis of initial BW. The animals were randomly assigned to 1 of 12 identical research pens (4 pens/block; 15 steers/pen), where each of the 4 research diets was assigned to 1 pen within each block as follows: (1) the whole plant corn silage-based diet was used as the control diet (WPCS), (2) the mixed forages-based diet was formulated by replacing a portion of whole plant corn silage with wheat straw (WPCSW), (3) the corn stalklage-based diet (CS), and (4) the sweet corn stalklage-based diet (SCS). The four diets were formulated to be isonitrogenous and isoenergetic with same forage to concentrate ratio. Experimental diets were fed for 90 d; a diet digestibility trial was conducted at the end of this period. There were no effects (P = 0.596) of treatment on dry matter intake, but average daily gain was greater for steers offered the WPCS diet, intermediate with WPCSW and SCS and lowest with CS (P < 0.001). Dry matter digestibility was greater (P = 0.005) for WPCS and SCS diets than for WPCSW and CS diets. The nutrients digestibility of CS was less than observed for WPCS diet (P < 0.05). The concentrations of ruminal volatile fatty acids were highest for WPCS diet, intermediate with WPCSW diet and lowest with SCS and CS diets (P < 0.001). Diets treatment had no effect on the α-diversity of rumen bacteria in steers (P > 0.05), but only caused the change of relative abundance of Ruminococcaceae and Prevotellaceae (P = 0.036 and 0.037, respectively). In conclusion, the WPCS-based diet exhibited the highest feeding value. The SCS and WPCSW offered suitable alternatives to a WPCS based diet offered to beef cattle, with limited negative influence on growth, apparent digestibility of nutrients and ruminal bacterial microbiota. In contrast, the value of a CS-based diet was relatively poor. However, it may still be economical to substitute WPCS with relative low-quality corn silage in feedlot cattle diets.

PSXIV-13 Supplemental essential oil blends plus 25-hydroxy-vitamin-D3 improve carcass characteristics in cattle finished under tropical conditions

Abstract 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 &amp;gt; 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 &amp;lt; 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.

Effects of increasing levels of soybean hulls in finishing diets of feedlot cattle fed free-choice hay on performance, roughage intake, and carcass characteristics

Our objective was to evaluate the effects of incremental inclusion rates of dietary soybean hulls (SH) on finishing performance, roughage intake (RI), and carcass characteristics in feedlot cattle fed free-choice hay. Angus × SimAngus-crossbred heifers (n = 60) and steers (n = 54) were stratified by sex and BW and assigned into 12 pens. Treatment 1 contained 5% soybean hulls, 70% ground corn (GC), 15% distiller grains, and 10% mineral supplement. Treatments 2 and 3 included an additional 5% and 10% SH in place of GC, respectively. Data were analyzed as a randomized complete block (BW) design using 2 different multiple linear regression analyses considering (1) the effects of total NDF intake (TNDFI), roughage NDF intake (RNDFI), and RI variability on growth and carcass characteristics and (2) the effects of concentrate NDF intake (CNDFI) and RI variability on RI. There were treatment × sex interactions ( P ≤ 0.03) for DMI, final BW and RI. In heifers, substituting 15% GC with SH increased DMI at the expense of RI. Substituting GC with SH did not affect DMI of steers, but feeding increasing SH decreased final BW. Average daily gain and DMI were negatively associated ( P ≤ 0.05) with TNDFI and RNDFI. The RI was negatively ( P ≤ 0.05) associated with CNDFI. The LM area of steer carcasses was negatively associated ( P < 0.05) with TNDFI and RNDFI. Despite differential responses to dietary treatments between steers and heifers, cost effectiveness of replacing a small portion of corn with SH will depend on the difference of feed costs.

Effect of protein source and nonroughage NDF content in finishing diets of feedlot cattle fed free-choice hay on growth performance and carcass characteristics.

One-hundred twenty crossbreed steers (initial body weight (BW) 566 ± 42 kg) were used to evaluate the interaction of protein source (PS) and nonroughage NDF content (NRFC) in finishing diets of feedlot cattle fed free-choice hay on performance and carcass characteristics. Steers were stratified by BW and randomly assigned to 8 pens (2 × 2 factorial) and fed for 104 ± 10 d. Four dietary treatments were investigated: (1) distillers’ dry grains with solubles (DDGS) and a low NRFC (DLF), (2) DDGS and a high NRFC (DHF), (3) soybean meal (SBM) and a low NRFC (SLF), (4) SBM and a high NRFC (SHF). Free-choice grass hay and concentrates were offered in a different bunk. Data were analyzed as a randomized complete block design. Do to the confounded effect of PS and protein intake, a linear regression was used to evaluate the effect of protein intake in growth performance. For gain to feed ratio (G:F) an interaction tended to occur (P = 0.10) between PS and NRFC. Steers on the DHF treatment had a lower G:F compared with SLF and SHF. Feeding SBM increased (P = 0.05) final BW, tended to increase (P = 0.06) average daily gain (ADG), and decreased (P = 0.05) hay intake (HI) compared with steers fed DDGS. There was a positive association (P ˂ 0.01) of crude protein intake with ADG and FBW. Dietary NRFC did not change (P ≥ 0.3) final BW, ADG, DMI, and HI. Protein source did not affect (P ≥ 0.16) hot carcass weight (HCW), longissimus muscle (LM) area, dressing, 12th rib fat thickness, or marbling score (MS). No differences were detected between NRFC for dressing, HCW, LM area, or MS (P ≥ 0.18); but diets with greater NRFC decreased (P = 0.03) the 12th rib fat thickness. Steers in the SHF treatment presented the lesser kidney-pelvic-heart fat compared with the remaining treatments (PS × NRFC interaction, P = 0.04). Soybean meal inclusion/increase in protein intake improved growth performance of feedlot steers compared with DDGS, despite protein intake meet the protein requirement. Increasing the NRFC did not affect growth or HI but decreased feed efficiency of steers fed DDGS.