High-grain Diet Research Articles

Short-term screening of multiple phytogenic compounds for their potential to modulate chewing behavior, ruminal fermentation profile, and pH in cattle fed grain-rich diets

In cattle, proper rumen functioning and digestion are intimately linked to chewing behavior. Yet, high grain feeding impairs chewing activity, increasing the risk of subacute ruminal acidosis and dysfermentation. This study aimed to screen 9 different phytogenic compounds for their potential to modulate chewing activity, meal size, rumino-reticular short-chain fatty acids (SCFA), and pH during consumption in a first daily meal and shortly thereafter in cattle fed a grain-rich diet. Treatments were control (total mixed ration without phytogenic) or addition of a phytogenic compound at a low or high dose. Phytogenic compounds and doses (all in mg/kg) were angelica root (6.6 and 66), capsaicin (10 and 100), gentian root (6.6 and 66), garlic oil (0.3 and 3), ginger extract (40 and 400), L-menthol (6.7 and 67), mint oil (15.3 and 153), thyme oil (9.4 and 94), and thymol (5 and 50), for the low and high groups, respectively. Before the start of the screening experiment, cows were fed to reach subacute ruminal acidosis conditions, confirmed with the time of ruminal pH <5.8 being 655 ± 148.2 min/d. During the screening experiment, the treatments were offered in a controlled meal (2.5 kg of DM for 4 h) as part of the daily diet with 65% concentrate. Each treatment was tested in 4 of the 9 cannulated Holstein cows using an incomplete Latin square design. Ruminal and reticular fluids were sampled before and after each treatment, and data collected before the meal were used as covariates. Chewing and ruminal pH were monitored during the treatment, followed by 2 h of complete feed restriction, and then 4 h of ad libitum feed intake without phytogenic. Data showed that supplementation of angelica root tended to linearly increase rumination time immediately after the first meal when feed was restricted (27.3, 41.9, and 42.6 ± 5.99 min for control, low and high groups, respectively). Capsaicin increased eating time (43.6, 49.4, and 66.4 ± 4.93 min) during consumption but did not affect ruminal total SCFA or mean ruminal pH. Garlic oil reduced the concentration of reticular total SCFA (75.7, 71.3, and 60.1 mM) and tended to decrease ruminal acetate-to-propionate ratio (2.50, 1.78, and 1.87 ± 0.177) with no effect on ruminal pH. The L-menthol affected reticular total SCFA quadratically (76.1, 64.9, and 81.0 ± 4.22%), and ruminal pH responded quadratically when feed was reintroduced ad libitum (6.0, 6.3, and 6.1 ± 0.07). Mint oil did not affect chewing or total SCFA during consumption, but the low dose increased ruminal pH (6.5, 6.7, and 6.5 ± 0.08). Thyme oil tended to lower the severity of ruminal acidosis. Overall, phytogenic compounds demonstrated distinct dose-dependent effects to beneficially influence chewing behavior, modulate fermentation, and mitigate ruminal acidosis in dairy cows under a high-grain challenge diet.

Comparison of the fermentation and bacterial community in the colon of Hu sheep fed a low-grain, non-pelleted, or pelleted high-grain diet.

Microbial fermentation in the hindgut is likely an important contributor to energy availability in ruminants, except for the rumen. This study aimed to investigate commensal bacteria in the colon influenced by diverse dietary niches. Fifteen male sheep were randomly allotted into three feeding groups: non-pelleted low-grain (CON, n = 5), non-pelleted high-grain (HG, n = 5), and pelleted high-grain (HP, n = 5) diets. The HG and HP groups had higher fermentation parameters than the CON group, especially acetate concentration (CON = 46.91; HG = 61.66; HP = 77.99). The HG diet altered the composition of commensal bacteria in the colon in comparison to the CON group, including the increase of genera related to acetate production (e.g., Acetitomaculum spp.), butyrate production (e.g., Coprococcus spp. and Subdoligranulum spp.), and starch degradation (e.g., Prevotella spp., Roseburia spp., and Oscillibacter spp.). The colon functional compendium had co-alteration with taxonomic changes that indicated non-pelleted HG diet caused a detrimental colonic niche. The HP diet specifically promoted the abundance of Ruminococcus, Olsenella, and Alloprevotella genera to achieve the highest acetate concentration and decreased the starch-degrader Roseburia spp. and Oscillibacter spp. in contrast to the HG group. Our results provide a systematic view of the microbial fermentation, community, and functional guilds in colonic digesta and mucosa in regard to using an HP diet to maintain colonic niche homeostasis under the adverse influence of the HG diet.Key Points• Non-pelleted and pelleted high-grain diets altered sheep colonic fermentation.• Non-pelleted and pelleted high-grain diets resulted in diverse microbial composition.• The pelleted method ameliorated microbial functions compared with the high-grain diet.

Effect of mixed live yeast and lactic acid bacteria on in vitro fermentation with varying media pH using a high-grain or high-forage diet

Two experiments were conducted to assess the effects of media pH and mixtures (SCEF) of live yeast [Saccharomyces cerevisiae (SC)] and lactic acid bacteria [Enterococcus faecium (EF)] on gas production (GP), dry matter disappearance (DMD), and volatile fatty acid (VFA) concentrations in batch culture using either high-forage (HF) or high-grain (HG) diets. Diets were evaluated in separate experiments, each as a complete randomized design with 2 (media pH 5.8 and 6.5) × 5 (control, three SCEF, monensin) factorial arrangement of treatments. The SCEF had varying ratios of SC:EF: 0:0 (control), 1.18:1 (SCEF1), 1.25:1 (SCEF2), and 1.32:1 (SCEF3), added on a log10 basis. For the HF diet, supplementation of SCEF had greater GP (P = 0.03) at pH 6.5 and greater DMD (P = 0.03) and VFA concentration (P &lt; 0.01) at pH 5.8 and 6.5 than control. For the HG diet, acetate:propionate (A:P) ratio at pH 6.5 was greater (P = 0.05) for SCEF than control. Increasing ratio of SC to EF in SCEF linearly (P &lt; 0.01) decreased GP and DMD and linearly increased acetate percentage at pH 6.5. These results suggest that optimizing the SC:EF ratio in a mixture of SCEF can help improve rumen fermentation.

The Effect of a High-Grain Diet on the Rumen Microbiome of Goats with a Special Focus on Anaerobic Fungi.

This work investigated the changes of the rumen microbiome of goats switched from a forage to a concentrate diet with special attention to anaerobic fungi (AF). Female goats were fed an alfalfa hay (AH) diet (0% grain; n = 4) for 20 days and were then abruptly shifted to a high-grain (HG) diet (40% corn grain, 60% AH; n = 4) and treated for another 10 days. Rumen content samples were collected from the cannulated animals at the end of each diet period (day 20 and 30). The microbiome structure was studied using high-throughput sequencing for bacteria, archaea (16S rRNA gene) and fungi (ITS2), accompanied by qPCR for each group. To further elucidate unclassified AF, clone library analyses were performed on the ITS1 spacer region. Rumen pH was significantly lower in HG diet fed goats, but did not induce subacute ruminal acidosis. HG diet altered prokaryotic communities, with a significant increase of Bacteroidetes and a decrease of Firmicutes. On the genus level Prevotella 1 was significantly boosted. Methanobrevibacter and Methanosphaera were the most abundant archaea regardless of the diet and HG induced a significant augmentation of unclassified Thermoplasmatales. For anaerobic fungi, HG triggered a considerable rise in Feramyces observed with both ITS markers, while a decline of Tahromyces was detected by ITS2 and decrease of Joblinomyces by ITS1 only. The uncultured BlackRhino group revealed by ITS1 and further elucidated in one sample by LSU analysis, formed a considerable part of the AF community of goats fed both diets. Results strongly indicate that the rumen ecosystem still acts as a source for novel microorganisms and unexplored microbial interactions and that initial rumen microbiota of the host animal considerably influences the reaction pattern upon diet change.

Effects of High-Grain Diet on the Quality of Meat and Carcass of Lambs and Economic Indices of Various Diets

The Brazilian sheep farming sector suffers from low productivity, related to the extensive animal production system and low availability of native fodder during most of the year. An alternative to the systems would be the use of a diet without roughage, allowing greater weight gain and better quality carcasses. The aim of this study was to investigate the effects of diets containing different proportions of grains on the quality of carcass and meat of lambs as well as the economic indices of various diets. Three diets containing different proportions of concentrate and roughage (100:0, 80:20, and 60:40) were supplied. The concentrate comprised 85% whole-grain corn and 15% commercial pelletized supplement. Twenty-four male lambs (no racial pattern; average body weight, 20.9 &amp;plusmn; 1.0 kg; age, 6 months) were randomly allotted to three collective bays for 52 days. Subsequently, the animals were slaughtered, and further analyses were performed. The diet with 100% concentrate achieved overall higher carcass yield, lower weight loss on cooking, and greater lipid oxidation. However, no diet affected weight gain, slaughter weight, carcass length and thorax depth, pH, temperature, color, water-holding capacity, and meat shear force (P &amp;gt; 0.05). The best economic indices were obtained with the diet containing 100% concentrate. Therefore, based on the results obtained, the use of 100% concentrated diet for lambs is the most suitable practice to improve the sheep production from a productive and economic point of view.

Effects of brewers\u2019 spent grain protein hydrolysates on gas production, ruminal fermentation characteristics, microbial protein synthesis and microbial community in an artificial rumen fed a high grain diet

BackgroundBrewers’ spent grain (BSG) typically contains 20% – 29% crude protein (CP) with high concentrations of glutamine, proline and hydrophobic and non-polar amino acid, making it an ideal material for producing value-added products like bioactive peptides which have antioxidant properties. For this study, protein was extracted from BSG, hydrolyzed with 1% alcalase and flavourzyme, with the generated protein hydrolysates (AlcH and FlaH) showing antioxidant activities. This study evaluated the effects of AlcH and FlaH on gas production, ruminal fermentation characteristics, nutrient disappearance, microbial protein synthesis and microbial community using an artificial rumen system (RUSITEC) fed a high-grain diet.ResultsAs compared to the control of grain only, supplementation of FlaH decreased (P < 0.01) disappearances of dry matter (DM), organic matter (OM), CP and starch, without affecting fibre disappearances; while AlcH had no effect on nutrient disappearance. Neither AlcH nor FlaH affected gas production or VFA profiles, however they increased (P < 0.01) NH3-N and decreased (P < 0.01) H2 production. Supplementation of FlaH decreased (P < 0.01) the percentage of CH4 in total gas and dissolved-CH4 (dCH4) in dissolved gas. Addition of monensin reduced (P < 0.01) disappearance of nutrients, improved fermentation efficiency and reduced CH4 and H2 emissions. Total microbial nitrogen production was decreased (P < 0.05) but the proportion of feed particle associated (FPA) bacteria was increased with FlaH and monensin supplementation. Numbers of OTUs and Shannon diversity indices of FPA microbial community were unaffected by AlcH and FlaH; whereas both indices were reduced (P < 0.05) by monensin. Taxonomic analysis revealed no effect of AlcH and FlaH on the relative abundance (RA) of bacteria at phylum level, whereas monensin reduced (P < 0.05) the RA of Firmicutes and Bacteroidetes and enhanced Proteobacteria. Supplementation of FlaH enhanced (P < 0.05) the RA of genus Prevotella, reduced Selenomonas, Shuttleworthia, Bifidobacterium and Dialister as compared to control; monensin reduced (P < 0.05) RA of genus Prevotella but enhaced Succinivibrio.ConclusionsThe supplementation of FlaH in high-grain diets may potentially protect CP and starch from ruminal degradation, without adversely affecting fibre degradation and VFA profiles. It also showed promising effects on reducing CH4 production by suppressing H2 production. Protein enzymatic hydrolysates from BSG using flavourzyme showed potential application to high value-added bio-products.

Anti-lipopolysaccharide antibody administration mitigates ruminal lipopolysaccharide release and depression of ruminal pH during subacute ruminal acidosis challenge in Holstein bull cattle.

The effects of anti-lipopolysaccharide (LPS) antibody on rumen fermentation and LPS activity were investigated during subacute ruminal acidosis (SARA) challenge. Eleven Holstein cattle (164 ± 14 kg) were used in a 3 × 3 Latin square design. Cattle were fed a roughage diet on days −11 to −1 (pre-challenge) and day 2 (post-challenge), and a high-grain diet on days 0 and 1 (SARA challenge). For 14 days, 0-, 2-, or 4-g of anti-LPS antibody was administered once daily through a rumen fistula. Ruminal pH was measured continuously, and rumen fluid and blood samples were collected on days −1, 0, 1, and 2. Significantly lower ruminal LPS activity on day 1 was observed in the 2- and 4-g groups than those in the 0-g group. In addition, significantly higher 1-hr mean ruminal pH on SARA challenge period (days 0 and 1) was identified in the 4-g group than in the 0-g group. However, rumen fermentation measurements (total volatile fatty acid [VFA], VFA components, NH3-N and lactic acid) and peripheral blood metabolites (glucose, free fatty acid, beta-hydroxybutyrate, total cholesterol, blood urea nitrogen, aspartate aminotransferase and gamma-glutamyl transferase) were not different among the groups during the experimental periods. Therefore, anti-LPS antibody administration mitigates LPS release and pH depression without the depression of rumen fermentation and peripheral blood metabolites during SARA challenge in Holstein cattle.

Changes in the predicted function of the rumen bacterial community of Japanese Black beef cattle during the fattening stages according to Kyoto Encyclopedia of Genes and Genomes (KEGG) analyses.

We investigated changes in the predicted functions of the rumen bacterial community in Japanese Black beef cattle during fattening. Nine cattle were fed a high-concentrate diet during the early, middle, and late fattening stages consecutively (10–14, 15–22, and 23–30 months of age, respectively). The rumen fluid and solid samples collected at each stage were subjected to sequencing analyses. The sequencing results were clustered and classified into operational taxonomic units (OTUs). Representative sequences and a raw counting table for each OTU were submitted to the Piphillin website. The predicted functions were revealed by the Kyoto Encyclopedia of Genes and Genomes database as the ratio of the total sequence. In the early stage, “Biosynthesis of secondary metabolites” was significantly higher in the fluid fraction than in the solid fraction. “Two-component system” in the middle stage was significantly lower and “Purine metabolism” in the late stage was significantly higher in the fluid fraction than those in the solid fraction. The fluid fraction was significantly correlated with acetic acid, propionic acid, and bacterial metabolism, such as “Biosynthesis of secondary metabolites” and “Sugar metabolism.” Moreover, the solid fraction was correlated with “Purine metabolism” and “Biosynthesis of secondary metabolism”. These results suggest that the rumen bacterial community in Japanese Black beef cattle adapts to changes in rumen conditions by altering their functions in response to a long-term high-grain diet.

Processing index of barley grain and dietary undigested neutral detergent fiber concentration affected chewing behavior, ruminal pH, and total tract nutrient digestibility of heifers fed a high-grain diet.

The objective of this study was to investigate the effects of processing index (PI) of barley grain and dietary undigested neutral detergent fiber (uNDF) concentration on dry matter (DM) intake, chewing activity, ruminal pH and fermentation characteristics, total tract digestibility, gastrointestinal barrier function, and blood metabolites of finishing beef heifers. The PI was measured as the density after processing expressed as a percentage of the density before processing, and a smaller PI equates to a more extensively processed. Six ruminally cannulated heifers (average body weight, 715 ± 29 kg) were used in a 6 × 6 Latin square design with three PI (65%, 75%, and 85%) × 2 uNDF concentration (low and high; 4.6% vs. 5.6% of DM) factorial arrangement. The heifers were fed ad libitum a total mixed ration consisting of 10% barley silage (low uNDF), or 5% silage and 5% straw (high uNDF), 87% dry-rolled barley grain, and 3% mineral and vitamin supplements. Interactions (P < 0.01) of PI × uNDF were observed for DM intake, ruminating and total chewing time, and DM digestibility in the total digestive tract. Intake of DM, organic matter (OM), starch, and crude protein (CP) did not differ (P > 0.14) between low and high uNDF diets, but intakes of NDF and acid detergent fiber were greater (P = 0.01) for high uNDF diets regardless of barley PI. Heifers fed high uNDF diets had longer (P = 0.05) eating times (min/d or min/kg DM) and tended (P = 0.10) to have longer total chewing times (min/kg DM) than those fed low uNDF diets. Additionally, heifers sorted (P = 0.01) against long particles (>19 mm) for high uNDF diets but not for low uNDF diets. Altering PI of barley grain did not affect (P > 0.12) total volatile fatty acid (VFA) concentration, molar percentages of individual VFA, or duration of ruminal pH < 5.8 and <5.6. Total VFA concentration was less (P = 0.01), acetate percentage was greater (P = 0.01), and duration of ruminal pH < 5.8 and <5.6 was less (P = 0.05) for high compared with low uNDF diets. Digestibility of DM, OM, and CP was greater (P = 0.02) for low vs. high uNDF diets with PI of 65% and 75%, with no difference between low and high uNDF diets at PI of 85%. Blood metabolites and gastrointestinal tract barrier function were not affected (P ≥ 0.10) by the treatments. These results suggest that increasing dietary uNDF concentration is an effective strategy to improve ruminal pH status in finishing cattle, regardless of the extent of grain processing, whereas manipulating the extent of barley processing did not reduce the risk of ruminal acidosis.

Gene function adjustment for carbohydrate metabolism and enrichment of rumen microbiota with antibiotic resistance genes during subacute rumen acidosis induced by a high-grain diet in lactating dairy cows

The high-grain diets fed to ruminants generally alters the structure and function of rumen microbiota, resulting in variations of rumen fermentation patterns and the occurrence of subacute rumen acidosis (SARA). To clarify the microbial mechanism for carbohydrate metabolism during SARA, 8 ruminally cannulated Holstein cows in mid lactation were selected for a 3-wk experiment. The cows were randomly divided into 2 groups, fed either a conventional diet (CON; 40% concentrate; dry matter basis) or a high-grain diet (HG; 60% concentrate; dry matter basis). Compared with the CON diet, the HG diet reduced average daily pH (5.71 vs. 6.13), acetate concentration (72.56 vs. 78.44 mM), acetate ratio (54.81 vs. 65.24%), and the ratio of the concentrations of acetate to propionate (1.87 vs. 3.21) but increased the concentrations of total volatile fatty acids (133.03 vs. 120.22 mM), propionate (41.32 vs. 24.71 mM), and valerate (2.46 vs. 1.68 mM) and the propionate ratio (30.51 vs. 20.47%). Taxonomic analysis indicated that the HG cows had a higher relative abundance of Ruminococcus, Eubacterium, Selenomonas, Ruminobacter, Succinimonas, Methanomicrobium, and Methanocaldococcus accompanied by a lower relative abundance of unclassified Firmicutes, unclassified Bacteroidetes, Bacteroides, Fibrobacter, Alistipes, Candidatus Methanoplasma, Methanomassiliicoccus, and Methanolobus. Carbohydrate-active enzyme annotation suggested that there was enriched abundance of glycosyltransferases (GT) 2, glycoside hydrolase (GH) 13, GH24, carbohydrate-binding module (CBM) 26, GH73, GH25, CBM12, GH23, GT8, CBM50, and GT9 and reduced abundance of GH78, GH31, S-layer homology, GH109, carbohydrate esterase 1, GH3, carbohydrate esterase 10, and GH43 in the HG group. Functional profiling revealed that the HG feeding mainly downregulated the pentose phosphate pathway of carbohydrate catabolism, acetate metabolism, propionate metabolism (succinate pathway), and methane metabolism, whereas it upregulated the Embden-Meyerhof-Parnas and Entner-Doudoroff pathways of glycolysis and the citrate cycle. Additionally, the HG feeding promoted the abundance of various antibiotic resistance genes and antimicrobial resistance gene families. These results elucidated the structure and function adjustment of rumen microbiota for carbohydrate metabolism and summarized the enrichment of rumen antibiotic resistance genes under the HG feeding, which expands our understanding of the mechanism underlying the response of rumen microbiota to SARA in dairy cattle.

PSVII-11 Fecal parameters as indicators of starch digestibility and feedlot performance of water buffaloes

Abstract This study evaluated fecal parameters indicative of starch digestibility of water buffaloes (Bubalus bubalis) of three genetic groups (GG: Jafarabadi, Mediterranean, and Murrah). Seventy-eight non-castrated males [n = 26 of each GG; 200 kg of initial body weight (BW); 210 days of age] were used. Animals were finished in feedlot, receiving a diet rich in starch [38.76% in dry matter (DM) basis]. Samples of feces, diet offered, and orts were collected for digestibility test during 3 consecutive days. Diet samples were incubated in situ in the rumen of cannulated buffaloes. The remaining material was submitted to analysis to quantify the indigestible neutral detergent fiber levels. Fecal starch (FS) determination was performed by near infrared reflectance spectroscopy. Final BW (BW, kg), metabolic BW (BW0.75, kg0.75), average daily gain (ADG, kg/day), DM intake (DMI, in kg/day, and %BW) were recorded. Data were analyzed using MIXED and CORR procedure in SAS, with significance considered if P ≤ 0.05. Starch digestibility and FS concentration are not influenced by GG (P ≥ 0.23), unlike fecal DM and fecal pH (P ≤ 0.04; Table 1). Although weak, negative correlations were detected between FS and BW (r = -0.247; P = 0.05) and BW0.75 (r = -0.261; P =0.03), as well as between fecal DM and BW (r = -0.245; P = 0.05), ADG (r = -0.341; P &amp;lt; 0.01), DMI, kg/day (r = -0.374; P &amp;lt; 0.01), and DMI, %BW (r = -0.335; P &amp;lt; 0.01) variables. The results demonstrate that there are differences among GG of water buffaloes regarding fecal parameters. Furthermore, the high FS content and the low fecal pH may indicate the low capacity of water buffaloes to digest starch. Thus, the research results provide evidence that water buffaloes are not able to use high-grain diets, and fecal parameters proved to be potential tools to evaluate the feedlot performance of these animals.

229 The effects of direct-fed microbial with and without monensin plus tylan on performance, feed efficiency and feeding behavior patterns in feedlot steers

Abstract Objectives of this study were to evaluate the effects of DFM with and without Monensin plus Tylan on feed efficiency and feeding behavior patterns in steers. Crossbred steers (n = 125; BW = 303 kg) were randomly assigned to 1 of 4 treatments in a 2 x 2 factorial design: (1) control (no feed additives), (2) DFM only (25 g/d; Natur’s Way), (3) Monensin (40 g/ton) plus Tylan only (MON) and (4) DFM and MON. In pens with GrowSafe feedbunks, steers were fed the grower diet for 14 d and transitioned to a finisher diet on 16 d. During the grower/transition phase, MON-fed steers had 9.5% higher (P &amp;lt; 0.05) ADG and improved F:G (7.8 vs 8.94; P = 0.06) and RFI (-0.28 vs 0.27 kg/d; P &amp;lt; 0.01) vs CON-fed steers. DFM-fed steers had lower (P &amp;lt; 0.01) ADG, but similar F:G and RFI than CON-fed steers. Daily variances of bunk-visit event frequencies were reduced (P &amp;lt; 0.01) in MON- vs CON-fed steers. During the finisher period, MON x DFM interactions (P &amp;lt; 0.10) were observed for ADG and F:G. MON-fed steers had numerically improved F:G (5%) when DFM was excluded, but not when DFM was included. MON-fed steers had lower RFI (P &amp;lt; 0.01; -0.23 vs 0.23 kg/d), whereas DFM-fed steers had higher RFI (P &amp;lt; 0.01) compared to respective controls. MON-fed steers ate less (P &amp;lt; 0.01) DMI, spent 9% more (P &amp;lt; 0.05) time consuming meals and had 14% slower (P &amp;lt; 0.01) meal eating rate then CON-fed steers. The DFM did not positively affect feed efficiency. Although the magnitude of improvement in feed efficiency due to MON was small, results demonstrated that MON may minimize digestive upsets by reducing daily variation in feeding behavior during diet transition and slow meal-eating rate on high-grain diets.

PSIV-23 Variations in chewing behavior and rumino-reticular pH in dairy cows during gradual adaptation to a high-grain diet

Abstract Physical effective fiber in the diet promotes chewing, contributing to the regulation of ruminal pH through saliva production, which leads to rumen health. However, lower dietary fiber content in high-grain diets may reduce rumination time and compromise ruminal pH regulation. The objective of this experiment was to evaluate rumination behavior and rumino-reticular pH variations during an 8-day adaptation to a 65% concentrate diet. For this study nine ruminally cannulated non-lactating Holstein cows were used. Prior to the initiation of the adaptation, cows were transitioned from a forage-only grass silage diet to a 65% DM concentrate diet over eight days. Rumination was monitored using RumiWatch halters (RumiWacthSystem ITIN+HOCH). Rumino-reticular pH was measured using eCow indwelling pH systems in five of nine cows recording data every 15 minutes. Data were analysed with SAS, the statistical model included day as fixed effect and cow was considered as random effect. Adaptation days had an effect (P &amp;lt; 0.01) on rumination time, number of rumination chews per minute, and mean daily (rumino-reticular) pH. Especially, rumination time decreased from 439 to 327±62.8 minutes per day from day 1 to 8, respectively. Concomitantly, rumination chews per minute decreased from 68.8 to 65.6±2.06, and mean daily pH decreased from 6.54 and 6.26±0.07, respectively. Nevertheless, daily dry matter intake (P = 0.23) and eating time (P = 0.37) were not affected during the adaptation period. In conclusion, adaptation to a high-grain diet and the associated decrease in physically effective fiber gradually reduced chewing activity and ruminal/reticular pH. However, compared to the forage-only diet, significant reduction in rumination time was only noted at the 65% concentrate level.

PSII-16 Effect of red osier dogwood extract on in vitro digestibility and fermentation characteristics of high-grain diet

Abstract Red osier dogwood (ROD) is an abundant native shrub plant in Canada and rich in phenolic compounds with antimicrobial properties. The objective of this study was to evaluate the effects of ROD extract supplementation on gas production (GP), DM disappearance (DMD) and fermentation characteristics in batch cultures with varying media pH. The study was a completely randomized design with 4 inclusion levels of ROD extract (0, 1, 3 and 5% of substrate) × 2 media pH (5.8 and 6.5) in a factorial arrangement. Substrate was a high-grain diet (HG) containing 10% barley silage and 90% barley-based concentrate mix (DM basis). Inoculum was obtained from 2 ruminally fistulated beef heifers offered the HG diet. Substrate (0.5 g DM) ground through a 1-mm sieve was incubated for 24 h in 3 replications including each combination of treatments. There was no interaction between media pH and inclusion level of ROD on GP, DMD and fermentation variables. Increased media pH (5.8 vs 6.5) increased (P &amp;lt; 0.01) GP (averaged 198 vs. 389 ml/g substrate), DMD (averaged 51.3 vs. 64.6%), and total volatile fatty acid production (averaged 74 vs. 83 mM). Increasing addition of ROD extract did not affect GP, but linearly (P &amp;lt; 0.05) decreased DMD from 56 to 46% at pH 5.8 and from 69 to 61% at pH 6.5. Increasing ROD extract linearly (P &amp;lt; 0.01) increased the proportion of acetate from 43 to 47% and 47 to 50% at pH 5.8 and 6.5, respectively. Acetate to propionate ratio increased from 1.68 to 1.93 and from 1.90 to 2.10 at pH 5.8 and 6.5, respectively. These results indicated that the decreased DMD along with increased acetate to propionate ratio with addition of ROD extract suggests ROD extract may be beneficial to HG fed cattle for reducing risk of rumen acidosis without negatively impacting fibre digestion.

PSXII-11 The effects of feeding finishing cattle benzoic acid and/or live active yeast (Saccharomyces cerevisiae) on feeding behaviour, growth performance, and carcass characteristics

Abstract In a randomized complete block design, 59 Angus-cross finishing steers were used to evaluate the effects of benzoic acid, active dry Saccharomyces cerevisiae or a combination of both when supplemented in a high-grain finishing diet on feeding behavior, animal performance, and carcass characteristics. Steers were fed for 106 d (77% high-moisture corn, 16% alfalfa haylage, 6% soybean meal, 1% mineral and vitamin supplement with salt and limestone) containing: no supplementation (CON; n = 15), 0.5% benzoic acid (ACD; n = 14), 3 g/hd/d active dry S. cerevisiae (YST; n = 15), or both 0.5% benzoic acid and 3 g/hd/d S. cerevisiae (AY; n = 11). Every 14 d steers were weighed, and ultrasound images for rib and rump fat thickness were collected at the beginning, middle, and end of the experiment. Insentec feeding stations were used to collect individual animal feeding behaviour data and DMI throughout the study. Data were analyzed using PROC GLIMMIX of SAS with initial BW as a covariate. Benzoic acid supplementation increased (P = 0.002) overall DMI compared to YST and AY steers, which was due to faster eating rates for ACD steers (P ≤ 0.008). Individual animal DMI variation was greater (P = 0.001) for ACD and AY steers. Rumen pH was greater (P = 0.006) for ACD steers vs. CON and AY steers (6.16, 5.84, and 5.66, respectively). Growth performance measures were similar (P ≥ 0.11) between treatment groups. Aspartate aminotransferase concentrations in blood were greatest (P ≤ 0.01) for YST steers, which was reflected in greater proportions of abscessed livers at slaughter. Carcass characteristics did not differ (P ≥ 0.68) between treatment groups. The results from this experiment suggest that steers fed a high grain finishing diet supplemented with benzoic acid, Saccharomyces cerevisiae or both had similar growth performance and carcass characteristics as a control group. The addition of benzoic acid increased eating rate and elevated rumen pH, which was ultimately reflected in increased DMI.

8 President Oral Presentation Pick: Use of electronic feed intake systems to assess feed bunk displacement events as an indicator of aggressive feeding behavior in beef cattle

Abstract Animal variation in social dominance within a herd has been shown to be associated with performance, feed efficiency and animal well-being. The objective of this study was to quantify disruptive feeding events in cattle fed a high-grain diet. Crossbred steers (n = 85) housed in a pen with GrowSafe bunks were used in this study. An algorithm was developed to quantify displacement events defined as an animal being displaced by another within 5 sec. These feed bunk displacement events were further separated into either displacer events or displacee events. A displacer event was defined as an animal displacing another (aggressive). A displacee event was defined as an animal being displaced (submissive). The displacer events as a proportion of total displacement events were used to classify animals as aggressive versus submissive (±0.5 SD). Animals with fewer displacer events as a proportion of total displacement events (submissive &amp;lt; 0.5 SD) had greater (P &amp;lt; 0.05) frequency and duration of bunk visit events and head down duration than the animals who initiated more displacer events as a total of displacement events (aggressive &amp;gt; 0.5 SD). Additionally, submissive animals also had a slower (P &amp;lt; 0.05) bunk visit eating rate than aggressive animals. The results of this initial analysis found that due to the associations between feed bunk displacements and feeding behavior, there may be potential to correlate this trait with temperament and performance traits as well as be a potential indicator of feed efficiency in confined cattle.

Effect of extracts from baccharis, tamarind, cashew nut shell liquid and clove on animal performance, feed efficiency, digestibility, rumen fermentation and feeding behavior of bulls finished in feedlot

There is a growing public concern on the use of antibiotics and ionophores in livestock and emerging antimicrobial resistance. Plant extracts and essential oils are natural alternatives having antimicrobial and antioxidant properties. This study evaluated the effects of a mixture of baccharis (Baccharis dracunculifolia) leaves and stems, tamarind (Tamarindus indica L.) seed, cashew (Anacardium occidentale) nut shell liquid, and clove (Syzygium aromaticum) essential oil on animal performance, feed intake, feed efficiency, apparent digestibility, molar concentration of volatile fatty acids and feeding behavior of bulls finished in the feedlot and fed high-grain diets. A total of 32 bulls (½ Angus vs. ½ Nellore) with a mean age of 24 ± 2.0 months and a mean body weight of 418 ± 4.51 kg were distributed in a completely randomized design with four diets and eight replications per diet. The four experimental diets were as follows: CONT – basal diet; MIX2 – basal diet and 2 g/animal/d of extracts from baccharis, tamarind, cashew nut shell liquid, and clove; MIX4 – basal diet and 4 g/animal/d of extracts from baccharis, tamarind, cashew nut shell liquid, and clove; MIX6 – basal diet and 6 g/animal/d of extracts from baccharis, tamarind, cashew nut liquid shell liquid and clove. Animal performance, dry matter, and other nutrients intake were similar among diets. Dry matter, neutral detergent fiber, and organic matter digestibilities were greater for the MIX2 when compared to other diets. There was an increase in propionate and a decrease in the acetate/propionate ratio when MIX6 was used. A similar effect was observed when orthogonal contrasts comparing the CONT diets with the addition of MIX was used. Feeding behavior was similar among the four diets. Our findings indicated that supplementation of baccharis, tamarind, cashew nut shell liquid, and clove oil (2, 4, and 6 g/animal/d) may be fed to beef cattle once it showed no adverse effects on feed intake and nutrient digestibility. Moreover, it was observed a higher concentration of propionate, a reduction in acetate/propionate ratio, and a greater digestibility of dry matter, neutral detergent fiber, and organic matter. However, more studies should be carried out to determine the effect of higher levels of MIX aiming to use it as a feed additive to improve animal performance and ruminal fermentation in beef cattle finished in feedlot.

123 Polyclonal antibody preparations from avian origin did not reduce plasmatic haptoglobin concentrations but increased ruminal NH3-N in beef steers during transition from forage to high-grain diets

Abstract This study investigated the effects of feeding an avian-derived polyclonal antibody preparation (PAP; CAMAS, Inc.) against Streptococcus bovis, Fusobacterium necrophorum, and lipopolysaccharides (40, 35, and 25% of the preparation, respectively) on plasmatic haptoglobin, ruminal short chain fatty acids (SCFA), and ammonia-N (NH3-N) concentrations of beef steers during a 21-d step-up adaptation to a high-grain diet. Eight ruminally cannulated Angus crossbred beef steers (658 ± 79 kg BW) were randomly assigned to treatments in a crossover design to be transitioned from a diet containing bermudagrass hay [Cynodon dactylon (L.) Pers.] plus 0.45 kg/d of molasses with 0 (CON) or 3 g/d of PAP (PAP) to a high-grain diet. Transition consisted of three 7-d steps of increased inclusion of cracked corn (35, 60, and 80% diet DM for STEP1, STEP2, and STEP3, respectively). On each transition d and 7 d after STEP3 (STEP3-7d), ruminal fluid samples were obtained every 3 h for 24 h. Blood samples were collected on d 0, 1, and 3 relative to each transition for haptoglobin determinations. Haptoglobin plasmatic concentrations increased (P = 0.03) on d 2 and 3 vs. d 1 during STEP2 and on STEP3 compared to STEP1 and STEP2 (P = 0.01). Steers receiving PAP had greater (P &amp;lt; 0.01) ruminal NH3-N concentration in STEP1; however, there were no effects of treatment on SCFA (P &amp;gt; 0.10). Total SCFA concentrations were affected by the step-up diets (P &amp;lt; 0.01); propionate concentration (Pro) was greater in STEP2 through STEP3-7d vs. STEP1 (P &amp;lt; 0.01), whereas acetate concentration (Ac) and Ac:Pro linearly decreased from STEP1 to STEP3-7d (P &amp;lt; 0.01). Feeding 3 g/d of polyclonal antibody preparations against Streptococcus bovis, Fusobacterium necrophorum, and lipopolysaccharides in a 21-d step-up adaptation to high-grain diets did not affect plasmatic haptoglobin or ruminal SCFA concentrations; however, it increased ruminal NH3-3 concentrations.

Metabolomic analysis of organic acids, amino acids, and fatty acids in plasma of Hanwoo beef on a high-protein diet.

Ketoacidosis of metabolic disease showed in beef cattle although body weight was increased by high-grain diets (HGDs). However, few studies have examined for health status related with metabolic disease of ketoacidosis following high-protein diet (HPD). Metabolomic analysis was performed for the monitoring of health status associated with metabolic disease of ketoacidosis in the plasma of Hanwoo heifers following a HPD. Hanwoo heifers of 24 months with 459 ± 42 kg weight were used under a 2 × 2 crossover design. The plasma was collected from control (n = 5) and HPD group (n = 5) on day 21 following diet adaptation for 20 days. Metabolic profiling analysis of organic acids (OAs), amino acids (AAs) and fatty acids (FAs) by gas chromatography-tandem mass spectrometry combined with star pattern analysis was performed in plasma. Levels of OAs, AAs and FAs were evaluated by Mann-Whitney test, PCA and PLS-DA. In HPD group, ketoacidosis as metabolic disease was monitored by elevated acetoacetic acid and 3-hydroxybutyric acid. In addition, the elevation of ketogenic AAs, reduction of medium chain FAs and OAs with energy metabolism in TCA cycle were monitored in HPD group. Star graphic pattern was characteristic and readily distinguished between control and HPD groups. In PLS-DA, two groups were separated with VIP score of top-ranked 10 FAs as important metabolites for discrimination. Elevation of ketone body including ketogenic AAs and reduced energy metabolism of FAs and OAs may useful for evaluation of health states associated with ketoacidosis from metabolic event by HPD in beef cattle.

Desempenho e comportamento ingestivo de cordeiros alimentados com dieta de alto grão

Neste estudo investiga-se o efeito de diferentes composições de dietas de alto grão na terminação de cordeiros sobre o desempenho e alterações no comportamento ingestivo e fisiológico. Foram utilizados 24 cordeiros machos, sem padrão racial definido com peso inicial médio de 20,9 kg, com 6 meses de idade. Foram elaboradas três dietas com diferentes proporções de concentrado e volumoso (100:0, 80:20 e 60:40), sendo a porção concentrada das dietas compostas por grão de milho inteiro associando ao suplemento protéico-mineral-vitamínico. Não houve efeito (P &gt; 0,05) das dietas teste para os consumos de matéria seca (MS), matéria mineral (MM), fibra em detergente neutro (FDN), carboidratos totais (CT) e nutrientes digestíveis totais (NDT), expressos em g/dia e % de peso vivo. As médias de ganho de peso total e diário e peso de abate foram semelhantes (P &gt; 0,05) entre as dietas, registrando-se ganho de peso diário de 0,302, 0,254 e 0,259 g/dia com 100, 80 e 60% de concentrado, respectivamente. Os cordeiros alimentados exclusivamente com concentrado diminuíram o tempo dedicado a ruminação (P ≤ 0,05), e apresentaram maior eficiência na alimentação (EAL) e ruminação (ERU). Os animais da dieta sem volumoso apresentaram acentuada variação de temperatura na região do rúmen, enquanto que cordeiros das dietas com 80 e 60% de concentrado apresentaram alterações de temperaturas próximas no mesmo período de avaliação. Todas as dietas avaliadas apresentaram desempenho satisfatório, e apesar das alterações observadas no comportamento ingestivo dos animais, essas não foram suficientes para prejudicar os índices de desempenho dos cordeiros.