The bovine nasal fungal community and associations with bovine respiratory disease.

Introduction: Effective identification and treatment of bovine respiratory disease (BRD) is an ongoing health and economic issue for the dairy and beef cattle industries. Bacteria pathogens Pasteurellamultocida, Mycoplasmabovis, Mannheimia haemolytica, and Histophilus somni and the virus Bovine herpesvirus-1 (BHV-1), Bovine parainfluenza-3 virus (BPIV-3), Bovine respiratory syncytial virus (BRSV), Bovine adenovirus 3 (BAdV3), bovine coronavirus (BoCV) and Bovine viral diarrhea virus (BVDV) have commonly been identified in BRD cattle; however, no studies have investigated the fungal community and how it may also relate to BRD. Methods: The objective of this study was to understand if the nasal mycobiome differs between a BRD-affected (n = 56) and visually healthy (n = 73) Holstein steers. Fungal nasal community was determined by using Internal Transcribed Spacer (ITS) sequencing. Results: The phyla, Ascomycota and Basidiomycota, and the genera, Trichosporon and Issatchenkia, were the most abundant among all animals, regardless of health status. We identified differences between healthy and BRD animals in abundance of Trichosporon and Issatchenkia orientalis at a sub-species level that could be a potential indicator of BRD. No differences were observed in the nasal fungal alpha and beta diversity between BRD and healthy animals. However, the fungal community structure was affected based on season, specifically when comparing samples collected in the summer to the winter season. We then performed a random forest model, based on the fungal community and abundance of the BRD-pathobionts (qPCR data generated from a previous study using the same animals), to classify healthy and BRD animals and determine the agreement with visual diagnosis. Classification of BRD or healthy animals using ITS sequencing was low and agreed with the visual diagnosis with an accuracy of 51.9%. A portion of the ITS-predicted BRD animals were not predicted based on the abundance of BRD pathobionts. Lastly, fungal and bacterial co-occurrence were more common in BRD animals than healthy animals. Discussion: The results from this novel study provide a baseline understanding of the fungal diversity and composition in the nasal cavity of BRD and healthy animals, upon which future interaction studies, including other nasal microbiome members to further understand and accurately diagnose BRD, can be designed.

Effect of a molasses-based liquid supplement on gastrointestinal tract barrier function, inflammation, and performance of newly received feedlot cattle before and after a transport stress.

The objective of this study was to determine the effect of a dry versus a molasses-based liquid supplement on ruminal butyrate concentration, gastrointestinal tract (GIT) barrier function, inflammatory status, and performance of newly received feedlot cattle. In experiment 1, 60 mixed breed steers (234 ±â€…2.1 kg) were weaned, held overnight at a sale barn, then transported 14 h to Purdue University. After arrival, steers were weighed, blocked by body weight, and allotted within block to treatments (six pens per treatment and five steers per pen). Diets consisted of 45% roughage and 55% concentrate (dry matter basis). Treatments differed in the supplement source as follows: DRY: 10% dry supplement or LIQUID: 10% liquid molasses-based supplement. Feed intake, average daily gain (ADG), and gain:feed were determined for the three 21-d periods and overall. In experiment 2, 16 crossbred heifers (246 ±â€…7.5 kg) were used (8 heifers per treatment). Diets were the same as in experiment 1 and were fed for 60 d. On d 56 ruminal fluid samples were collected at 0, 3, 6, and 9 h after feeding. To mimic a stress event, heifers were transported for 4 h on d 61, rested overnight, and transported 12 h on d 62. Blood was collected from heifers immediately prior to transport and immediately upon their return. Gut barrier function using a Cr-EDTA marker was determined after transportation. Data were analyzed using the GLIMMIX procedure of SAS. Steers fed the liquid supplement had greater (P ≤ 0.03) ADG through d 42 and overall compared to steers fed the dry supplement. Feed intake did not differ (P = 0.25) between treatments from d 0 to d 21. However, steers fed the liquid supplement showed greater (P < 0.001) dry matter intake after d 21 and overall compared to those fed the dry supplement. Steers fed the liquid supplement tended (P < 0.09) to have reduced serum haptoglobin and lipopolysaccharide-binding protein (LBP) compared to those fed the dry supplement. Heifers fed the liquid supplement had greater (P = 0.02) Cr in urine and tended (P = 0.07) to have lower serum LBP after transport compared to those fed the dry supplement. Heifers fed the liquid supplement had 72% lower serum haptoglobin before, but only a 19% lower serum haptoglobin after transport compared to animals fed the dry supplement (treatment × time; P = 0.07). Therefore, the liquid supplement altered GIT barrier function, and improved inflammatory status, resulting in increased growth of receiving cattle.

Stress from weaning, feed restriction, transportation, and gastrointestinal acidosis can cause inflammation and intestinal damage, resulting in decreased absorptive capacity and immune defense capability. Gastrointestinal inflammation has a significant catabolic cost and causes nutritional resources to be directed away from anabolic processes. Molasses-based liquid supplements have the potential to improve gastrointestinal tract (GIT) barrier function in stressed, newly received feedlot cattle through increased ruminal production of butyrate from sugar. Therefore, the objective of this study was to determine the effect of a dry versus a molasses-based liquid supplement on ruminal butyrate production, GIT barrier function, inflammatory status, and performance of newly received feedlot cattle. We demonstrate that a molasses-based liquid supplement increased ruminal butyrate concentrations, altered GIT barrier function, decreased serum haptoglobin and lipopolysaccharide-binding protein, and improved the growth of stressed receiving cattle compared to a dry supplement.

Technical Note: A procedure to place urinary catheters in 1- and 6-week-old preweaned Holstein heifer calves for the in vivo evaluation of intestinal permeability.

Oral administration of indigestible markers and subsequent urine collection is a useful method to determine in vivo gastrointestinal tract (GIT) permeability in cattle for research purposes. However, urine sampling techniques often rely on total waste collection, which reduces the ability to perform more frequent sampling and obtain accurate volumes and sterile samples. An alternative is urethral catheterization, though the feasibility of this technique has not been thoroughly tested in preweaned Holstein heifer calves. The study objective was to develop a urethral catheter placement procedure in preweaned Holstein heifer calves for continuous and accurate urine collection to evaluate GIT permeability using an indigestible marker. Fifteen Holstein heifer calves had catheters placed at approximately 1 wk (8.0 ± 1.5 d) and 6 wk (40.0 ± 1.5 d) of age. During the procedure, calves were individually housed and restrained. The vulva was sterilized and then a sterile, lubricated speculum was inserted into the vagina. A sterile 0.09 cm diameter guidewire was guided into a lubricated, sterile 10 French Foley catheter. The catheter was inserted at approximately 5 through 7 cm into the urethral opening, guided into the bladder, and the catheter balloon was filled with 10 mL of water. The guidewire was removed, and urine flow confirmed correct placement before a 4-L urinary drainage bag was attached to the catheter. After catheterization (24 h), 1 L of chromium (Cr)-ethylenediaminetetraacetic acid was orally dosed to the calves. Calf health observations were made six times over a 48-h period, and any occurrence of vaginal discharge, tissue discharge in catheter, bleeding, inflammation, or abnormal urine was considered a localized reaction. The proportion of localized reactions for each age group was determined using Microsoft Excel, and the total Cr output was analyzed using PROC GLIMMIX. Localized reactions occurred for 20.0% of the 1-wk-old calves and 13.3% of the 6-wk-old calves. In the first 4 h, urine was collected every 15 min, and there were no overall Cr output differences (P = 0.38; 10.28 ± 3.21 mg Cr) when comparing 1- and 6-wk-old calves. However, 1-wk-old calves tended (P = 0.08) to have greater overall Cr output at 480 min (19.2%) and 1,440 min (41.9%) when compared with 6-wk-old calves. In summary, urinary catheterization is a viable urinary collection method for the determination of in vivo GIT permeability in preweaned Holstein heifer calves.

Neonatal calves are highly susceptible to enteric disease during their first few weeks of life, and enteric disease is the leading cause of preweaning morbidity and mortality. A consequence of enteric disease is greater gastrointestinal tract (GIT) permeability in neonatal calves, which is also influenced by reduced intestinal maturity and environmental factors. Therefore, an accurate and precise method of evaluating GIT permeability in neonatal calves is necessary to develop appropriate treatment and mitigation strategies. The oral administration of indigestible markers and measurement of their presence in urine is an accepted method to determine the total GIT permeability in mature heifers. However, current urine collection methods in preweaned heifer calves may not be reliable. Therefore, the study objective was to develop a urinary catheterization method to collect urine accurately and precisely for the in vivo determination of GIT permeability in 1- and 6-wk-old Holstein heifer calves. It was determined that the urinary catheterization procedure and collection system developed in this study were viable and could be applied when evaluating GIT permeability in preweaned Holstein heifer calves using orally dosed indigestible markers.

Enteric methane emissions, growth, and carcass characteristics of feedlot steers fed a garlic- and citrus-based feed additive in diets with three different forage concentrations.

One hundred and forty-four Angus × Simmental steers were allotted by body weight (BW; 363 kg), breed composition, and farm origin to a 3 × 2 factorial arrangement of six treatments (4 pens per treatment) to determine the effect of Mootral (garlic + citrus extract; 0.25% of the diet dry matter [DM] vs. 0.0%) on methane (CH4) emissions, growth, and carcass characteristics of feedlot cattle. During the first 84 d, cattle were fed three different forage concentrations in the diet (15%, 41.5%, or 68% corn silage) with or without Mootral. From day 85 to slaughter, corn silage was included at 15% of the diet DM with or without Mootral. CH4 emissions were measured on day 42 to 46 and day 203 to 207. Data were analyzed using the GLIMMIX procedure of SAS. Mootral did not affect CH4 emissions on days 42 to 46 (P ≥ 0.47), but there was a forage effect, where steers fed the 68% corn silage emitted more CH4 on a g/d (P = 0.05) and a g/kg of dry matter intake (DMI; P = 0.007) basis and tended (P = 0.07) to produce more CH4 on g/kg BW basis compared to steers fed the 15% corn silage diet. On day 203 to 207, steers fed Mootral emitted less (P ≤ 0.03) CH4 on a g/d, g/kg DMI, and g/kg BW basis compared to steers not fed Mootral. There was an interaction (P = 0.03) between forage concentration and Mootral for DMI from day 0 to 84, where Mootral decreased DMI of steers fed 15% corn silage but did not affect DMI of steers fed 41.5% or 68% corn silage. There were no effects (P ≥ 0.22) of forage concentration or Mootral on BW or average daily gain at any time, or on DMI from day 84 to slaughter and overall. However, overall calculated net energy for maintenance (NEm) and net energy for gain (NEg) tended to be greater for steers fed Mootral (P ≤ 0.10). Intake from day 0 to 84 was lower and gain:feed from day 0 to 84 and overall was greater (P = 0.04) for steers fed 68% compared to steers fed 41.5% corn silage. Calculated NEm and NEg from day 0 to 84 and overall were greater for steers fed 68% corn silage compared to steers fed 41.5% corn silage (P ≤ 0.03). Mootral tended to decrease (P ≤ 0.09) fat thickness and yield grade. In conclusion, increasing forage concentration increased CH4 emissions and Mootral decreased CH4 production in 15% corn silage diets and tended to improve carcass leanness.

Methane (CH4) production from enteric fermentation in ruminant animals is a contributor to global CH4, which is a greenhouse gas. Mootral (Mootral SA, Rolle, Switzerland) is a feed supplement that contains garlic and bitter orange extracts that are known to inhibit methanogenic bacteria. The objective of the current study was to quantify CH4 production and determine growth, intake, and carcass characteristics of feedlot steers fed Mootral in diets with a low, medium, and high forage concentration. Our findings demonstrate that increasing forage concentration increased CH4 emissions and that Mootral decreased CH4 production in 15% corn silage diets and improved carcass leanness. Mootral could be used in commercial feedlots and other grain-feeding scenarios as an effective method to decrease CH4 emissions.

Identification of bovine respiratory disease through the nasal microbiome.

BACKGROUND: Bovine respiratory disease (BRD) is an ongoing health and economic challenge in the dairy and beef cattle industries. Multiple risk factors make an animal susceptible to BRD. The presence of Mannheimia haemolytica, Pasteurella multocida, Histophilus somni, and Mycoplasma bovis in lung tissues have been associated with BRD mortalities, but they are also commonly present in the upper respiratory tract of healthy animals. This study aims to compare the cattle nasal microbiome (diversity, composition and community interaction) and the abundance of BRD pathogens (by qPCR) in the nasal microbiome of Holstein steers that are apparently healthy (Healthy group, n = 75) or with BRD clinical signs (BRD group, n = 58). We then used random forest models based on nasal microbial community and qPCR results to classify healthy and BRD-affected animals and determined the agreement with the visual clinical signs. Additionally, co-occurring species pairs were identified in visually BRD or healthy animal groups. RESULTS: Cattle in the BRD group had lower alpha diversity than pen-mates in the healthy group. Amplicon sequence variants (ASVs) from Trueperella pyogenes, Bibersteinia and Mycoplasma spp. were increased in relative abundance in the BRD group, while ASVs from Mycoplasma bovirhinis and Clostridium sensu stricto were increased in the healthy group. Prevalence of H. somni (98%) and P. multocida (97%) was high regardless of BRD clinical signs whereas M. haemolytica (81 and 61%, respectively) and M. bovis (74 and 51%, respectively) were more prevalent in the BRD group than the healthy group. In the BRD group, the abundance of M. haemolytica and M. bovis was increased, while H. somni abundance was decreased. Visual observation of clinical signs agreed with classification by the nasal microbial community (misclassification rate of 32%) and qPCR results (misclassification rate 34%). Co-occurrence analysis demonstrated that the nasal microbiome of BRD-affected cattle presented fewer bacterial associations than healthy cattle. CONCLUSIONS: This study offers insight into the prevalence and abundance of BRD pathogens and the differences in the nasal microbiome between healthy and BRD animals. This suggests that nasal bacterial communities provide a potential platform for future studies and potential pen-side diagnostic testing.

Effect of aspirin to intentionally induce leaky gut on performance, inflammation, and carcass characteristics of feedlot cattle.

The negative impacts of stress on gastrointestinal tract (GIT) barrier function can result in compromised animal growth and health. Aspirin is known to cause mucosal injury leading to increased gut permeability and tight junction damage and can be used as a model to study leaky gut in cattle. The objective of this study was to determine the long-term impact of aspirin-induced chronic leaky gut on cattle growth and carcass attributes. Two treatments were evaluated in two studies: control (no aspirin) or 0.25% of the diet dry matter (DM) aspirin fed daily. Diets consisted of 50% corn, 24% dried distillers grains, 20% corn silage, and 6% supplement on a DM basis. In experiment 1, sixteen Angus × Simmental heifers, allotted by body weight (BW) and breed composition, were fed diets for 154 d. On day 155, heifers were dosed with 1 liter of a 180-mM Cr-ethylenediaminetetraacetic acid solution using an esophageal tube and had urine collected every 1.5 to 3 h for 48 h for analysis of Cr as a measure of gut leakiness. In experiment 2, ninety-six Simmental × Angus steers (355.0 ± 14.8 kg) were allotted by BW and breed composition and fed treatment diets for 159 d. Weight was recorded monthly and serum was collected on day 159 and analyzed for lipopolysaccharide-binding protein (LBP), interleukin-6 (IL-6), serum amyloid A (SAA), haptoglobin, and aspartate aminotransferase (AST). Data were analyzed using the MIXED procedure of SAS. Heifers fed 0.25% aspirin in experiment 1 excreted more Cr into urine compared with heifers not fed aspirin (overall treatment effect, P = 0.01). In experiment 2, aspirin tended to increase serum LBP (P = 0.06) but had no effect on concentrations of IL-6, haptoglobin, SAA, or AST (P ≥ 0.25). Aspirin tended to decrease average daily gain (P = 0.10), decreased hot carcass weight and rib-eye area (P ≤ 0.05), and increased fat thickness, marbling score, and yield grade (P ≤ 0.02). Aspirin tended to increase kidney, pelvic, and heart fat percentage (P = 0.10) and had no effect on liver abscesses (P ≥ 0.80). This study indicates that leaky gut induced by long-term administration of aspirin has negative impacts on feedlot performance and carcass composition. The negative impact of aspirin-induced leaky gut on animal performance suggests that chronic leaky gut caused by other factors (subacute acidosis, stress) may be a significant problem for the feedlot industry.

Feed intake, nutrient digestibility, and selected rumen parameters in feedlot bulls fed diets with different feed additives.

An experiment was conducted to evaluate the feed intake, nutrient digestibility and selected rumen parameters in feedlot bulls fed diets containing different feed additives. Six rumen-cannulated Nellore bulls (age = 8 ± 1.0 months; initial BW = 225 ± 13.2 kg) were distributed in a 6 × 6 Latin square design. Six experimental diets based on 30% corn silage and 70% concentrate on a dry matter (DM) basis were evaluated. Diets differed in feed additive on a DM basis, as follows: 1.4% bicarbonate and magnesium oxide in 3:1 ratio (BOX); 36 ppm lasalocid sodium (LAS); 30 ppm monensin sodium (MON); 25 ppm virginiamycin (VIR); 30 ppm monensin sodium plus 25 ppm virginiamycin (MV); and 3.15% commercial mineral supplement containing D-limonene and exogenous α-amylase (EOA). The experiment lasted 144 d, with six periods of 24 d. Each period consisted of 14 d for dietary adaptation, 3 d for feces and urine collection, and 7 d for omasal and ruminal digesta collection. Bulls fed the BOX diet showed greater (P < 0.05) intake of DM, organic matter (OM), neutral detergent fiber (apNDF), crude protein (CP), and starch compared to the other diets. Diets with LAS, MON, VIR, MV, or EOA did not influence (P > 0.05) the DM, OM, apNDF, CP, or starch intake of feedlot bulls. Bulls fed the EOA diet showed greater (trend; P = 0.09) ruminal digestibility of starch compared to the other diets. The feed additives did not affect (P > 0.05) the intestinal or total tract digestibility of starch, rumen pH, microbial efficiency, total rumen fluid, dilution rate, rate of intake, rate of degradation, or passage rate of the DM, OM, apNDF, and starch. In conclusion, LAS, MON, VIR, MV, and EOA diets reduced nutrient intake compared to BOX. Although all feed additives presented similar effects on rumen pH, temperature, and kinetics the presence of exogenous α-amylase in the EOA diet may increase ruminal starch digestibility and apparent total tract digestibility of DM and OM.

On-farm colorimetric detection of Pasteurella multocida, Mannheimia haemolytica, and Histophilus somni in crude bovine nasal samples.

This work modifies a loop-mediated isothermal amplification (LAMP) assay to detect the bovine respiratory disease (BRD) bacterial pathogens Pasteurella multocida, Mannheimia haemolytica, and Histophilus somni in a colorimetric format on a farm. BRD causes a significant health and economic burden worldwide that partially stems from the challenges involved in determining the pathogens causing the disease. Methods such as polymerase chain reaction (PCR) have the potential to identify the causative pathogens but require lab equipment and extensive sample processing making the process lengthy and expensive. To combat this limitation, LAMP allows accurate pathogen detection in unprocessed samples by the naked eye allowing for potentially faster and more precise diagnostics on the farm. The assay developed here offers 66.7-100% analytical sensitivity, and 100% analytical specificity (using contrived samples) while providing 60-100% concordance with PCR results when tested on five steers in a feedlot. The use of a consumer-grade water bath enabled on-farm execution by collecting a nasal swab from cattle and provided a colorimetric result within 60 min. Such an assay holds the potential to provide rapid pen-side diagnostics to cattle producers and veterinarians.

Arginine supplementation may improve color and redox stability of beef loins through delayed onset of mitochondrial-mediated apoptotic processes.

The objective of this study was to evaluate the effects of arginine (ARG) and/or lysine (LYS) supplementation on meat quality and oxidative stability of beef loins. Steers (n = 40) were split among four dietary treatments (control, ARG, LYS or ARGLYS). The loins (longissimus lumborum) were obtained at 1 day postmortem and aged either 14 or 28 days prior to cutting of steaks for 7 days of display. No impacts of diet treatments on instrumental tenderness, water-holding capacity and fatty acid profiles were found (P > 0.05). Extended aging significantly decreased lipid oxidative stability, color stability and reducing ability of loins. However, steaks from ARG and ARGLYS maintained superior color stability coupled with lower mitochondrial membrane permeability and higher cytochrome c redox stability compared to control (P < 0.05). These results indicate that ARG supplementation can improve color stability of beef loins possibly through delayed onset of mitochondrial-mediated apoptotic processes.

Reconstituted and ensiled corn or sorghum grain: Impacts on dietary nitrogen fractions, intake, and digestion sites in young Nellore bulls.

Two experiments were conducted: (1) to evaluate the effect of ensiling time and grain source on dietary nitrogen fractions; and (2) to verify the influence of concentrate level, processing method and grain source on intake, microbial efficiency, and digestibility by young Nellore bulls. In Experiment 1, corn and sorghum grains were milled, reconstituted to 35% moisture, and ensiled in a bag silo for 10 different times. There were three replications per ensiling time and grain source. Samples from each replication were analyzed in triplicate for total nitrogen (N), non-protein nitrogen (NPN), soluble N, insoluble N, and neutral detergent insoluble nitrogen (NDIN). In Experiment 2, five Nellore bulls were used in a 5 × 5 Latin square design. Four diets were comprised of 28.4% corn silage, 10.7% supplement, and 60.9% dry ground corn, dry ground sorghum, reconstituted and ensiled corn, or reconstituted and ensiled ground sorghum. An additional diet comprised of 45% corn silage, 10.7% supplement, and 44.3% dry ground corn (Roughage+) was used. Each experimental period lasted 22 days, with an adaptation period of 14 days followed by 5 days of total feces and urine collection and 3 days of collecting omasal samples. Data were analyzed using the MIXED procedure of SAS 9.4. The reconstitution and ensiling process reduced (P < 0.05) the insoluble N fraction, increased (P < 0.05) non-protein nitrogen of corn and sorghum grains, tended (P = 0.052) to increase microbial efficiency, and increased (P < 0.05) intestinal and total digestion of dry matter (DM), organic matter (OM), crude protein (CP), and starch. The concentrate level affected neither (P > 0.05) DM intake nor rumen pH. On the other hand, bulls fed diets based on 72% concentrate showed greater (P < 0.05) DM, OM, and CP digestibility compared with those fed a diet based on 55% concentrate. In addition, animals fed diets based on corn grains (both reconstituted and ensiled or dry) presented greater (P < 0.05) intestinal and total starch digestion compared to those fed sorghum grain. Therefore, the reconstitution process can reduce the insoluble N fraction and increase nutrient availability.

Use of aspirin to intentionally induce gastrointestinal tract barrier dysfunction in feedlot cattle.

Stress negatively affects the gastrointestinal tract (GIT) barrier function, resulting in compromised animal health. A deeper understanding of how diet and stress impacts the GIT barrier function in feedlot cattle is needed. Aspirin decreases mucus production and mucosal repair in the GIT and could be used as a model for GIT barrier dysfunction research. The objective of this study was to evaluate the effectiveness of aspirin to induce GIT barrier dysfunction in beef cattle. In experiment 1, sixteen crossbred heifers (425.0 ± 8.6 kg) were allotted to 0, 50, 100, or 200 mg/kg body weight (BW) aspirin doses based on BW. Experiment 1 consisted of two periods separated by 4 wk where four heifers per treatment received the same aspirin dose during each period. Heifers were fed a 49.4% corn silage and 50.6% concentrate diet. The 200 mg/kg BW aspirin treatment was dosed as a 100 mg/kg BW aspirin oral bolus 36 and 24 h prior to Cr-ethylenediaminetetraacetic acid (EDTA) dosing (1 liter; 180 mM). The 50 and 100 mg/kg BW aspirin treatments were dosed as an oral bolus 24 h prior to Cr-EDTA dosing. Urine was collected every 3 h for 48 h and analyzed for Cr. Serum was collected at 0 and 48 h and analyzed for lipopolysaccharide-binding protein (LBP), interleukin-6, serum amyloid A (SAA), haptoglobin, and aspartate aminotransferase. In experiment 2, sixteen crossbred steers (576.0 ± 14.2 kg) fed a similar diet were allotted by BW to the 0 and 200 mg/kg BW aspirin treatments (eight steers/treatment) and were slaughtered 24 h after the last dose. Jejunal tissues were collected, and claudin (CLDN) 1, 2, and 3, occludin, and zonula occludens tight junction messenger ribonucleic acid (mRNA) expression was determined. Data were analyzed using the MIXED procedure of SAS. Urinary Cr excretion increased linearly at hours 3, 6, 9, and 12 (P ≤ 0.04) as aspirin dose increased from 0 to 200 mg/kg. Aspirin linearly increased Cr absorption (P = 0.02) and elimination (P = 0.04) rates and linearly decreased mean retention time of Cr (P = 0.02). Aspirin increased SAA (P = 0.04) and tended to increase LBP (P = 0.09) in serum but did not affect any other serum inflammatory marker (P ≥ 0.19). Aspirin tended to increase jejunal CLDN-1 mRNA expression (P = 0.10) but did not affect the mRNA expression of other genes regulating tight junction function (P ≥ 0.20). Results from this study indicate that aspirin disrupts the GIT barrier function in beef cattle and has a potential as a model in GIT permeability research.

Effect of calcium oxide and soybean hull addition to feedlot diets containing dried distillers grains and corn stover on steer performance, carcass characteristics, and digestibility.

The objective of this study was to determine the effect of soybean hulls (SBH) and/or calcium oxide (CaO) on rumen pH, digestibility, and performance of steers fed diets containing dried distillers grains with solubles (DDGS). In experiment 1, Angus × Simmental steers (n = 112, body weight [BW] = 364 ± 7.8 kg) were allotted to 1 of 4 diets arranged as a 2 × 2 factorial and placed in 16 pens (7 steers/pen, 4 pens/treatment, and 28 steers/treatment). Factors were SBH (0% or 30% of diet dry matter [DM]) and CaO (0% or 1%) inclusion. Basal diets contained 20% corn stover, 30% DDGS, and 4% supplement. Diets with SBH contained 14.1% or 15.0% corn and diets without SBH contained 43.9% or 44.8% corn. In experiment two, four steers (BW = 510 ± 9.8 kg) were allotted to a 4 × 4 Latin square (21 d periods) to determine the effects of CaO and SBH on ruminal pH, volatile fatty acid (VFA), nutrient digestibility, and digestion kinetics. Statistical analyses were conducted using the MIXED procedure of SAS. In experiment 1, BW did not differ among treatments (P ≥ 0.46). Overall carcass-adjusted gain did not differ due to SBH or CaO inclusion (P ≥ 0.13); however, there was an interaction (P = 0.01) where CaO improved gain in steers fed no SBH, but not in steers fed SBH. Steers fed SBH consumed more DM than steers not fed SBH (P = 0.02) and an interaction tended to occur (P = 0.06) where CaO increased dry matter intake in steers fed no SBH, but not in steers fed SBH. Calcium oxide increased hot carcass weight and yield grade (interaction; P ≤ 0.04) and tended to increase fat thickness (interaction; P = 0.08) in steers fed no SBH, but not in steers fed SBH. Dressing percentage, longissimus muscle area, % kidney, pelvic, heart fat, and marbling score did not differ among treatments (P ≥ 0.14). Total VFA concentrations were greater with SBH inclusion and with CaO addition (P < 0.01). Digestibility of DM, neutral detergent fiber (NDF), and acid detergent fiber (ADF) was greater with CaO addition (P ≤ 0.04) and NDF and ADF digestibility were greater with SBH inclusion (P < 0.001). Inclusion of SBH did not affect (P ≥ 0.26) rate of digestion (k d) or passage (k p). Addition of CaO tended to increase mean retention time (P = 0.09). An interaction between SBH inclusion and CaO addition occurred for k d (P = 0.01), where CaO increased k d in steers fed SBH, but decreased k d when steers were fed no SBH. Total N excretion tended to be lower with SBH inclusion and CaO addition (P = 0.07). In conclusion, CaO enhances performance of cattle fed corn, DDGS, and corn stover diets, but not when corn is partially replaced by a fiber-based energy feed.

Effects of maternal protein supplementation and inclusion of rumen-protected fat in the finishing diet on nutrient digestibility and expression of intestinal genes in Nellore steers.

The study aimed to evaluate nutrient digestibility and intestine gene expression in the progeny from cows supplemented during gestation and fed diets with or without rumen-protected fat (RPF) in the feedlot. Forty-eight Nellore steers, averaging 340 kg, were housed in individual pens and allotted in a completely randomized design using a 2 × 2 factorial arrangement (dams nutrition × RPF). Cows' supplementation started after 124 ± 21 days of gestation. The feedlot lasted 135 days and diets had the inclusion of zero or 6% of RPF. Digestibility was evaluated by total feces collection. Steers were slaughtered using the concussion technique and samples of pancreas and small intestine were collected immediately after the slaughter to analyze α-amylase activity, and the expression of SLC5A1, CD36, and CCK and villi morphometry. Feeding RPF increased nutrients digestibility (p < 0.01). There was no effect of maternal nutrition on digestibility and α-amylase activity in steers (p > 0.05). Duodenal expression of SLC5A1, CD36, and CCK increased in the progeny from restricted cows. In conclusion, protein restriction during mid to late gestation of dams has long-term effects on small-intestine length and on expression of membrane transporters genes in the duodenum of the progeny. However, maternal nutrition does not affect digestibility in the feedlot.

Effect of ruminally protected arginine and lysine supplementation on serum amino acids, performance, and carcass traits of feedlot steers1.

One hundred twenty Angus × Simmental steers [322 ± 4.8 kg initial body weight (BW)] were blocked by BW and randomly allocated to 4 treatments arranged as a 2 × 2 factorial to evaluate the effects of supplemental arginine (none or 63 g/d of a 15.6% metabolizable arginine), supplemental lysine (none or 40 g/d of a 25% metabolizable lysine), and their interaction on performance and carcass composition of feedlot steers during a 170-d feeding period. The basal diet [dry matter (DM) basis] contained 52% dry-rolled corn, 22% dried distillers grains with solubles, 20% corn silage, and 6% vitamin-mineral supplement. Lysine balance was estimated to be -10.3 to -10.8 g for diets that did not contain supplemental lysine, and arginine supply was estimated to be +9.7 g for diets that did not contain supplemental arginine during period 1 (days 0 to 87). Lysine and arginine supplies met or exceeded requirements in period 2 (days 88 to 170). Rumen-protected arginine and lysine were top dressed daily until slaughter at a common BW (622 ± 5.5 kg). Data were analyzed using the MIXED procedure of SAS. Body weight, average daily gain, and DM intake were not affected (P ≥ 0.14) by arginine or lysine supplementation. However, lysine increased gain:feed (P = 0.05) during period 1. Lysine decreased serum urea nitrogen (P = 0.03) on day 87, increased (P = 0.01) longissimus muscle (LM) area, decreased (P ≤ 0.01) fat thickness and yield grade, and tended (P = 0.06) to increase moisture content of LM steaks. There tended to be an interaction for moisture content of steaks (P = 0.09), where arginine supplementation increased moisture content to a greater extent in steaks from cattle supplemented with lysine compared with steaks from cattle not fed supplemental lysine. Arginine tended to increase the proportion of Choice grade carcasses (P = 0.09) but did not change lipid content of steaks (P = 0.59). Arginine tended to decrease serum glutamate (P = 0.09) and lysine (P = 0.07) after 87 d of feeding. In conclusion, supplemental rumen-protected arginine and lysine did not improve performance, but lysine can increase carcass muscle and leanness, and although arginine did not increase lipid content of steaks, it may favorably shift carcasses to a greater quality grade.

Alkali addition and roughage inclusion effect on performance and carcass characteristics of feedlot steers fed diets containing 60% dried distillers grains with solubles.

Three experiments were conducted to determine the effectiveness of calcium hydroxide (Ca(OH)2) addition and roughage inclusion on digestibility, performance, and carcass characteristics of steers fed 60% dried distillers grains with solubles (DGS). Statistical analyses for studies were conducted using the MIXED procedures of SAS. In experiment 1, 48 steers (353.5 ± 7.55 kg) were allotted to individual pens and fed 1 of 3 diets (dry matter [DM] basis) containing 60% dried DGS, 20% corn silage, and 4% supplement with: 1) 14.5% corn and no Ca(OH)2; 2) 14% corn and 2% Ca(OH)2; and 3) 14.5% additional corn silage and no Ca(OH)2. Steers fed Ca(OH)2 consumed the least (P = 0.03) and steers fed added corn silage consumed the most and had the least gain:feed (P = 0.02). Gain and carcass quality were not affected by treatment (P ≥ 0.48). In experiment 2, 112 steers (375.3 ± 19.25 kg) were allotted to pens (four pens per treatment; seven steers per pen) arranged as a 2 × 2 factorial (roughage × Ca(OH)2) and fed one of four diets (DM basis) containing 60% dried DGS, 17% corn silage, and 4% supplement with: 1) 17.5% corn silage and no Ca(OH)2; 2) 17% corn silage and 2% Ca(OH)2; 3) 17.25% corn stover and no Ca(OH)2; and 4) 17% corn stover and 2% Ca(OH)2. Added stover decreased average daily gain (ADG) compared to added corn silage (P = 0.04). Ca(OH)2 increased ADG when steers were fed stover, but not when steers were fed only corn silage (P = 0.05; interaction). In experiment 3, six ruminally cannulated steers (initial body weight = 352 ± 14.8 kg) were randomly allotted to a 6 × 6 Latin square design to determine the effects of roughage inclusion (corn, corn silage, stover) and Ca(OH)2 addition (0% or 2%) on ruminal characteristics. Feeding stover decreased total volatile fatty acid(s) (VFA) concentration and DM digestibility compared to corn silage or corn (P < 0.01), whereas Ca(OH)2 resulted in greater total VFA concentrations and DM digestibility (P ≤ 0.02). Stover increased rate of DM degradation (K d) and rate of particle outflow from the rumen (P ≤ 0.04) but decreased extent of DM digestion and mean retention time (P ≤ 0.02) compared to corn or silage. Ca(OH)2 increased K d (P < 0.01) and tended to increase (P = 0.06) liquid passage rate. In conclusion, added roughage did not improve performance of cattle fed 60% dried DGS. Ca(OH)2 may decrease intake and maintain performance of cattle fed 60% dried DGS with corn silage as the roughage source and increases ADG when corn stover replaces a portion of the corn silage.

Total nutrient digestibility and small intestine starch digestion in Nellore and Angus young bulls fed a whole shelled corn diet.

Eighteen Nellore and 18 Angus young bulls with BW of 381 ± 12 kg were randomly assigned into two feeding groups (whole shelled corn [WSC] or ground corn with silage [GC]) to evaluate the interaction of breed and diet on total nutrient digestibility, pancreatic α-amylase, and maltase activity and SLC5A1expression in the small intestine. Experimental diets (DM basis) included (a) a diet containing 30% corn silage and 70% GC and soya bean meal-based concentrate and (b) a diet containing 85% WSC and 15% of a soya bean meal- and mineral-based pelleted supplement. The treatments were Nellore fed GC diet; Nellore fed WSC diet; Angus fed GC diet; and Angus fed WSC diet. Total faecal collection for the digestibility trial occurred from day 48 until day 50 of the experimental period. Feeding the WSC diet reduced DM and NDF intake (p < 0.01). Angus had greater DM and nutrient intake in kg/day (p < 0.01). However, there was no breed effect on DM and nutrient intakes based on percentage of BW (p > 0.19). Angus had greater starch digestibility (p = 0.03) than Nellore. Cattle fed the WSC diet had greater DM, NDF and starch digestibility (p < 0.01) compared with those fed the GC diet. The activity of pancreatic α-amylase (U/g of protein) was greater in Nellore (p < 0.01) and was not affected by diet (p = 0.52). In duodenum, maltase activity (U/g of protein) was greater in bulls fed GC diet (p = 0.02). Expression of the gene SLC5A1was not affected by breed or diet (p > 0.05). In conclusion, Nellore had less capacity to digest starch. However, they did not have less pancreatic α-amylase and duodenal maltase activity compared to Angus. The use of the WSC diet increases DM and total nutrient digestibility.

Effect of a hydrolyzed mannan- and glucan-rich yeast fraction on performance and health status of newly received feedlot cattle1.

A 2-part experiment was conducted to determine the effects of a blend of specialized mannan- and glucan-rich fractions of yeast (Select-TC, Alltech Inc.) on the health status and performance of steers during the first 2 mo of the feedlot period. Eighty crossbred steers were acquired from commercial sale barns in Mississippi and Georgia and transported to Purdue University. All animals were fed a corn silage-based receiving diet and were checked and treated daily for respiratory disease as needed following established treatment protocols. In Exp. 1, 64 steers (246.5 ± 4.7 kg initial weight) were blocked by BW and randomly allocated to 2 treatments to determine the impact of supplementation of a hydrolyzed mannan- and glucan-rich yeast fraction for 56 d on BW, ADG, daily DMI, and G:F: hydrolyzed yeast fed at 13 g (as-fed)/steer daily (TC) or nonsupplemented control (CON). Steers in Exp. 1 were housed in bedded pens with 2 animals per pen [n = 16 pens (32 steers)/treatment]. In Exp. 2, 16 steers (247.1 ± 5.4 kg initial BW) were similarly allotted to 2 treatments (CON and TC), individually penned, and subjected to a lipopolysaccharide (LPS) endotoxin challenge on day 62 or 63 after the start of the study to determine the animal's response to an inflammatory agent. Serum samples and rectal temperatures were taken every half an hour from -2 to 8 h relative to LPS injection from steers in Exp. 2. Data were analyzed as a complete randomized block design using the MIXED procedure of SAS. Morbidity for both experiments did not differ (P ≥ 0.16). Weight, ADG, DMI, and G:F did not differ among treatments (P ≥ 0.32) in Exp. 1. After the LPS infusion in Exp. 2, rectal temperatures (P = 0.03) and serum NEFA concentration (P = 0.04) were decreased in TC compared with CON steers. Concentrations of blood urea nitrogen (P = 0.31), glucose (P = 0.70), insulin (P = 0.57), and cortisol (P = 0.77) did not differ by treatment after LPS administration. Serum IL-6 concentrations were decreased (P < 0.0001), and interferon-γ concentrations tended to be greater (P = 0.07) in TC compared with CON steers after LPS infusion. Serum cytokine and metabolite results indicate that Select-TC improved health and metabolic status of LPS-challenged cattle, but this did not result in quantifiable improvements in performance in the conditions observed in this study.

Performance, insulin sensitivity, carcass characteristics, and fatty acid profile of beef from steers fed microalgae.

Heterotrophic production of microalgae biomass provides a consistent, high-quality source of docosahexaenoic acid (DHA; C22:6 n-3) in triglyceride oils that could be used as a ration supplement for feedlot steers to improve nutritional qualities of beef. Sixty Angus × Simmental steers (438 ± 6.4 kg) were allotted to two treatments (30 steers each, six pens, five steers/pen) to determine the effects of ForPLUS (DHA-rich microalgae Aurantiochytrium limacinum; 63.6% fat; 17.9% DHA; 30 mg/kg Sel-Plex; Alltech Inc.) on performance, insulin sensitivity, LM fatty acid composition, and meat quality. Steers were fed basal diets containing 45% corn, 30% distillers dried grains with solubles, 20% corn silage, and 5% supplement. Basal diets were formulated to contain 16.1% CP and 1.32 Mcal/kg NEg. Treatments were delivered to steers in a ground corn-based top-dress (454 g total/steer) and contained no microalgae for control steers or 100 g/steer daily of ForPLUS for microalgae steers. A glucose tolerance test (GTT) was performed 10 d prior to slaughter. Steers were slaughtered when a target pen BW of 621 kg was achieved. Fatty acid oxidation potential was determined by measuring thiobarbituric acid reactive substances (TBARS) on LM samples collected 24 h after slaughter and aged for 48 h or 21 d. Weight and BW gain did not differ during the study (P ≥ 0.13); however, steers fed microalgae remained in the feedlot seven more days compared to steers fed the control diet (111 vs. 104 d; P = 0.04). Overall DMI decreased (P = 0.002) and G:F increased during the second half of the study (P = 0.04) in steers fed microalgae compared to steers fed the control diet. Steers fed microalgae secreted less insulin (P = 0.01) and took longer to clear glucose (P = 0.01) during a 2-h GTT. Carcass traits did not differ between treatments (P ≥ 0.23). Microalgae had no effect on n-6 content (P = 0.67), but more than doubled the n-3 fatty acid percentage and the n-3:n-6 ratio of the LM (P < 0.0001). The percentage of n-3 fatty acids C20:5 and C22:6 were increased (P < 0.0001) 4-fold and 6.25-fold, respectively, by microalgae supplementation. Concentration of TBARS did not differ in LM aged for 48 h (P = 0.91); however, when aged for 21 d, steers fed microalgae tended to produce LM with greater TBARS concentration compared to steers fed the control diet (P = 0.08). In conclusion, DHA-rich microalgae decreased DMI of steers, and increased n-3 fatty acids and beef oxidation in steaks aged for 21 d.

Metabolomics Profiling to Determine the Effect of Postmortem Aging on Color and Lipid Oxidative Stabilities of Different Bovine Muscles.

The objective of this study was to identify metabolites that could be associated with oxidative stability of aged bovine muscles. Three muscles (longissimus lumbrum (LL), semimembranosus (SM), and psoas major (PM)) from seven beef carcasses at 1 day postmortem were divided into three sections and assigned to three aging periods (9, 16, and 23 days). Although an increase in discoloration was found in all muscles with aging, LL was the most color/lipid oxidative stable, followed by SM and PM (P < 0.05). Lower myoglobin and nonheme iron contents were observed in LL compared to those in SM and PM (P < 0.05). The HPLC-ESI-MS-based metabolomics analysis identified metabolites that were significantly responsive to aging and/or muscle type, such as acyl carnitines, free amino acids, nucleotides, nucleosides, and glucuronides. The results from the current study suggest that color and oxidative stability could be associated with aging but are also muscle-specific. Further studies determining the exact role of the identified metabolites in the color and oxidative stability of beef muscles are warranted.

Effect of supplemental ß-carotene compared to retinyl palmitate on fatty acid profile and expression of mRNA from genes involved in vitamin A metabolism in beef feedlot cattle.

To examine the effects of dietary ß-carotene (ßC) or retinyl palmitate (RP) on fatty acid (FA) profile and mRNA expression, samples were collected from 24 Angus-cross calves that were allotted to four treatments consisting of RP supplemented at 2200 IU/kg, and synthetic ß-carotene (SßC) supplemented at one, five or 10 times RP. Longissimus muscle (LM) cis-9, trans-11 conjugated linoleic acid was greater in RP compared to SßC1X (P = 0.04). The polyunsaturated:saturated FA increased linearly (P = 0.04) in the LM as dietary SßC increased. Expression of ßC oxygenase 2 (ßCO2), an enzyme that cleaves ß-carotene, was greater in the LM for SßC1X compared to RP and decreased linearly as SßC increased (P ≤ 0.02). Peroxisome proliferator activated receptor γ (PPARγ) expression in the LM increased in SßC1X compared to RP (P = 0.03); however, PPARγ and retinoic acid X receptor α (RXRα) expression decreased linearly (P = 0.02) in the LM with increasing SßC. Retinoic acid receptor α (RARα) expression tended (P = 0.10) to decrease linearly in the LM with increased SßC. In conclusion, SßC supplementation increased mRNA expression of some lipogenic genes in the LM, but increasing dietary SßC inhibited their expression and tended to increase polyunsaturated FA.