bluuebunny/crossref_metadata_2025 huggingface dataset:
355 Determining the bioavailability of copper carbonate (Emerald-C) and tribasic copper chloride relative to copper sulfate in feedlot steers under moderate antagonistic pressure
Authors: Henderson Jacob A , Hansen Stephanie L
Published: September 2024

Copper (Cu) from Cu sulfate (CuSO4) may be more susceptible to antagonism when fed in cattle diets high in sulfur and molybdenum, but other Cu supplements may be better able to avoid this. The objective of this study was to determine the bioavailability of Cu carbonate (CuCO3; Emerald-C, Old Bridge Minerals, Old Bridge, NJ) and tribasic Cu chloride (TBCC; Intellibond-C, Selko, Indianapolis, IN) relative to CuSO4 when fed to steers supplemented with 2 mg Mo/kg DM and 0.1% S. Angus crossbred steers [n = 84; body weight (BW) = 282 ± 19.3 kg] were enrolled (n = 12 per treatment) in a 96-d study and fed a corn-silage based diet with one of seven Cu supplementation strategies: no supplemental Cu (CON), 5 or 10 mg supplemental Cu/kg DM from CuSO4, 5 or 10 mg supplemental Cu/kg DM from TBCC, or 5 or 10 mg supplemental Cu/kg DM from CuCO3. Steers were housed in pens equipped with GrowSafe feed bunks (GrowSafe Systems Ltd., Airdire, AB, Canada) with six steers per pen. The GLM procedure of SAS 9.4 was used to determine the bioavailability of CuCO3 and TBCC relative to CuSO4 using both liver and plasma Cu. The MIXED procedure of SAS was used to analyze liver Cu, plasma Cu, and growth performance data. Contrasts compared CON vs. 5 mg/kg, CON vs. 10 mg/kg, 5 mg/kg vs. 10 mg/kg, CuCO3 vs. CuSO4, TBCC vs. CuSO4, and CuCO3 vs. TBCC. The bioavailability of CuCO3 relative to CuSO4 based on liver and plasma Cu was 89 (P < 0.01) and 133% (P = 0.21), respectively. The bioavailability of TBCC relative to CuSO4 based on liver and plasma Cu was 88 (P < 0.01) and 100% (P = 0.82), respectively. Over the 96-d trial, liver Cu decreased 66% in CON, from 74 to 21 mg Cu/kg DM. Steers receiving CuCO3 had greater plasma Cu concentrations than those receiving TBCC on d 56 (P = 0.05) but were similar by d 96 (P = 0.39). Copper supplemented steers had greater dry matter intake (DMI) than CON (P = 0.01). Steers supplemented with CuCO3 had greater DMI than those receiving TBCC (P = 0.05). Steers receiving TBCC tended to have greater gain:feed than those receiving CuSO4 (P = 0.08), but gain:feed did not differ between CON and supplemented treatments (P ≥ 0.6). In conclusion, CuCO3 and TBCC may be less available to steers under moderate antagonistic pressure based on liver Cu, but Emerald-C CuCO3 may result in greater Cu in circulation. More research is needed to evaluate the impact of feeding CuCO3 on systemic Cu metabolism and how factors such as initial Cu status impact relative bioavailability results.
357 Injectable trace mineral improves immune response and outcome of Mannheimia haemolytica infection in feedlot steers
Authors: Hong Suyeon , Rients Emma L , Franco Carlos , McGill Jodi , Hansen Stephanie L
Published: September 2024

Trace minerals, such as selenium, copper, zinc, and manganese, are important in the immune response. These trace minerals are included in an injectable trace mineral product, Multimin90, which has previously been utilized to boost the immune response during vaccination. However, little is known about its effects on morbid animals. Angus-crossbred steers [n = 32; body weight (BW) = 284 ± 8.5 kg] were used to determine the effects of Multimin90 (ITM; 1 mL/45 kg BW) before or during treatment for bacterial respiratory infection. Steers were fed a common ryelage-based growing diet without supplementation of Zn, Cu, Mn and Se for 4 to 6 wk prior to and during the challenge study. The study was completed in two groups (n = 14 to 18) for sampling logistics. Steers were stratified by BW into three treatments: CON (control, saline injection; n = 9), ITMPRE (ITM 6 d before infection; n = 12) and ITMPOST (ITM 2 d post infection; n = 11). Steers were shipped for 6 h and received at ISU Animal Resource Station (Ames, IA) 7 d before being intratracheally infected with M. haemolytica strain D153 at 9.48 × 108 colony forming units on d 0 followed by tulathromycin treatment 2 d post infection (dpi). Liver biopsies were collected -10, 2 and 10 dpi. Blood and bronchoalveolar lavage (BAL) samples were collected on 0, 2 and 5 dpi. Statistics were analyzed using a two-way ANOVA (mixed-effects model) with Tukey’s multiple comparisons test in Prism v9.2.0 (GraphPad Software, Inc). Liver and plasma were analyzed for trace mineral concentration, all steers had adequate trace mineral status prior to and throughout disease challenge. Steers were monitored for signs of clinical illness after inoculation by a trained observer blinded to treatment using a modified Wisconsin clinical scoring system, including cough, nasal discharge and ear score. Compared with CON, steers in ITMPRE and ITMPOST had lesser clinical scores (P < 0.05); treatment did not affect rectal temperatures, which peaked 2 or 3 dpi (Time P = 0.02). There was no difference between treatment in the detection of M. haemolytica in BAL or nasopharyngeal swab samples (P ≥ 0.14). In BAL cells, there were increased frequencies of gamma delta T cells and natural killer cells 5 dpi in ITM treated steers compared with CON (P ≤ 0.04). Treatment did not affect the frequencies of alveolar macrophages, neutrophils, B cells, CD4+ and CD8+ T cell populations in BAL cells (P ≥ 0.15). Overall, ITM administration in TM adequate steers at arrival or during respiratory disease treatment positively affects lung cell recruitment and clinical scores with no negative impacts on disease outcome compared with controls. Further work in TM deficient animals or with more aggressive disease challenge is warranted.
353 Zinc supplementation prior to transit and transit duration effects on feedlot performance and muscle fatigue of beef steers: Part I – Performance and Muscle Fatigue
Authors: Baumhover Allison M , Ortner Brock M , Thomson Daniel U , Schwartzkopf-Genswein Karen S , Hansen Stephanie L
Published: September 2024

This study investigated zinc (Zn) as a mitigation strategy for transit-induced muscle fatigue. Recently weaned Angus-cross steers (n = 80) were stratified by body weight (BW = 265 ± 18.0 kg) to a 2×2 factorial. Dietary (DIET) treatments of no supplemental Zn (Zn0) or 100 mg supplemental Zn/kg DM (Zn100; Zn as ZnSO4), were fed for 42 d before transit. Along with a transit duration (DUR) of 8 h (~707 km; 8H) or 18 h (~1,608 km; 18H) on d 0. Upon return, and for 56 d post-transit, all steers received Zn100. Individual feed disappearance was monitored using GrowSafe bunks (1 bunk/pen; 5 steers/pen). Body weights were collected on d -42, -41, -1, 0 (on truck), 1 (off truck), 2, 7, 28, 55, and 56. Blood samples for analysis of non-esterified fatty acid (NEFA) and serum L-lactate were collected on d -1, 1, 2, and 7. Data were analyzed via ProcMixed of SAS (experimental unit = steer; 15 to 20/treatment) as a 2 × 2 factorial, with fixed effects of DIET, DUR, and the interaction. Individual initial (d -42) BW was used as a covariate in BW analysis. Average DMI of d -11 to d -2 (pre-trucking) was used as a covariate in post-transit DMI analysis. Blood parameters were log-transformed and analyzed as repeated measures with repeated effect of day. Pre-transit (d -1) concentrations were used as a covariate. Pre-transit average daily gain (ADG) and dry matter intake (DMI) were greater (P ≤ 0.02) and feed efficiency (gain to feed; G:F) tended to be greater (P = 0.10) in Zn100 vs. Zn0. BW on d -1 and 7 (P = 0.01) was greater for Zn100 than Zn0. There was a DIET effect and DUR tendency on post-transit G:F where Zn0 was greater than Zn100 (P ≤ 0.01) and 18H tended to be greater than 8H (P = 0.05). 56-d post-transit ADG was least for Zn100-8H (DIET×DUR, P = 0.02). Post-transit DMI was greatest for Zn0-8H with Zn100-8H being the lowest and other treatments being not different (DIET × DUR, P = 0.04). Diet did not affect L- lactate or NEFA concentrations (P > 0.13). NEFA was greater for 18H vs. 8H on d 1 and 2 but less on d 7 (DUR×DAY, P < 0.01). There was a DUR×DAY effect (P ≤ 0.01) for L-Lactate where 8H tended to be greater than 18H on d 1, but by d 2 8H was lesser than 18H, and on d 7 they were not different. In conclusion, longer transit duration increases some indicators of muscle fatigue and Zn supplementation improved pre-transit performance. Receiving Zn supplementation after trucking also improved the post-transit performance of those not previously supplemented with Zn.
400 Effect of pH on in vitro ruminal metabolism of trans-10 18:1 and trans-11 18:1
Authors: Fernandes Tatiane , Manuel Chica , Vahmani Payam , Alves Susana P , Dugan Mike , Bessa Rui JB
Published: September 2024

Dietary C18 unsaturated fatty acids are extensively biohydrogenated by rumen microbiota into 18:0 and trans-18:1 isomers. Usually, the biohydrogenation (BH) pathways produce mostly 18:0 and trans-11 18:1 as the main intermediate. However, when fed low-forage diets that decrease the rumen pH, the main BH intermediate often is the trans-10 18:1 isomer. This change in BH, called the trans-10 shift, is associated with milk fat depression, but despite that, little is known about the triggers of the trans-10 shift and its ecological role in rumen microbiota. Microbiota stressed by low rumen pH may benefit from increased trans-18:1 availability favoring the production of the trans-18:1 isomer with a slower rate of BH. Thus, we hypothesize that at low rumen pH conditions, the BH of trans-10 18:1 will be slower than that of trans-11 18:1. We tested that with an in vitro experiment using batch incubation in Hungate tubes, replicated in 5 wk. In each run, 24 tubes were allocated at 6 treatments and 4 incubation times (0, 6, 24 and 48 h). The treatments resulted from the combination of 2 buffering solution pH (6.74 vs. 5.85) and 3 substrates: 1) Control (60 mg feed DM) 2) T10 (Control plus 1.2 mg of trans-10 18:1) and 3) T11 (Control plus 1.2 mg of trans-11 18:1). Volatile fatty acids (VFA) and long-chain fatty acids were analyzed by gas chromatography. Data were analyzed using the 2 × 3 factorial arrangement for each incubation time. Low pH resulted in less 30 to 37% DM disappearance than those with high pH at all incubation times (P < 0.05). The decrease in VFA with low pH was less expressive (≈17%) and only evident at 24 and 48 h incubation times. The low pH also decreased (P < 0.05) the BH of 18:1n-9 (less ≈47 to 53%), 18:2n-6 (less 30 to 34%) and 18:3n-3 (less 20 to 22%) at 24h and 48h incubation times, respectively. The disappearance of trans-11 18:1 was 14.6% at 6 h, 29.0% at 24 h and 32.8% at 48 h and was not affected by pH. The disappearance of trans-10 18:1 was dependent on pH. At 6 h and high pH the disappearance of both was similar, but at low pH the disappearance of trans-10 18:1 was much less (9.8%) than that of trans-11 18:1. However, at 48 h and low pH, the disappearance was similar between isomers and the disappearance of trans-10 18:1 was much greater (46.6%) than trans-11 18:1. In summary, the BH of trans-10 18:1 is less at low pH than at high pH, and this could in part explain its abundance in some practical ruminant feeding conditions. Acknowledgements: Fundação para a Ciência e a Tecnologia (FCT) funding through PTDC/CAL-ZOO/29654/2017(RumOmics), PTDC/CAL-ZOO/4515/2021(Gene2Rumen), UIDB/00276/2020 (CIISA), and LA/P/0059/2020 (AL4Animals) projects.
476 Induced hindgut acidosis in sheep affected gut permeability and ruminal fermentation
Authors: Linder Haley F , Loman Brett R , Fries Ryan C , Gutierrez-Nibeyro Santiago D , Garrett Edgar F , McCann Joshua C
Published: September 2024

Leaky gut may be caused by acidotic conditions in the hindgut and lead to systemic inflammation and negative effects on the gastrointestinal tract. The objective was to determine the effects of induced hindgut acidosis in sheep on cecal pH, ruminal fermentation, and gut permeability. Ruminally and cecally cannulated ewes [n = 11; body weight (BW) = 49 ± 4 kg] were assigned to one of two treatments: control (CON; n = 5) or induced hindgut acidosis (HGA; n = 6). To induce hindgut acidosis, 3 g wheat starch/kg BW per 24 h was continuously infused via the cecal cannula for 4 d. Control ewes received a constant infusion of deionized water. The diet contained 40% grass hay pellets, 35% whole shelled corn, 15% dried distillers grains, and 10% alfalfa cubes. Chromium EDTA was dosed once daily via the cecal cannula as a marker of gut permeability. Rumen, cecal, and fecal samples were collected to determine pH and volatile fatty acids (VFA). Rumen fluid was collected on d 4 for an ex vivo fermentation. Flasks were incubated for 24 h to determine pH, VFA, ammonia and in vitro dry matter digestibility. Tissue samples from the ileum, cecum, and colon were mounted in Ussing chambers to measure transepithelial electrical resistance (TEER). There was a treatment × time effect (P = 0.05) for cecal pH with HGA ewes having lesser cecal pH after d 1. By d 4, cecal pH had declined to 5.07 for HGA ewes compared with CON ewes which remained above 6.40 throughout the experiment. A treatment × time interaction was also observed (P < 0.01) for fecal pH and followed the same trend as cecal pH. Rumen pH was not affected (P = 0.87) by the interaction of treatment and time but was affected (P < 0.01) by treatment as ewes on the HGA treatment had a lesser rumen pH than CON ewes. Control ewes had lesser ruminal VFA and ammonia concentrations than HGA ewes (P < 0.01). Urinary Cr recovery was not affected by the interaction of treatment and time, or treatment (P ≥ 0.13). In vitro dry matter disappearance was not affected by cecal infusion treatment (P = 0.60). There was no effect (P = 0.78) of treatment on ex vivo pH. There were no effects (P ≥ 0.11) of treatment, time, or their interaction on ex vivo ammonia or total VFA concentration. In cecal tissue, TEER tended (P = 0.09) to be greater in CON ewes than HGA ewes. In contrast, TEER was not different (P ≥ 0.83) in ileal or colonic tissues between treatments. Induced hindgut acidosis in sheep altered rumen fermentation and tended to increase ex vivo measures of cecal permeability, but did not affect ex vivo rumen fermentation.
475 Effects of diet composition and feed delivery regimen on growth performance, rumen buffering characteristics, carcass outcomes, and liver abscess prevalence of finishing steers
Authors: Schneid Kasi N , Young James D , Lawrence Ty , Richeson John T , Samuelson Kendall L
Published: September 2024

Liver abscesses present significant challenges for the beef industry, yet understanding of the interplay between diet composition, eating behavior, and ruminal acidosis in finishing cattle and their effects on liver abscess prevalence and growth performance is lacking. Therefore, this study investigated the independent and interactive effects of dietary starch concentration and feed delivery regimen on growth performance, rumen buffering characteristics, carcass outcomes, and prevalence of liver abscesses in finishing beef steers. On d 0, beef steers [n = 720; body weight (BW) = 407 ± 4.53 kg) were sorted into 12 blocks according to BW and assigned to 1 of 4 treatments arranged as a 2 × 2 factorial (12 pens/interaction treatment; 24 pens/main effect) in a randomized complete block design. Treatments were finishing diets with low (49.1%; CON) or high (64.4%; HOT) starch concentration fed to steers receiving consistent feed delivery (REG) or randomized variations (ERR) in feed quantity (85% followed by 115% of the previous 4-d average once per week) and delivery time (delayed for 1, 2, 3, or 4 h twice per week). The 3 steers closest to the median BW in each pen were administered a 3-axis accelerometer ear-tag to quantify time spent ruminating and an indwelling rumen bolus to measure ruminal pH for the first 150 d of the study. Fecal score (1 = hard and dry consistency to 5 = water like consistency) and fecal pH were recorded on d 0, 56, 112, and before harvest. Daily dry matter intake (DMI) variability was greatest (P < 0.01; diet × feed delivery interaction) for CON + ERR, intermediate for HOT + ERR, and least for HOT + REG and CON + REG. No additional interactions (P ≥ 0.14) between diet and feed delivery regimen were observed. Feeding HOT increased total liver abscesses (P < 0.01) by 21.7 percentage points and liver scars (P < 0.01) by 12.7 percentage points compared with CON. Additionally, steers consuming HOT had less (P ≤ 0.05) final BW, average daily gain, DMI, gain-to-feed ratio, hot carcass weight, marbling score, and yield grade than CON. Steers fed HOT also had fewer daily rumination minutes (P < 0.01; diet × day interaction), lower fecal pH (P < 0.01; diet × day interaction) lower ruminal pH (P = 0.04), and less desirable fecal scores (P = 0.02) vs. CON. Feed delivery regimen did not affect (P ≥ 0.21) growth performance, rumen buffering characteristics, carcass traits, or liver abscess prevalence. Increasing the concentration of readily fermentable starch fed to finishing steers reduced growth and carcass performance, ruminal pH, and fecal pH, while increasing the proportion of liver abscesses. In contrast, inducing erratic DMI did not affect growth performance or carcass outcomes.
472 Evaluating the effects of acidosis and bacterial concentrations on the development of liver abscesses in beef steers
Authors: Childress Kallie D , Hales Kristin E , Nagaraja T G , Lawrence Ty , Amachawadi Raghavendra G , Sanchez Nicole C Burdick , McDaniel Zach S , Line Dalton J , Thompson-Smith Aubrey , Hanratty Ashlee Noelle , Dornbach Colten W , Abbasi Mina , Shi Xiaorong , Galyean Michael , Ballou Michael A , Machado Vinicius , Broadway Rand R
Published: September 2024

We evaluated the association of diet type, ruminal acidosis bout frequency, and intraruminal bacterial inoculum concentration on liver abscess (LA) development in steers. Beef × dairy steers [n = 40, initial body weight (BW) = 107 ± 11 kg] were assigned randomly to 1 of 5 treatments that included either a high-dose (HD; 1 × 109 and 1 × 109 CFU/mL) or a low-dose (LD; 1 × 106 and 1 × 106 CFU/mL) of Fusobacterium necrophorum subsp. necrophorum and Salmonella enterica serovar Lubbock, respectively. Treatments included: NCON = high-forage diet with no intraruminal inoculation; CON+HD = high-forage diet with a single, HD inoculation; 2AD+HD = 2 acidotic diet cycles with a single, HD inoculation; 4AD+3LD = 4 acidotic diet cycles with a series of 3 LD inoculations; and 4AD+HD = 4 acidotic diet cycles with a single, HD inoculation. Individual animal was the experimental unit. Continuous data were analyzed using mixed models, and categorical data were analyzed as binomial proportions with treatment, time, and their interactions as the fixed effects. Hematology was evaluated before harvest on d 21 to evaluate indications of systemic disease. Although no difference was observed in rumenitis among treatments (P = 0.79), steers with LA presented with 8 percentage points greater rumenitis than steers without LA. Steers consuming the high-forage diet also presented with rumenitis. Prevalence of LA was 0, 37.5, 37.5, 50, and 12.5% for NCON, CON+HD, 2AD+HD, 4AD+3LD, and 4AD+HD, respectively (P = 0.68). A key observation of this study was that steers fed a high-forage diet presented with LA when dosed with of F. necrophorum and S. enterica, even in the absence of the acidotic diet.
152 Overview of probiotic supplementation and opportunities to improve cow-calf production
Authors: Moriel Philipe , Izquierdo Vinicius S , Brauner Cassio , Vendramini Joao M B
Published: September 2024

The growing concern of increased antimicrobial resistance and their adverse effects on host microbiota and health has led to the investigation of new alternatives to achieve pathogen control and promote host health. By definition, probiotics (also known as direct fed microbials; DFM) are live microorganisms that confer a health benefit to the host when administered in adequate amounts. Probiotics supplementation has been an effective management practice to improve health and performance of the livestock through the inhibition of pathogens and improvement of feed digestion. Several modes of action provide explanations for the improved health and reduced morbidity in livestock, including: direct inhibition of pathogen growth via production of anti-bacterial factors and competition for dietary ingredients (growth substrates); intestine protection by activating mucus production, which acts as reservoir of antibodies, mucins, and antimicrobial peptides, and as a selective barrier for trapping pathogens and other unwanted substances; competition against pathogens for binding sites; support for optimal intestinal barrier integrity; biofilm formation; and reduction in inflammation by modulating the release of immunoglobulins and pro- and anti-inflammatory cytokines. Moreover, probiotics support the production of a cascade of enzymes that improve digestibility of starch, fat, protein, and fiber in the gastrointestinal tract. Combined, the aforementioned modes of action and improved digestibility explain the increased livestock health and performance following probiotic supplementation reported in several species. Spore forming bacteria have been the primary microorganisms used as probiotics due to their stability and viability after processing, storage, and manipulation. This presentation will summarize ongoing and published data on probiotic supplementation to improve cow-calf production, including studies evaluating probiotic supplementation to optimize post-weaning growth and reproduction of developing Bos indicus-influenced beef heifers. Moreover, the presentation will include the potential effects of probiotic supplementation on nutritional management of beef cows during gestation and early lactation, with emphasis on the future offspring growth performance and immune response. It has also been observed that neonatal gut colonization is crucial for the developing gut and naïve immune system and has long-term health effects. Thus, partial data on microbiome and metabolome of beef cows and their calves will also be shared in this presentation.
151 Microbial inoculant effects on cool- and warm-season grass silage
Authors: Vendramini Joao M B , Moriel Philipe
Published: September 2024

Silage has been the preferred method of forage conservation in many regions of the world, primarily due to frequent rainfall during the period of maximum forage growth and limited opportunities to preserve forage as hay. Corn and sorghum are the main forages conserved as silage, but cultivation of annual summer crops is costly and may be risky due to variable climactic conditions. Therefore, livestock producers have relied on perennial grasses as a source of forage for conservation as silage. However, most grasses have undesirable characteristics that reduce the potential of achieving satisfactory fermentation and conservation, such as limited dry matter concentration, and morphological and chemical characteristics. Several management practices have been developed with the objective of improving grass silage fermentation and nutritive value, and microbial inoculants have been among the most used management practices. Nonetheless, most microbial inoculants have been tested and developed for corn silage and later recommended to grass silage with limited scientific evidence for the efficacy of the specific inoculant. The most used grasses as forages are divided into cool- (C3) and warm-season (C4) perennial grasses with notorious differences between them. Cool-season grasses have greater water-soluble carbohydrates and lesser structural carbohydrates concentrations than warm-season perennial grasses, which are desirable traits for better silage fermentation and positive microbial inoculant effects. Warm-season perennial grasses have greater accumulation of starch as non-structural carbohydrate, which does not directly contribute to silage fermentation. In addition to the limitations mentioned previously, warm-season perennial grasses have decreased dry matter concentration and nutritive value, reducing the likelihood of achieving desirable fermentation. A literature review was conducted to evaluate the effects of microbial inoculant on nutritive value and fermentation characteristics (pH, lactic acid, acetic acid, butyric acid, and ammonia concentrations) of grass silage. In addition, the effect of different microbial inoculants (homofermentative vs. heterofermentative) was evaluated. Lastly, results from current research projects testing the effects of microbial inoculants on silage microbiome and gas production were presented.
153 Use of probiotics in feedlot diets
Authors: Engle Terry E , Schutz Jennifer , Cappellozza Bruno Ieda
Published: September 2024

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.
207 Efficacy of sheep and goats during intensive grazing for the control of field bindweed (Convolvulus arvensis)
Authors: Spurling Ryan A , Olsen Brandi L , Stroud Sarah K , Thacker Eric T , Thornton-Kurth Kara J , Hill Shane A , Page Chad M
Published: September 2024

Sheep and goats prefer forbs and browse, respectively, which make them ideal for targeted grazing of weeds. However, this grazing may negatively affect sheep and goat performance. The objectives of the study were to monitor the effects of intensive grazing on sheep and goat performance and forage selection, as well as reduce Convolvulus arvensis. To do this, sheep [n = 40; average body weight (BW) 74 kg ± 1.45 kg] and goats (n = 40; average BW 45 kg ± 1.45 kg) grazed six paddocks, each an acre in size, on a wildlife refuge area managed by the Utah DNR near Richmond, Utah. The flock was in each paddock for 3.5 to 4 d. Paddock rotation corresponded with the amount of forage in each plot. Sixteen ground coverage measurements/day, split between morning and night, were taken. Measurements estimated percentages of ground cover, litter cover, and bare ground. Bite counts were taken at dusk and dawn to record the number of weedy forb, grass, native forb, and shrub bites. One ewe or doe was randomly observed for 5 min, then the observer would randomly select another ewe or doe until 4 does and 4 ewes were sampled. Body weights and body condition scores (BCS) of ewes and does were taken at d 0 and 22. The GLIMMIX procedure of SAS with main effects of species and days on pasture was used to analyze ground cover, bite counts, weight, and BCS with paddock as the random variable. Bare ground increased (P = 0.006) by day in each paddock. Both ground and litter cover decreased over time in each paddock (P < 0.05). There was no difference (P > 0.10) in number of bites of native forbs or grasses between sheep and goats. A species × day effect (P = 0.02) occurred where sheep consistently had 20 more bites of weedy forbs than goats, except for at d 12 where goats took 27 more bites of weedy forbs than sheep. Goats consumed an average of 10 bites more (P = 0.03) shrubs than sheep. Consumption of grasses increased (P = 0.006) in each pasture between d 0 and 22, but no species difference (P = 0.80) was observed. There was a day effect where both species lost 3.6 kg between d 0 and 22 (P = 0.22) which represented 5% of sheep and 8% of goat BW from the start of the trial; however, body condition score increased (P < 0.05) by one-half a score on a 5-point scale between d 0 and 22 in both species. The results of this study indicate that sheep will graze more field bindweed than goats. Sheep and goats in this grazing system may see some losses in productivity, therefore stage of production and supplementation strategy should be considered to optimize rangeland health and minimize negative effects on animal performance.
209 Prevalence of subclinical selenium deficiency in Oregon grazing sheep using whole blood analysis
Authors: Hasan Daniella , Bionaz Massimo
Published: September 2024

The objective of this study was to understand the status of microminerals in sheep across the state of Oregon and determine the association with management, including dietary supplementation, with major focus on Se, as Oregon is a region considered low in soil Se. Fifty-five sheep farms encompassing >70% of the counties in Oregon were enrolled in this study, and tentatively, 10% of the ewes in the flock were selected (but not fewer than 3 and not more than 10 ewes). To be enrolled, ewes must have been dry (non-lactating), fed a local forage diet for the last 3 consecutive months, be between the ages of 2 and yr old, have lambed at least once before, have a body condition score between 2 and 4 on a 5-point scale, and observably healthy. A questionnaire regarding rearing practices, mineral supplementation protocol, and observed health or production deficits was sent to the producers. Whole blood (3 mL) was collected in a royal blue trace mineral-free tube from each animal and digested in concentrated nitric acid and hydrogen peroxide, then diluted in distilled water, and analyzed via ICP-MS. Commercial standards were used to calibrate the ICP-MS for >14 microminerals and heavy metals including Se. Data were normalized using Indium as an internal standard before quantification using the standard curve. Available normal reference ranges for whole blood for all minerals were identified using published literature. For Se in whole blood, normal ranges were defined as 120 to 350 ng/mL. Intra and inter-flock variance was plotted, and the proportion of animals in each farm below or above the normal range was quantified. Interflock spread was between 8 and 519 ng/mL with a median of 211 ng/mL. Forty-seven percent of farms had at least one deficient animal. Results indicated that subclinical Se deficiency (< 120 ng/mL without reported production deficits) was prevalent in forage-fed dry ewes even when mineral supplements were offered ad-lib. Overall, these findings indicate a need to screen for Se deficiency to evaluate the efficacy of the mineral supplementation protocol.
211 United States Department of Agriculture National Animal Health Monitoring System Goat 2019 study: Regional prevalence of gastrointestinal nematodes and lungworms in the United States
Authors: Miller James , Avery Ryan , Urie Natalie , Branan Matthew , Burke Joan M
Published: September 2024

One objective of the United States Department of Agriculture National Animal Health Monitoring System Goat 2019 study (September 2019-April 2020) was to determine the prevalence of gastrointestinal nematode (GIN) and lungworm infection in goats across the US. Feces were collected from 5,176 animals on 318 operations in 24 states and results were consolidated into 4 regions: Northwest (3 states, 34 operations), Northeast (9 states, 89 operations), Southeast (9 states, 132 operations) and Southwest (3 states, 63 operations). Feces from each operation were mixed and cultured to allow eggs to hatch and develop, The Baermann technique was used to recover infective third-stage larvae from cultures. GIN identification included Haemonchus, Trichostrongylus, Teladorsagia, Oesophagostomum and Nematodirus. Lungworm (Muellerius/Protostrongylus) first-stage larval presence was also noted. Frequencies were calculated and Haemonchus were found on 18.6 ± 3.5 % of the operations (Northwest, 27.0 ± 16.5 %; Northeast, 13.1 ± 4.7 %; Southeast, 15.9 ± 5.1 % and Southwest, 29.2 ± 9.4) %); Trichostrongylus on 97.2 ± 1.4 % of the operations (Northwest, 100 %; Northeast, 98±1.1 %; Southeast, 97.0 ± 2.2 % and Southwest, 95.7±4.2 %); Teladorsagia on 80.3 ± 4.0% of the operations (Northwest, 97.1 ± 2.4%; Northeast, 71.6 ± 9.1%; Southeast, 88.6 ± 4.6% and Southwest, 75.7 ± 7.3%); Oesophagostomum on 38.2 ± 4.3% of the operations (Northwest, 73.1 ± 9.2%; Northeast, 39.6 ± 7.1 %, Southeast, 46.4 ± 8.2% and Southwest, 15.5 ± 6.0%); Nematodirus on 7 ± 2.6 % of the operations (Northwest, 7 ± 5.1%; Northeast, 5.2 ± 4.7 %, Southeast, 0 % and Southwest, 20.8 ± 8.6 %); and lungworms on 35.4 ± 4.2 % of the operations (Northwest, 69.1 ± 9.8 %; Northeast, 52.2 ± 9.1 %, Southeast, 33.4±6.9% and Southwest, 8.3±3.3%). Results indicated that Trichostrongylus was the most prevalent followed by Teladorsagia, Oesophagostomum, lungworms, Haemonchus and Nematodirus. Prevalence of all GIN and lungworms were similar within regions except Nematodirus and lungworms, which were less in the southeast and southwest, respectively. Due to project seasonal timing and sampling logistics, fecal collection was conducted from fall through early spring which may have influenced prevalence, specifically the most pathogenic GIN, Haemonchus. This study provided valuable insight into USA regional prevalence of GIN and lungworms in goats.
213 Lipopolysaccharide-induced alterations in the liver metabolome of St. Croix and Suffolk sheep
Authors: Johnson Samanthia R , Bentley Kelsey L , Bowdridge Scott , Ogunade Ibukun M
Published: September 2024

The development of resistance in parasites due to overuse of anthelmintics has resulted in a marked decrease in the efficacy of these drug classes. Recent research efforts have focused on exploring alternatives such as selection for parasite-resistant breeds with the implication that immunocompetence may align with parasite resistance. Two breeds that are often investigated are the St. Croix (STC), a resistant hair breed, and Suffolk (SUF), a susceptible wool breed sheep. The liver has a vital role in metabolism in the body and metabolizes lipopolysaccharide (LPS), which triggers whole body response through the production of appropriate metabolites, cytokines and immune cells. The objective of this study was to investigate the breed differences in liver metabolome of sheep, with divergent resistance to parasites, in response to LPS. Both STC and SUF sheep (n = 9/breed) were challenged with LPS, intravenously and liver biopsies were collected prior to challenge (HR0), 2 h post-challenge (HR2) and 6 h post-challenge (HR6). Liver tissue samples were subjected to quantitative untargeted metabolome analysis using chemical isotope labelling/ liquid chromatography- mass spectrometry. A total of 874 metabolites were detected and identified. Metabolomics also revealed that 8 pathways (pyrimidine metabolism, pantothenate and CoA biosynthesis, beta-Alanine metabolism, valine, leucine and isoleucine degradation, valine, leucine and isoleucine biosynthesis, folate biosynthesis, arginine and proline metabolism and glutathione metabolism) were altered (P ≤ 0.05) between STC and SUF sheep prior to LPS challenge. A total of 10 pathways (folate biosynthesis, glycine, serine and threonine metabolism, tyrosine metabolism, glycerophospholipid metabolism, purine metabolism, cysteine and methionine metabolism, taurine and hypotaurine metabolism, glutathione metabolism, thiamine metabolism and pantothenate and CoA biosynthesis) were altered (P ≤ 0.05) between STC and SUF sheep at HR 2. Only 2 pathways (glycerophospholipid metabolism and purine metabolism) were altered (P ≤ 0.05) between STC and SUF sheep at HR 6. Results highlight the metabolic differences that exist between breeds as well as indicate the significance of amino acid metabolisms that drive cell proliferation, oxidative stress amelioration and inflammation in response to LPS.
470 Reducing crude protein levels with amino acid supplementation in the finishing diets of heavy Duroc sire line pigs: Effects on growth performance and nitrogen balance in males and females
Authors: de Almeida André M , Alvarez-Rodriguez Javier , Latorre Maria-Angeles
Published: September 2024

Nutrition represents 70% of pig production costs, particularly protein; then, decreasing protein costs is of capital importance. Reducing crude protein (CP) contents to levels below recommended whilst supplementing with amino acids (AAs) is an interesting strategy to reduce costs without decreasing production performances with environmental benefits. It has been conducted essentially in lean genotypes during the growth stage. Few studies address heavy genotypes or differences between males and females during the finishing period. Our objective is to study productive performances of heavy [Duroc X (Landrace X Large-White)] male and female pigs during the finishing stage under a 2% CP reduction with crystalline AA supplementation, hypothesizing that both sexes will equally be affected. In total, 60 males and 60 females were used. At 9 wk of age, animals were allotted in split-sex pens (6 pigs/pen, 0.9 m2/animal) with water and dry feed ad libitum. At 15 wk of age, when pigs weighed an average of 68 kg, two isoenergetic diets with different CP levels were provided (145 and 125 g CP/kg, control and low-CP) during the last 42 d of fattening, under the ideal protein concept. In the low-CP diet, crystalline AAs were added. Feed intake was measured daily, and animals were weighed every 3 wk to calculate average daily feed intake (ADFI), average daily gain (ADG), feed conversion ratio (FCR) and N balance on d 21 and 42. Data were analyzed using the simple least squares models that included dietary treatment and sex and their interaction as fixed effects with the pen as the experimental unit. At d 21, animals weighed 90 to 95 kg with males being 5 to 6 % heavier (P < 0.01). No significant differences were recorded regarding diet. The same difference (P < 0.001) was recorded at day 42, with males (119-122 kg) being 7.25% heavier than females in both treatments. Males had 16% higher ADGs than females in both treatments (P < 0.0001) No differences were recorded for ADFI as a consequence of sex for both diets. FCRs were higher in females of both nutritional treatments (P < 0.0001). Retained N was 22% greater in males than in females for both dietary treatments. The N efficiency was greater in Low CP males by comparison with low CP females and control males, whereas control CP females had decreased N efficiency compared with all other experimental groups. Results demonstrate that the 20g/kg CP reduction supplemented with AAs can efficiently be used in heavy Duroc sire line genotypes during the finishing phase without a decrease in production parameters with females having poorer growth performances than males, whereas N efficiency was impaired when females had no limiting dietary CP.
469 Reducing crude protein levels with amino acid supplementation in the finishing diets of heavy Duroc sire line pigs: Effects on carcass and meat traits in males and females
Authors: de Almeida André M , Ripoll Guillermo , Latorre Maria-Angeles , Alvarez-Rodriguez Javier
Published: September 2024

Nutrition represents 70% of pig production costs, particularly protein; therefore, decreasing protein costs is of capital importance. Reducing crude protein (CP) contents to levels below recommended whilst supplementing with amino acids (AAs) is an interesting strategy to reduce costs without decreasing production performances. It has been conducted essentially in lean genotypes during the growth stage. Few studies address heavy genotypes or sex differences during the finishing period. Our objective is to study carcass and meat (loin) traits of heavy [Duroc X (Landrace X Large-White)] male and female pigs during the finishing stage under a 2% CP reduction with crystalline AA supplementation, hypothesizing that both sexes will be affected equally. In total, 60 males and 60 females, 9 wk old animals were used and allotted in split-sex pens (6 pigs/pen) with water and dry feed ad libitum. At 15 wk of age, when pigs weighed an average of 68 kg, two isoenergetic diets with different CP levels were provided (145 and 125 g CP/kg, control and low-CP) during the last 42 d of fattening. In the low-CP diet, crystalline AAs were added. On last day of the trial, animals weighed 116.5 kg on average and were slaughtered. Hot carcass weights and yields, ham fat thickness, lean meat percentage and boar taint by human nose scoring were determined. Loin samples (one per pen) were used to determine thawing losses, pH, color, Texture Profile Analysis (TPA: hardness, cohesiveness, springiness) and chemical composition (moisture, ash, protein, collagen, fat, and saturated fat). Data were analyzed using the simple least squares models that included dietary treatment and sex and their interaction as fixed effects with the pen as the experimental unit. Carcass weights were greater in control males than in females (91.2 vs 85.7 kg; P < 0.05). No effect of sex or diet was detected on carcass yields, lean contents or ham subcutaneous fat thickness. There was a great impact of sex for loin subcutaneous fat thickness, with males having 7 to 8% greater values in both dietary treatments (P = 0.011). Low-CP females had a greater percentage of carcasses of greater lean content compared with the three other groups (P < 0.05). Boar taint, carcass pH, color traits, chemical analysis and TPA did not differ across diets. A strong dietary influence was noticeable with animals of both sexes in the Low-CP diets having greater fat and saturated fat contents than animals in the control groups (P = 0.02). In conclusion, the 20g/kg CP reduction supplemented with AAs can efficiently be used in heavy Duroc sire line genotype during the finishing phase without leading to major impairments in carcass or meat traits, regardless of sex.
468 Maternal resilience to gestational social stress impacts growth and behavior of suckling pigs
Authors: Luttman Andrea M , Siegford Janice M , Raney Nancy E , Ernst Catherine W
Published: September 2024

Social stress during gestation has been demonstrated to influence piglet health, growth, and behavior. This study aimed to classify pigs exhibiting resilience or vulnerability to gestational social stress using salivary cortisol and characterize differences in their piglets during lactation. At 30 d of gestation, 40 gilts and first parity purebred Yorkshire pigs were socially mixed in group pens (n = 8/pen). Saliva was collected at 1200 h each day at -1, 0, +1, +2, +3, +7d relative to social mixing. Salivary cortisol pattern was used to identify 6 females whose salivary cortisol concentrations returned to baseline as stress resilient (SR) and 6 females whose salivary cortisol concentrations remained increased as stress vulnerable (SV). After farrowing, all piglets of the 12 SR and SV sows had birth weight, weaning weight, and pre-weaning average daily gain (ADG) recorded. At approximately 3 wk of age (18 ± 2d), piglets underwent a novel object test (NOT) by lowering a novel object into each farrowing crate and capturing continuous overhead video recording for 10 min. Videos were manually decoded for each piglet to identify three behavioral measures: latency to touch the object, total time spent interacting with the object, and number of object touches. At 1 d pre-weaning (24 ± 4 d) total skin lesions were recorded for each piglet. All data were analyzed using linear mixed models correcting for sow parity (1 or 2), sex, body weight, age, and litter. Birth weights did not differ between those born to SR or SV sows (SR: 1.3 ± 0.1 kg, SV: 1.3 ± 0.1kg, P = 0.668). However, suckling piglets born to SR sows had significantly greater ADG compared with those born to SV sows (SR: 183 ± 4 g/d, SV: 168 ± 4 g/d, P = 0.010) resulting in significantly greater weaning weights (SR: 5.7 ± 0.1kg, SV: 5.5 ± 0.1kg, P = 6.7e-09). We detected no differences in any of the NOT measures. At the end of lactation, offspring born to SR sows tended to have fewer skin lesions than those born to SV sows (SR: 0.73 ± 0.12, SV: 1.32 ± 0.12, P = 0.065). These results suggest that maternal resilience to gestational social stress is associated with improved suckling pig growth performance and reduced intra-litter aggression.
340 Training cognitive skills to improve integration and application of knowledge in animal physiology
Authors: Stucke Rachael M , Vautier Allison N , Enns Kellie , Cadaret Caitlin N
Published: September 2024

Case-based learning immerses students in real-world scenarios, prompting observation, action, and reflection to enhance cognitive skills. The open-ended nature of such learning can challenge students to reach greater levels of critical thinking; however, we have noticed that without guidance, students often do not know how to approach these types of questions. Therefore, the objective of this study was to investigate how two low-input interventions strategies may help train cognitive skills and improve student performance. Three semesters of an undergraduate physiology course employed a case-based assessment strategy, which included three-unit case studies and one cumulative final case study. Semester 1 (S1; n = 48) represented no intervention, Semester 2 (S2; n = 59) included two dedicated class periods of instructor led guidance on approaching case studies, and Semester 3 (S3; n = 95) utilized an online peer evaluation platform, where students evaluated and provided feedback to each other. For S2 and S3 the interventions first took place between case study 1and case study 2. In all semesters, students also received individualized feedback from the instructor or teaching assistants after each case study. In S2 and S3 pre-semester and post-semester surveys were administered to understand changes in perceptions of their own cognitive skills. In S2 and S3, case study grades decreased and increased (P < 0.05), respectively, between the first and second case study. The average grade on case studies after intervention was greatest (P < 0.05) in S3 where peer intervention was employed, compared with S1 or S2, which did not differ. When comparing changes in perceptions between the beginning and end of the semester, student confidence in their cognitive skills, determined by agreeance with Likert scale statements, tended to increase more (P < 0.10) in S3 compared with S2 (7.9% vs. 3.4%, respectively). The most notable change was agreeance with the statement “I can take multiple ideas from different concepts and combine them to create new understanding” which increased 7.0% and 16.5% in S2 and S3, respectively. Interestingly, free response questions indicated that students did not enjoy peer evaluation and felt that it was not beneficial to their learning. However, these data indicate that students benefited most from peer led intervention, when evaluated by student performance and perceptions of their cognitive skills. Peer evaluation provides a unique opportunity for students to actively engage in the learning process and to practice cognitive skills. This process holds dual benefit as reviewing peers requires students to reflect, analyze, and evaluate, which are cognitive skills also needed to solve the case studies.