bluuebunny/crossref_metadata_2025 huggingface dataset:
Vegetation type, not the legacy of warming, modifies the response of microbial functional genes and greenhouse gas fluxes to drought in Oro-Arctic and alpine regions
Authors: Fry Ellen L , Ashworth Deborah , Allen Kimberley A J , Chardon Nathalie Isabelle , Rixen Christian , Björkman Mats P , Björk Robert G , Stålhandske Thomas , Molau Mathias , Locke-King Brady , Cantillon Isabelle , McDonald Catriona , Liu Hongwei , De Vries Franciska T , Ostle Nick J , Singh Brajesh K , Bardgett Richard D
Published: November 2023

Climate warming and summer droughts alter soil microbial activity, affecting greenhouse gas (GHG) emissions in Arctic and alpine regions. However, the long-term effects of warming, and implications for future microbial resilience, are poorly understood. Using one alpine and three Arctic soils subjected to in situ long-term experimental warming, we simulated drought in laboratory incubations to test how microbial functional-gene abundance affects fluxes in three GHGs: carbon dioxide, methane, and nitrous oxide. We found that responses of functional gene abundances to drought and warming are strongly associated with vegetation type and soil carbon. Our sites ranged from a wet, forb dominated, soil carbon-rich systems to a drier, soil carbon-poor alpine site. Resilience of functional gene abundances, and in turn methane and carbon dioxide fluxes, was lower in the wetter, carbon-rich systems. However, we did not detect an effect of drought or warming on nitrous oxide fluxes. All gene–GHG relationships were modified by vegetation type, with stronger effects being observed in wetter, forb-rich soils. These results suggest that impacts of warming and drought on GHG emissions are linked to a complex set of microbial gene abundances and may be habitat-specific.
The impact of platform mounting systems used in rope parks on tree vitality
Authors: Szewczyk Grzegorz , Kraj Wojciech , Mitka Bartosz , Bożek Piotr , Tylek Paweł
Published: November 2023

Platforms mounted in rope parks cause injuries to trees. A new method for mounting platforms uses clamps, which are theoretically less damaging to trees. The aim of the study was to determine changes in the vitality of Scots pine (Pinus sylvestris L.) and European beech (Fagus sylvatica L.) in response to both old and new platform mounting systems. In the old system, wooden brackets are embedded in the cut fragments of tree trunks. The new system utilizes clamps that hug the trunks. A vitality assessment was carried out for control trees and trees with platforms on the basis of changes in the assimilation apparatus and the degree of thinning of the outer parts of the tree crowns. The visual assessments differentiated between four classes 0–3. We conducted the visual assessment of tree vitality four years after the installation of the platforms. The level of trunk circumference damaged at the platform attachment point was determined using photogrammetric measurements and laser scanning technology. The obtained results were compared to the vitality recorded for the control trees. Trees that initially had better vitality showed a clear decrease in vitality of ~0.5 class. Trees that initially had worse vitality showed a clear increase in vitality, ranging from 0.25 class for pines to 1 class for beeches. Pine and beech trees reacted differently to injuries caused by platform installations. Pine trees responded with a slight increase in vitality, while beech trees experienced a decrease of over a hundred percent. The reactions were more pronounced for the new type of platform. Although the new method of platform installation caused more damage to the surface of tree trunks, its impact on tree vitality was not significantly greater than that of the old system. Since the new system allows, in the long term, to change the position on the tree and adjust the clamping force to the trunk, it can be recommended for use in practice despite the overall slightly worse state of the trees when compared to trees with the old mounting system.
A framework of moderators in social norm-based message persuasiveness based on a systematic review
Authors: Chen Junhan , Xia Shilin , Lin Tong
Published: November 2023

Social norm-based messages have been widely used for persuasion. However, the current trend that research focuses on using social norm theories rather than theorizing about social norms may hinder theory advancement. Although there are efforts theorizing moderators in norm–behavior relationship, the empirical studies testing the theories have yielded mixed findings, and the unclear focus on social norm-based messages versus perceived norms may impede theorizing the communication process regarding social norm-based persuasion. To bridge this gap, our study takes an inductive approach based on 85 studies to create a framework of moderators in social norm-based message persuasiveness. The framework identifies five factors moderating the effect of descriptive norm messages on behavioral intentions and two factors for injunctive norm messages. This framework lays a foundation for theorizing the mechanism of social norm-based message persuasiveness, highlights empirically supported conditions for message persuasiveness, and offers practical implications for designing targeted social norm-based messages.
Pulling the field out of a “One Variable, One Role” mindset: maximizing the theoretical value of interaction terms in communication’s mediation models
Authors: Holbert R Lance , Song Hyunjin , Ellithorpe Morgan E , LaMarre Heather L , Baik Elizabeth S , Tolan Colleen M
Published: November 2023

Recent analytical work reveals the need to assess mediated interactions (independent variable-by-mediator multiplicative terms) in mediation models to ensure the proper reporting of indirect effects. Besides their analytical value, mediated interactions can aid theory development. This study adds a theoretical support structure to this emergent analytical imperative and provides a theory-driven decision tree for incorporating mediated interactions into communication models. More broadly, mediated interactions are used as a basis to encourage the field to move beyond a “one variable, one role” approach to model building. Monte Carlo simulations reflecting common communication research practices were constructed and 1,920,000 datasets were analyzed to reveal the relative upsides and minimal risk incurred from assessing mediated interactions. In addition, the analyses elucidate the downsides incurred from not exploring these relationships when they are present in a population. The implications of these findings for future research and theory development are explored.
118 Variance Components for Age at First Calving and Yearling Weight When Accounting for Age Differences at Fixed Breeding Dates in a Contemporary Group
Authors: Giess Lane K , Speidel Scott E , Boldt Ryan J , Shafer Wade R , Thomas Milton G , Enns R Mark
Published: November 2023

The ability of a heifer to calve earlier in a breeding season has implications on the economic success of heifers in a production system. Heifers that calve earlier in a calving season have increased calf performance, improved subsequent fertility, and a longer productive life in the herd. Production systems typically breed heifers during fixed breeding dates, with heifers of variable ages in the same contemporary group. The objective of this study was to determine if heifer yearling weight (YW) or age differences going into a fixed breeding period influenced the additive genetic variance of age at first calving (AFC) explained in a multi-breed population. Heifer fertility data were obtained from International Genetic Solutions. Females with exposure and calf production records were used to identify individuals calving between 630 and 810 days of age. Females with embryo transfer, multiple birth progeny, and an age differential (DIFF) greater than 100 days were excluded. Age differential was defined as the difference in days between an individual’s birth date and the earliest birth date of an animal in a defined contemporary group. Contemporary group was defined as; breeder, herd, year born, birth and yearling group. After data filtering, there were 149,350 calving records. A 3-generation pedigree file was used containing 365,637 animals, with 37,420 unique sires and 219,533 unique dams. Two bivariate multi-trait animal models for AFC and YW with random additive genetic and residual effects and fixed effects of contemporary group, breed proportion, and % retained hybrid vigor were used. The first model consisted of the aforementioned effects while the second model included DIFF as an additional fixed effect. Analyses were performed using ASReml 3.0. When DIFF was not included as a fixed effect, the additive, residual and phenotypic variances for AFC were 126.1, 456.8, and 582.9 d2, respectively, and the genetic correlation between AFC and YW was 0.36 ± 0.02. When DIFF was included as a fixed effect, the additive, residual, and phenotypic variances for AFC were 10.0, 326.0, and 336.0 d2, respectively. The genetic correlation between AFC and YW was 0.19 ± 0.04. In the absence of DIFF, the heritability estimates for AFC and YW were 0.22 ± 0.01 and 0.44 ± 0.01, respectively but were 0.03 ± 0.003 and 0.44 ± 0.01 respectively, when DIFF was included. Age differential was a significant effect on AFC at –0.86 (P < 0.0001). The low additive variance of AFC when accounting for DIFF suggests that the influence of a female's age going into a fixed breeding date explains much of the variation in AFC. The low heritability estimate for AFC and genetic correlation with YW suggests that selection for improved AFC will be difficult using this method and that producers should instead focus on improved management practices to ensure females calve earlier in a calving season.
117 Combining Large Broiler Populations into a Single Genomic Evaluation: Dealing with Genetic Divergence
Authors: Tabet Joe Menwer , Bussiman Fernando , Breen Vivian , Misztal Ignacy , Lourenco Daniela
Published: November 2023

Combining populations that diverged at some point is a common practice, especially in poultry, where generation intervals are short and genetic evaluations should be available often. This study assessed whether combining large, divergent broiler populations into one genomic evaluation is feasible and the best strategy for doing that in single-step GBLUP. The pedigree for populations 1 and 2 included 397,954 and 411,780 animals, of which 154,911 and 168,429 were genotyped. Phenotypes for body weight (g), carcass yield (%), mortality (0-1), and feet health (0-6) were available for 397,954 animals in population 1 and 411,780 in population 2. A four-trait model was used in the analyses, and the genetic differences between the two populations were modeled in different ways: M1) included an extra fixed effect that accounted for population origin; M2) added origin-specific fixed effects, where the animal origin was concatenated with all fixed effects in the model. The two models were compared against a conventional model without accounting for the animal origin as a fixed effect (M0). Unknown parent groups (UPG) were fit to account for the genetic differences in M0, M1, and M2; therefore, they were set based origin population of the animal and sex. The models were evaluated based on accuracy, bias, and dispersion from the linear regression (LR) method and predictive ability (PA), where GEBV in the reduced data was compared against phenotypes adjusted for fixed effects. Validations were done separately in single and multi-populations to better assess the benefits of combining the two populations. Overall, the accuracy obtained by PA was less than by LR. No apparent accuracy, PA, bias, and dispersion differences were observed among the multi-population models across all traits. This was also true when comparing validation parameters in a multi-population against the ones from a single population. However, we observed that animals from one population were always superior to the other. A multi-trait model was applied, treating the same trait in each population differently. Genetic correlations between the same trait in different populations were moderate to low, suggesting that the two lines should possibly be evaluated separately. Defining whether populations should be combined in a single evaluation may go beyond validation parameters. Identifying if traits are the same across populations is crucial for the feasibility of combined evaluations.
120 Using Simulated Data to Evaluate the Accuracy of Selection Signature Detection Methods in Varying Scenarios
Authors: Retief Anel , Brito Luiz F F , Visser Carina
Published: November 2023

The identification of molecular signatures of selection has become increasingly important in recent years. The detection of selection signatures can aid in both population characterization as well as the detection and identification of genes and advantageous mutations within populations. Various statistical methodologies have been developed to detect directional selection signatures based on different demographic or selection models. The detection of definite evidence of selection on genomes remains a challenge, as other events in the demographic history of a population under investigation may imitate the effects of selection on the genetic variation in the genome. To accurately detect selection signatures, researchers need to consider the large number of methodologies available as well as the factors influencing the detection of selection signatures. Using simulated data, it is possible to evaluate several methods and factors on a larger number of genotypes without the expense of genotyping several animals. The objective of this study was to simulate several sheep populations that have undergone different selection pressures, with varying parameters that may possibly influence the accuracy of detecting selection signatures and testing multiple methods of selection signature detection to find the most reliable method for each scenario. Sheep populations were simulated with varying numbers of QTL (5, 100, 2000) and h2 (0.15, 0.4). The populations were then expanded through either selection for high, low, or random genetic values. Thereafter the populations were selected for sample sizes of 20, 200 and 1000 individuals, resulting in a total of 54 populations for analysis. The populations were then subjected to ROH, iHS, Fst and XP-EHH analysis. After the most effective method for detection of selection signatures for each scenario was identified, the influence of effective population size, generations of animals included in the sample, relatedness, and sex of individuals on the accuracy of each method was tested. Preliminary results indicated that the accuracy of XP-EHH as well as ROH increased with larger population sizes, as well as greater numbers of QTL. Further results of this study will be presented at the conference.
121 Quantifying Genetic Relationships to Maintain Genetic Diversity in the Canadian Dairy Population
Authors: Obari Christiana O , Makanjuola Bayode O , Schenkel Flavio S , Miglior Filippo , Maltecca Christian , Baes Christine F
Published: November 2023

Intensive selection pressure coupled with the use of a limited number of high genetic merit sires has resulted in reduced effective population size and increased levels of inbreeding in dairy cattle populations. The increased rate of inbreeding amplifies the frequency of recessive deleterious alleles, possibly leading to inbreeding depression in economically important traits, such as disease resistance, fertility and production. To better understand the relationship of available and active breeding sires to Canadian herds, quantifying genetic relationships between these groups could prove insightful. The genetic relationship value (R-value) represents the average number of alleles identical by descent shared between an animal and a reference population and is currently estimated based on pedigree information. Furthermore, the average R-value indicates the relationship of a sire to the rest of the population. Estimating the R-value between sires and individual herds may offer a more refined tool for producers to select sires that are less related to their specific herds. The aim of this study was to quantify and characterize R-values between individual sires and individual herds within the Canadian Holstein population. To quantify R-values, a dataset comprised of 11,914 sires born between 1953 and 2020 and 584,740 active cows born between 1997 and 2022 from 5,592 herds was considered. Active cows were defined as those currently alive, on milk recording, and actively contributing to the national milk inventory. Active sires were considered those used to breed the active cows. All data were provided by Lactanet Canada and analyses were carried out on PEDIG using the par2 program for relationship estimation. Results indicate that herd-level R-values (i.e., R-values estimated using individual sires and individual herds) showed variation. The R-value of individual sires to individual herds containing active cows ranged from 0.43% to 32.38. This result indicates that outbred sires are available to individual farmers when the population is considered at the herd level, and that the development of herd-level R-values may provide a selection tool which promotes the use of less related sires. Next steps include developing and estimating genomic R-values and comparing them with the pedigree-based R-values for the genotyped Canadian Holstein population. By better understanding of the relationship of available breeding sires to individual Canadian herds, a simple tool for producers to identify sires which are less related to their herds can be developed.
122 Comparison of Algorithms for Approximation of Accuracies for Single-Step Genomic Best Linear Unbiased Predictor Models
Authors: Ramos Pedro Vital Brasil , Garcia Andre , Retallick Kelli J , Bermann Matias , Misztal Ignacy , Lourenco Daniela
Published: November 2023

The theoretical accuracy of breeding values can be calculated based on the prediction error variances obtained from the diagonal of the inverse of the left-hand side of the mixed model equations. However, inverting the coefficient matrix is not computationally feasible for an extensive system of equations, especially if genomic information is available. Thus, different algorithms to approximate accuracies have been proposed. We aimed to compare the efficiency of two algorithms implemented in the accf90GS and accf90GS2 software from the BLUPF90 family. The accf90GS algorithm approximates accuracies based on the diagonal of the genomic relationship matrix (G). In turn, the accf90GS2 uses block sparse inversion of G-1. The data for this study were provided by the American Angus Association (Saint Joseph, MO) and included phenotypes of three growth traits and eleven carcass traits, 1,235,930 genotyped animals, and pedigree ranging from 4,315,913 to 12,492,581 animals. Three analyses were performed: 1) comparison of the approximated accuracies between algorithms; 2) comparison between approximated and exact accuracies; and 3) evaluation of the impact of adding genotyped animals, with and without phenotypes, in the approximated accuracies. The results were obtained for genotyped animals (group 1) and genotyped animals without phenotypes (group 2). The complete datasets under multi-trait models with ssGBLUP and the algorithm for proven and young were used for analysis 1. A subset of data under single-trait models was used for analyses 2 and 3, so it was possible to calculate the exact accuracies. In analysis 1, the correlations of groups 1 and 2 ranged from 0.55 to 0.74 and 0.38 to 0.65, respectively. The growth traits presented the lowest correlations. In addition, the slope was under 0.75 for both groups. These results suggest that the approximated accuracies are considerably different, especially for growth traits and genotyped animals without phenotype. The accf90GS2 algorithm presented the highest correlations with exact accuracies, which indicates that it is more efficient than the accg90GS algorithm. The intercept was almost zero for both approximation methods, whereas the slope ranged from 0.937 to 1.234 and 0.819 to 0.949 for accf90GS and accf90GS2 accuracies, respectively. This suggests a minor overestimation and underestimation by the accf90GS2 and accf90GS algorithms, respectively. The increase in mean accuracy due to adding genotyped animals with phenotypes was higher for accf90GS2. According to the results, the algorithm implemented in accf90GS2 is recommended for genetic evaluations because of its efficiency and precision.
402 Awardee Talk: Stress-Induced Dna Methylation Changes and Their Implications in Livestock Production
Authors: Baker Emilie C , Earnhardt-San Audrey L , Cilkiz Kubra Z , Littlejohn Brittni P , Cardoso Rodolfo C , Ghaffari Noushin , Long Charles R , Riggs Penny K , Randel Ronald D , Welsh Thomas H , Riley David G
Published: November 2023

It is well known that pre- and post-natal stressors can impact livestock phenotype and performance. However, less is known about the molecular mechanisms responsible for the changes observed in individuals exposed to stress. A proposed mechanism is epigenetic modifications, such as DNA methylation (DNAm). Epigenetic marks are considered a bridge between the environment and genetics because the marks shift in response to environmental stimuli. Stress induced alterations of DNAm can result in changes in gene expression which could be the driver behind altered phenotype. “Omic” technologies have allowed the study of how DNAm patterns change in response to stressors in livestock species. Stressors such as weaning, transportation, and heat stress have altered DNAm patterns. These changes in methylation patterns have been associated with changes in immune function, growth, and behavior. Prenatal stressors have also modified DNAm patterns within the offspring, with some differences persisting later in life. These stress induced DNAm alterations can be transgenerational, potentially affecting livestock productivity and health over multiple generations. Not all alterations are negative; certain stress-induced modifications could allow animals to adapt better to stressors and changing conditions. These marks may indicate exposure of the animal to stress and the possible long-term effects on productivity. There is potential for using methylation patterns as a noninvasive way to monitor stress levels and assess animal welfare. Understanding how the methylome responds to stressors and how it contributes to performance will be beneficial for future selection decisions. More research is needed to identify management practices that might mitigate the negative impacts of stress induced DNAm changes and how the industry can take advantage of the role DNAm has in adapting to stressors and new environments. The epigenome will likely play a critical role in the livestock industry's future as the climate shifts and consumer demands focus more on animal welfare.
149 Marker Effect P-Value for Large Genotype Populations with the Algorithm for Proven and Young
Authors: Leite Natalia , Bermann Matias , Tsuruta Shogo , Misztal Ignacy , Lourenco Daniela
Published: November 2023

The single-step method (ssGBLUP) allows for simultaneous evaluations of populations composed of genotyped and non-genotyped animals. As a GBLUP-based method, the output of ssGBLUP is breeding values. However, interest might rely on the estimation of SNP effects and on how genome segments are associated with the phenotype of interest. When that is the case, SNP effects can be obtained from a linear transformation of breeding values, and P-values can be used as a measure of estimation certainty. P-values are derived from the prediction error variance of SNP effects, which relies on the prediction error (co)variance matrix of breeding values obtained from the inverse of the left-hand side of the mixed model equations (LHS). However, inverting the LHS becomes unfeasible with large, genotyped populations. Therefore, alternative strategies to overcome this problem and obtain p-values with increasing genotyped populations might be evaluated. In this study, we aimed to estimate marker effect p-values when the algorithm for proven and young (APY) was used to approximate the predictor error (co)variance for animals in a large, genotyped population. We estimate P-values of SNP marker effects for PWG in an Angus cattle population. The dataset was composed of around 844K phenotyped animals, 450K genotypes, and 1.8M pedigree records. Analyses were split into two sets. In the first set, a reduced genotype data of 50K was used, so p-values obtained from a direct-inverse of LHS using the regular G-1 (Exact_G) or APY G-1 (Exact_GAPY) were compared with APY G-1 and an approximation of the prediction error variance that did not require the inversion of the LHS (Approx_GAPY). In the second set of analyses, P-values with Approx_GAPY were estimated with the full genomic set of 450K (Approx_GAPY_450K), and computational requirements were recorded. All analyses were performed in three replicates. In the first set of analyses, genome-wide association with Exact_G uncovered two significant regions in chromosomes 7 and 20. Along all replicates, the same regions were also identified with Exact_GAPY and Approx_GAPY, indicating that similar resolutions are obtained with exact and approximated p-values. Results from Approx_GAPY_450K showed that, with a complete genome set, besides the two regions in chromosomes 7 and 20, two new regions in chromosomes 6 and 14 were identified. On average, the entire procedure for obtaining P-values with 450K genotyped animals had an elapsed wall clock time of 24h with a maximum memory usage of 87.6 GB. Altogether, our results suggest that with APY and the approximation of the prediction error variance, current computational boundaries for obtaining marker effect P-values for large genotyped populations should be lifted.
53 Establishing a Pan-Epigenome for Cattle and Sheep
Authors: McKay Stephanie , Murdoch Brenda M , Hagen Darren E
Published: November 2023

Genetic and epigenetic factors contribute towards phenotypic variation in complex traits. Epigenetic modifications can affect transcription and translation and have been shown to influence variation in economically important phenotypes in agricultural species. The onset of pangenomics in livestock species is disconnected from pan-epigenomics and hence lacks a fully comprehensive view of diversity in livestock species. To establish a pan-epigenome for cattle and sheep we are comprehensively characterizing epigenomic conservation and diversity through examination of 5-methylcytosine, 5-hydroxymethylcytosine, histone marks H3K4me3, H3K27ac, H3K4me1 and H3K27me3, open chromatin, chromatin accessibility and n6-methyladenosine in the liver, muscle and prefrontal cortex of Brahman, Angus and Holstein cattle as well as Suffolk, Rambouillet and Katahdin sheep. Finally, comparative epigenomics is being used to identify orthologous regions of the sheep and bovine epigenomes that harbor conserved epigenetic modifications and variants. The establishment of a cattle and sheep pan-epigenome will increase our understanding of how different genomes, epigenomes, and gene products from diverse breeds of cattle and sheep affect a variety of important biological phenotypes, supporting more accurate prediction of traits and improving breeding strategies.
161 A System Dynamics Model of Bovine Respiratory Disease Epidemiology and Prevention Strategies in an Integrated Beef Production System
Authors: Kacheri-Moolan Lijith , Kaniyamattam Karun , Tedeschi Luis O
Published: November 2023

Bovine respiratory disease (BRD) is a complex multifactorial disease that results in more than $1 billion in economic losses for the United States beef cattle industry, accounting for approximately 30% of the total antimicrobial use (AMU) in food animal production systems. The prevalence and production losses due to BRD vary significantly between different production systems, and is influenced by the host, pathogen, and environmental risk factors. These multiple risk factors together have a cumulative effect and will increase the prevalence of the disease if no preventive strategies are implemented in the system. Moreover, the increased AMU to treat BRD results in antimicrobial resistance, further complicating the issue. A linear, event-based solution to address such a complex problem will fail to consider the feedback loops and time delays in the system and may cause unintended consequences that might make the problem even more complex. Hence, we propose a more comprehensive system dynamic model to simulate an integrated beef production system with respect to BRD and predict the dynamic behavior of the system under different preventive strategies currently available to the beef industry. Our conceptual model accounts for host risk factors (auxiliary variables in the model) like age, nutritional status, daily weight gain, prior exposure to pathogens, and genetics. The environmental risk factors such as air quality, transportation, temperature humidity index, overcrowding, and source of animals were also included in the model. The various preventative strategies to reduce the incidence of BRD, including vaccination, biosecurity, adequate colostrum, and nutrition, were also added to the model. The key outcome variables considered were net profitability and AMU. The model simulates multiple scenarios by leveraging the auxiliary variables and can provide information about the system’s net profitability and total AMU. The model explains the interconnected effect of various risk factors associated with BRD in multiple complex scenarios and helps understand the combined effect of adopting various preventive strategies and host-environmental factors in controlling BRD. The initial result from our dynamic model suggests that using a combination of preventive measures and avoiding the selected host-environmental risk factors can minimize AMU while improving profit. The long-term goal of our modeling effort is to enable the beef system stakeholders to make informed decisions and strategies to mitigate the impact of BRD, thereby contributing to improved profitability. Through a systems-thinking approach, our model can contribute to addressing the challenges in BRD management currently faced by the US-based integrated beef production systems.
165 Evaluation of the Use of Prenatal Immune Stimulation on the Ability to Alter Postnatal Immune Function in Weaned Pigs
Authors: Burdick Sanchez Nicole C , Mitchell Ty M , Broadway Paul R , Bowen Brooke M , Davis Emily M , Dobbins Thomas W , Barker Samantha N , Legako Jerrad F , Petry Amy L , Carroll Jeffery A
Published: November 2023

One of the most lacking areas where improvements can be made in swine production is in the area of swine health. This study was designed to determine whether exposure to low dose endotoxin (lipopolysaccharide; LPS) during gestation can enhance immunity to a subsequent LPS challenge in piglets after weaning. Pregnant Camborough sows (parity: 2.6 ± 1.4) were assigned to prenatal immune stimulation (LPS; n = 7; administered 2.5 µg/kg BW LPS i.m. at d 78 ± 1.8 of gestation) or saline treatment groups (CON; n = 7). From the 2 prenatal treatment groups, barrows (n = 17 LPS, 17 CON) were identified at weaning (21 ± 1.3 d of age) to subsequently receive a post-weaning LPS challenge. On d -7, barrows were transported to the USDA-ARS Livestock Issues Research Unit in Lubbock, TX where they were housed in individual pens in an environmentally controlled building with ad libitum access to water and a starter ration. On d -1, pigs were fitted with indwelling jugular catheters and subcutaneous temperature loggers. On d 0, pigs were challenged i.v. with LPS (10 µg/kg BW) and blood samples were collected at -2, 0, 1, 2, 4, 6, 8, 12, and 24 h relative to LPS challenge. Data were analyzed using PROC MIXED in SAS, specific for repeated measures. There was a treatment × time interaction for subcutaneous temperature (P < 0.01), where temperature increased more quickly at 1 and 2 h post-challenge in LPS compared with CON pigs. There was a tendency (P = 0.08) for less change in white blood cells, relative to baseline values, in LPS compared with CON pigs. There was a treatment × time interaction (P = 0.01) for lymphocyte concentrations where concentrations were reduced in LPS compared with CON pigs at 8 h post-challenge. There was also a treatment × time interaction (P = 0.01) for the change in eosinophil concentrations, where there was less change in eosinophil concentrations from 1 to 12h in LPS compared with CON pigs. There was a tendency (P = 0.08) for a treatment × time interaction for serum interleukin-6 (IL-6), where concentrations were reduced in LPS compared with CON pigs at 2h (P = 0.01) and tended to be reduced at 1 and 4h post-challenge (P ≤ 0.11). There was a tendency (P = 0.06) for a treatment × time interaction for IL-8, where concentrations were reduced in LPS compared with CON pigs at 1 and 4h (P ≤ 0.01) and tended to be reduced at 2h post-challenge (P = 0.06). Granulocyte macrophage colony stimulating factor and tumor necrosis factor-α tended (P ≤ 0.08) to be reduced in LPS compared with CON pigs. These data suggest that exposure to endotoxin in utero can influence the postnatal innate immune response to endotoxin. Thus, it is possible to influence the innate immune response of pigs in utero, which may serve as a method to positively influence postnatal immune responsiveness.
106 Using a Novel Direct-Fed Microbial as an Alternative for Tylosin Phosphate to Control Liver Abscesses and Decrease Antimicrobial Use in Finishing Beef Steers
Authors: Hoffman Ashley A , Fernando Samodha C , Wells James E , Woerner Dale R , Manahan Jeff L , Long Nathan S , McDaniel Zach S , Smock Taylor M , Line Dalton J , Broadway Paul R , Carroll Jeffery A , Burdick Sanchez Nicole C , Hales Kristin E
Published: November 2023

Our objective was to evaluate the use of a novel direct-fed microbial as an alternative to antimicrobials to decrease liver abscesses in feedlot cattle. Angus beef steers (n = 240; initial BW = 263 ± 18.0 kg) were used in a randomized complete block design comprised of 3 BW blocks and 3 pen replications per treatment. Experimental treatments were randomly assigned to pen within BW block and consisted of: 1) negative control, dietary supplement contained no tylosin phosphate (NCON); 2) positive control, dietary supplement contained tylosin phosphate (PCON); 3) positive control with tylosin phosphate removed the last 65 d of the feeding period (PCONW); and 4) novel direct-fed microbial fed at 1 g mixture/animal with 1 × 1011 CFU/g (DFM). By design, initial BW did not differ (P = 0.79) among treatments, and at the end of the 59-d receiving period, there were no differences in final BW (P = 0.25). From d 0 to d 30, ADG, DMI, DMI as a percentage of BW, and G:F did not differ (P ≥ 0.21). Likewise, ADG, DMI, DMI as a percentage of BW, and G:F, from d 31 to d 59, were not different (P ≥ 0.30). From d 0 to d 59, there were no differences in ADG, DMI, DMI as a percentage of BW, nor G:F (P ≥ 0.20). During the finishing period, live- and carcass-adjusted final BW did not differ (P ≥ 0.57) among treatments. During the finishing period, there were also no differences in ADG, DMI, DMI as a percentage of BW, or G:F (P ≥ 0.17). Carcass-adjusted ADG, DMI as a percentage of BW, and G:F also did not differ (P ≥ 0.16). Across treatments, no differences in HCW were noted (P = 0.84). Dressing percentage, marbling score, longissimus dorsi (LM) area, 12th-rib fat thickness, and calculated yield grade (YG) were not different among dietary treatments (P ≥ 0.32). Liver abscess incidence and severity were not affected by dietary treatments (P ≥ 0.13). The inclusion of a novel direct-fed microbial in finishing cattle diets did not affect growth performance, carcass characteristics, nor the prevalence of liver abscesses. However, the removal of tylosin phosphate 65 d before harvest numerically resulted in the lowest frequency of severe liver abscesses when compared with steers not fed tylosin phosphate.
104 Development of an Experimental Model to Induce Liver Abscesses in Steers Using an Acidotic Diet Challenge and Oral Bacterial Inoculation
Authors: McDaniel Zach S , Hales Kristin E , Nagaraja T G , Amachawadi Raghavendra G , Lawrence Ty E , Tennant Travis C , Carroll Jeff A , Burdick Sanchez Nicole C , Galyean Michael , Smock Taylor M , Ballou Michael A , Machado Vinicius , Davis Emily M , Broadway Rand
Published: November 2023

The objective of this study was to develop a model for liver abscesses (LA) in Holstein steers by using an acidotic diet or acidotic diet plus intraruminal inoculation of Fusobacterium necrophorum, Salmonella enterica serotype Lubbock, and Truperella pyogenes. Holstein steers (n = 40; initial BW = 84.9 + 7.1 kg) were individually housed and randomly assigned to either a negative control diet (CON), an acidotic diet (AD), or an acidotic diet plus intraruminal inoculation with the bacterial mixture [ADB; (1 × 109 colony forming unit (CFU)/mL of each bacteria]. Steers in AD and ADB were cycled on (3 d) and off (2 d) a high-starch diet 20 days before intraruminal inoculation of ADB. Following inoculation, AD and ADB remained on the acidotic diet for the remainder of the study. Ruminal pH boluses were randomly inserted into 19 steers across treatments to monitor ruminal pH throughout the study. Steers were euthanized and necropsied to record gross pathology on the lung, rumen, liver, and colon. Culture techniques were used to determine the prevalence inoculated bacteria within LA. Quantitative polymerase chain reaction methods were used to quantify F. necrophorum in rumen tissue. Data were analyzed as a completely randomized design with animal as the experimental unit, where an α of ≤ 0.05 determined significance. Liver abscess prevalence was 43% in ADB vs. 0% in AD and CON treatments (P < 0.01). Ruminal damage was 51.1% greater in ADB than in AD and 78.6% greater than in CON (P ≤ 0.05). There were no pathological differences in the lungs and colons among treatment groups (P ≥ 0.14). There was a treatment × time interaction for ruminal pH, where pH decreased below 5.6 in AD and ADB calves during each cycle of the acidotic diet (P < 0.01). The ADB contained a greater concentration of F. necrophorum subsp. Necrophorum and subsp. Fundliforme within rumen tissue (P ≤ 0.03). Of the LA cultured, 100% contained F. necrophorum, 50% S. enterica, and 0% contained T. pyogenes. The F. necrophorum subsp. Necrophorum was phylogenetically typed and identical to the strain (FN-8LI) infused in the bacterial inoculation. These data suggest that acidotic diet in combination with intraruminal inoculation of the bacterial mixture is sufficient to induce liver abscesses and provides insight on possible mechanisms and origins of LA. Further studies are needed to validate these results and determine if this model may be used to study novel intervention methods.
6 Hands-On Iii: Building Digital Twins for Precision Livestock Farming: Data Analytics and Big Data Challenges
Authors: Tao Jian , Mendes Egleu D M , Pi Yalong , Cassity Alyssa , Male Revanth Reddy , Kaniyamattam Karun , Duffield Nick , Tedeschi Luis O
Published: November 2023

Precision livestock farming (PLF) is an emerging field that uses technology to optimize livestock production and management. It involves using sensors, cameras, and other data collection devices to gather information on animal behavior, health, and welfare. A digital twin is a virtual replica of a physical system that can be used for simulation, testing, and optimization. This tutorial will provide an overview of the procedure for creating a PLF digital twin with cameras and sensors. We will discuss the benefits of PLF, the hardware and software components needed, and the steps involved in creating a digital twin. PLF digital twins have a range of potential applications and benefits, including improved livestock health and welfare, increased productivity, and efficiency, and reduced environmental impact. At the end of the tutorial, we will host a roundtable discussion of the potential applications and benefits of PLF digital twins.
181 Effects of Moderate Exercise Regimen on Reproductive Development of Replacement Beef Heifers Reared in Drylots at a High Stocking Density
Authors: Rahmel Logan W , Cooke Reinaldo F , Mackey Shea , Pickett Autumn , Colombo Eduardo , Drewery Mason , Cordero Juan , Daigle Courtney L , Harvey Kelsey M M
Published: November 2023

This experiment evaluated the physiological and reproductive responses of beef heifers reared at a high stocking density and provided with access to an exercise area. Ninety Angus × Brahman heifers were ranked by age (257 ± 2 days), body weight (BW; 216 ± 2 kg), and temperament score on day 0 and assigned to a) 1 of 6 drylot pens (10x14 m pens; 10 heifers/pen) resulting in a stocking density of 14 m2/heifer (DENS), or b) 1 of 3 paddocks (2-ha paddocks; 10 heifers/paddock) resulting in a stocking density of 2,000 m2/heifer (CON). On day 15, 3 DENS pens were randomly selected and given access to an exercise area (DENS-EX) for 1 hour three times weekly. Negligible forage was available for CON heifers, whereas all heifers received the same limit fed diet which averaged 13 kg/heifer daily of a corn-based diet. Heifer shrunk BW was recorded after 16 h of feed and water withdrawal on days -3 and 225 for average daily gain calculation. On day 0, heifers were fitted with a pedometer behind their shoulder and an ear tag (CowManager, Select Sires, Plain City, OH) to record behavioral responses. Each week, pedometer results were recorded, and blood samples were collected for puberty evaluation via plasma progesterone. Heifers from CON had more (P < 0.05) steps per week compared with DENS and DENS-EX, and DENS-EX heifers had more (P < 0.05) steps per week compared with DENS. Heifers from CON spent more (P < 0.05) time ruminating and eating compared with DENS and DENS-EX. No treatment effects (P ≥ 0.12) were detected for heifer BW gain or temperament variables. Heifers from DENS experienced delayed puberty attainment given a greater (P < 0.05) proportion of CON heifers were pubertal by day 98 compared with DENS and DENS-EX, whereas a greater (P < 0.05) proportion of DENS-EX heifers were pubertal by day 154 compared with DENS heifers (treatment × day interaction, P < 0.01). Collectively, results from this experiment demonstrate that providing heifers reared at a high stocking density access to an exercise area does not result in similar reproductive responses as those reared on pasture at a low stocking density. This work is supported by the USDA National Institute of Food and Agriculture (#2021-67015-34083).
21 Beef Cattle and Global Warming
Authors: Rotz Alan
Published: November 2023

Beef cattle production is an important contributor to global warming both nationally and globally. Through a national life cycle assessment, we have determined that the production of beef cattle in the U.S. produces about 243 Tg of carbon dioxide equivalents (CO2e) in global warming with an intensity of 21 kg CO2e/kg of carcass weight. This is about 3.5% of the national inventory of greenhouse gas (GHG) emissions. Globally, the Food and Agriculture Organization (FAO) estimates the direct GHG emissions from all cattle other than dairy and their manure to be about 2,260 Tg or about 4.5% of the total global GHG emission. An important consideration in calculating the contribution of beef cattle is the assumed global warming potentials (GWP) used to relate the warming effect of methane and other compounds to that of CO2. Recommended values have varied over the past 20 years as we learn more about the warming potential of various gases. Values assumed affect published assessments, so it is important to consider the GWP values used when comparing studies. Methane is unique among the major compounds affecting global warming because it has a relatively short life in the atmosphere (half-life of about 8 years). Methane released by cattle and their manure oxidizes in the atmosphere returning the carbon originally fixed by growing plants back to CO2 completing a natural cycle. To better represent the warming effect of methane in the atmosphere, a model called GWP* has been introduced. To use this model, the change in emission rate over time must be quantified. Compared with 50 years ago in the U.S., we are now producing 20% more meat using about 15% fewer cattle. We estimate that the GHG intensity in cattle production has decreased 34%, and the total GHG emission related to beef cattle production has decreased 21% over this period. Considering the change that has occurred, using the GWP* model reduces the global warming impact of U.S. beef cattle by over 50% relative to the use of the commonly accepted current GWP factors. Global change is more difficult to quantify. The FAO estimates that over the past 50 years, the global number of non-dairy cattle has increased about 39% with a 78% increase in meat production and 36% increase in related methane emissions. Applying these data indicates that use of the GWP* model decreases the warming effect of global cattle by about 20%. When making policy decisions to mitigate GHG emissions, it is important to properly represent the relative warming effect of the important greenhouse gases.