bluuebunny/crossref_metadata_2025 huggingface dataset:
116 Using Theoretical and Realized Accuracies to Estimate Changes in Heritabilities
Authors: Misztal Ignacy , Breen Vivian , Lourenco Daniela
Published: November 2023

Under genomic selection, heritabilities for strongly selected traits are reduced, and antagonism between production and fitness traits can intensify. However, estimating genetic parameters by established methods such as REML or Bayesian with large genomic data is computationally expensive or unfeasible. In this study, we investigated the use of theoretical and realized accuracies to estimate heritabilities. The first dataset for pigs included 161k phenotypic records for a growth trait (GT), 27k phenotypic records for a fitness trait (FT), and 55k animals were genotyped. The second dataset for broilers contained 820K phenotypes for a growth trait (GT), and 154k animals were genotyped. Theoretical accuracies (r) were calculated as r = sqrt(Nh2/(Nh2+Me)) assuming the number of independent chromosome segments (Me) of 5k and the number of observations (N) equal to the number of genotypes or phenotypes, whichever was smaller. Estimated accuracies were calculated by the linear regression (LR) method. Assumed heritabilities were recent estimates for pigs (0.21 for GT and 0.04 for FT) and an older estimate for broilers (0.30). For the pig dataset, the theoretical and realized accuracies were similar: 0.82 and 0.84 for GT, and 0.42 and 0.43 for FT, suggesting that the assumed heritabilities were realistic. For the broiler dataset, the theoretical and realized accuracies differed: 0.94 and 0.56, indicating possible large differences between real and assumed heritabilities. Both accuracies could be made equal at 0.89 by assuming a heritability of 0.13. Such a heritability was also found to provide a realistic estimate of the genetic gain with recent data. Comparisons of theoretical and realized accuracies may be used as a tool to estimate changing heritabilities over successive generations at a low cost. Similar formulas may enable low-cost estimation of genetic correlations.
134 Estimating the Heritability of Nitrogen and Carbon Isotopes in the Tail Hair of Beef Cattle
Authors: e Silva Luis Prada , Moradi Morteza , Warburton Christie
Published: November 2023

The natural abundance of nitrogen isotopes (δ15N) in animal tissues is related to the ability of cattle to lose less nitrogen in the urine and has been used to estimate nitrogen use efficiency and feed efficiency. Carbon isotope enrichment (δ13C) has also been used to estimate feed conversion ratio and grazing behavior in beef cattle. There are significant variations between the individual beef cattle in the same environment for δ15N and δ13C of the tail hair. Thus, the objective was to determine the heritability of δ15N and δ13C in the tail hair of tropically adapted beef cattle to further validate their use in genetic breeding programs. A total of 497 Bos indicus steers (269 Brahman and 228 Droughtmaster) were used, and the steers had reliable pedigree information for three generations as they were part of the beef cattle genetic evaluation system in Australia. Two single, mixed breed, contemporary groups of steers are used including the steers weaned in 2019 (n = 254) and steers weaned in 2020 (n = 243). Samples of tail switch hair representing hair segments growing during the dry season were collected and analyzed for δ15N and δ13C. Fixed effects fitted in the linear regression model were age, breed, year (as contemporary groups), and average daily gain during the different seasons. The heritabilities of δ15N and δ13C in the tail hair were estimated at 0.43 ± 0.14, and 0.41 ± 0.15, respectively, which indicates both are moderately heritable traits. The genetic correlation between δ15N and δ13C was negative at -0.78 ± 0.16, and the phenotypic one was -0.40 ± 0.04. The negative correlation can be explained by the contrasting isotope fractionation in the urine of cattle, as urine has less δ15N and more δ13C than the diet. The findings of this study have shown for the first time that both δ15N and δ13C in the tail hair of cattle are heritable traits. These results support the feasibility of utilizing tail hair isotopes as a promising approach for identifying cattle with greater nitrogen use efficiency, which is a key trait in low-protein diets. Moreover, genetic selection for nitrogen-efficient cattle can reduce the environmental impact of beef production.
136 Evaluation of the Relationship Between Hair Coat Shedding Ability, Apparent Forage Digestibility, and Mineral Status in Angus Cattle
Authors: Loftin Margaret P , Burnett Randy , Rude Brian , Smith Trent
Published: November 2023

The objective of this study was to evaluate the relationship between winter hair coat shedding ability, apparent forage digestibility, and mineral status in Angus females. Data were collected on fall calving purebred Angus females with calves from March until July in 2019 (n = 10), 2020 (n = 31), 2021 (n = 39), and 2022 (n = 41). Dams were observed once monthly by two trained technicians for winter hair coat shedding and were given a visual score of 1 to 5 with 1 indicating complete shed and 5 indicating no shedding of the winter hair coat. Month of first shed (MFS) was determined when a female reached an average winter hair shedding score of > 3.5 for any given month. Fecal samples were collected during the grazing months of March, May, and July for 5 consecutive days and were then analyzed via proximate analysis to calculate apparent digestibility of dry matter (DM), ash, acid detergent fiber (ADF), and neutral detergent fiber (NDF) of forage. Liver and blood plasma samples were collected during the grazing months of March and July and analyzed via ICP-OES for mineral concentrations of K, Ca, Mg, Na, Fe, and Zn. Data were analyzed using the MIXED procedure of SAS with a significance declared at P < 0.05. The model included MFS, grazing month, and MFS by grazing month interaction. Interactions of MFS by month were observed for DM, NDF, ADF and liver Fe concentration. For DM, NDF, and ADF, within the grazing month of May, individuals with MFS in April and May were similar and greater when compared with June and July which were similar. Interpretation of these results show no clear trend of an association between hair shedding ability and apparent digestibility; however, some differences based on MFS existed. Further research into this area is important in understanding changes in overall cow performance due to adaptability.
133 Genetic Parameter Estimation for Dry Matter Required in Angus Cattle
Authors: Sánchez-Castro Miguel A , Passafaro Tiago L , Bernal-Rubio Yeni L , Andersen Kent J , Donald Nkrumah J , Jorgensen Nicholas
Published: November 2023

Dry matter intake (DMI) is critical to determine feed efficiency in cattle. However, this trait is expensive and difficult to measure on an individual basis. An alternative to overcome such limitations is to approximate DMI by using mathematical models to estimate the dry matter required (DMR) for animals originally fed in groups. High genetic correlations (e.g., rg>0.95) have been informed between DMI and DMR. Thus, DMR has been proposed as an indicator trait for DMI in genetic evaluations. Few reports exist about genetic parameters associated to DMR and, when available, estimates have been obtained with datasets of limited size (~1,500 animals with phenotypes). Additionally, previous reports have focused on older animals during the finishing phase, such that mathematical models employed to derive DMR have not explicitly accounted for the presence of weaner calves on the data. Therefore, the objective was to estimate genetic parameters for DMR using a moderately large dataset that included weaning and yearling Angus bulls. A total of 8,121 records of estimated DMR were available for analyses. From these records, 6,324 belonged to weaned males whose phenotype was obtained using an equation proposed by NRC to predict DMR for calves. The 1,797 remaining records pertained to yearling bulls for which a different NRC equation was employed. First, a single-trait animal model was implemented to estimate genetic parameters for DMR, with contemporary group (defined as year of test and pen within the testing facility), test length and age of the animal when entering to the test (linear covariate) being included as fixed effects, while animal was considered a random effect. Afterwards, a bivariate model that included weaning weight (WW) as a correlated trait was implemented. In this model, the same effects were included for DMR but for WW, fixed effects included sex, weaning contemporary group and age of dam (BIF classes), while direct genetic, maternal genetic, and maternal permanent environmental effects were considered as random. For both models, a reduced pedigree was used to estimate variance components by tracing back 5 generations from animals having phenotypes. A total of 12,212 and 56,023 animals were included in the univariate analysis and the bivariate analysis, respectively. Heritability (h2) estimates (± SE) for DMR were 0.43 (± 0.04) and 0.49 (± 0.03) under univariate and bivariate model, respectively. Genetic correlation between DMR and WW was 0.69 (± 0.03), with a h2 estimate of 0.29 (± 0.01) for WW. Heritability estimates for DMR obtained with both models resembled those of DMR reported in literature. Results suggested that substantial additive genetic variation exists for DMR and, consequently, indirect genetic progress for DMI can be attained if selecting for DMR. Further studies are required to validate DMR as an indicator trait for DMI in larger Angus populations.
152 Leveraging Rfid Technology to Investigate the Genetic Associations Between Feeding Behavior and Leg Health in Floor-Raised Broilers
Authors: Carvalho Alves Anderson A , Araujo Fernandes Arthur F , Breen Vivian , Hawken Rachel , Rosa Guilherme J M
Published: November 2023

Leg disorders (LD) pose serious welfare issues in broiler chickens. The objective of this study was to investigate the suitability of using feeding behavior (FB) traits as potential leg health indicators in floor-raised broilers. The data used were recorded from 95,711 pure-line chickens of both sexes. The individual FB was monitored continuously on a feeder visit basis with a radio-frequency antenna system. The visit-log data were clustered into daily observations for different FB traits and averaged for the 1st week period after the trial started. The FB traits were daily feed intake (DFI1), number of visits (NV1), time spent at the feeder (TSF1), visiting activity interval (VAI1), number of visited feeders (NVF1), and walked distance visiting feeders (WD1). The LD traits were tibial dyschondroplasia (TD), hock-burn (HB), footpad (FP), rotated legs (RO), bowed-in (BI), and bowed-out (BO) leg structure deformities. Multi-trait linear-threshold models were fitted using Bayesian inference for estimating (co)variance components. The heritability (h2) posterior averages and standard deviations (within parentheses) ranged between 0.09 (0.01) and 0.52 (0.03) for LD traits, and between 0.09 (0.01) and 0.47 (0.02) for FB traits. Genetic correlations (rg) between FB and LD traits ranged from null to weak. TD presented negative rg with NV1 (-0.13), TSF1 (-0.14), NVF1 (-0.11), and WD1 (-0.14), indicating that some alleles involved in broiler activity are favorably associated with a potential reduction in the risk of TD-caused bone lesions. Conversely, FP presented unfavorable rg with the same traits (ranging from 0.21 to 0.32), except for TSF1 (-0.08). When compared with the remaining FB traits, DFI1 generally presented the opposite relationships with TD and FP, with positive (0.16) and negative (-0.18) genetic correlations observed for the first and the latter, respectively. Angular and rotational deformities (RO, BI, and BO) did not present significant correlations with FB traits, apart from the weak correlation found between BO and TSF1 (0.11). General activity indicators such as NV1, NVF1, and WD1 could represent earlier selection criteria to reduce TD incidence, although the potential undesired selection response for FP must be further investigated.
96 Animal Genomes to Phenomes: Funding and Perspectives from Usda-Nifa
Authors: Van Goor Angelica G , Sullivan Timothy , Tobias Christian
Published: November 2023

The National Institute of Food and Agriculture (NIFA) is the extramural science-funding agency of the USDA that invests in and advances agricultural research, education, and extension to solve societal challenges. Animal genome to phenome (G2P) research is an important area of investment at NIFA. This presentation aims to: 1) highlight past investments in animal G2P; 2) discuss the alignment of animal G2P within current USDA and NIFA priorities; 3) bring awareness to Multistate Committee opportunities; 4) highlight current funding opportunities; and 5) provide perspectives on the future of animal G2P at NIFA with attention to the central dogma of phenomics.
166 Pre-Weaned Calves Have Increased Cortisol Concentrations Post-Wildfire Smoke Exposure
Authors: Ranches Juliana , Hernandez Gracia M P , Santos Aline R , Ferreira Matheus , Cruickshank Jenifer
Published: November 2023

The western states of the U.S., home to some of the largest cattle operations in the country, are increasingly experiencing losses related to wildfire events. Wildfires are predicted to intensify with climate change; rising temperatures, droughts, and drier climatic conditions. Although wildfires do not directly endanger most humans and animals, the resultant smoke can disperse great distances and increase disease susceptibility and death in populations removed from its origin. There is a lack of literature on how wildfire smoke exposure can affect livestock physiology, health, and productivity. Therefore, this study aimed to evaluate changes in blood markers of cattle naturally exposed to wildfire smoke. Eighteen beef-on-dairy calves (Jersey X Simmental) from a commercial farm were enrolled in this study at birth (May to June 2022). Blood samples for analysis of cortisol, acute phase proteins, and pro- and anti-inflammatory cytokines were collected before (June to August), during (September), and after smoke exposure (September and October), in a total of seven collections. Additionally, rectal temperature and health scores were collected from each calf at those time points. Air quality (AQ) data, specifically particulate matter (PM2.5; EPA standard for AQ; 35 µg/m3) near the study location (Vale, OR), was obtained from the AirNow database. For statistical analysis, calf was considered the experimental unit, and all data were analyzed using the MIXED procedure of SAS (SAS Inst. Inc., Cary, NC). Air quality before smoke exposure was considered adequate, and PM 2.5 was, on average, 4.9 µg/m3 from June to August. In September, a wildfire reduced AQ at the study location, increasing PM 2.5 to an average of 44.6 µg/m3 for four consecutive days. After the fire was contained, AQ improved, and PM2.5 dropped to 8.6 ug/m3. Blood cortisol concentrations changed over time (P < 0.001). Cortisol concentrations of samples collected before smoke exposure did not differ (P = 0.89) at 4.4, 2.0, and 1.9 ng/mL (SEM:1.3). Cortisol concentrations increased (P < 0.001) and peaked during smoke exposure, at 10.3 and 7.0 ng/mL (SEM:1.4). Immediately after smoke exposure, cortisol concentrations averaged 6.3 ng/mL, intermediate between those before and during smoke exposure (P = 0.89; SEM:1.3). Interestingly, in the last post-smoke exposure sample, cortisol concentration averaged 9.5 ng/mL, similar to concentrations during smoke exposure (P = 0.99; SEM:1.3). This increase in cortisol concentration post-smoke exposure was unexpected but likely explained by the calves having been weaned two days before this final sampling. In summary, calves naturally exposed to wildfire smoke had increased blood cortisol concentrations with concentrations similar to those observed shortly after post-weaning, a practice known to be challenging and stressful for calves.
103 Development of a Novel, Experimental, Minimally Invasive Model to Investigate the Genesis and Etiology of Liver Abscesses in Cattle
Authors: Broadway Paul R , Nagaraja T G , Lawrence Ty E , Amachawadi Raghavendra G , Carroll Jeffery A , Sanchez Nicole C Burdick , Galyean Michael , Hales Kristin E
Published: November 2023

Most research surrounding liver abscesses involves post-hoc evaluation of naturally occurring abscesses in production settings. Few studies have been designed to experimentally induce abscesses with the purpose of identifying a time course, causality, and associated physiological implications. Therefore, we set out to develop a minimally invasive, reliable, and repeatable model to induce liver abscesses in calves in a controlled research environment to elucidate the genesis and etiology of the disease, with the ultimate goal of developing abscess reduction strategies. Experiment 1 was an attempt to induce abscesses by intraruminal inoculation with Fusobacterium necrophorum, Salmonella lubbock, and Truperella pyogenes (FST) following an intravenous lipopolysaccharide challenge. Holstein steers were harvested 3- and 10-d after inoculation, but no abscesses were detected. Experiments 2 and 3 involved diet manipulation by cycling calves on and off a high-starch, acidotic diet followed by intraruminal inoculation of microbes. In Experiment 2, Holstein calves were fed a negative control diet, an acidotic diet, and an acidotic diet plus bacterial inoculation with FST. No abscesses formed in the control or acidotic diet calves, but 43% of calves fed the acidotic diet with FST inoculation formed liver abscesses, suggesting that acidosis alone is insufficient to produce abscesses. In Experiment 3, treatments consisted of Holstein steers fed a negative control, an acidotic diet, an acidotic diet plus ruminal Fusobacterium necrophorum (F), and an acidotic diet plus Fusobacterium and Salmonella (FS). Again, there were no abscesses in the control or calves fed an acidotic diet alone; however, 40% of calves receiving F presented with an abscess, and 50% of the calves that received FS presented with abscesses. These data suggest that ruminal acidosis in conjunction with a ruminal load of pathogens commonly associated with liver abscesses provides a model that will induce liver abscesses. While the role of barrier dysfunction in the rumen and the lower gastrointestinal tract in formation of abscesses is not fully understood, this work provides a foundation to further explore the etiology of this disease and potential mitigation strategies.
178 Tag Your It: Use of Wearable Biometric and Remote Sensing Technology to Monitor Animal Growth, Performance, and Efficiency in Extensively Managed Landscapes
Authors: Parsons Ira L , Webb Stephen , Karisch Brandi B , Stone Amanda E , Street Garrett
Published: November 2023

Energy budgets in grazing cattle are notoriously difficult to study given complex environmental and physiological interactions between plants and animals, each operating according to individual grazing budgets. However, these synergistic energy pathways can be modeled using a series of mechanistic relationships describing forage resource distribution and animal behavior, each which can be observed with high levels of accuracy and precision using biometric sensors and remote sensing technology. The objective of this study is to demonstrate the coordination of data inputs into a coherent framework utilizing biometric and remote sensing technology. Crossbred steers (n = 10) were fitted with GPS and video tracking collars (Vectronic) and accelerometers (Wildbytes technologies), then managed for 286 days as part of a broader research grazing ecology project on pasture (~11.54 hectare) comprised of bermudagrass (Cynodon dactylon) and tall fescue (Festuca arundinacea) and equipped with an automated walk-over-weigh (TruTest) scale system. Distribution of forage quality was sampled monthly with a ½ m2 quadrat using a 20 x 20-meter grid (n = 297) and remotely assessed via an unmanned aerial vehicle (Matrice 100) mounted hyperspectral camera (MicaSense) at 8 cm resolution. Animal behavior was predicted utilizing a trained randomforest prediction algorithm, and linked to geo-location and forage quality at the spatial-temporal scale in Program R. We then constructed animal ethogram, distribution of forage quality, and spatial-temporal distribution of animal behavior across the grazing landscape for a test period. We found steers allocated the greatest proportion of time to grazing and resting behaviors, 30 and 60% respectively, with the remainder dedicated to ruminating and walking behaviors. A diurnal, circadian rhythm in animal behavior demonstrates that steers grazed between 0900 and 1000 in the morning, and again between 1300 and 2000 in the evening, while resting behavior dominated the hours between 0300 and 0900, with a slight increase in grazing behavior noted at 0600, or approximately sunrise. Animal behavior linked forage availability showed steers selectively grazed areas with higher NDVI signatures, while seeking sources of water and cover to practice resting behavior. Given the need to develop robust models predicting forage intake and energy in grazing animals to improve sustainability and environmental metrics, animal tracking and biometric technologies offer a vital solution to improving management of extensively managed grazing livestock.
180 Differences in Gene Expression in Granulosa Cells Harvested from Fertile and Sub-Fertile Beef Heifers
Authors: Hollingsworth Rachel , Banerjee Priyanka , Dyce Paul W W
Published: November 2023

Infertility in beef replacement heifers is one of the leading contributors to economic losses in the cow-calf sector of the beef production industry. Successful reproduction is complex, involving multiple tissues and biological systems. This complexity makes identifying the leading causes of subfertility difficult. One potential source of fertility issues is poor oocyte health. As developing oocytes are dependent on granulosa cells (GCs) and physically coupled with GCs, we hypothesized that the gene expression profile would be different between the GCs from fertile heifers and those from sub-fertile heifers. The objective of this study was to identify differences in gene expression in GCs collected from beef heifers of differing fertility status, either fertile or sub-fertile. To gather this information, Angus-Simmental crossbred heifers underwent an estrus synchronization and fixed-time artificial insemination (AI) protocol (7-Day CO-synch + CIDR). At 41 days post-AI, heifers were pregnancy checked through ultrasound and palpation. Heifers pregnant to AI were classified as fertile (n = 8). Any heifers that remained non-pregnant following AI were exposed to bulls of proven fertility for 61 days. Bull-exposed heifers were evaluated for pregnancy 34 days after the bulls were removed. The non-pregnant heifers following both AI and natural service were classified as sub-fertile (n = 5). Pregnancies were terminated in fertile heifers, and heifers from both groups were allowed to resume normal cyclicity before GCs being harvested. RNA was extracted from GCs and quality was checked for each sample. Total RNA from GCs of 13 heifers was subjected to the library preparation and sequencing on the Nova-Seq platform. Through the application of DESeq2, 79 genes were identified as significantly differentially expressed genes (DEGs) with P-value < 0.05 and absolute (log2 fold change) > 0.5 including DNER, HOXD10, CD52, CXCL12, and HOXD11. DEGs, along with co-expressed genes, were over-represented in pathways associated with the regulation of MAP kinase activity, regulation of serine/threonine kinase activity, MHC protein binding, and plasma membrane signaling receptor complex. Through the pursuit of knowledge regarding the function of top DEGs, increased sample size, and more diverse sample collection time points, we may improve our understanding of the causation of heifer fertility issues. Improving our knowledge of heifer infertility has the potential to develop therapeutic options, and in turn, increase the efficiency and sustainability of cow-calf production systems.
210 Effects of Dietary Supplementation of Peanut Skins (Arachis hypogaea) on Performance, Digestibility, and Rumen Fermentation of Cattle: a Meta-Analysis
Authors: Osuolale Oluwatoyin Rukayat , Idowu Modoluwamu , Pech-Cervantes Andres A , Taiwo Godstime A , Eichie Francisca , Ogunade Ibukun M , Terrill Thomas H
Published: November 2023

This study aimed to estimate the magnitude of effects of dietary inclusion of Peanut skins (PS) byproduct (Arachis hypogea L.) on intake, total-tract digestibility, and rumen fermentation of cattle via meta-analysis. Data were collected following the PRISMA methodology. Nine manuscripts and a graduate thesis met the inclusion criteria from 1983 to 2010. The effect size was estimated by calculating the weighted raw mean differences (RMD) between PS vs. control diets. The RMD was compared with a robust variance estimation method followed by a meta-regression and a dose-response analysis fitting the diet characteristics like crude protein content (CP), NDF content, ether extract content (EE), tannin content, and PS level in diet (0 to 40%) as covariates. Dietary PS decreased (P < 0.01) total-tract CP digestibility (52.0 vs. 64.3%), final body weight (371.5 vs. 397.9 kg), and average daily gain (1.14 vs. 1.44 kg/d) among treatment comparisons. Likewise, PS decreased total VFA (92.6 vs. 107.6 mmol/L) and NH3N (8.22 vs. 12.1 mg/dL), but no effects were observed on rumen pH (6.47 vs. 6.14), Acetate (47.8 vs.50.4%), Propionate (31.9 vs. 33.1%), and Butyrate (8.4 vs. 11.2%) molar proportions. Although there was a high between-cluster variance, dietary PS increased the ether extract digestibility (77.5 vs. 70.2%) among treatment comparisons. The subset and dose-response analysis revealed that PS should not exceed 8% (DM basis) in the diet to prevent negative effects on CP digestibility and animal performance. In conclusion, the results of this meta-analysis do not support the dietary inclusion of PS in cattle diets beyond 8%.
222 High Throughput Screening of Bovine Mastitis from Raw Milk Using Maldi-Tof Ms and Machine Learning
Authors: Sarkar Sumon , Thompson Jonathan , Everhart Nunn Savana L , Clayton Beth
Published: November 2023

To prevent pathogenic microorganisms associated with mastitis from entering the food supply, raw milk must be screened. This study investigated whether MALDI-TOF-MS combined with machine learning algorithms is a cost-effective method for screening dairy milk samples at high throughput. Raw milk from animals was analyzed using matrix-assisted laser desorption ionization mass spectrometry. Mass spectra were obtained for a training dataset of composite milk samples (n = 226) collected from a local dairy. The peaks from the mass spectra were then transported into a machine learning model, which detected non-obvious patterns that correspond with the mastitis condition. Finally, the diagnostic accuracy of the new model was evaluated using a separate set of milk samples (scoring set; n = 100). For optimal performance, decision trees, random forest models, gradient boosted trees, and neural network models were investigated. The results show that the gradient boosted decision tree model performs best for mastitis diagnosis, with simultaneous sensitivity and specificity greater than 0.8. The decision tree approach is conceptually straightforward and identifies candidate biomarker molecules indicative of mastitis. The combined MALDI TOF plus machine learning approach is effective for detecting mastitis in dairy cows and is likely a viable option for diagnosing a wide range of animal health issues. The MALDI TOF method is suitable for high-throughput screening because it only requires a microliter of inexpensive reagents.
420 Integrating Livestock and Cropping Systems: Interseeding Cereal Rye into Corn for Late Season Grazing
Authors: Soder Kathy J
Published: November 2023

The objective of this project was to evaluate the effect of interseeding cereal rye (Secale cereale) into corn (Zea mays) for use as grazed forage after corn grain harvest on corn grain yield and additional grazing day· ha-1. In a 4-year study, corn was planted (64,246 plants· ha-1) in spring on two, 4.8-ha fields in central Pennsylvania. Cereal rye was interseeded (135 kg· ha-1) into the corn at the V4-V6 stage. Corn was harvested as grain in November and each field was divided into six, 0.8-ha paddocks and randomly assigned to either grazed (GRAZ) or ungrazed (NG) treatments. Beef cattle frontal-grazed three of the paddocks (four cows· paddock-1) in each field approximately four to five weeks after corn grain harvest and, if re-growth allowed, again in early spring before subsequent corn planting. Corn grain, corn fodder (after grain harvest), and cereal rye yields were monitored each fall. Cereal rye growth was also monitored in early spring. Statistical analyses on corn grain yield and forage biomass were conducted using the MIXED procedure in SAS 9.4 (SAS Institute, Cary, NC, USA). Least square means were separated using Fisher’s least significant difference test (α = 0.05). There were no site by treatment interactions, therefore means are presented as an average across both sites (Table 1). Corn grain, corn stover, and cereal rye yields were affected by year. Corn grain yields did not decrease as a result of grazing, or of repeated plantings of corn, ranging from 9,516-10,088 kg· ha-1 across GRAZ and NG paddocks except in 2019 (dry year) when corn grain yields averaged 6,053 kg· ha-1 across both GRAZ and NG treatments. Spring grazing only occurred in one year (2021) due to insufficient cereal rye growth in the other years. On average, the cereal rye (plus the corn stover) provided enough forage for an additional 115-130 grazing days· ha-1 in the fall. Results of this study showed that when corn is harvested too late in the year to establish a cover crop, interseeding annual forages into growing corn provides winter ground cover and an opportunity for late season grazing. Interseeding cereal rye into the corn did not negatively impact corn grain yields with repeated corn planting. While early spring growth of the cereal rye has the potential to provide even greater forage yields than fall, it is much less dependable than fall due to the potential of delayed spring growth or lack of winter precipitation under the conditions of the current study.
418 Awardee Talk: Heat Stress-Mediated Muscle Dysfunction
Authors: Selsby Joshua T
Published: November 2023

Ongoing climate change with more frequent, longer-lasting, extreme heat events, threatens advances in efficient production and costs the U.S. Swine Industry more than $900 million annually. Continued selection for rapid lean tissue accretion may further compromise heat resistance as it is associated with greater metabolic heat production. The long-term objective of our work is to develop therapeutic strategies to mitigate the deleterious consequences of prolonged, environment-induced heat stress (HS) with a driving philosophy that elucidation of cellular and systemic pathologies caused by prolonged hyperthermia is a prerequisite to development of etiological interventions. Our working model suggests that in skeletal and cardiac muscle, HS causes Ca2+ dysregulation and subsequent mitochondrial dysfunction, which results in free radical injury and metabolic dysregulation. Oxidative stress may impair autophagy, the very process intended to remove damaged mitochondria, and contribute to an accumulation of damaged mitochondria. Our most recent data indicate that during HS, barrows were able to maintain growth despite a higher rectal temperature than gilts. Further, among other changes, HS caused mitochondrial hyper-fusion in gilts and dysregulation of the muscle metabolome was greater in gilts than barrows. Additionally, we discovered HS caused sex-specific reductions in mitochondrial function. These changes were associated with decreased degradation of autophagosomes and markers of mitophagy in muscle from gilts, but not barrows. Finally, muscle from barrows appeared resistant to oxidative stress, whereas in muscle from gilts, HS increased oxidative modification of lipids and nucleic acids. In an independent experiment, we considered HS-mediated consequences in the myocardium and discovered that 1 day of HS caused ventricle-specific architectural and biochemical changes in gilts. Our future work will focus on continued testing of our working model and consideration of recovery from HS as well as development of effective management and therapeutic strategies that can be economically deployed to offset HS-mediated losses.
249 The Effects of Breed and Early Supplementation on Bovine Intramuscular Fat Deposition, Adipogenic and Lipogenic Gene Expression
Authors: Udoka Aliute-Nkoyo S , Jacobs Joshua L , Duckett Susan K
Published: November 2023

Wagyu cattle are known to deposit greater amounts of intramuscular fat, which can directly increase quality grade and carcass value. Supplementation can positively influence animal production and overall nutrient acquisition when used strategically. The objectives of this study were to evaluate 1) the effect of breed and early supplementation on intramuscular and subcutaneous fat deposition in Wagyu and Hereford cross calves, and 2) changes in adipogenic and lipogenic gene expression in longissimus muscle (LM) biopsies from Wagyu and Hereford cross calves during an early supplementation period. Angus cows (n = 34) were artificially inseminated with semen from a Wagyu bull. A Hereford bull was utilized as a clean-up bull. From this breeding, Wagyu cross steers (n = 8) and Hereford cross steers (n = 9) were produced and were placed on study on day 100 of age. At this time, calves were allowed access to four SuperSmart Feeder stalls and were individually supplemented with steam-rolled corn at 0.5% body weight (BWT). Calves were ultrasounded on day 0, day 43, and day 86 of the study to evaluate intramuscular fat deposition and backfat thickness. An longissimus muscle (LM) biopsy was taken on day 0 and day 86 of the study to evaluate gene expression. Supplemented steers tended (P < 0.10) to have more backfat than non-supplemented steers. Intramuscular fat amount differed (P < 0.05) by breed, while ribeye area tended (P < 0.10) to differ by breed. Wagyu exhibited a greater (P < 0.05) amount of intramuscular fat at the beginning and at the end of the study. Breed did not (P > 0.05) influence backfat thickness. Neither breed nor supplementation affected (P > 0.05) average daily gain or final body weights. Platelet-derived growth factor alpha (PDGRFA) and SREBP cleavage-activating protein (SCAP) differed (P < 0.05) between biopsy phases. Fatty acid binding protein-4 (FABP4) and stearoyl-coA desaturase-1 (SCD1) did not differ (P > 0.05) between breed or biopsy phase. In conclusion, changes in gene expression could indicate enhanced preadipocyte proliferation during this stage of calf development. Overall, supplementation altered backfat deposition but did not alter intramuscular fat levels. Opposingly, sire breed influenced intramuscular fat levels at an early age. A deeper understanding of the physical and molecular effects of supplementation and sire breed could provide additional avenues for manipulating adipose tissue.
254 Intestinal Oxidative Damages By F18+Escherichia Coli and Its Amelioration with an Antibacterial Bacitracin Fed to Nursery Pigs
Authors: Duarte Marcos Elias Elias , Stahl Chad , Kim Sung Woo
Published: November 2023

This study investigated the intestinal oxidative damages caused by F18+Escherichia coli and its amelioration with an antibacterial bacitracin fed to nursery pigs. Thirty-six weaned pigs (6.31 ± 0.08 kg BW) were allotted in RCBD. Treatments were: NC, not challenged/not treated; PC, challenged (F18+E. coli at 5.2 × 109 CFU)/not treated; AGP, challenged (F18+E. coli at 5.2 × 109 CFU)/treated with bacitracin (30 g/t). The F18+E. coli was orally inoculated to pigs on challenged treatments at d 7. The unchallenged pigs received an oral dose of sterile saline solution. The fecal score was recorded daily. Body weight and feed intake were recorded weekly. On d 14 and 28, fecal and blood samples were collected. On d 28, all pigs were euthanized to collect intestinal samples. F18+E. coli counting, microbiota composition, and intestinal health variables were analyzed. Data were analyzed using the mixed procedure on SAS 9.4. Overall, PC reduced (P < 0.05) ADG (353 to 282 g), G:F (0.71 to 0.55), villus height (527 to 394 µm), and VH:CD (2.22 to 1.58), whereas AGP increased (P < 0.05) ADG (298 to 344 g), and G:F (0.55 to 0.61). PC increased (P < 0.05) fecal score from d 7 to 14 (3.0 to 4.6), from 14 to 21 (2.8 to 3.9), and from d 21 to 28 (2.5 to 3.2); increased F18+E. coli (5.9 to 7.5 log DNA) in feces at d 14, and protein carbonyl (2.15 to 3.61 nmol/mg protein) in jejunal mucosa. AGP reduced (P < 0.05) fecal score from d 7 to 14 (4.6 to 4.0) and from d 14 to 21 (3.9 to 3.4) and reduced F18+E. coli (4.3 to 3.9 log DNA) in jejunal mucosa. PC reduced (P < 0.05) Prevotella stercorea (5.1 to 1.5%) population in jejunal mucosa, whereas AGP increased (P < 0.05) Phascolarctobacterium succinatutens (3.0 to 10.0%) and reduced (P < 0.05) Mitsuokella jalaludinii (8.7 to 2.0%) populations in feces. Collectively, F18+E. coli challenge increased fecal score and disrupted the microbiota composition, harming intestinal health by increasing oxidative stress and damaging the intestinal epithelium, ultimately impairing growth performance. Dietary bacitracin reduced oxidative damages caused by F18+ E. coli thereby protecting intestinal health by reducing F18+E. coli population in jejunal mucosa and fecal score, consequently improving the growth performance of nursery pigs.
256 Effects of Lactobacillus Fermentate Replacing Bacitracin on Biomarkers Associated with Bacterial Cell Wall Recognition and Intestinal Integrity in Pigs
Authors: Duarte Marcos Elias Elias , Deng Zixiao , Eckhardt Erik , Kim Sung Woo
Published: November 2023

Two experiments were conducted to evaluate the efficacy of Lactobacillus fermentate (LBF) as postbiotic on immune response and barrier function in jejunal mucosa of nursery pigs challenged with F18+Escherichia coli. Sixty-four pigs (32 barrows and 32 gilts) weaned at 21 d of age with 7.9 ± 0.5 kg in Exp. 1 (n = 32) and 6.6 ± 0.7 kg in Exp. 2 (n = 32) were allotted based on a randomized complete block design with sex and initial BW as blocks. The treatments were NC: no challenge/no supplement; PC: E. coli challenge/no supplement; AGP: E. coli challenge/bacitracin (30 g/t feed); and PBT: E. coli challenge/postbiotic (2 kg/t feed). Pigs were fed a basal diet for 28 d, formulated to meet the nutrient requirements of NRC (2012). At d 7, the challenged pigs were orally inoculated with F18+E. coli. At d 28, pigs were euthanized to collect jejunal tissue to analyze gene expressions involved in bacterial cell wall recognition, immune response, and intestinal barrier function. Data were analyzed using the Proc MIXED of SAS 9.4. The PC tended to reduce (P = 0.097) the relative expression of PGLYRP2A (1.12 to 0.76) and increased (P < 0.05) TLR4 (0.98 to 1.67) and NOD1 (0.99 to 1.56) compared with NC. The AGP tended to increase (P = 0.074) PGLYRP2A (0.76 to 1.15) and tended to reduce (P = 0.099) PGLYRP3 (1.21 to 0.82) compared with PC. The PBT increased (P < 0.05) PGLYRP4 (0.86 to 1.53) compared with PC. The AGP tended to reduce (P = 0.085) TLR4 (1.67 to 0.98) compared with PC. The AGP and the PBT reduced (P < 0.05) NOD1 (1.56 to 0.98 and 0.97, respectively) compared with PC. The PC tended to increase (P = 0.079) CD14 (1.13 to 2.13) compared with NC, however, PBT tended to reduce (P = 0.091) it (2.13 to 1.27) compared with PC. The AGP increased (P < 0.05) interferon-γ (1.13 to 1.21) and the PBT tended to increase (P = 0.096) it (1.13 to 1.63) compared with PC. The AGP tended to increase (P = 0.082) claudin-1 (0.85 to 1.81) compared with PC. In conclusion, F18+E. coli challenge upregulated the expression of pathogen recognition genes, including TLR4, CD14, and NOD1, which can increase the production of cytokines associated with pro-inflammatory response. The AGP showed a trend towards increasing the intestinal barrier function, possibly by increasing the expression of interferon-γ and reducing the expression of genes associated with pathogen recognition. The PBT enhanced the immunocompetence of nursery pigs by increasing the expression of interferon-γ and PGLYRP4, and reducing the expression of genes associated with pathogen recognition including NOD1 and CD14, which may indicate a reduction of the pathogen invasion.
257 Effects of Prebiotic Galactooligosaccharide (GOS) on Hindgut Microbial Composition of Pigs During the Peri-Weaning Period
Authors: Boston Timothy E , Wang Feng , Xi Lin , Kim Sung Woo , Fellner Vivek , Scott Mark F , Ziegler Amanda L , Van Landeghem Laurianne , Blikslager Anthony T , Odle Jack
Published: November 2023

Galactooligosaccharide (GOS) is a prebiotic containing beta-linked galactose oligomers of 2 to 8 units. Previously, GOS positively impacted post-weaning growth performance and altered jejunal morphology. In this study, GOS-enriched whey permeate (Milk Specialties Global, Eden Prairie MN) was supplemented to piglets in farrowing and nursery phases. To maximize pre-weaning GOS intake, novel gruel creep feeders were used. Piglets from 24 litters received either no creep feed (NC), creep without GOS (CG-) or creep with 5.0% GOS (CG+) followed by a phase 1 nursery diet without (NG-) or with 3.8% GOS (NG+). At d 22 (pre-weaning) and d 31 (post-weaning), 6 pigs per treatment were euthanized for sample collection. DNA was extracted from cecal and rectal swabs for downstream 16S rRNA sequencing via Illumina MiSeq (Zymo Research Corp, Irvine CA). An amplicon sequence variant (ASV) table was created using the DADA2 pipeline in R and taxonomy assignment was performed using the SILVA database. Average sequencing depth after filtering was 138,323 and low sequencing counts were discarded based on 20% prevalence. Data were analyzed using the lmer and adonis procedures in RStudio ver. 4.2.2. Analysis of 16S rRNA genes did not detect pre- or post-weaning GOS effects on Chao1, Simpson, or Shannon alpha diversity measures (P > 0.1). Similarly, no pre-weaning GOS effects were detected in Principal Coordinates Analysis (PCoA) beta diversity plots (P > 0.1); however, pigs fed GOS post-weaning segregated from controls (P < 0.01). The relative abundance of several genera including Fusicatenbacter and Collinsella increased by 2.0 and 1.3-fold, respectively, in the cecum of NG+ pigs, whereas, Bacteroides decreased by 3.8-fold (FDR, P < 0.05). In the rectum, relative abundance of Corprococcus decreased by 2.0-fold and Fusicatenbacter increased by 1.5-fold in NG+ pigs compared with NG- pigs (FDR, P < 0.05). Collectively, these genera in the cecum and rectum comprise of less than 3% of the total community. In contrast, lactobacillus in the cecum (33%) and rectum (21%) had a large relative abundance but was unaffected by treatment. We conclude that supplementation of GOS in the post-weaning phase 1 nursery diet alters the hindgut microbial community and may contribute to improvements in growth performance.
272 Effects of Increasing Dose of a Novel Hybrid Bacterial 6-Phytase on Apparent Total Tract Nutrient Digestibility, Release of Free Myoinositol, and Retention of Calcium and Phosphorus in Pigs
Authors: Choi Hyunjun , Kim Sung Woo
Published: November 2023

The objective of this study was to investigate the effects of increasing dose of a novel hybrid bacterial 6-phytase on apparent total tract digestibility (ATTD) of energy and nutrients, plasma concentrations of free myoinositol, and retention of calcium (Ca) and phosphorus (P). A total of 15 barrows (21.5 ± 1.4 kg BW) were allotted to a triplicate 5 × 5 Latin square design with 5 dietary treatments and 5 periods per each square. Pigs were individually housed in a metabolism crate. Five dietary treatments consisted of 5 levels of phytase-supplemented diets with increasing phytase units (0, 500, 1,000, 1,500, and 2,000 FTU/kg). Diets contained nutrients meeting the requirement except for Ca and P. Degree of deficient Ca and P content in the NC diet were 0.22 and 0.17%, respectively. Each period lasted 10 days consisting of a 5-d adaptation period and 5-d collection period for total collection. Data were analyzed using orthogonal polynomial contrasts using the Proc MIXED and optimal phytase levels were determined using the NLMIXED of SAS. The increasing phytase supplementation linearly increased (P < 0.05) average daily gain (651 to 695 g/d) and tended to linearly increase (P = 0.072) gain to feed ratio (0.53 to 0.56). Increasing phytase supplementation linearly increased (P < 0.01) ATTD of Ca and P and retention of Ca and P and also showed quadratic effects (P < 0.01). Increasing phytase supplementation linearly increased (P < 0.01) myoinositol content in plasma and also showed quadratic effects (P < 0.05). Broken line analyses showed that ATTD of Ca (P < 0.01) and retention of Ca (P < 0.01) were increased until phytase supplementation were increased (79.4 to 92.1% and 77.4 to 91.4%) from 0 to 671 FTU/kg (SE = 67; P < 0.01) and 0 to 668 FTU/kg (SE = 72; P < 0.01), respectively. Broken line analyses showed that ATTD of P (P < 0.01) and retention of P (P < 0.01) were increased (59.0 to 80.1% and 55.7 to 78.2%) until phytase contents were increased from 0 to 783 FTU/kg (SE = 91; P < 0.01) and 0 to 776 FTU/kg (SE = 76; P < 0.01), respectively. The broken line analyses showed that myoinositol contents in plasma (P < 0.01) were increased (13.2 to 23.2 µmol/L) until phytase supplementation were increased from 0 to 624 FTU/kg (SE = 174; P < 0.01). In conclusion, increasing phytase supplementation up to 2,000 FTU/kg feed improved ATTD of Ca and P, retention of Ca and P, complete hydrolysis of phytate, and growth performance of pigs compared with a P-deficient diet. Phytase supplementation at a range of 600 to 800 FTU/kg feeds provided the optimal improvement of Ca, P, and phytate utilization.