bluuebunny/crossref_metadata_2025 huggingface dataset:
422 The use of 3D kinematics for improved gait assessment in broilers
Authors: Bench Clover , Lowen Emily , Desrosiers Nicole , Korver Doug
Published: September 2024

Genetic selection for high growth rates in broiler chickens has resulted in larger broilers and changes in broiler gait. Traditionally, broiler gait is assessed using visual observation which is subjective and labor intensive. In contrast, newer technologies are available which can be adapted to objectively score changes in broiler gait, thereby, increasing the validity and reliability of gait scoring with less labor required. The objective of this study was to compare the use of 3D kinematics versus visual scoring to assess broiler gait. Second, to determine how strain and age affect 3D kinematic gait metrics in broilers. Four strains of broiler chickens were used; two heritage strains: 1957 (H57; n = 52) and 1977 (H77; n = 51); and two commercially available strains: Cobb (n = 50) and Ross (n = 53). All broilers were weighed weekly throughout the study. Kinematic markers were placed along the spine and bony landmarks of each leg. Commercial strains had kinematic recordings and body weights (BW) recorded every week for 4 wk while Heritage strains had measurements recorded every week for 6 wk. Visual gait scoring was completed using a 5-point scale each week by two trained observers. Data were analyzed using the correlation procedure in SAS to determine the relationship between visual gait score and kinematic metrics as well as the GLIMMIX procedure to determine the effects of strain, age, and strain x age on all gait parameters. There was a weak positive correlation (r < 0.2) between visual gait score and all kinematic metrics. Cobb were the heaviest strain (1,292.6 ± 14.71 g P < 0.001) while H57 broilers were the lightest (326.4 ± 9.99 g P < 0.001). Each week, the BW of all strains increased significantly. Total Stride Time differed significantly by strain (P < 0.001; Cobb: 26.3 ± 0.47 cs, Ross: 23.1 ± 0.39 cs, H77: 23.7 ± 0.28 cs, H57: 21.5 ± 0.26 cs) and Age (P < 0.01; Commercial: wk 3: 21.8 ± 0.54 cs, wk 6: 28.1 ± 0.68 cs and Heritage: wk 3: 19.7 ± 0.42 cs, wk 8: 25.4 ± 0.52 cs). Total stride length (SL) also significantly differed by strain. Cobb had the longest SL of the two commercial strains (P < 0.001; 88.6 ± 1.94 mm) while H77 had the longest stride of the heritage strains (97.9 ± 1.51 mm). Total SL also increased with age resulting in longer stride times. Heavier birds, such as Cobb, had longer stride Times and SL compared with lighter birds such as the H57 strain. In conclusion, visual gait score and kinematic metrics were not found to be measuring the same things. However, kinematics can be a used as an informative and objective tool for assessing gait metrics associated with broiler lameness such as changes in stride length and stride time.
142 Programming effects of early-life exposure to heat stress in cattle
Authors: Laporta Jimena
Published: September 2024

As the Earth’s temperature continues to increase, the livestock industry faces a growing challenge related to heat stress. Heat stress significantly impacts the global dairy and beef industries, affecting milk and meat production, reproductive health, and the general welfare of animals. This presentation will showcase how early-life exposure to heat stress in cattle, specifically during the prenatal (in utero) and postnatal (pre-weaning) phases of the life of a calf, can program them for a lifetime. Our studies have aimed to understand the physiological and behavioral changes that early-life heat stress induces and the molecular mechanisms underlying long-term programming effects on growth, survival, and lifetime performance. Using a multifaceted approach, we have investigated the transcriptomic, epigenetic, and metabolic responses of calves exposed to heat stress or provided with heat abatement during critical developmental periods. Our studies shed light on how early-life exposure to heat stress alters the developmental trajectory of cattle, potentially influencing their resilience to future environmental challenges and overall productivity. Strategies for mitigating heat stress in beef cow-calf pairs and pregnant dairy cows (e.g., pasture artificial shade and evaporative cooling, respectively) will be discussed. These research insights will aid in developing targeted management strategies and breeding programs to reduce the adverse programming effects of heat stress in cattle, ensuring the sustainability and resilience of livestock production systems in the face of climate change.
83 Genotype-by-environment interaction with high-dimensional environmental data: an example in pigs
Authors: Bussiman Fernando , Lourenco Daniela , Chen Ching-Yi , Holl Justin W , Misztal Ignacy , Vitezica Zulma G
Published: September 2024

This study investigated using environmental covariates to model correlated herd effects and genotype-by-environment interaction (GE), as well as their impact on the prediction accuracy of genomic evaluations in pigs. We used air, dew/frost, wet-bulb, and earth-skin temperatures, relative humidity, rainfall, wind speed and direction. Average daily gain (ADG) and backfat thickness (BFT) from a terminal pig line were analyzed by 6 different models: MG, which included herd as an uncorrelated random effect; ME30, which considered 30 d of daily weather information to correlate herd effects; and ME100, which used 100 d of daily climate covariates; MGE30, same as ME30 but also considering the GE as the Hadamard product of the genomic relationship matrix and the environmental covariates matrix; MGE100, same as ME100 but including the GE; and MTM, a traditional multiple-trait model with each herd as a different trait. All animals were genotyped and phenotyped; therefore, the statistical model of choice was GBLUP. Validation was based on LR method, and focal animals were those born in the last year. Accuracy, bias, and dispersion did not change among models, except for MTM. Comparing all models against MTM, the accuracy increased by 38% for BFT, whereas only slightly increased for ADG. Among all 11 herds, only 4 showed a genetic correlation stronger than 0.80 for BFT, while this number was much greater for ADG. When the model has a variable accounting for environmental effects like herd in the case of MG, using weather information to correlate environments or adding the GE term has little benefit for genomic predictions.
87 Estimation of genetic parameters for activity levels in North American Holstein cattle
Authors: Moulder Caitlin N , Maskal Jacob M , Kalbaugh Kirby , Pacheco Hendyel , Boerman Jacquelyn , Brito Luiz F
Published: September 2024

High-producing dairy cows face various challenges during their productive life, including metabolic and infectious diseases, heat stress, and intensive management practices. Therefore, dairy cattle breeding programs have begun to focus on novel traits related to the overall resilience of the cows. Resilience has been defined as the ability of an animal to be minimally affected or to recover quickly from environmental disturbances while maintaining a certain level of productivity. In dairy cattle, resilience can be evaluated using measurements of longitudinal indicator traits, such as activity level, which are repeatedly measured throughout the lifetime of the animal. Variability in activity (defined in this study as average steps per hour and daily steps taken) might be a key indicator of resilience, due to activity of contemporary group animals deviating from normal behavior in less resilient cattle. Before resilience indicators are defined based on variability in certain longitudinal traits, there is a need for evaluating the genetic background of the source variable. Therefore, the primary objective of this study was to estimate variance components and genetic parameters of activity traits in lactating Holstein cows. The data was collected from a large dairy farm located in Indiana, using milking systems. Records from 6,332 Holstein cows for the traits of average activity per hour and number of daily steps were used in the analyses. The models used for the estimation of variance components included the significant (P < 0.05) fixed effects of contemporary group defined based on the concatenation of calving year and season, parity number (1, 2, 3+), pregnancy group (0 mo, 1-3 mo, 4-6 mo, and 7-9 mo), and days in milk (2-wkclasses), and the random effects of direct additive genetic, permanent environment, and residual effects. Genetic parameters were estimated for average activity per hour and daily steps for all parities together. Heritability estimates were calculated based on single-trait repeatability models and the (AI) REML method implemented in the BLUPF90+ software. Daily steps taken had a heritability (± SE) of 0.05 (± 0.02) and a repeatability of 0.29 (± 0.02). Activity per hour had a heritability estimate of 0.12 (± 0.04) and a repeatability of 0.57 (± 0.01). These results indicate that activity level is heritable in North American Holstein cattle and can be added to selection indexes if proven to be a key auxiliary trait for improving dairy cattle sustainability. As a next step, we will investigate the genetic relationship of activity traits with other relevant traits and derive resilience indicators based on variability in activity level.
115 Confidence intervals for validation statistics with data truncation in genomic prediction
Authors: Bermann Matias , Legarra Andres , Munera Alejandra Alvarez , Misztal Ignacy , Lourenco Daniela
Published: September 2024

Validation by data truncation is a common practice in genetic evaluations because of the interest in predicting the genetic merit of a set of young selection candidates. Two of the most used validation methods in genetic evaluations are predictivity (correlation between pre-adjusted phenotypes and EBV) divided by the square root of the heritability) and the linear regression (LR) method. Both methods compare predictions with the whole and partial datasets obtained by removing the information related to a set of validation individuals. Confidence intervals (CI) for predictivity and the LR method can be obtained by k-fold validation or bootstrapping. Analytical or frequentist CI are unavailable for predictivity and the LR method and would be beneficial to avoid running several validations. The analytical CI can also help test the quality of bootstrap intervals. This study aimed to derive analytical CI for predictivity, and statistics included in the LR method (bias, dispersion, ratio of accuracies, and reliability). The CI for the bias, dispersion, and reliability depends on the (co)variances of the EBV across the individuals in the validation set. The CI for the ratio of accuracies and predictivity were obtained through the Fisher transformation. We showed the adequacy of the analytical CI using simulation. The analytical CI were closer to the simulated ones. Bootstrap CI tend to be narrower than the simulated ones. Estimating the sampling variation of predictivity and the statistics in the LR method without replication or bootstrap is possible for any dataset with the method proposed in this study. All the formulas derived in this study were implemented in a new program belonging to the BLUPF90 suite called Validationf90.
116 Contribution of X-chromosome to the genetic variance of litter size and stillbirth in pigs
Authors: Veroneze Renata , Chen Ching-Yi , Holl Justin W , Misztal Ignacy , Bermann Matias , Lourenco Daniela
Published: September 2024

Genes with important roles in reproduction traits have been described in pig X-chromosome (SSCX), which may contribute considerably to genetic variance and could impact the accuracy of genomic prediction. The phenotypic data set includes information on 82,580 litter size records from 34,346 sows. Additionally, there were 108,006 in the pedigree, and genotypes for 41,492 SNPs, of which 1,435 in SSCX, were available for 30,000 animals. Three different approaches were used to estimate variance components for the total number born and number of stillborn. In the first approach, only SNPs in the autosomes were used and the model included the additive genetic (u), permanent environment (p), and residual (e) random effects. In the second approach, the same model was adopted; however, the data included SNPs in the autosomes and in the X chromosome. For both models, it was assumed that u~N(0,H⊗Vu), e~N(0,I⊗Ve) and p~N(0,I⊗Vp), wherein H is a relationship matrix that combines pedigree and genomic information; and, Vu, Vp, and Ve are the (co)variance matrices for the random additive genetic, permanent environment, and residual effects, respectively. In the third approach, the random additive genetic effects associated with the X-chromosome (s) were included in the model described before. Then, it was assumed that s~N(0,Hx⊗Vs), where Hx is the genomic relationship matrix for the X-chromosome and Vs is the additive genetic variance associated with the SSCX. All analyses were carried out using GIBBSF90+. Table 1 shows variance components for the three approaches. For both traits, additive genetic variance and heritabilities were similar across the approaches. The additive genetic variance for the SSCX was small, accounting for approximately two percent of the total additive genetic variance. Including the X chromosome as a separate effect and using Hx as a covariance matrix captured only a small part of the additive genetic variance. The additive variance across approaches did not differ. For total number born and number of stillborn, using the SSCX SNPs to build Hx did not provide extra benefit compared with fitting those SNP in the regular H matrix.
198 Discovery of key functional SNP markers associated with feed efficiency in beef cattle
Authors: Lam Stephanie , Guan Leluo , Plastow Graham , Cánovas Ángela
Published: September 2024

Beef production contributes to approximately 2.4% of the total Greenhouse Gas emissions in Canada. Improving beef cattle feed efficiency (FE) may lead to improved energy partitioning and resource use, thereby improving the sustainability of the beef industry. Our objective was to identify differentially expressed key regulatory genes and associated novel functional SNP markers linked to FE in Canadian beef cattle using RNA-Sequencing (RNA-Seq) of rumen tissue collected from 48 beef cattle [n = 16 Angus, n = 16 Charolais, n = 16 Kinsella (Composite Hybrid including Angus, Charolais, Galloway, Hereford, Holstein, Brown Swiss, and Simmental)] selected for extreme FE phenotypes. In total, 11 key regulatory genes (MYH1, MYL2, MYLPF, TNNC2, EIF4B, RHOD, TCEANC, CKM, ENSBTAG00000040518, SERPINB2, and USP43) were significantly differentially expressed (DE) between extreme Residual Feed Intake (RFI) groups (low-RFI n = 8, high-RFI n = 8 per breed) using CLC Genomics Workbench (FDR < 0.05; |FC| >2). Using an optimized RNA-Seq variant calling pipeline using STAR and BCFtools, a total of [total (unique to low-RFI, unique to high-RFI)] 75 (36, 39), 78 (42, 36), and 53 (35, 18) uniquely fixed functional SNPs were located within coding regions of these 11 functional candidate genes, in low- and high-RFI animals in the Angus, Charolais, and Kinsella breeds, respectively. Considering all functional SNPs uniquely identified in low- or high-RFI groups for all breed comparisons, the majority of SNPs were identified in MYH1, EIF4B, and SERPINB2 genes, which function together in metabolically demanding biological processes (P < 0.05) related to muscle contraction, muscle system, and muscle filament function processes. Additionally, EIF4B and SERPINB2 genes were found to have a role in signaling pathways that coordinate cell growth and immune function, respectively. Using RNA-Seq to identify key regulatory genes and associated functional SNPs linked to FE may uncover important genetic markers that influence the regulation of FE in beef cattle.
204 Changes in DNA methylation 5 days after exposure to acute heat stress in beef cattle skeletal muscle
Authors: Reith Rachel R , Gibbs Rachel , White Melanie R , Parrish Brooke L , Fuller Anna M , Schmidt Ty B , Yates Dustin T , Petersen Jessica L
Published: September 2024

The objective of this study was to investigate the effects of acute heat stress on the skeletal muscle epigenome using reduced representation bisulfite sequencing (RRBS). March-born crossbred (5/8 Red Angus, 3/8 Simmental) steers (n = 14; average body weight = 308.7 kg) were exposed to heat stress (HS) conditions of 35°C + 35% relative humidity (Temperature Humidity Index = 81) for 12h/d for 2 d (48 h). Longissimus dorsi samples were collected via biopsy and flash-frozen in liquid nitrogen immediately following the HS period at 48 h and from the contralateral longissimus dorsi 5 d later. DNA was isolated and underwent RRBS using 150 bp paired-end reads at an achieved average depth of 15.3 million reads/sample. Reads were trimmed and mapped to a bisulfite-converted bovine genome (ARSUCD1.2). Methylation calls were extracted and used to identify differentially methylated regions (DMRs) with methylkit in R comparing samples collected 5 d post-HS to those taken immediately post-48 h of HS. Differentially methylated regions (1,000 bp) had q < 0.05 and at least a 15% difference in methylation. There were 1,015 DMRs in genes. Hypomethylated DMRs 5 d post-HS included IGF1R, IGF2, IGF2BP1, IGFBP4, IGF2R, IKBKB, and IL34. Hypermethylated DMRs 5 d post-HS included FGF5, FGFR1, and FGFR3. There were 81 DMRs in putative promoter regions (2000 bp 5’ of a gene). MYLK2, SIGIRR, and 25 other genes had hypomethylated promoter regions. Genes that contained DMRs were used as input for DAVID to explore KEGG pathways. Enriched pathways (P < 0.1) included multiple hormone pathways, MAPK, PI3K-Akt, HIF-1, and VEGF. Hypomethylation of IGF-related genes and hypermethylation of FGF-related genes suggests impaired growth capacity post-HS, as does the enrichment of MAPK and PI3K-Akt pathways. Hypomethylation of SIGIRR’s promoter region, IL34 and IKBKB, indicates enhanced anti-inflammatory activity given their known regulation of inflammatory cytokine production. This, coupled with enrichment of the HIF-1 and VEGF pathways, suggests regulatory dampening of HS-induced oxidative stress. These findings reveal key regulatory changes in muscle growth, inflammatory response, and oxidative stress activity for cattle recovering from acute HS. Previous cattle skeletal muscle RNA studies predicted that HS altered metabolism, inflammation, and oxidative stress pathways, similar to the methylation results of this study. Overall, evidence suggests growth dysregulation, which may help explain observed HS-induced poor growth due to HS, as well as subsequent anti-inflammatory activity during recovery from HS.
341 Impact of genomic selection for growth on feet and leg structure in Angus cattle
Authors: Trujano Zuleica , Hidalgo Jorge , Retallick-Riley Kelli J , Garcia Andre , Lourenco Daniela , Misztal Ignacy
Published: September 2024

Historically fitness and production traits have shown an antagonistic relationship at the genetic level. Genetic selection mainly focused on growth traits (GT) might have influenced feet and leg structure traits (FT; recently added trait), causing changes over time. We aimed to examine genetic parameter changes in FT and GT over time in Angus cattle. Currently, genetic parameters are estimated using Variance Components Estimation (VCE), which has limitations in handling large datasets and is time demanding. To address these limitations, we explored the use of predictivity-based formulas to estimate heritability and genetic correlations in GT. The analysis was conducted using the blupf90+ family of programs. To estimate variance components (VCE), sampled data (2011-2022) from the American Angus population included 311K GT records [birth (BW), weaning weight (WW), and post-weaning gain (PWG)], ~70K FT records [foot claw set (CS) and foot angle (FA)], and 142K genotypes. FT are taken on the worst foot of the animal and can be scored multiple times throughout the life of the animal, but in this study, we did not include repeated records. The dataset was split into 5-yr intervals. Since FT ranged from 5 to 9, and 5 is ideal, a negative correlation is desired between FT and GT. The correlation FA-PWG, changed in an undesirable way over time, as it changed from -0.10 to 0.02 in the last interval. The correlation FA-WW is becoming more favorable over time, shifting from 0.05 to -0.15. The GT selection process shifted the correlations between CS and GT in the desired direction, changing from positive (~0.1) to almost zero in the more recent two intervals. To test the predictivity-based formulas, Genomic Estimated Breeding Values (GEBV) were estimated using GT data from 6.3M animals born from 2000 to 2022, and 900K genotyped animals. The data were divided into four slices, with a 2-yr validation period. Over time, heritabilities remained constant: ~0.3 for BW and WW, and ~0.2 for PWG. Correlations between GT also remained constant, approximately at 0.45 for BW-WW, 0.30 for BW-PWG, and 0.75 for WW-PWG. Although the formulas show promising results for heritabilities, interpreting the outcomes of genetic correlation estimation remains unclear, needing further tests. While certain correlations between FT and GT suggest a positive impact of genetic selection, some undesirable outcomes are realized. Probably due to the early FT genetic selection implementation (2019). This emphasizes the need for a multi-trait genomic selection approach to mitigate genetic antagonism. Adopting predictivity-based formulas reduces the time for genetic parameter estimation and allows the use of complete data instead of sampled data, as currently done in VCE.
309 Synergistic optimization: Utilizing genomic insights to enhance strategies for joint selective (deep) phenotyping and recursive creation of genomic reference populations - Sponsored by EAAP
Authors: Gengler Nicolas , Markey Alice , Lemal Pauline , Chen Yansen , Wilmot Hélène , Schroyen Martine
Published: September 2024

Synergistic optimization is a process combining different elements achieving better results than would be possible by optimizing each element individually. Our objective will be to design systems where genotyping and phenotyping complement each other to achieve superior performance. Deep phenotyping can be defined as a comprehensive and detailed approach to characterize traits of animals, including those based on the study of intermediate phenotypes representing not only the phenome, but also e.g., the metabolome, the proteome, and the transcriptome (i.e., -omics phenotypes). Often these phenotypes are also called high-throughput but this should not be considered being a synonym for being cheap. Interplay between genotyping and (deep) phenotyping has a major impact on the acquisition of genetic knowledge but could also be used in the context of genomic evaluations (i.e., as intermediate correlated features such as high-throughput or -omics phenotypes). While past studies have largely focused on ways to integrate deep phenotyping to gain new knowledge but also to support genetic and genomic evaluations, phenotyping and especially deep phenotyping currently requires massive investment, limiting its effective and widespread use under field, but also in experimental conditions. This problem extends to complex phenotype-taking as feed intake, methane emissions or in general use of expensive sensors. Even with all the possible investments, many phenotyping efforts are limited by the poor choice of animals. This presentation will address and introduce the topic of genome-enabled optimization of (deep) phenotyping taking into account the facts that genotypes are in many cases much cheaper than phenotyping, can be performed at early stages, and can help organize animal sampling in an efficient manner. The last point is also linked to validation techniques comparing predicted to observed phenotypes and closely related to recursive genomic reference population building issues. Techniques used in other fields such as chemometrics (i.e., infrared spectra prediction building) will be proposed to optimize covering genetic variability. In the context of recursively performed genomic evaluations (i.e., increasing reference population at each round) population accuracy and bias of prediction will be addressed. Moreover, long term genetic contribution and population structure issues will have to be considered. Based on literature and practical examples systematically organized sampling techniques will be presented to discuss basic principles as covering observed genomic and expected phenotypic diversity and long-term effects of recursively created genomic reference populations.
311 Effect of feeding butyric acid on growth performance and metabolic indicators of dairy calves before weaning: A meta-analysis
Authors: Kihal Hacib , Puyalto Monica , Mallo Juan Jose
Published: September 2024

This meta-analysis aimed to evaluate the effect of feeding butyric acid (BA) on growth performance and metabolic indicators in dairy calves. A literature search was conducted to identify in vivo research studies carried out on BA supplementation in dairy calves. Inclusion criteria were in vivo studies, dairy calves, weaning, BA, and inclusion doses of BA. Twenty-three papers with 80 data and 1,132 calves were selected. Data extracted included the number of calves in control and treatment groups and measures of variance of responses (standard error or standard deviation). The response variables were production performance including body weight (BW), average daily gain (ADG) feed efficiency (FE), and metabolic indicators including blood glucose and beta-hydroxybutyrate (BHB) concentrations. A random effect of model was used to examine the raw mean difference and standardized mean difference between BA supplementation and the control group. The analysis was conducted using the metafor package of Rstudio. Butyric acid moderately improved the growth performance and metabolic indicators responses of calves with substantial heterogeneity (59 < I2 < 73%, P < 0.01). Final BW and ADG were increased by 2.7 kg and 48.1 g/day, or > 0.6 and > 0.4 standard deviation units (P < 0.05), respectively. However, FE was increased by BA supplementation but not significantly different. For metabolic indicators, glucose concentration was greater with BA supplementation with > 0.4 standard deviation unit, (P < 0.05). However, BA supplementation did not affect the blood concentration of BHB (P > 0.05). In conclusion, the meta-analysis results demonstrated that BA constitutes an important energy source for dairy calves. Butyric acid is effective in promoting growth performance and intestinal health and, yet, increasing production profits.
5 Hands-on 3: Introduction to developing Python computational pipelines for predictive machine learning modelling of livestock data
Authors: Tulpan Dan
Published: September 2024

This hands-on workshop aims to offer examples of computational pipelines that apply traditional predictive machine learning modelling techniques to animal science datasets with the purpose of solving classification and/or regression problems. The objective of this workshop is to provide the attendants with fully functional and customizable computational pipelines developed in Python. The workshop is structured in a hands-on format and includes a combination of basic notions about machine learning and relevant algorithms, evaluation measures, evaluation strategies and Python code examples. To avoid technical problems related to installing a Python environment on personal computers, we recommend the registrants to acquire access on the Repl.it platform (https://replit.com/) by creating a free account prior to attending the workshop. Detailed information will be provided before the beginning of the workshop at the following URL: http://animalbiosciences.uoguelph.ca/~dtulpan/conferences/asas2024/
20 Trace metal homeostasis in growing cattle
Authors: Daniel Jean-Baptiste , Martín-Tereso Javier
Published: September 2024

Apparent trace metal absorption and tissue retention upon incremental levels of supplemental Zn, Cu, and Mn were studied in growing cattle. A total of 60 Holstein bulls were enrolled for the study and fed for 28 d a diet consisting of barley straw (15%), molasses (10%) and pelleted concentrate (75%; Zn = 78 ppm, Cu = 15 ppm, Mn = 91 ppm). Thereafter, 20 bulls were randomly selected and slaughtered for determination of baseline tissue trace metal composition. The remaining 40 bulls [body weight (BW) = 394 ± 20 kg] were then blocked based on BW in 8 blocks of 5 bulls each. Bulls within a block were randomly assigned one of the diets differing in supplemental levels of Zn, Cu, and Mn (all from sulfate form) with the following dietary contents of Zn, Cu and Mn, respectively: No supplement (38, 7, and 47 ppm), Dose 1 (61, 11, and 68 ppm), Dose 2 (78, 15 and 91 ppm), Dose 3 (123, 26, 136 ppm) or Dose 4 (195, 43, and 214 ppm). These diets were fed for 12 wk, and complete collection of feces and urine were performed on wk 4, 8 and 12 for assessment of trace metals balance and apparent absorption. Gastrointestinal tissues, whole organs (heart, liver, spleen, and kidney), bile, cervical vertebra, and tibia were collected at slaughterhouse from all bulls. All samples were dried, ground, and analyzed for minerals. Data were processed using dietary treatment as a continuous variable and also as categorial variable. Both approaches adjusted for the fixed effect of block (Proc Mixed, SAS 9.4). Whole-body Zn, Cu and Mn balance quadratically increased (P < 0.05) with supplementation, with a significantly higher values for Dose 4 compared with all other dietary treatment (Figure 1, P < 0.05). Dose 4 also led to a 2-fold increase in urinary Zn and Cu excretions (P < 0.05), and a 4-fold increase in urinary Mn excretion (P < 0.01). Although magnitudes of change were moderate (8 to 15%), increasing dietary Zn supply linearly increased spleen Zn content (P = 0.03), and tended to increase ruminal and hepatic Zn content (P < 0.10). Hepatic Cu linearly increased from 264 to 667 mg/kg DM with increasing dietary Cu supply (P < 0.01), whereas Cu concentration in bile only increased at Doses 4 and 5 (P < 0.01). Increasing Mn supply resulted in quadratic increase of ruminal and biliary Mn content from 340 to 1140 mg/kg DM, and from 0.32 to 1.38 mg/L, respectively. Small intestine and cecum Mn concentrations linearly and quadratically increased (about 2-fold increase, P < 0.05) with incremental supply of Mn. Homeostatic regulation mechanisms were apparently overwhelmed at the greatest Zn, Cu and Mn supplementation levels evaluated in this study.
27 Effects of particle size and trace mineral source on vitamin stability in premix
Authors: De Araujo Davi Brito , Boerboom Gavin M , Busink Ronald , Grandia Jeroen
Published: September 2024

Trace minerals and vitamins are necessary in diets for multiple physiological processes related to structural development, catalytic and regulatory systems in the animal. They become especially important when animals are challenged. These ingredients are commonly added to commercial diets through a concentrated mix, a premix. Unfortunately, vitamins are relatively unstable, and minerals are highly reactive, leading to reduction of the vitamins by the minerals. Feeding a mineral of a different particle size can influence this mechanic, as well as a different source, for example hydroxy trace minerals. The objective of this work was to evaluate vitamin A stability in presence of different sources of trace minerals as well as premix conditions. A microcrystalline cellulose matrix was created by dissolving vitamin A in an organic solvent (IPA). A fixed amount of vitamin MCC mix was added to a sample tube per analysis, containing common premix vitamin and mineral levels. Fixed amount of moisture and antioxidant (BHT) was added to evaluate these effects. Results on the effect of moisture indicated that 10% moisture addition had a large effect on vitamin A stability, reducing it by over 50% after 11 d. Vitamin A loss in premixes containing no moisture showed no difference between MCC mixes containing no mineral and ones containing hydroxy Cu, whereas there was a significant drop in vitamin A with CuSO4. Vitamin A stability was significantly affected by a lower particle size Cu source, with CuSO4 below 75 µm showed almost full degradation after 13 d. Hydroxy Cu showed relatively low degradation for its particle size. Overall, the results showed that moisture and particle size can have a huge impact on vitamin A stability, with BHT or antioxidants only partly being able to reduce this. Feeding a higher quality trace mineral source such as hydroxy trace minerals lead to a less reactive Cu, and hence, a higher vitamin A stability.
258 Administering the maternal bovine appeasing substance improves productivity and health responses of high-risk steers during a 60-d feedlot receiving period
Authors: Pickett Autumn , Cooke Reinaldo F , Mackey Shea
Published: September 2024

This experiment compared health, performance, and economical responses of newly received high-risk cattle administered the maternal bovine appeasing substance (mBAS). Angus-influenced newly weaned steers (n = 120) were purchased from an auction facility. Steers arrived at the research feedyard on d -1 and an initial shrunk body weight (BW) was recorded (199 ± 1 kg). Steers were ranked by shrunk BW and assigned to 1 of 2 treatments at initial processing on d 0: a) 10 mL of a mBAS (Ferappease; FERA Diagnostics and Biologicals; College Station, TX) or b) 10 mL of mineral oil (CON; placebo). Treatments were applied topically to the nuchal skin area (5 mL) and above the muzzle (5 mL). Steers were vaccinated, dewormed, implanted, castrated, and received a metaphylaxis treatment at initial processing, and then distributed into 10 drylot pens according to BW and treatment (n = 12 steers/pen, 5 pens/treatment). Feed intake and incidence of bovine respiratory disease (BRD) were recorded daily (d 0 to 60). Blood and hair samples from the tail switch were collected on d 0, 14, 28, 42, and 60. Steers were sampled for nasal microbiota analysis via nasal swab on d 0, 14, and 28. Final shrunk BW was recorded on d 61. Values from d 0 were used as a covariate in each respective analysis. Steer BW gain and final BW did not differ between treatments (P ≥ 0.46). Incidence of BRD were also similar between mBAS and CON steers (56.7% for both treatments; P = 0.99). A greater (P = 0.04) proportion of mBAS calves diagnosed with BRD required a single antibiotic treatment to regain health (70.6 vs. 47.0%), while mortality was greater (P = 0.03) in CON calves diagnosed with BRD (17.6 vs. 2.9%). Relative abundance (%) of Mycoplasma in nasal microbiota was reduced (P < 0.01) in mBAS steers compared with CON (34.7 vs. 27.4%). Cortisol concentration of in hair from the tail-switch was less (P = 0.01) on d 28 for mBAS compared with CON steers. Administering mBAS improved (P ≤ 0.05) total pen-based (“deads-in calculation”) BW change (498 vs. 309 kg) and feed efficiency (0.148 vs. 0.097 kg/kg) during the 60-d receiving period, resulting in greater (P = 0.04) profit in mBAS vs. CON pens ($-123 vs. $1,000/pen). Collectively, administration of mBAS to steers at the beginning of a 60-d receiving period decreased physiological stress markers, improved immunocompetence, reduced mortality, and increased pen-based productivity and overall economical responses.
265 Factors influencing greenhouse gas measurements in beef cattle: Understanding GreenFeed results
Authors: Guarnido-Lopez Pablo , Menendez Hector M , Tedeschi Luis O
Published: September 2024

The environmental impact of the livestock industry, particularly concerning greenhouse gas (GHG) emissions, has become a growing concern. Addressing this challenge requires accurate and efficient measurement methods for monitoring and mitigating gas emissions. One noteworthy method is the GreenFeed (GF), developed by C-Lock Inc., designed to measure methane (CH4) emissions and carbon dioxide (CO2) concentrations in ruminants through a real-time non-invasive monitoring device with reduced labor intensity and a high level of precision. The GF is the most used equipment to measure GHG in cattle; however, there is still considerable variability that is not explained due to the variation among animals. Thus, the objective of this work is to analyze other environmental factors influencing GF measurements in cattle to explain the variability observed. For this, a total of 127 yearling Angus steers were evaluated for GHG emissions through 6 GF units placed in 6 different pastures (n = 21 to 22 animals/pasture). Animals were evaluated from June to August (2023) at the South Dakota State University Cottonwood Field Station (Cottonwood, SD). The mean values of GHG evaluated were 174g CH4/d and 5,885 g CO2/d, showing a coefficient of variation (CV%) of 41% and 27%, respectively. To evaluate GHG variation, we used ANOVA type III (package car in R) for the following variables measured by the GF: temperature, wind speed, wind direction, variance influenced by the GF unit by itself, and animal factors as the number of visits and the duration per visit. Table 1 shows the percentage of variance explained by all these factors on the variation of CH4 and CO2; between-animal variation (13 and 15.5%), the GF unit (7.2 and 6.3%), duration of visits (2.7 and 2.8%), wind speed (1.7 and 1.3%), temperature (1.3 and 0.0%), wind direction (0.1 and 0.1%) and number of visits (0.3 and 0.0%). The residual error of the model represented 73.7% for CH4 and 73.9% for CO2, indicating the vast percentage of non-explained variance in these two gases, which, in this case, could be associated with different grazing systems or stocking density of animals in the different pastures. Results of this study demonstrate how other factors, non-related to the animal or the type of feed, may contribute to explaining the variation observed in CH4 and CO2 emissions. In future experiments, these factors should be considered to improve the accuracy of measurements and establish smaller differences between groups/individuals.
263 Public perspectives of calf handling: A survey of Canadians
Authors: Goldhawk Christy , Adams Cindy , Pajor Edmond A
Published: September 2024

In North American beef production handling and restraint of young calves is integral to animal welfare and management practices. This study used a mixed method approach to gather public perceptions of three handling and restraint methods common on beef operations in western Canada (RW - Roping and Wrestling, NF – roping and NordForks, and TT – Tilt Table). Canadian participants (n = 551) recruited by CloudResearch to represent the national demographics participated in an online survey that included videos of each handling method to ascertain preferences and acceptability. Prior to watching the videos, participants were given industry information about handling and restraint or generic information regarding hay as a control information statement within the topic of agriculture. The survey also collected information about knowledge of the beef industry, animal welfare, and empathy toward animals. The reasons for preferences were described as presence of a perceived positive attribute and absence of a perceived negative for most preferred methods, and inversely when explaining least preferred method. The findings focused on calf’s experience, perception of handler actions, and pragmatic balancing of handler needs and a good life for the calf. Methods were rated as more acceptable for participants that ate meat consistently, knew more about the beef industry, and, to a lesser extent, if the individual had a lower animal empathy score (Table 1). Acceptability was not affected by providing information about the practices; however, information about handling and restraint did elicit more pragmatic reasoning. Most participants preferred TT over NF and RW (P < 0.001) and found TT more acceptable as well (P < 0.001). The TT was the most preferred method due to calf experience and human handling, notably the absence of dragging a calf, which was predominant in why participants selected NF or RW as their least preferred method. Consistency of themes highlights that the Canadian public has a fundamental expectation of value for the quality of life of the calf, humane handling, and pragmatism which aligns with beef sustainability initiatives and represent points of connection for building trust between industry and the public.
367 Changing the conversation: Evaluating feedyard closeouts and the beef system on a carcass basis
Authors: Sperber Jessica L
Published: September 2024

Beef cattle genetics, management, technologies and nutritional strategies are ever evolving, and current US trends favor feeding cattle to heavier carcass endpoints and optimizing quality grade. The average number of days on feed (DOF) in the US has increased year after year, averaging 195 and 183 DOF for steers and heifers, respectively, as reported by Elanco Benchmark data in 2021. As DOF increase, cattle live performance, including average daily gain and feed efficiency decline; however, hot carcass weight (HCW) becomes significantly heavier. Although a reduction in live feed conversion occurs as cattle are fed for extended DOF, the kilograms of additional live gain that result as kilograms of gain on the carcass, termed carcass transfer, increase linearly. As DOF are extended, carcass transfer has been reported to increase up to 88 %. As a result of genetic advancements, technologies, and feeding longer, HCW has trended heavier over the last 60 yr, with 2024 USDA HCW reported for April as 11.3 and 9.5 kg heavier for steers and heifers, respectively, year after year. According to mandatory price reporting data, approximately 74 % of fat cattle marketed in the US are sold as dressed beef. As we continue to feed to heavier endpoints and longer DOF, the profitability of selling on a carcass-basis increases. With the increase in carcass transfer as DOF extend, this presentation will attempt to address that cattle live performance should be adjusted to a carcass-basis for feedyards to appropriately capture the inflection point at which cost of additional gain equals the price received for the additional gain.
8 Gestational heat stress: Implications for pregnancy success and offspring development in swine
Authors: Johnson Jay S , Byrd MaryKate Harrod
Published: September 2024

Gestating sows are particularly sensitive to heat stress due to their large mass and greater metabolic heat production associated with increased reproductive organ and fetal development. Unfortunately, the heat stress sensitivity of gestating sows has increased over the past decades due to genetic and genomic advances that have improved litter sizes and reproductive efficiency. When combined with the greater frequency and severity of heat waves and high temperatures, it is likely that reproductive issues associated with heat stress exposure will continue to be a concern for the swine industry. It is well understood that high temperatures pose a challenge to gestating sows and their developing offspring. Research from 50 to 60 yr ago demonstrated that heat exposure results in a decrease in viable embryos and an increase in embryonic mortality, particularly when gestating sows are subjected to heat stress in the first trimester. Additionally, late gestation heat stress exposure can increase the rate of stillborn piglets and reduce the total number of liveborn piglets. Although the reasons for these losses are multifactorial, the direct influence of maternal body temperature and total stress load on the intrauterine environment can play a significant role during these critical stages. For offspring that survive to birth, prospects for a healthy, productive, and stress-free life are at risk due to the long-lasting effects of in utero heat stress, which include greater postnatal stress sensitivity and decreased productivity. Therefore, understanding and mitigating gestational heat stress in pigs is of great importance to ensure the sustainability and profitability of swine production.
297 Digestibility, blood parameters, and skin barrier function of dogs fed hydrolyzed salmon proteins
Authors: Fanelli Natalia dos Santos , de Godoy Maria Regina Cattai , Mioto Julio
Published: September 2024

Conventional pet food diets include meat meals as the primary source of protein. However, hydrolysate proteins have been used due to their improved digestibility and decreased allergic response. Novel sources of salmon protein hydrolysate have been developed, but limited information demonstrating the nutritional value of these proteins is available. Therefore, the objectives of this study were to evaluate apparent total tract digestibility (ATTD), blood parameters, and skin barrier function of adult dogs fed two novel sources of salmon hydrolysate protein. This study was approved by the Institutional Animal Care and Use Committee of the University of Illinois. The novel protein sources included one salmon protein hydrolysate concentrate (SPHC) and one salmon protein hydrolysate isolate (SPHI). Three diets were formulated to meet adult dog nutrient requirements. The first diet contained chicken meal (control), but the second and third diets contained one of the novel ingredients as the main source of protein. Thirty dogs were assigned to the experimental diets in a complete randomized design, with 10 dogs per treatment. The experimental period lasted 90 d after a 15-d adaptation period to the control diet. Fecal samples were collected during the last 5 d of the study and were used to calculate ATTD. Blood and skin parameters were collected on d 0, 45, and 90. Blood was analyzed for serum chemistry and complete blood count for 42 metabolites, and skin was examined for barrier function by evaluating hydration, sebum, and transepidermal water loss on the right and left pinas, upper back, and inguinal locations. The statistical model to assess ATTD included treatment as fixed effect and dog as random effect, while for blood and skin parameters, dog was the random effect, and day was included as a repeated measure to determine the effect of treatment by day. Results demonstrated that ATTD of dry and organic matter was greater (P < 0.05) in SPHI than in the control diet, and ATTD of crude protein and gross energy were greater (P < 0.05) in both salmon hydrolysates compared with the control diet. Creatinine was greater (P < 0.05) in SPHI, alanine aminotransferase was greater (P < 0.05) in SPHC, and cholesterol was less (P < 0.05) in SPHC on d 45 and 90 compared with baseline measurements. Skin hydration in the inguinal location was greater (P < 0.05) in SPHC than in control and SPHI diets. In conclusion, diets containing salmon hydrolysate were more digestible when compared with control diet. Blood parameters were within the normal range for healthy adult dogs, although reduced cholesterol was observed in the SPHC diet over time, which can be beneficial for dogs suffering from hypercholesteremia. In addition, skin barrier function was improved in the inguinal location for the SPHC diet.