Residual Gain Research Articles

The Effect of Preselection on the Level of Bias and Accuracy in a Broiler Breeder Population, a Simulation Study.

Many breeding programmes have to perform preselection, as genotyping and phenotyping all potential breeder candidates is often not a feasible option. There is need to understand how preselection affects the quality of the genomic estimated breeding values (EBVs) at final selection and thereby can affect genetic progress. This simulation study evaluated nine different preselection strategies in a broiler breeder programme and their effect on the quality of the (genomic) EBVs and genetic progress for three different traits: body weight (Body Weight), residual feed intake (RFI) and body weight gain (Gain). All birds have Body Weight recorded at preselection, but only the preselected birds were phenotyped for RFI and Gain and genotyped. The following criteria and intensities were studied: preselection based on phenotypic Body Weight (P), on a BLUP index (B) or on an ssGBLUP Index (G). Additionally, all criteria were studied with three different selection intensities, 10% of the males and 30% of the females (P10, B10, G10), 15% of the males and 45% of the females (P15, B15, G15) and 20% of the males and 60% of the females (P20, B20, G20). The accuracy at preselection with G10 was more accurate than B10 for both RFI and Gain (0.71 vs. 0.58 and 0.65 vs. 0.55 respectively), and also G15 was more accurate than B15 for both RFI and Gain (0.72 vs. 0.63 and 0.67 vs. 0.64 respectively); thus, the difference in accuracy reduces with an increasing number of birds being preselected. Differences in accuracy at final selection were mostly notable in the RFI trait between P10, B10 and G10, where G10 showed the highest accuracy (0.82 vs. 0.84 vs. 0.86 respectively). This difference in accuracy for RFI disappeared when more animals were preselected. For Body Weight and Gain, the BLUP preselection resulted in the highest accuracy at final selection when selection intensity decreased. The dispersion bias of EBVs at final selection was most pronounced in the P10 and P15 for Body Weight (0.81 and 0.92) but disappeared at P20 (0.97). The dispersion bias for all other criteria and traits was relatively small. Genetic progress was mostly affected when P10 or P15 was used at preselection, where the progress in Body Weight was noticeably higher, but prominently lower for RFI and Gain. The BLUP and ssGBLUP preselection had very similar genetic progress across traits and showed comparable improvements in the selection index. In conclusion, with high preselection intensity, the use of ssGBLUP at preselection might be favoured as there is an improvement in genetic progress across traits in all scenarios, which is due to the increased preselection accuracy. When preselection intensity decreases, the benefit of using ssGBLUP over BLUP at preselection disappears.

The Multi-Loci Genotypes of the Myostatin Gene Associated with Growth Indicators of Intensively Fattened Lambs of Latvian Sheep.

Myostatin (MSTN), a member of the TGFβ superfamily, negatively affects skeletal muscle growth and controls muscle development at stages of pre-natal muscle growth. Marker-assisted selection with molecular markers of the MSTN gene can be used in animal husbandry for higher-quality and more economically profitable lambs. The study aims to identify multi-locus genotypes within the MSTN gene regions as molecular markers for fattening, feed efficiency, and carcass traits in Latvian sheep. This analysis was conducted on 76 intensively fattened male lambs representing six breeds in Latvia. Nine genotypes were identified based on four SNPs in the promoter and exon 1 regions, while six and four SNPs in introns 1 and 2 led to the formation of 14 and 10 genotypes, respectively. Six genotypes identified in the 3'UTR were significantly linked to traits such as birth weight, slaughter yield, muscle development, fat depth, average daily gain, dry matter intake, and feed efficiency. Genotypes of intron 1 were associated with slaughter yield, while genotypes of intron 2 were linked to fat depth, dry matter intake, and residual weight gain. The study concludes that MSTN gene SNPs can be used in selection to enhance sheep breeds in Latvia and improve economic outcomes for breeders.

Diagnosis of schizophrenia by integrated saccade scores and associations with psychiatric symptoms, and functioning.

Eye movement as a neurobiological biomarker of schizophrenia. We aim to estimate diagnostic accuracy of integrated pro/antisaccade eye movement measurements to discriminate between healthy individuals and schizophrenic patients. We compared the eye movement performance of 85 healthy individuals and 116 schizophrenia-stable patients during prosaccade and antisaccade tasks. The difference eye movement measurements were accumulated by stepwise discriminant analysis to produce an integrated score. Finally, the diagnostic value of the integrated score was calculated by the receiver operating characteristic (ROC) area under the curve (AUC), and the best sensitivity and specificity were calculated based on the given cutoff values. Using discriminant analysis, an integrated score included the residual gain and latency (step) during the prosaccade test, the error rate, and the corrected error rate during the antisaccade test. We found that the integrated score could well classify schizophrenia patients and healthy individuals with an accuracy of 80.6%. In the ROC, Youden's index was 0.634 (sensitivity = 81.0%, specificity = 82.4%) and AUC was 0.871. There were significant difference patterns of correlation between the severity of psychiatric symptoms and daily functioning and diagnostic eye movement measurements. Using only 2 saccade tasks to discriminate well between schizophrenia patients and healthy controls, suggesting that abnormalities in saccade behavior is a potential biomarker and efficient diagnostic tool for identifying schizophrenia. The underlying neuropathologic mechanisms associated with abnormal saccades may provide insights into the intervention and diagnosis of schizophrenia.

Residual feed intake and gain alters the performance and carcass traits in Nellore cattle.

The residual intake and gain (RIG) aims to select animals that present low feed intake in relation to the expected. This study aimed to evaluate the associations of selection for RIG with performance and carcass traits in Nellore cattle. Initially, residual feed intake (RFI) and residual gain (RG) were determined. From this, the RIG was calculated, and the animals were classified as efficient and inefficient for RIG. The efficient animals for RIG showed higher daily weight gain (DWG), Longissimus muscle area (LMA), and mid-test metabolic body weight (MMBW) than the inefficient ones. No significant correlations were found between subcutaneous fat thickness (SFT), marbling (MAR), LMA, MMBW, and the RIG. Thus, it's concluded that the RIG is a measure that can be used to identify and select animals with higher rates of DWG and LMA without changes in the dry matter intake (DMI), SFT, and MAR. However, this index should still be observed with caution, as it may be dependent on body size. Based on the findings, the selection of animals according to the RIG can be an important factor to generate phenotypic evolution in characteristics such as weight gain and rib eye area without adverse effects on the carcass fat deposition.

PSIX-28 Optimization of feeding trial length for evaluating feed efficiency in sheep

Abstract Feed efficiency tests are well established for beef cattle, but testing for sheep remains rare due to the lack of appropriate equipment and standardized protocols. To explore the optimum trial length for evaluating feed efficiency in sheep, freshly weaned Rideau Arcott ewe lambs [n = 80; 4to 5 mo of age and body weights (BW) of 16 to 25 kg] were enrolled in a 65-d feeding trial, following a 20-d adaptation period. A mixed ration containing barley gain and protein supplement pellets were offered twice daily, and lambs had ad libitum access to feed, water and bedding straw during the trial period. Daily feed intake of individual lambs was monitored with Vytelle SENSE feed bunks, BW was recorded biweekly, as well as on two consecutive days at the start and end of the trial. Lambs that had died or had abnormal growth patterns from sickness were removed, resulting in 62 lambs remaining in the final dataset. Optimum trial length for measuring feed intake (DMI) and average daily gain (ADG) were evaluated with R Software (v. 4.3.3) via a post-hoc analysis of constructing shortened trial lengths from the regular test. The DMI and ADG values from the shortened trial datasets were compared with those from regular trial days with correlation (Pearson and Spearman tests) and linear regression analyses. There were 64 shortened trial lengths for DMI by 1 d increments, and 15 sub-datasets for ADG consisting of trial lengths between every two BW measurements. Residual feed intake (RFI), residual average daily gain (RADG), and residual intake and BW gain (RIG) were calculated for and compared between the regular trial length (65 d) and favorable shortened trial lengths based on DMI and ADG evaluations. Correlation, regression and agreement analyses were used to determine the optimum trial lengths for RFI, RADG and RIG evaluations. Results showed that DMI and ADG measurements could be shortened to 42 (r > 0.95, R2 > 0.90, β > 0.95, P < 0.001) and 56 d (r > 0.96, R2 > 0.93, β > 0.96, P < 0.001), respectively. Additionally, trial length for RFI, RADG, and RG evaluations could be reduced to 56 d (r > 0.95, R2 > 0.91, β > 0.95, CCC > 0.95, P < 0.001), primarily due to the trial length requirement for accurate ADG measurement. Reducing the duration of trials for evaluating feed efficiency in sheep not only reduces testing costs, fostering greater uptake among sheep producers, but also allows for the evaluation of more lambs annually, thereby enhancing the overall productivity and profitability of the sheep industry.

197 Hepatic mRNA expression of innate and adaptive immune genes in beef steers with divergent residual body weight gain

Abstract Immune function has a pivotal role in dictating the overall health and productivity of cattle. In a proficient immune system, the liver assumes an integral function in detoxification and metabolic processes and contributes substantially to overall production and immunity. In this study, we evaluated the hepatic mRNA expression of genes involved in innate and adaptive immunity in crossbred beef steers with positive or negative residual body weight (BW) gain (RADG). Positive-RADG beef steers (n = 8; RADG = 0.76 kg/d) and negative-RADG beef steers (n = 8; RADG = -0.64 kg/d) were identified from a group of 108 growing crossbred beef steers (average BW = 286 ± 380kg) after a 56-d performance testing period. At the end of the 56-d period, liver tissue samples were collected from the beef steers for RNA extraction and cDNA synthesis. The mRNA expression of 84 genes involved in innate and adaptive immunity were analyzed using pathway-focused PCR-based arrays. The mRNA expression of genes with false discovery rate-adjusted P-values (FDR) ≤ 0.05 and absolute fold change (FC) ≥ 1.2 were determined to be differentially expressed. Out of the 84 genes analyzed, four genes [interleukin (IL)-2, MYD88, CD-80, NFkB-1] were differentially expressed and were all upregulated in positive compared with negative-RADG beef steers. Gene ontology pathway enrichment analysis of the differentially expressed genes revealed that pathways related to positive regulation of IL-17 production, cellular response to lipopolysaccharide, and positive regulation of lymphocyte activation were enriched in the positive-RADG steers (P ≤ 0.05). In conclusion, our study revealed that positive-RADG beef steers had increased expression of genes and pathways involved in pathogen recognition and initiation of responses to effectively fight off infections while mitigating excess inflammatory reactions compared with negative-RADG steers, which might explain, in part, the improved feed efficiency of these beef animals

Feed efficiency and enteric methane emissions indices are inconsistent with the outcomes of the rumen microbiome composition

The correlation between enteric methane emissions (eME) and feed efficiency (FE) in cattle is linked to the anaerobic fermentation of feedstuffs that occurs in the rumen. Several mathematical indices have been developed to predict feed efficiency and identify low methane emitters in herds. To investigate this, the current study aimed to evaluate the rumen microbial composition in the same group of animals ranked according to six different indices (three indices for FE and three for eME). Thirty-three heifers were ranked into three groups, each consisting of 11 animals, based on FE (feed conversion efficiency - FCE, residual weight gain - RG, and residual feed intake - RFI) and eME indices (production, yield, and intensity). Rumen fluids were collected using a stomach tube and analyzed using 16S rRNA and 18S rRNA, targeting rumen bacteria, archaea, and protozoa. The sequencing analysis revealed that the presence of unique microbial species in the rumen varies across animals ranked by the FE and eME indices. The High RG group harbored 17 unique prokaryotic taxa, while the High FCE group contained only seven. Significant differences existed in the microbial profiles of the animals based on the FE and eME indices. For instance, Raoultibacter was more abundant in the Intermediate RFI group but less so in the Intermediate RG and Intermediate FCE groups. The abundance of Entodinium was higher while Diplodinium was lower in the High FCE group, in contrast to the High RG and High RFI groups. Methanobrevibacter exhibited similar abundances across eME indices. However, the heifers did not demonstrate the same production, yield, and intensity of eME. The present findings underscore the importance of standardizing the FE and eME indices. This standardization is crucial for ensuring consistent and reliable assessments of the composition and function of the rumen microbiome across different herds.

Plasma proteomic analysis reveals key pathways associated with divergent residual body weight gain phenotype in beef steers.

We utilized plasma proteomics profiling to explore metabolic pathways and key proteins associated with divergent residual body weight gain (RADG) phenotype in crossbred (Angus × Hereford) beef steers. A group of 108 crossbred growing beef steers (average BW = 282.87 ± 30 kg; age = 253 ± 28 days) were fed a high-forage total mixed ration for 49 days in five dry lot pens (20-22 beef steers per pen), each equipped with two GrowSafe8000 intake nodes to determine their RADG phenotype. After RADG identification, blood samples were collected from the beef steers with the highest RADG (most efficient; n = 15; 0.76 kg/d) and lowest RADG (least efficient; n = 15; -0.65 kg/d). Plasma proteomics analysis was conducted on all plasma samples using a nano LC-MS/MS platform. Proteins with FC ≥ 1.2 and false-discovery rate-adjusted p-values (FDR) ≤ 0.05 were considered significantly differentially abundant. The analysis identified 435 proteins, with 59 differentially abundant proteins (DAPs) between positive and negative-RADG beef steers. Plasma abundance of 38 proteins, such as macrophage stimulating 1 and peptidase D was upregulated (FC ≥ 1.2, FDR ≤ 0.05) in positive-RADG beef steers, while 21 proteins, including fibronectin and ALB protein were greater (FC < 1.2, FDR ≤ 0.05) in negative-RADG beef steers. The results of the Gene Ontology (GO) analysis of all the DAPs showed enrichment of pathways such as metabolic processes, biological regulation, and catalytic activity in positive-RADG beef steers. Results of the EuKaryotic Orthologous Groups (KOG) analysis revealed increased abundance of DAPs involved in energy production and conversion, amino acid transport and metabolism, and lipid transport and metabolism in positive-RADG beef steers. The results of this study revealed key metabolic pathways and proteins associated with divergent RADG phenotype in beef cattle which give more insight into the biological basis of feed efficiency in crossbred beef cattle.

Calibration requirement for Epoch of Reionization 21-cm signal observation. Part III. Bias and variance in uGMRT ELAIS-N1 field power spectrum

Power spectrum of H i 21-cm radiation is one of the promising probes to study large scale structure of the universe and understand galaxy formation and evolution. The presence of foregrounds, that are orders of magnitude larger in the same frequency range of the redshifted 21-cm signal has been one of the largest observational challenges. The foreground contamination also hinders the calibration procedures and introduces residual calibration errors in the interferometric data. It has been shown that the calibration errors can introduce bias in the 21-cm power spectrum estimates and introduce additional systematics. In this work, we assess the efficacy of 21-cm power spectrum estimation for the uGMRT Band-3 observations of the ELAIS-N1 field. We first evaluate the statistics of the residual gain errors and perform additional flagging based on these statistics. We then use an analytical method to estimate the bias and variance in the power spectrum. We found that (a) the additional flagging based on calibration accuracy help reduce the bias and systematics in the power spectrum, (b) the majority of the systematics at the lower angular scales, ℓ< 6000, are due to the residual gain errors, (c) for the uGMRT baseline configuration and system parameters, the standard deviation is always higher than the bias in the power spectrum estimates. Based on our analysis we observe that for an angular multipole of ℓ∼3000, 2000 hours of `on source time' is required with the uGMRT to detect redshifted 21-cm signal at 3-σ significance from a redshift of 2.55. In this work we only consider the power spectrum measurement in the plane of the sky, an assessment of residual gain statistics and its effect on multifrequency angular power spectrum estimation for the uGMRT and the SKA like telescopes will be presented in a companion paper.

Correlation of residual feed intake, residual average daily gain, and residual intake and gain to carcass and steak characteristics of Hereford × Brahman steers

Correlation of residual feed intake, residual average daily gain, and residual intake and gain to carcass and steak characteristics of Hereford × Brahman steers

Hepatic mRNA expression of innate and adaptive immune genes in beef steers with divergent residual body weight gain

Immune function plays a pivotal role in dictating the overall health and productivity of cattle. In a proficient immune system, the liver assumes an integral function in detoxification and metabolic processes and contributes substantially to overall production and immunity. In this study, we evaluated the hepatic mRNA expression of genes involved in innate and adaptive immunity in crossbred beef steers with positive or negative residual body weight gain (RADG). Positive-RADG beef steers (n = 8; RADG = 0.73 kg/d) and negative-RADG beef steers (n = 8; RADG = -0.69 kg/d) were identified from a group of 108 growing crossbred beef steers (average BW = 556 ± 38 kg) after a 56-d performance testing period. At the end of the 56-d period, liver tissue samples were collected from the beef steers for RNA extraction and cDNA synthesis. The mRNA expression of 84 genes involved in innate and adaptive immunity were analyzed using pathway-focused PCR-based arrays. The mRNA expression of genes with false discovery rate-adjusted P-values (FDR) ≤ 0.05 and absolute fold change (FC) ≥ 1.2 were determined to be differentially expressed. Out of the 84 genes analyzed, four genes (IL-2, MYD88, CD-80, NFkB-1) were differentially expressed and were all upregulated in positive compared with negative-RADG beef steers. IL-2 is a cytokine that plays a critical role in the immune response by activating and proliferating T-cells, which are important for fighting infections. MYD88 is an adaptor protein that is essential for signaling by toll-like receptors, which are involved in pathogen recognition. CD80 is a protein that is expressed on the surface of antigen-presenting cells and plays a critical role in the initiation of an immune response. The activation of NF-κB leads to the production of cytokines and chemokines that help to recruit immune cells to the site of infection. The upregulation of the aforementioned genes in positive-RADG beef steers suggests that they had a better ability than negative-RADG beef steers to quickly recognize pathogens and initiate appropriate responses to effectively fight off infections without causing inflammatory reactions, potentially contributing to their better feed efficiency.

Performance, feed efficiency, feeding behavior, and cortisol concentration of lambs ranked for Residual Feed Intake and Residual Intake and Gain.

This study aimed to evaluate the performance, feed efficiency, feeding behavior, and cortisol concentrations of lambs ranked into different groups of Residual Feed Intake (RFI) and Residual Intake and Gain (RIG). Forty Santa Inês lambs with a mean initial age of 120 ± 30 days and mean initial (IBW) and final body weight (FBW) of 28.9 ± 3.2 and 43.7 ± 3.9 kg, respectively, were used. The animals were fed at an automatic feed and water station (Intergado®) for 60 days and classified at the end of the experiment as low-RFI/RIG, medium-RFI/RIG, and high-RFI/RIG according to RFI and RIG. Performance, feed efficiency measures, ingestive behavior, temperament, and cortisol concentrations were measured, and Pearson's correlation analysis was performed to evaluate the relationship between the variables studied. The variables that differed most between RFI groups were dry matter intake, feed conversion, and feed efficiency, with better values in efficient animals (RFI-). Regarding the RGI groups, the average daily gain of animals classified as RIG- was 19.37% lower than that of animals classified as RIG± and 39.28% lower than that of animals classified as RIG+. Only the hourly feeding rate per day (p = 0.04) differed significantly between RFI and RIG classes, while no differences were observed for the ingestive behavior variables or cortisol. The number of visits to the feed bunk (total, with or without intake) showed no correlation with any performance or efficiency measure. Identifying animals ranked into different RFI and RIG classes shows that more efficient animals have a lower feed intake for the same weight gain and spend less time at the feed bunk.

Incorporating body measurement traits to increase genetic gain of feed efficiency and carcass traits in Japanese Black steers.

The objective of the present study was to comprehensively evaluate whether body measurement traits, including body weight and body size, could be used as indicators of genetic selection for feed efficiency and carcass traits in Japanese Black steers. First, we estimated the genetic parameters for body measurements, feed efficiency, and carcass traits. Second, we estimated the correlated responses in feed efficiency and carcass traits when selection was applied to one or multiple-body measurement traits. In total, 4,578 Japanese Black steers with phenotypic values of residual feed intake (RFI) and residual body weight gain (RG) as feed efficiency traits and carcass weight (CWT) and beef marbling standard (BMS) as carcass traits were used. Eleven body measurement traits were measured at the start and finish of the fattening periods (BMT1 and BMT2, respectively), and their growth during the fattening period (BMT3) was used for genetic analyses. The results of genetic parameters showed that the heritability estimates were low to moderate (0.10 to 0.66), and the genetic correlations among body measurement traits were also estimated to be positively moderate to high in each measuring point (0.23 to 0.99). The genetic correlations of body measurement traits with RFI and BMS were estimated to be low (-0.14 to 0.30 and -0.17 to 0.35, respectively), but those with CWT were positively low to high (0.12 to 0.97). The genetic correlation estimates between BMT3 and RG were moderate to high (0.38 to 0.78). Second, correlated responses were estimated under positive selection for body measurement traits. Positive selection for BMT2 and BMT3 increased CWT and RG; however, positive selection for body measurement traits resulted in no change in RFI and BMS. Favorable directions of genetic gains, which were positive for RG, CWT, and BMS and negative for RFI, were obtained by selection indices, including multiple traits in BMT1. Our results suggest that using only one-body measurement trait as an indicator of genetic selection for RFI is difficult. However, body measurement traits can be indirect indicators of improved RG. Our results also suggest that genetic improvement of both RFI and RG without reducing CWT and BMS could be achieved using selection indices that account for a balance of body conformation using multiple-body measurement traits in Japanese Black cattle.

Genomic analysis of feed efficiency traits in beef cattle using random regression models.

Feed efficiency plays a major role in the overall profitability and sustainability of the beef cattle industry, as it is directly related to the reduction of the animal demand for input and methane emissions. Traditionally, the average daily feed intake and weight gain are used to calculate feed efficiency traits. However, feed efficiency traits can be analysed longitudinally using random regression models (RRMs), which allow fitting random genetic and environmental effects over time by considering the covariance pattern between the daily records. Therefore, the objectives of this study were to: (1) propose genomic evaluations for dry matter intake (DMI), body weight gain (BWG), residual feed intake (RFI) and residual weight gain (RWG) data collected during an 84-day feedlot test period via RRMs; (2) compare the goodness-of-fit of RRM using Legendre polynomials (LP) and B-spline functions; (3) evaluate the genetic parameters behaviour for feed efficiency traits and their implication for new selection strategies. The datasets were provided by the EMBRAPA-GENEPLUS beef cattle breeding program and included 2920 records for DMI, 2696 records for BWG and 4675 genotyped animals. Genetic parameters and genomic breeding values (GEBVs) were estimated by RRMs under ssGBLUP for Nellore cattle using orthogonal LPs and B-spline. Models were compared based on the deviance information criterion (DIC). The ranking of the average GEBV of each test week and the overall GEBV average were compared by the percentage of individuals in common and the Spearman correlation coefficient (top 1%, 5%, 10% and 100%). The highest goodness-of-fit was obtained with linear B-Spline function considering heterogeneous residual variance. The heritability estimates across the test period for DMI, BWG, RFI and RWG ranged from 0.06 to 0.21, 0.11 to 0.30, 0.03 to 0.26 and 0.07 to 0.27, respectively. DMI and RFI presented within-trait genetic correlations ranging from low to high magnitude across different performance test-day. In contrast, BWG and RWG presented negative genetic correlations between the first 3 weeks and the other days of performance tests. DMI and RFI presented a high-ranking similarity between the GEBV average of week eight and the overall GEBV average, with Spearman correlations and percentages of individuals selected in common ranging from 0.95 to 1.00 and 93 to 100, respectively. Week 11 presented the highest Spearman correlations (ranging from 0.94 to 0.98) and percentages of individuals selected in common (ranging from 85 to 94) of BWG and RWG with the average GEBV of the entire period of the test. In conclusion, the RRM using linear B-splines is a feasible alternative for the genomic evaluation of feed efficiency. Heritability estimates of DMI, RFI, BWG and RWG indicate enough additive genetic variance to achieve a moderate response to selection. A new selection strategy can be adopted by reducing the performance test to 56 days for DMI and RFI selection and 77 days for BWG and RWG selection.

PSVII-8 Genome-Wide Association Studies for Feed Efficiency and Growth Traits in American Mink

Abstract Feed efficiency (FE) traits contribute to the economic output of mink production systems as feed costs comprise the largest proportion of their variable expenses. However, the genetic architecture underlying FE-related traits is largely unknown in American mink. The objective of this study was to identify potential genetic variants and candidate genes associated with feed efficiency and growth traits, including body weight (BW), average daily gain (ADG), daily feed intake (DFI), feed conversion ratio (FCR), residual feed intake (RFI), residual gain (RG), residual intake and gain (RIG), and Kleiber ratio (KR). Genome-wide association studies (GWAS) were performed using deregressed estimated breeding values (DEBVs) of 1,255 to 2,160 individuals (as pseudophenotypes), genotyped with the Affymetrix Mink 70K single nucleotide polymorphisms (SNP) array. Association analyses were performed using the mixed linear model in GCTA software. A total of 36 SNPs located on 11 different chromosomes were significantly (FDR &amp;lt; 0.01) associated with eight feed efficiency and growth traits, among which nine SNPs had pleiotropic effects on at least two analyzed traits. The phenotypic variance (of DEBVs) explained by all significant SNPs for BW, ADG, DFI, FCR, RFI, RG, RIG, and KR, were 0.54%, 2.35%, 0.51%, 2.45%, 0.03%, 3.67%, 0.21%, and 2.60%, respectively. Furthermore, 191 genes were identified within 1-Mb windows around these significant SNPs. These regions included candidate genes such as FABP6, ADAMTS18, ADGRB3, GRM8, DSCAM, COL9A1, and CSRP2, previously associated with feed efficiency and growth traits in other livestock species. Gene ontology analyses revealed that these genes were involved in molecular functions such as ATPase activity and ATP binding, which provide the direct energy source for the body. To our knowledge, this is the first GWAS to identify genetic variants and biological mechanisms associated with FE and growth traits in American mink. These findings provide a biological foundation for improving these traits using genomic selection programs to select more efficient mink.

PSIII-10 Hepatic Mrna Expression of Genes Related to Innate and Adaptive Immune Genes in Beef Steers with Divergent Residual Body Weight Gain

Abstract Immune function plays an important role in overall animal health and productivity. In this study, we evaluated the hepatic mRNA expression of genes involved in innate and adaptive immunity in crossbred beef steers with positive or negative residual body weight gain (RADG). Positive-RADG beef steers (n = 8; RADG = 0.34 kg/d) and negative-RADG beef steers (n = 8; RADG = -0.27 kg/d) were selected from a group of 108 growing crossbred beef steers (average BW = 556 ± 38 kg) after a 42-d performance testing period. At the end of the 42-d period, liver biopsies were collected from the beef steers for RNA extraction and cDNA synthesis. The mRNA expression of 84 genes involved in innate and adaptive immunity were analyzed using pathway-focused PCR-based arrays. The mRNA expression of genes with false discovery rate-adjusted P-values (FDR) ≤ 0.05 were considered to be differentially expressed. Out of the 84 genes analyzed, four genes (IL-2, MYD88, CD-80, NFkB-1) were differentially expressed and were all upregulated in positive-RADG, compared with negative-RADG beef steers. IL-2 is a cytokine that plays a critical role in the immune response by activating and proliferating T-cells, which are important for fighting infections. MYD88 is an adaptor protein that is essential for signaling by toll-like receptors, which are involved in pathogen recognition. CD80 is a protein that is expressed on the surface of antigen-presenting cells and plays a critical role in the initiation of an immune response. The activation of NF-κB leads to the production of cytokines and chemokines that help to recruit immune cells to the site of infection. The upregulation of the aforementioned genes in positive-RADG beef steers suggests that they had a better ability than negative-RADG beef steers to quickly recognize pathogens and initiate appropriate responses to effectively fight off infections without causing inflammatory reactions. This is essential to optimize immune function and minimize the impact of immune activation on growth and production. As a result, more energy and nutrients are available to support improved growth rate and feed efficiency.

322 Metabolic Pathway and Rumen Bacterial Taxa Associated with Divergent Residual Body Weight Gain Phenotypes in Beef Cattle

Abstract We applied metabolomics and 16S rRNA gene sequencing to determine the metabolic pathway and ruminal bacterial taxa associated with divergent residual body weight (BW) gain phenotype in crossbred beef steers. A group of 108 crossbred growing beef steers (average BW = 282.87 ± 30 kg) were fed a forage-based diet for a period of 56 d in a confinement dry lot equipped with GrowSafe intake nodes to determine their residual body weight gain (RADG) phenotype. After RADG identification, blood and rumen fluid samples were collected from beef steers with the greatest RADG (most efficient; n = 20; 0.76 kg/d) and least RADG (least efficient; n = 20; -0.65 kg/d). Metabolome analysis of the plasma and rumen fluid samples was conducted using chemical isotope labelling/liquid chromatography–mass spectrometry. Differentially abundant metabolites in each of the plasma and rumen fluid samples between the two groups of beef steers were determined using a false discovery rate (FDR)-adjusted P-values ≤ 0.05 and area under the curve (AUC) &amp;gt; 0.80. Rumen and plasma metabolic pathways that were differentially enriched or depleted (P ≤ 0.05) in beef steers with positive RADG compared with those with negative RADG were determined by the quantitative pathway enrichment analysis. A total of 1,629 metabolites were detected and identified in the plasma of the beef steers; eight metabolites including alanyl-phenylalanine, 8-hydroxyguanosine, and slaframine were differentially abundant (FDR ≤ 0.05; AUC &amp;gt; 0.80) in beef steers with divergent RADG; five metabolic pathways including steroid hormone biosynthesis, thiamine metabolism, propanoate metabolism, pentose phosphate pathway, and butanoate metabolism were enriched (P ≤ 0.05) in beef steers with positive RADG, relative to negative RADG steers. A total of 1908 metabolites were detected and identified in the rumen of the beef steers; results of the pathway enrichment analysis of all the metabolites revealed no metabolic pathways in the rumen were altered (P ≥ 0.05). The rumen fluid samples were also analyzed using 16S rRNA gene sequencing to assess the bacterial community composition. We compared the rumen bacterial community composition at the genus level using a linear discriminant analysis effect size (LEfSe) to identify the differentially abundant taxa between the two groups of beef steers. The LEfSe results showed greater relative abundance of Bacteroidetes_vadinHA17 and Anaerovibrio in steers with positive RADG compared with the negative RADG group, while steers in the negative RADG group had greater relative abundance of Candidatus_Amoebophilus, Clostridium_sensu_stricto_1, Pseudomonas, Empedobacter, Enterobacter, and Klebsiella compared with the positive RADG group. Our results demonstrate that beef steers with positive or negative RADG exhibit differences in plasma metabolic profiles and some ruminal bacterial taxa which probably explain their divergent feed efficiency phenotypes.

PSI-25 Associations Between Feeding Behavior, Residual Feed Intake, and Residual Average Daily Gain in Performance Tested Yearling Angus Bulls and Heifers

Abstract The objective of this study was to evaluate relationships among feeding behaviors, off-test residual feed intake (RFI), and residual average daily gain (RADG) EPD for performance tested cattle. Eighty-seven angus bulls and thirty-two angus heifers (n = 119) were fed a high forage diet consisting mainly of ground hay and corn silage for 57 days using the Vytelle feed system. The variables evaluated were time spent visiting the bunk, time with head down, number of visits, RFI, average DMI, DMI, RADG, ADG, and quadrant location of RFI and ADG. RFI and ADG are plotted for each individual animal, which places that individual into one of four quadrants (1 = Favorable RFI/ Below average ADG, 2 = Favorable RFI/ Above average ADG, 3 = Unfavorable RFI/ Below average ADG, 4 = Unfavorable RFI/ Above average ADG). The data were analyzed by gender, using non-parametric Spearman’s Rho in JMP to determine variable relationships. A very strong positive correlation was observed in yearling bulls for the time spent with head down and the length of time spent at the bunk (0.8331, P &amp;lt; 0.0001). Also, a moderate correlation for the animals individual RFI and total number of visits (0.4924, P &amp;lt; 0.0001). A very strong negative correlation was observed for yearling bulls in the average amount consumed and the total number of visits to the bunk (-0.8380, P &amp;lt; 0.0001). Also, a weak negative correlation was observed in the animals individual RADG and RFI (-0.2777, P &amp;lt; 0.0001). Similarly, a strong positive correlation in yearling heifers was observed in head down and length of time spent at the bunk (0.9457, P &amp;lt; 0.0001). A strong negative correlation was observed in yearling heifers for the total number of visits and the average amount of feed consumed per each visit (-0.5293, P &amp;lt; 0.0018). Also, a moderate negative correlation in each animals individual RADG and RFI (-0.4822, 0.0052*). While a moderate positive correlation of individual animal RFI and the total number of visits was observed for the yearling bulls, the yearling heifers showed no significant correlation between the two. Our studies show that feeding behavior on a high forage diet is similar to that of behaviors shown on a high concentrate diet by others. Although there was a significant, but weak relationship between RFI and RADG, the strength of the relationship is such that one cannot be used predict the other and they are measuring different components of the animal’s efficiency.

Direction-of-arrival estimation for a nested array with gain-phase error and impulse noise

To solve direction-finding problems for nested arrays under conditions of impulse noise and gain–phase errors, this paper proposes a direction-of-arrival (DOA) estimation method. First, a correntropy with an adaptive kernel length combined with an infinite norm of a variable weight value is proposed to suppress impulse noise. Then, the auxiliary array elements are used to realize the initial calibration of the amplitude and phase errors. On this basis, a DOA estimation method without a spectral peak search is proposed; this method is robust for arrays that still have residual gain–phase errors after calibration. Our method overcomes the difficulties of DOA estimation for nested arrays under conditions of gain–phase errors and impulse noise. Compared with traditional methods, the proposed method does not require prior knowledge, does not require a spectral peak search and has high superiority and robustness; a series of experiments have verified its superiority. In addition, a Cramér‒Rao bound (CRB) for angle estimation under conditions of gain–phase errors and impulse noise is proposed in this paper.

The environmental performance of plastic packaging waste management in Germany: Current and future key factors

AbstractPlastic is a popular packaging material, but also criticized as a symbol for the make‐use‐dispose economy because of its short lifespan, its dependency on fossil fuels, and its potential contribution to marine litter. To identify current and potential future key factors for the environmental performance of plastic packaging waste (PPW) management in Germany, a life cycle assessment considering five different pathways of PPW (including deposit‐refund systems, separately collected lightweight packaging waste, and treatment of non‐source‐separated residual waste) was performed. The analysis related to the year 2017 and also considered prospective changes in the background system until 2050 by adapting inventories to shared socioeconomic pathways in line with the Paris Agreement. Key factors for the environmental performance were determined by perturbation analysis. Source separation, quality and quantity of recycled plastics, and emissions from the thermal utilization of residues were identified as key factors for the environmental performance of PPW management. While benefits of PPW management are expected to decrease due to prospective system changes, source separation and the separation of plastics from residual waste gain in importance. Potential measures for improving the environmental performance should focus on long‐term key factors, especially separating PPW from the residual waste (in households or in waste treatment facilities) as well as increasing the quantities and qualities of recycled plastics. The present study showed that the evaluation of system performance in view of changing boundary conditions is key to identify optimal configurations of future PPW management.