Performing Department
(N/A)
Non Technical Summary
As a high quality, high demand end-product, United States beef serves a critical role in the sustainability of the growing population. The producers of this beef at all levels, from the cow-calf sectors to the feedlots to the packers, continually look to improve product and efficiency in their operations while also ensuring the sustainability of their operations. Selection opportunities to improve feed efficiency and product quality are evolving, and we propose the inclusion of animal behavior and temperament in this goal. We theorize that activity levels are potentially the result of an animal's level of stress and will influence feed efficiency and meat quality. We propose to evaluate the complex relationships between activity, feed efficiency, stress, immune function, and meat quality among beef steers to obtain preliminary data to support our hypotheses with the following objectives:Determine whether accelerometer activity data is correlated with feed efficiency, flight speed, and meat quality traits.Determine whether there are health, stress, molecular profile or methane emission differences between animals with high and low steps and mounting behavior.In objective 1, we will obtain total steps taken, and the mounting behavior of each animal using 3-axis accelerometers from 701x (Fargo, ND, USA) over a 147-day feed efficiency study and determine whether there are relationships with flight speed, feed efficiency, and meat quality. In objective 2, we propose to examine the relationships between total steps and mounting behavior with hematology, cytokine, metabolomic, metagenome, methane emissions, and gene expression data.This research will provide a more accurate and objective measure of beef steer activity/temperament, and will identify potential contributors to temperament (i.e., stress, immune responses). The research proposed here is important because it will provide definitive links to beef production outcomes based on an improved measure of an animal's behavior or temperament. Through these novel methods, the cellular and metabolic effects of animal behavior and temperament, and the links to feed efficiency, health, and meat quality may become clear. This project will enable future work to develop application-based tests that producers can utilize for selection to improve efficiency and meat quality in their herd.
Animal Health Component
15%
Research Effort Categories
Basic
60%
Applied
15%
Developmental
25%
Goals / Objectives
Our long-term goal is to improve feed efficiency in beef steers through novel discovery of associations between temperament and efficiency. Temperament has historically been evaluated using single-time point methods that can be confounded by numerous variables. The proposed work includes novel techniques for describing temperament that include continuous monitoring of animal activity and mounting behavior. The project objectives are; 1) Determine whether accelerometer activity data as a measure of temperament is correlated with feed efficiency, flight speed, stress, and meat quality traits and begin to collect data for a future GWAS and 2) Determine whether there are health, stress, molecular profile, or methane emission differences between animals with high or low steps and mounting behavior.
Project Methods
Objective 1:Crossbred weaned steers (N = 100) from the University of Wyoming (UW) Beef Herd will be transitioned to the Laramie Research and Extension Center (LREC) multipurpose feedlot for 147 day feed efficiency trial utilizing the Vytelle SENSE™ system. Steers will be fitted with 701x xTPro tags to continuously monitor activity (steps, mounting behavior, heart rate) and will be weighed every 2 weeks for the duration. Feed efficiency metrics will be calculated from weight and intake data including feed conversion ratio (FRC), residual feed intake (RFI), and average daily gain (ADG). To complement the novel metrics of behavior via the 701x tags, traditional metric of flight speed will be measured at initiation, mid-point, and end of the feed efficiency period utilizing exit velocity from the chute/scale.At the end of the feeding period cattle will be transported to a commercial harvesting facility and will undergo antemortem inspection by the U.S. Department of Agriculture Food Safety Inspection Service. Overall quality grade and official marbling score of each carcass will be determined by USDA-AMS graders. Personnel from UW will record hot carcass weight, fat thickness, ribeye area, percent kidney-pelvic-heart fat, lean and skeletal maturity, and final yield grade. Additionally, longissimus color will be determined via the Hunter Lab Miniscan at the 12th rib interface. A longissimus dorsi sample from the anterior end of the striploin portion will be collected from both sides of each carcass, aged for 14 days, steaks will be cute (2.5 cm thick) and frozen for evaluation of descriptive trained sensory analysis, tenderness evaluation, and chemical analyses.Data collected in objective 1 including feed intake, body weight gain, feed efficiency, flight speed, and meat quality will be evaluated for correlations with total steps and mounting behavior phenotypes obtained from the 701x ear tags using the CORR procedure of SAS.Objective 2:Blood samples will be collected from all animals at the beginning of the study, mid-study, and end of the study for hematology analysis and plasma and in Tempus tubes for RNA. At the end of the study a hair sample will be collected for cortisol, an indicator of long-term stress. While these samples will be collected on all animals and stored, for the purposes of this project, subsampling will be performed for subsequent analyses. Fourty steers will be sub-selected based on steps and mounting behavior where 10 of the highest and lowest of both categories and will be harvested at the University of Wyoming Meat Laboratory instead of transport to a commercial harvesting facility. At harvest, longissimus dorsi muscle and amygdala brain tissue samples will be collected. Meat quality phenotypes will mimic those described in Objective 1.Hematology assay will include a 5-part complete blood count on all 100 samples using the Heska HT5 instrument. To determine whether there are correlations between hematology parameters and activity, data will be analyzed with a repeated measure, mixed model with a correlation structure that is allowed to change between time points. The model will include total steps or number of mounts as a fixed effect, animal as a repeated effect, and a random residual term.Hair and plasma from the animals described above for the sub-selection (n = 40) will be analyzed for cortisol and cytokine and acute phase protein, respectively. Hair from the hip will be clipped as close to the skin as possible using a surgical clipper blade. Hair will be washed and dried several times with methanol, pulverized into a powder using a freezer mill and 50mg will be used for cortisol ELISA assay (Arbor Assays, Ann Arbor, MI). Plasma will be used to evaluate 15 cytokines and chemokines with the bovine Milliplex multiplex assay (Millipore Sigma,Burlington, MA, USA). We will also evaluate acute phase proteins alpha-1 acid glycoprotein, haptoglobin, and C-reactive protein with ELISA assays. All samples will be run in triplicate. Data analysis will include total steps or number of mounts as a fixed effect, animal as a repeated effect, and a random residual term.Longissimus dorsi muscle tissue will be collected from animals with high (N=10) and low (N=10) step count only at slaughter. A single cell suspension will be generated from freshly collected muscle tissue using dispase II and collagenase enzymes. Cells will be counted and assessed for viability, slowly frozen in recovery media, and stored in a liquid nitrogen tank until they can be processed for library preparation using 10X Genomics technology. For library preparation, cells will be counted and loaded onto a 10X Chromium Controller (10X Genomics, Pleasanton, CA, USA) at the Integrated Microscopy Core at UW to generate single cell gel emulsions. Libraries will be generated from 8,000 cells per animal using the 3' library and gel bead kit (10X Genomics) and sequenced using an Illumina NextSeq 2000 in the Integrated Microscopy Core at UW. The data will be processed using Seurat packages in R-Studio to obtain cell clusters. Differentially expressed genes will be identified in each cluster and between high and low groups. Data will be reported using FDR adjusted P-values.RNA-seq on amygdala tissue (n=40) and whole blood collected in Tempus tubes (n=40) from animals with high and low step counts and high and low mounting behavior will be performed. Total RNA will be isolated from the amygdala using the Rneasy Plus kits from Qiagen. Total RNA from whole blood will be isolated using the Tempus RNA isolation spin kit (Thermo). Absorbance ratios of A260/280 ≥1.8 and RNA integrity numbers ≥8 will be required for samples used for RNA-seq libraries. Libraries will be generated with the Illumina Total RNA Stranded Library preparation kit and sequenced on a NextSeq 2000 to a depth of 60-80 million reads per library. Transcripts will be aligned to the ARS-UCD1.2 bovine genome assembly and read counts will be generated. Groups with total steps and mounting behavior will be analyzed separately for differentially expressed genes, each using the high and low classification in the model. Data will be reported using FDR adjusted P-values.One milliliter of plasma from steers (n=40) at the end of the feed test with high and low steps and mounting behavior will be shipped on dry ice to Metabolon (Morrisville, SC) for their Global Metabolomics assays using LC-MS.Metabolon will curate and perform bioinformatic analysis on the data and provide us with metabolites that differ between animals with high and low step counts, along with data visualization figures and tables.To evaluate whether animals with variation in activity or aggressive behavior differ in the amount of methane production, we propose utilization of the GreenFeed system (C-Lock Inc.) with a subset of steers (N=10/treatment, n=40) who will be isolated in a separate pen with 2 GreenFeed systems. The GreenFeed systems will be set up to deliver 25 grams of feed every 30 seconds up to eight times during one visit and a total of 5 visits per day are allowed with 2 hour intervals between visits. When the animals obtain the pellets, the system measures gas fluxes of Methane (CH4) and Carbon Dioxide (CO2) from individual animals.Rumen fluid from steers with high and low steps and high and low mounting behavior (n=40) will be collected via oral lavage, flash frozen, and stored at -80 ºC. Genomic DNA will be isolated and then further purified using the QIAmp PowerSoil Minikit (Qiagen). A Qubit4, and Agilent 5300 Fragment analyzer will be utilized to determine quality and quantity with DNA integrity numbers reported. Libraries will be generated with the Rapid Barcoding 96 kit (Oxford Nanopore Technologies, UK) and will be sequenced on a PromethION instrument (Oxford Nanopore). Data will be analyzed with EPI2ME developed by Metrichor Ltd for Oxford Nanopore.