Meat Science Commons^™

The Detection Of Morbidity Using A Remote Sensing Ear Tag On Newly Received Steers And Feedlot Performance And The Effects Of Feeding Experior And Optaflexx On Carcass Characteristics And Meat Tenderness In Beef Steers, Lauryn O. Smidt

Department of Animal Science: Dissertations, Theses, and Student Research

Two experiments were conducted to evaluate the effects of remote sensing health technology and growth-promoting feed additives on feedlot cattle performance, health outcomes, and carcass characteristics. In the first study, 638 crossbred steers (initial BW = 270 kg; SD = 18.6 kg) were used in a randomized block design to assess the effectiveness of a remote sensing ear tag (RST; HerdDogg, Seward, Nebraska) versus conventional pen-rider observation (PR) for detecting morbidity during a 35-d receiving period and subsequent 180-d finishing period. No differences were detected between PR and TAG for ending BW, average daily gain (ADG), dry matter intake (DMI), …

Carcass Mass And Cooling Dynamics As Determinants Of Beef Color, Tenderness, And Dark-Cutting Risk, Grace C. Johnson

Department of Animal Science: Dissertations, Theses, and Student Research

Discoloration in beef has important implications to the beef industry. Dark-cutting (DC) beef remains one of the most economically significant color defects; however, industry prevalence has only marginally declined (≈ 0.1%) despite mitigation efforts. This lack of improvement largely stems from research focused on pre-harvest stress and glycogen depletion leading to dark, firm, and dry (DFD) beef. However, not all darkcutting beef originates from DFD phenotypes. Atypical dark-cutting (ATDC) phenotypes have recently been observed and do not exhibit the classic metabolic indicators of DFD. This trend coincides with steadily increasing carcass weights in the beef industry and raises the possibility …

Lipid Deposition In Beef Cattle, Kyra L. Elliott

Department of Animal Science: Dissertations, Theses, and Student Research

Both the amount and types of lipid deposition in beef cattle are key determinants of carcass value and meat quality. Amounts of intramuscular, subcutaneous, and visceral fat influence carcass grading outcomes, palatability, and composition traits that are important to beef producers as well as consumers. The objectives of this thesis were to: 1) compare beef grading camera estimates of intramuscular fat to amounts of chemically extractable lipid, 2) characterize the lipidomes of beef intramuscular fat, subcutaneous fat, and lean muscle using shotgun lipidomics, and 3) identify and characterize a novel genetic variant in cattle that may have important implications for …

Integrating Growth Performance And Pathogen Detection To Investigate Disease Resilience In Commercial Swine, Emmalise Hope Marie Meyer

Department of Animal Science: Dissertations, Theses, and Student Research

Disease resilience is an important trait in commercial swine production, influencing both animal health and growth performance under natural disease challenge. The primary objective of this study was to integrate growth performance data with longitudinal pathogen detection to better understand factors contributing to disease resilience in commercial pigs. A population of 1,014 pigs across four batches was monitored from weaning through the grow-finish phase, with body weights collected to calculate average daily gain (ADG). Genome-wide association analyses were conducted using BayesC and BayesIM approaches to identify genomic regions associated with growth performance. Longitudinal pathogen surveillance was performed using pen-level oral …

Application Of High-Pressure Processing To Improve The Color Of Dark Beef, Kara Ann Reynolds

Department of Animal Science: Dissertations, Theses, and Student Research

Deviation of beef from the bright cherry-red color preferred by consumers is often discounted or discarded at retail, resulting in substantial annual economic loss to the beef industry. One such deviation is dark cutting beef, which is characterized by a darker lean appearance that is undesirable to consumers and often rejected. Similarly, beef from mature cattle tends to exhibit a darker surface color, which can also reduce consumer acceptability. High-Pressure processing (HPP) has been investigated as a strategy to improve the color of dark cutting beef. Previous studies have focused on identifying pressure levels and holding times that optimize color …

Using High-Pressure Processing To Improve The Quality Of Dark-Cutting Beef, Ashley A. Hahn

Department of Animal Science: Dissertations, Theses, and Student Research

Previous studies have shown high-pressure processing (HPP) can be utilized to improve lean color of dark-cutting beef color by increasing the lightness and redness of steaks. However, the optimal parameters of length of time product is held under pressure and at which pressure must be applied have yet to be fully defined. Furthermore, the impact of HPP on color labile muscles in dark-cutting beef are currently unknown. Therefore, two studies were designed and specific efforts were focused on first defining optimal parameters for color stable muscles, followed by determining the effect of HPP on dark-cutting color labile muscles.

In the …

The Invisible Meat Microcosmos: Investigations Of Processed Meats' Specific Spoilage Organisms, Rebecca Furbeck

Department of Animal Science: Dissertations, Theses, and Student Research

As humankind grows in population, so will our need to compete against bacterial populations which spoil foodstuffs before we are able to consume them. This dissertation aims to identify the bacterial communities responsible for meat spoilage, and the mechanisms that govern the behaviors of these organisms. The literature review summarizes the state of knowledge regarding factors that influence meat microbiome composition, and how analytical methods can influence research outcomes. Study 1 aimed to identify the impact of additional ingredients and processing steps on the microbial ecology of processed turkey products. The main specific spoilage organisms (SSOs) belonged to the orders …

The Impact Of Oxidative Stress On Postmortem Meat Quality, Nicolas J. Herrera

Department of Animal Science: Dissertations, Theses, and Student Research

Tenderness is the primary factor to influence consumer palatability in fresh meat. The tenderization of muscle is dependent on proteolytic mechanisms, including calcium dependent, non-lysosomal endogenous enzymes such as calpains and proteasomes. These mechanisms have been indicated alongside apoptosis early postmortem as cascades of apoptotic events promote ideal conditions for postmortem tenderization. Recent literature has identified oxidative stress-mediated events to be linked to apoptotic activity. Oxidative stress is defined as the overwhelming production of reactive species compared to homeostatic, endogenous antioxidants present within muscle systems. These conditions exhaust antioxidant function and facilitate reactive species to alter protein, lipid, or nucleic …

Evaluation Of Microbial Community Dynamics Impacting The Shelf-Life Of Processed Meats, Chad G. Bower

Department of Animal Science: Dissertations, Theses, and Student Research

The objective of this study in its entirety was to utilize high next-generation genetic sequencing to evaluate the microbial communities involved with processed meat spoilage. High throughput 16S rRNA gene sequencing on the Illumina MiSeq© platform was used alongside traditional plating methods to characterize the growth and composition of bacterial communities in processed meats. Previous results from this lab indicated a relatively high prevalence of Pseudomonas in cooked, sliced, and vacuum packaged deli meats, which was contrary to conventional wisdom. Therefore, four studies were designed to further evaluate the factors that may influence microbial communities in processed meats. Study 1 …

Evaluation Of Growth Promoting Implant Strategies And Days On Feed On Finishing Heifer Performance And Evaluation Of Optimal Reimplant Times For Finishing Heifers And Steers, Caitlin A. Ohnoutka

Department of Animal Science: Dissertations, Theses, and Student Research

Two experiments evaluated the effects of delayed, long-acting coated implants or uncoated implants to non-implanted heifers fed for constant or varying days on feed. In Exp. 1, heifers were implanted with either Revalor-XH on d 1, Revalor-200 on d 1, Revalor-XR on d 1, or Revalor-200 on d 70 compared to non-implanted control heifers when fed for an average of 198 d. In Exp. 2, heifers were implanted with Revalor-200 on d 1 and reimplanted with Revalor-200 on d 100, Revalor-XH on d 1, or not implanted and fed for different days on feed: 151, 165, 179, or 193. Implanting …

Identifying Breed Effects For Cow Mature Weight, Madeline J. Zimmermann

Department of Animal Science: Dissertations, Theses, and Student Research

Mature weight (MWT) in beef cattle has increased over the past 30 yr. In general, larger cows are costlier to maintain than smaller cows, and their profitability depends on their production environment. A wide range of beef production environments exist in the United States. There are also a variety of beef cattle breeds that can be chosen and mated to create a type of cow which will be optimally suited to excel in a given environment. However, there remains a need for tools allowing effective comparison among breeds to facilitate such decision making. Unfortunately, estimated progeny differences ( …

Evaluation Of Alpha Amylase Containing Corn On Finishing Cattle Performance And Digestibility, Melissa L. Jolly-Breithaupt

Department of Animal Science: Dissertations, Theses, and Student Research

One digestion and four finishing trials were conducted to evaluate the effect of a new corn hybrid containing an α-amylase trait, Syngenta Enogen Feed Corn (SYT-EFC) on site and extent of digestion, ruminal fermentation parameters, and feedlot performance. Experiments utilized corn containing the enzymatic gene compared to controls, the near isoline parental corn (NEG) or commercially available corn grain (CON), processed as dry-rolled corn (DRC) or high moisture corn (HMC) in diets with dry [distillers grains plus solubles (DGS)] or wet (Sweet Bran) milling byproducts. The corn grain of the experimental diets were fed as the sole grain source, comprising …

The Effects Of Feed Additives In Beef Finishing Systems And The Effect Of Rumen Degradable Protein Supplementation In Corn Residue Grazing Systems With The Use Of Distillers On Growth Performance, Robert M. Jones

Department of Animal Science: Dissertations, Theses, and Student Research

One receiving trial evaluated the effect of the feed additive monensin (trade name: Rumensin) on steer growth performance in the receiving period while evaluating the effects of two receiving vaccinations on morbidity and mortality of newly received calves. No differences were observed in growth performance, morbidity rate or mortality rate between treatments for the first 28 d of receiving. A finishing trial evaluated the effect of the feed additive ractopamine hydrochloride (trade name: Optaflexx) on feedlot growth performance and carcass characteristics of crossbred yearling steers fed to differing degrees of finish. Feeding ractopamine hydrochloride at 300 mg improved ADG, G:F, …

Antimicrobial Interventions Applied To Beef Sub-Primals For The Control Of Escherichia Coli And Their Impact On Ground Beef Quality, Kelly Ann Mccarty

Department of Animal Science: Dissertations, Theses, and Student Research

Due to their severe health implications, seven shiga toxin-producing E. coli (STEC) serotypes were declared adulterants by USDA-FSIS in raw, non-intact beef products. Small business beef processing facilities are being asked to implement an intervention on the beef sub-primals and trim they receive for ground beef production. This study evaluates the efficacy of reducing rifampicin-resistant E. coli (E. coli^Rif) using 4.5% lactic acid (LA), 2.5% Beefxide™ (BX), and 380 ppm peroxyacetic acid (PAA) when applied by dip, spray or electrostatic spray (ESS) to the mostly fat lateral surface and mostly lean medial surface of beef shoulder …

Effects Of Feeding Field Peas On Fresh Beef Quality, Hope Voegele

Department of Animal Science: Dissertations, Theses, and Student Research

The objective of this study was to evaluate the use of field peas during two phases of production (grazing and finishing) on fresh beef quality. A total of 232 crossbred steers and heifers were randomly assigned to one of six dietary treatments in a 3x2 factorial consisting of 3 pasture and 2 finishing supplementations. The pasture phase consisted of 1) no supplement, 2) field peas at 0.5% BW, or 3) dry-rolled corn supplement at 0.5% of BW. The finishing phase consisted of 1) field peas at 20% DM or 2) no field peas. During this two-year study, steers (year 1) …

The Influence Of Diet And Oxidation On Calcium Retention Of The Mitochondria In Fresh Beef, Emery K. Wilkerson

Department of Animal Science: Dissertations, Theses, and Student Research

Distillers grains (DG) contribute to cattle sarcoplasmic reticulum (SR) membrane instability by increasing poly-unsaturated fatty acid (PUFA) content in the SR membrane, possibly resulting in early postmortem calcium (Ca) leakage and improved tenderness. Mitochondria are relatively easy to isolate intact and provide the opportunity to study Ca in an SR model. The objective of this research was to determine the influence of diet and oxidation on Ca release from mitochondria. Cattle (n = 48) were fed a corn-based finishing diet with or without deoiled, dried DG (50% DM basis). Steaks from each strip loin were aged for 2, 8, …

Evaluation Of Hematological And Serum Biochemical Profiles Associated With The Supplementation Of Zilpaterol Hydrochloride To Feedlot Heifers, Sara Elizabeth Sieren

Department of Animal Science: Dissertations, Theses, and Student Research

Supplementation of zilpaterol hydrochloride (ZH; Zilmax^®) to cattle has been suggested to have a negative impact on well-being of cattle. The objective of this study was to evaluate the hematological and serum biochemical profiles in feedlot heifers supplemented with ZH in a minimal stress environment. Heifers were randomly assigned to one of two treatment groups: Control (CON no ZH), or ZH (supplemented with ZH at 8.33mg/kg of feed on a DM basis). The study was conducted over a period of 25 d (-2 to 23), with three serum collection periods [-2 to 4 d (ZH supplementation began on …

Evaluation Of The Metabolic Response, Blood Chemistry Profile, And Cardiac Morphology Of Beef Heifers Supplemented With Zilpaterol Hydrochloride Followed By An Endocrine Induced Stress Challenge, Joe O. Buntyn

Department of Animal Science: Dissertations, Theses, and Student Research

The objective of this study was to determine the metabolic, stress, hematology, organ weights, histology and cardiac anatomical features of beef heifers supplemented with zilpaterol hydrochloride (ZH) when exposed to a corticotropin-releasing hormone (CRH) and arginine vasopressin (VP) challenge. Crossbred heifers (n = 20; 556 ± 7 kg BW) were randomized into two treatment groups: 1) Control (CON): no ZH, and 2) Zilpaterol (ZIL): supplemented with ZH at 8.33 mg / kg (DM basis). The ZIL group was supplemented ZH for 20 d, with a 3-d withdrawal period. On d 24, heifers received an intravenous bolus of CRH (0.3 µg …

Effects Of Salt And Nitrite Concentration On The Shelf Life Of Deli-Style Ham, Regan Elise Stanley

Department of Animal Science: Dissertations, Theses, and Student Research

Deli-style hams were manufactured to measure the effects of salt and nitrite concentration on shelf life and physicochemical characteristics. Three replications of deli-style ham treatments were manufactured in a 3 x 4 factorial arrangement of salt concentration (0.7%, 1.4%, or 2.1%, meat block basis) and nitrite concentration and source (0 ppm, 100 ppm or 200 ppm sodium nitrite, SN, or 100 ppm sodium nitrite equivalent from pre-converted celery juice powder, CP; Veg Stable 506, Florida Food Products). Salt concentration, water activity, cook yield, and texture profile analysis (TPA) were measured on w 0. Color, pH, residual nitrite, and aerobic and …

Development Of Terminal And Maternal Economic Selection Indices In Beefmaster Cattle, Kathleen Pearl Ochsner

Department of Animal Science: Dissertations, Theses, and Student Research

In the design of economic selection indices, the relative importance of traits in the breeding objective is reflected by their relative economic weighting. The objective of this study was to develop two economic selection indices for Beefmaster cattle: one for a terminal production system and one for a maternal production system. The terminal index was developed assuming bulls are mated to mature cows with all resulting progeny harvested. The maternal index was developed assuming bulls are mated to a combination of heifers and mature cows, with resulting progeny retained as replacements or sold at weaning.

National average prices from 2010 …

Impact Of Finishing Diets With De-Oiled Distillers Grains Or Antioxidant Containing Supplement On Beef Shelf Life, Katherine I. Domenech-Pérez

Department of Animal Science: Dissertations, Theses, and Student Research

In its entirety this dissertation intended to address the impact of feeding several forms of de-oiled corn distillers grains plus solubles and the effect of supplementing OmniGen-AF as a potential antioxidant source for extending beef shelf life. In study one we learned that despite the de-oiling process, greater inclusion levels (65%, DM basis) of de-oiled wet distillers grains plus solubles (WDGS) causes an increase in polyunsaturated fatty acids (PUFA) similar to the levels obtained with full-fat WDGS. Lower inclusion levels (35 and 50%, DM basis) of de-oiled WDGS have intermediate PUFA content in comparison to 65% de-oiled WDGS, full-fat WDGS …

The Effect Of Salt Reduction On The Microbial Composition And Quality Characteristics Of Sliced Roast Beef And Turkey, Chad Gary Bower

Department of Animal Science: Dissertations, Theses, and Student Research

This study analyzed the effects of salt reduction on microbiological composition and quality characteristics of deli-style turkey breast and roast beef. Turkey breast and roast beef were manufactured with four different salt concentrations: 1.0%, 1.5%, 2.0%, and 2.5% on a meat block basis in addition to sugar, phosphate, and water. Samples were cooked, chilled overnight, sliced, and packaged. On the day of slicing, samples were evaluated for water activity, cooking yield, proximate composition and percent salt. Samples were evaluated throughout 18w of refrigerated storage for pH, texture profile analysis, aerobic plate count (APC), and anaerobic plate count. Bacterial communities were …

Genetic Parameters For Docility, Weaning Weight, Yearling Weight And Intramuscular Fat Percentage In Hereford Cattle, José A. Torres-Vazquez

Department of Animal Science: Dissertations, Theses, and Student Research

Temperament in cattle can be described as the reactivity or fear response to human handling, and it is important to beef cattle producers not only from a human safety but also due to potential correlations with other economically traits. Before a docility selection metric can be added to a genetic evaluation, any potential antagonisms with economically relevant traits should be quantified. The objective was to estimate genetic parameters, including genetic correlations, for chute score (CS), weaning weight (WW), yearling weight (YW), and intramuscular fat percentage (IMF) in Hereford cattle. Single-trait and bivariate animal models were used to estimate heritabilities and …

Beef Systems Management Strategies: Calving Date Selection, Estrus Synchronization, And Post-Weaning Management, Benjamin T. Tibbitts

Department of Animal Science: Dissertations, Theses, and Student Research

The objective of an invited review and four experiments was to evaluate production implications and economic efficiencies of beef systems strategies involving calving date selection, utilization of reproductive technology, and post-weaning management of heifers and steers. The invited review in chapter II considers factors that influence a producer’s decision on when to calve beef females. The calving date decision impacts the entire beef production cycle and must take into account any environmental conditions, available resources, and cite specific advantages and/or disadvantages. Understanding the importance of varying physiological state and nutrient demands associated with lactation and gestation is critical to optimizing …

Production And Economic Efficiencies Of Intensified Cow–Calf Production Management Systems, Jason M. Warner

Department of Animal Science: Dissertations, Theses, and Student Research

The objective of four experiments conducted was to evaluate production and economic efficiencies of intensified cow-calf production management systems. The first experiment tested the effect of calf age at weaning on cow and calf performance and feed utilization at 2 locations. Body weight change from early to conventional weaning time was greater for early-weaned cows. Cow BCS and conception rates were not impacted by weaning. Calf BW at conventional weaning time was greater for conventionally-weaned calves than early-weaned calves at ARDC, but greater for early-weaned than conventionally-weaned calves at PHREC. Calf ADG per unit of total feed energy intake was …

Performance, Body Temperature And Blood Metabolites Of Feedlot Steers As Influenced By Environmental Conditions And Supplementation Of Zilpaterol Hydrochloride, Bradley M. Boyd

Department of Animal Science: Dissertations, Theses, and Student Research

Trial one was conducted at the United States Meat Animal Research Center (MARC) near clay center, NE during the summer of 2014. The objective of this trial was to measure the effects of supplementing zilpaterol hydrochloride (ZH) for the final 21 days of the finishing period, and shade, on performance, body temperature, respiration rate, and mobility of finishing beef steers. Feeding ZH increased hot carcass weight, dressing percent, longissimus muscle area, and reduce USDA yield grade. Shade did not affect steer performance and did not reduce body temperature. Zilpaterol hydrochloride increased respiration rate when compared to control cattle and had …

Genomic Analysis Of Sow Reproductive Traits: Identification Of Selective Sweeps, Major Genes, And Genotype By Diet Interactions, Melanie D. Trenhaile

Department of Animal Science: Dissertations, Theses, and Student Research

Reproductive traits, such as litter size and reproductive longevity, are economically important. However, selection for these traits is difficult due to low heritability, polygenic nature, sex-limited expression, and expression late in life. Marker-assisted selection may provide an alternative to increase genetic progress.

Nebraska Index Line (NIL) has been selected for litter size related traits since 1981. It is one of the main contributing lines to the UNL reproductive longevity resource population (n > 1,500), which was genotyped for 60,000 SNPs, phenotyped for age at puberty (AP), lifetime number of parities (LTNP), litter size traits, and other reproductive traits, and fed …

Dietary Strategies For Mitigation Of Methane Production By Growing And Finishing Cattle, Anna C. Pesta

Department of Animal Science: Dissertations, Theses, and Student Research

Interest in reducing methane (CH₄) emissions by cattle has increased recently. Loss of feed energy as CH₄ represents both an environmental concern and an energetic loss to the animal. Manipulation of dietary composition has proven to be an effective mitigation strategy. Experiments were conducted to evaluate the effect of several dietary characteristics on CH₄ production in growing and finishing cattle, and to develop a novel, non-invasive method for quantifying emissions from animals in a production setting. Short-term gaseous emissions of CH₄ and carbon dioxide (CO₂) were measured and the CH₄:CO_{2 …}

Effects Of Feeding Distillers Grains Throughout Different Phases Of Production On Shelf Life Of Ground Beef, Brandy D. Cleveland

Department of Animal Science: Dissertations, Theses, and Student Research

These studies analyzed the effects of feeding distillers grains on the shelf life of cooked and raw ground beef, and how the addition of postmortem or dietary antioxidants impact shelf life.

For study one, cattle were assigned to backgrounding diets containing low or high concentrations of wet distillers grains (WDGS) and either corn gluten feed or modified wet distillers grains (MDGS) during finishing. For study two, cattle were fed one of five finishing diets; corn, wet distillers grains (WDGS), WDGS + vitamin E, WDGS + Ethoxyquin/TBHQ, or WDGS + vitamin E + Ethoxyquin/TBHQ.

Shoulder clods from each dietary treatment were …

Corn Plant Maturity Effect On Yield And Nutritional Quality: Corn Silage Inoculation On Performance Of Cattle Fed Silage With Or Without Live Yeast Added, Cassandra A. Row

Department of Animal Science: Dissertations, Theses, and Student Research

Corn plots were serially harvested over two years to evaluate nutrient, digestibility, and yield change as plants matured from half-milk line through black layer. In yr 1 (2013), two corn plots were used, one short season (102 d), and one normal season (111 d). Year two used two Pioneer hybrids (111 d; 112 d). Silage yield and silage DM increased quadratically as maturity increased (P ≤ 0.01). Percent NDF increased quadratically (P = 0.01), and NDF-digestibility decreased linearly (P < 0.01) as maturity increased. This study suggests there is a delicate balance between plant maturity, nutrient content, and silage yield. A finishing study using 320 yearling steers (initial BW = 417 ± 22.7 kg) evaluated the effect of using a silage inoculant or not on performance and carcass characteristics. Treatments were designed as a 2×2×2 factorial arrangement with factors being no inoculant (CON) or use of inoculant (Buchnerii spp.; B500) at silage harvest, silage fed at 15 or 40% of diet DM, and presence (LEV) or absence (noLEV) of Levucell SC yeast product fed at 14.2 g/hd/d. Performance data were analyzed with pen as the experimental unit, with 5 pens/treatment. There was a three-way interaction for final live BW, HCW, ADG, and G:F (P < 0.05). Feeding corn silage at 40% inclusion instead of 15% inclusion increased DMI and decreased G:F. At 15% silage inclusion, the B500 LEV treatment had the lowest ADG. At 40% silage inclusion all treatments were similar for ADG (P ≥ 0.06). When including silage at 15%, using B500 inoculant, the addition of LEV did not …