Animal Sciences Commons^™

Selection Objective For Improving Efficiency Of Beef Cattle, Jose A. Barron Lopez

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

Simulation studies based on 1000 cows were used to evaluate biological and economic efficiency of level of milk production and two production systems, and to estimate economic values for a breeding objective and selection indexes for beef cattle. Published data were used as information for this study. Average 10-yr prices, reproduction, survival, growth, carcass characteristics, and genetic parameters from journal papers were used in the simulations. In the first study, low (L), medium (M), and high (H) milk production cows, and calf-fed and yearling systems, were analyzed. Biological and economic efficiencies were estimated for weaning and slaughter endpoints. In the …

Beef Cattle Production: Understanding The Effect Of Heifer Development System, Late Gestation Protein Supplementation, And Ovarian Steroidogenic Environment On Productivity, Reproduction, And Longevity, Adam Summers

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

Beef cattle longevity is related to reproductive success, which can be influenced by development system and maternal environment. Three experiments were conducted to determine the impact of development system, maternal protein supplementation, and ovarian steroidogenic environment on beef cattle reproduction. Experiment 1 evaluated the effect of heifer development system on heifer performance and reproduction. Heifers developed on corn residue (CR) had reduced BW from prebreeding through pregnancy diagnosis compared with drylot (DL) developed heifers, but there was no difference in reproductive performance. A subset DL and CR heifers were placed in an individual feeding system to …

The Impact Of Genetic Background On Body Temperature Regulation In Beef Cattle During Periods Of Heat And Cold Stress, Jeremy T. Howard

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

Cattle are reared in environments that differ and vary greatly in climate, thus the ability to regulate body temperature across multiple environments is essential. However, inherent differences between animals do exist and can influence their response to extreme temperatures. The objectives of the current study were to model the impact of myostatin genotype (MG) on body temperature during heat and cold stress and conduct a genome-wide association study (GWAS) to better understand the genetic basis of body temperature regulation during extreme temperatures.

Crossbred steers and heifers (n= 239) with varying degrees of Piedmontese influence were fed in four groups over …

Spoilage Of Wet Distillers' Grains Plus Solubles When Stored In A Bunker, Jana L. Harding

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

Five studies evaluated the impact of spoilage of wet distillers grains plus solubles (WDGS) on nutrient composition, nutrient losses, and cattle performance. Exp. 1 and Exp. 2 utilized barrels to evaluate the ability of various cover treatments to prevent nutrient changes and losses due to spoilage. In Exp. 3, a 140-d barrel study was conducted to mimic bunker storage under ambient temperature but with no precipitation. Barrels were weighed and sampled on 28 day intervals. In Exp. 4, a 130-d finishing study utilized 60 individually-fed steers fed 3 treatments: a dry-rolled corn based diet (control) and 2 diets containing 40% …

The Effects Of Social And Environmental Enrichments On Leg Strength And Welfare Of Tom Turkeys, Patricia A. Weber

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

Two trials (T1, T2) were conducted to determine the effects of enrichment: A) broiler chick addition on early mortality and B) providing environmental enrichments on leg strength and welfare of tom turkeys. Trial 1A utilized 248 1d poults and 8 3d broiler chicks. Four pens of 32 poults were placed for the control. Four pens of 30 poults and two 3d broiler chicks were placed for the trt group. Trial 2A utilized 296 1d poults and 24 3d broiler chicks. Four trts were randomly divided among 16 pens (20 birds/pen). Trt 1 brooders were placed with assistance finding resources. Trt …

Intestinal Flow Of Microbial Protein And Rumen Undegradable Protein In Cattle Fed Corn Distillers’ Grains And Solubles, With Emphasis During Lactation, Ezequias Castillo Lopez

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

Metabolizable protein (MP) is the true protein absorbed by the intestine, supplied by rumen undegradable protein (RUP) and microbial crude protein (MCP). This research was focused on evaluating the effect of dried distillers grains with solubles (DDGS) on the nature and supply of MP, with emphasis during lactation.

Experiment 1 evaluated the use of DNA markers and the effects of fermentation time and DDGS on rumen microbial growth

in vitro. Treatments were 1) CONTROL, 0% DDGS; 2) 20% DDGS replacing corn; 3) 20% DDGS replacing soybean meal and 4) 20% DDGS replacing corn and soybean meal. Results indicate that …

The Effect Of Dam Parity On Progeny Growth Performance, Passive Immunity, And Gastrointestinal Microbiota, Erin E. Hinkle

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

Previous research has shown that parity (P) 4 progeny have greater weaning weights and decreased microbial diversity compared to P1 progeny. Three experiments were conducted to evaluate litter performance, passive immunity, and fecal microbiota among P1 and P3 dams and their progeny. In experiment 1, 56 P1 and 49 P3 dams and their progeny’s litter and growth performance, immunoglobulin (IgG and IgA) concentrations, and gut microbiota were evaluated. In experiment 2, 48 pigs per P were selected to determine growth performance, immunoglobulin (IgG and IgA) concentrations, and gut microbiota. In experiment 3, 8 dams per P were selected. At birth, …

Utilization Of Corn Condensed Distillers’ Solubles And Forages In Management Systems For The Cow-Calf Enterprise, Jason M. Warner

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

Of the annual expenses necessary to maintain a beef cow, feed and forage are the greatest and most variable. Thus, nutrition programs for cow-calf operations must be developed using economical feedstuffs that optimize cowherd performance. The corn dry-milling industry provides several feedstuffs that are often the most economical sources of energy and protein, but considerations for storage and handling are necessary. Two experiments evaluated an alternative form of storing corn condensed distillers solubles (CCDS) by applying to grass hay windrows before baling. Round bales were treated with either 0 or 20% (Exp. 1); or 0, 16, and 32% (Exp. 2) …

Alternative Fabrication Methods For The Beef Carcass, Justine J. Hosch

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

To fabricate heavier beef carcasses alternative fabrication methods for the chuck and round were evaluated. Carcasses (364 to 386 kg) were selected for forequarter (n=32) and hindquarter (n=30) evaluation. Forequarter breaks at the third/fourth and fifth/sixth rib, with the rib beginning at the sixth/seventh rib, were processed into whole muscles. Bone, lean trim, fat, and muscles were weighed and Longissimus dorsi (LD) steaks were subject to Warner-Bratzler Shear Force (WBS). Both subprimals had over 60% lean yield and no differences among WBS results (P=0.49, 0.39, respectively). To evaluate effects of modifying the chuck/rib break short rib …

Hepatic Mitochondrial Efficiency In Lines Of Mice Differing In Feed Intake, Thomas Murphy

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

Selection was practiced for high (MH) and low (ML) heat loss using direct calorimetry to create lines of mice differing in feed intake per unit BW (FI/BW). Selection occurred for both criteria in each of 3 replications (R); an unselected control (MC) was also maintained in each replicate. A total of 25 generations of selection was practiced; the 9 lines are presently maintained without selection. As a percentage of MC, mice of MH and ML lines differed in heat loss and FI/BW by 56 and 34%, respectively, when selection ceased. The 218 male mice measured in the present study came …

Mechanism And Control Of Beef Toughening During Retail Display In High Oxygen Modified Atmosphere Packages, Lasika S. Senaratne

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

This research was conducted to elucidate the mechanism and factors (diet, aging time, antioxidant level, and retail display time) affecting beef toughening in retail display under high oxygen atmosphere packages (HiOx-MAP; 80% O₂ and 20% CO₂). In the first study, effects of HiOx-MAP on color and lipid stability of beef m. longissimus lumborum steaks from yearlings fed corn or 30% wet distillers grains plus soluble (WDGS) diets supplemented with (150 mg/kg) or without (0 mg/kg) AGRADO-PLUS (AG) antioxidants were studied. Steak color-shelf life was extended (P < 0.0001) by HiOx-MAP compared to oxygen permeable film packages (PVC-OW). Steaks from corn+AG-supplemented cattle had (P ≤ 0.05) less discoloration and lower lipid oxidation levels …

Genomic Analysis Of Characteristics In Swine Contributing To Sow Longevity, Julie Kathleen Tart

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

Selection for improved sow lifetime reproductive longevity is of growing importance to swine producers due to recent increases in sow culling rates. Traditional selection results in minimal response due to low heritability and late expression of the trait; incorporation of DNA markers into selection programs could be a more economically viable tool and improve lifetime reproductive performance.

In order to assess the relationship between markers and reproductive longevity, 967 gilts from two maternal crossbred lines were evaluated for age at puberty (AP), litter size traits, and number of successful parities (SP). Females were culled only for death, unsoundness, or reproductive …

Treatment With Or Elimination Of Vascular Endothelial Growth Factor A (Vegfa) Results In Altered Mrna Abundance Of Undifferentiated Spermatogonia Niche, Renewal And Differentiation Factors, Kevin M. Sargent

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

Vascular Endothelial Growth Factor A (VEGFA) and its receptors are important for vascular development in the testis. Roles of VEGFA have been proposed in undifferentiated spermatogonia where proangiogenic isoforms are suggested to promote their self-renewal while antiangiogenic isoforms stimulate their differentiation. Thus, we treated male rats in vivo (perinatally with IP injections from P0-P2) with different VEGFA isoforms or an antibody to VEGFAxxxb (antiangiogenic isoforms) to determine if this would affect testis morphogenesis, expression of genes regulating the spermatgonial stem cell (SSC) niche and genes that regulate cell survival. Testis morphogenesis with VEGFA164 (1mg) isoform treatment increased cord area, reduced …

Nutrient Mass Balance And Performance Of Feedlot Cattle Fed Barley Based Diets In Large Pens In Western Canada, Erin M. Hussey

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

Three separate large pen commercial feeding trials with approximately 9,000 heifers with either eight or ten reps/treatment were conducted at a Western Feedlots Ltd.- High River, a commercial feedyard near High River, AB, Canada. For all three experiments, Near Infrared Spectroscopy (NIRS) was used to segregate feed barley. In Exp. 1, barley was segregated based on digestible energy (DE) content as predicted by NIRS and heifers were fed low or high DE barley, or a 50:50 blend of the two. Feeding low DE barley improved weight gain, dry matter intake (DMI), and mortality; with little effect on carcass composition compared …

Utilization Of Corn Residue, Winter Range, Or Dry Lot In Beef Heifer Development Systems, Stetson P. Weber

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

Post-weaning heifer development systems that maximize reproductive efficiency and reduce input costs associated with feed is beneficial for cow/calf producers. Two research experiments were conducted to evaluate the effect of post-weaning development systems in beef heifers. In Exp. 1 heifers were developed on corn residue (CR), or dry lot (DL). Heifers developed in DL had increased BW after winter treatment until breeding. Both heifer groups were similar in percent of heifers cycling, AI conception, AI pregnancy, and final pregnancy diagnosis. A subset of AI pregnant heifers were blocked by weight and stratified by winter development system and individually fed using …

Effects Of Feeding Insect-Protected Corn And Corn Residue To Cattle, And Evaluation Of Distillers’ Grains Storage When Mixed With Crop Residue On Cattle Performance, Barry Weber

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

Research has been conducted on genetically modified corn fed to livestock since the introduction of insect resistant hybrids. While the overwhelming conclusion of these trials demonstrate nutritional equivalency to corn from non-transgenic hybrids, the introduction of new transgenes and combinations of resistance traits necessitates continued evaluation of genetically modified corn hybrids. Expansion of the ethanol industry has resulted in the increased availability of co-products for use as a livestock feed, as well as an increase in crop residues that offer unique opportunities for use by cattle producers. A finishing trial was conducted with corn and corn silage from MON 89034, …

Supplementing Distillers' Grains In Extensive Beef Cattle Systems, Kelsey Rolfe

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

A 3-yr study evaluated effects of supplementing modified wet distillers grains with solubles during summer grazing and subsequent feedlot sorting on long yearling steers. During summer grazing, supplemented steers had greater ADG and were more profitable than non-supplemented steers. At feedlot entry, supplemented steers were 48 kg heavier than non-supplemented steers. Feed efficiency and DMI were not different between supplementation treatments during finishing. Supplemented steers were fed 24 fewer days to reach a similar 12^th rib fat thickness, had greater LM area, and lower marbling compared to non-supplemented steers. Overall profitability favored supplementing steers because less expensive summer gains …

Nutrient Management In Beef Feedlots And Forage Replacement With Byproduct And Crop Residues, Annie J. Doerr

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

Finishing cattle performance and mass balance was evaluated with Micro-Aid was fed in diets containing wet distillers grains plus solubles (WDGS) at 35% (DM basis). Micro-Aid is a feed ingredient derived from a Yucca extract which contains saponins, and was included in the treatment diet at 1 g/hd daily in the supplement. There was no difference in performance and carcass characteristics between treatments. In the winter experiment, cattle fed Micro-Aid had a greater amount of OM and DM removed from the pen surface. Micro-Aid in the diet increased the amount of manure N and decreased N lossis in the winter. …

Evaluation Of Condensed Distillers’ Solubles And Field Peas For Feedlot Cattle, Anna C. Pesta

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

Limited previous research has investigated feeding high levels of condensed distillers solubles (CDS) as an energy source for feedlot cattle. As an energy dense and relatively inexpensive by-product feed from ethanol production, CDS may provide another opportunity to replace high priced corn in finishing diets. Two feedlot studies and one metabolism study were conducted to evaluate the effects of feeding CDS in both corn-based diets, and in combination with other by-product feeds on cattle performance and carcass characteristics. Inclusion of up to 36% CDS, providing 9.4% dietary fat improved performance relative to a corn-based control, with the optimum level of …

Study Of The Innovative Self-Powered Sensor Based Smart Wireless Identification And Tracking Tag For Production Agriculture Application, Kumud Dhakal

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

A prototype smart animal ear tag has been developed to meet the United States Department of Agriculture (USDA) animal disease traceability requirement. This novel ‘Smart Tag’ is a self–powered device capable of complete animal identification and tracking. Information on animal health, breeding and vaccination records can also be locally stored and retrieved from these small, economical and securely accessible wireless tags. These smart tags are capable of self-organizing into wireless ad-hoc networks for data reporting and retrieval. This work presents study of the distance coverage of a ‘Smart Tag’ and a cost-benefit analysis of ‘Smart Tag’ implementation. The mean distance …

Feeding Low-Fat Wet Distillers' Grains And Beef Quality, Asia Haack

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

Feeding distillers grains to cattle decreases shelf life stability of retail displayed steaks due to the increased polyunsaturated fatty acid (PUFAs) content. High levels of PUFAs cause rapid oxidation of the fats in meat. To improve shelf life, a low-fat distillers grain ration, without solubles (LFWDG; 4.72% fat), was compared to a traditional diet containing wet distillers grains plus solubles (TWDGS; 6.91% fat) and a corn-based control diet (Corn; 3.64% fat). Strip loins (M. longissimus lumborum) from 45 USDA Choice steers (15 per dietary treatment) were selected to determine the effects of diet on fatty acid profile, fat composition, oxidation, …

The Effects Of Freezing And Thawing Rates On Tenderness And Sensory Quality Of Beef Subprimals, Jerilyn Hergenreder

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

To evaluate processing methods for frozen beef subprimals, the effects of freezing and thawing rates on tenderness and sensory properties were evaluated. There were six treatments: fresh-never-frozen 14-day wet aged, fresh-never-frozen 21-day wet aged, blast frozen–fast thawed, blast frozen–slow thawed, conventionally frozen–fast thawed, and conventionally frozen–slow thawed (all frozen subprimals were aged for 14d prior to freezing). Three subprimal cuts - ribeye rolls (n = 90), strip loins (n = 90), and sirloins (n = 90) - were utilized with three replications of five samples per treatment per week (total of 9 weeks, N = 270). Blast freezing occurred by …

The Effect Of Calving Season And Wintering System On Cow And Calf Performance And Economics From Conception Through Finishing And The Effect Of Supplementing Dried Distillers Grains To Calves In Forage Based Systems, William Griffin

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

Three experiments were conducted to determine the effect of calving season and cow wintering systems on cow and calf performance and economics from conception to slaughter, the effect of supplementing steers dried distillers grains while grazing cool season dominated meadow, and a meta-analysis was conducted to determine the effect supplementing dried distillers grains to cattle in forage based growing systems.  In the first experiment, cows were bred to calve in spring, summer or fall.  Calves from each system were managed as calf-feds or yearlings and followed through finishing.  Altering calving season impacted cow BW and BCS but did not affect …

Effects Of Early Feed Restriction During Delayed Placement On The Performance And Gut Health Of Broilers, Rashed Abdullah Alhotan

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

Newly hatched chicks may experience long periods of fasting prior to placement in commercial hatcheries.  Three trials were conducted to investigate the effects of early feed restriction and various supplements on the performance and gut health of broiler chicks brooded either in battery cages or floor pens.  The trials lasted for 14, 21, and, 22 days respectively.  In trial 1, chicks were subjected to 3 periods of fasting after hatch (36, 24, or 12 h).  A short period of fasting (12 h) was associated with a lower feed:gain ratio compared to the longer periods (36 and 24 h).  In trial …

Regulation Of Immediate Early And Epithelial–Mesenchymal Transition Genes Expression By Adipocytokines In The Female Reproductive Tract, Zhufeng Yang

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

Individuals who are overweight or obese are at increased risk for cancer.  However, the mechanistic link between obesity and cancer is poorly defined.  Adipose tissue produces hormones and pro-inflammatory cytokines with mitogenic properties.  Many of these hormones and cytokines are altered in obese individuals and may lead to disruption of the normal balance between cell proliferation, differentiation, and apoptosis. Thus, the objective of this study was to determine how adipocyte-derived factors regulate the expression of genes that contribute to cell proliferation and migration.  To compare immediate early gene (cell proliferation) and epithelial-mesenchymal transition (cell migration) gene expression between untreated and …

Analysis Of Long-Term Selection (28 Generations) For Reproduction, Growth, And Carcass Traits In Swine, Wan-Ling Hsu

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

The objectives were 1) to estimate responses from 28 generations of selection for increased pigs born alive (BA) with additional selection for increased 180 d weight (WT) and longissimus muscle area (LMA) and decreased backfat (BF) in the last eight generations, 2) to estimate genetic parameters for an array of traits, and 3) to investigate whether a plateau in response for BA has occurred. All lines were derived from the same Large White/Landrace composite population. Index selection for ovulation rate and embryo survival (G0-11) was initiated in L2 in 1981; L1 was selected randomly control line for L2 (G0-23). L2 …

Effects Of Feeding High Levels Of Wet Distillers Grains And Straw On Beef Quality, Siroj Pokharel

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

This research was conducted to investigate the effects of feeding high levels of wet distillers grains plus solubles (WDGS) with straw on fatty acids profiles, lipid stability, retail color, and proximate composition (fats and moisture) of aged beef. Cattle (n = 336; 270 ± 9 kg) were fed corn/5% straw; 40 Distillers grain (WDGS)/5% straw; 70 WDGS/8% straw; 70 WDGS/25% straw; 77.5 WDGS/9% straw; 77.5 WDGS/17% straw, and 85 WDGS/10% straw on dry matter (DM) basis. There were significant increases in the proportions of polyunsaturated fatty acids (PUFA), omega 6, omega 3, and trans fatty acids when high levels …

Variation In Response To Both Natural And Experimental Infection With Porcine Circovirus 2b, Theresa P. Bohnert

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

In animals, disease progression can be influenced by genetics, environment, management practices, and the type of pathogen. Infection with porcine circovirus 2 (PCV2) causes development of diseases known as porcine circovirus 2-associated diseases (PCVAD), for which there is currently no treatment. In Trial 1, weanling unvaccinated barrows and gilts (n = 229) from two genetic lines were bled at d14, 49, and at necropsy to assess disease progression from natural infection using antibodies (ELISA) and viral copy counts (quantitative PCR). Virus was isolated from infected pigs and sequenced to determine the strain responsible for infection. At d49, 113 animals …

Animal Performance And Diet Quality While Grazing Corn Residue, Jennifer A. Gigax

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

Grazing cattle on corn residue as a winter feed source has become an integral part of many Nebraska producers’ management plans. Utilizing corn residues extends the grazing season and is often more economical than grazing winter range or dry lot situations. Corn residue is high in OM and NDF, moderate in digestibility, and low in CP. Cattle grazing corn residues may need to be supplemented with a protein source to meet requirements. The development and application of DNA technology to create new corn hybrids has improved yields with fewer inputs, leading to a continued low cost food supply for consumers. …

Dried Distillers' Grain With Solubles In Laying Hen And Pullet Rations, Mahmoud K. Masa'deh

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

The objective of this dissertation was to test different inclusion rates of dried distillers grains with solubles (DDGS) with or without enzyme supplementation.  Study one was conducted to test DDGS at 0, 5, 10, 15, 20, or 25% on egg production parameter (24 through76 wk). As DDGS increased, egg wt. decreased during Phase I.  However; no difference in egg wt. was observed during Phase II.  Yolk color linearly increased with increasing DDGS level.  Nitrogen and P retention increased as DDGS increased.  Nitrogen and P excretion decreased with increasing DDGS.  Study two was conducted to test DDGS inclusion of 0, 2.5, …