Life Sciences Commons^™

Mid-Gestation Maternofetal Inflammation Impacts Growth, Skeletal Muscle Glucose Metabolism, And Inflammatory Tone In The Ovine Fetus During Late Gestation, Zena Hicks

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

Our 1^st and 2^nd studies assessed the impact of mid-gestation maternofetal inflammation on growth, skeletal muscle glucose metabolism, and inflammatory tone in the late gestation ovine fetus. The objective was to determine if inducing maternofetal inflammation during peak placental growth would lead to more profound IUGR characteristics in the fetus. MI-IUGR fetuses exhibited reduced body and skeletal muscle weights and hallmark asymmetric growth at late gestations. Fetuses had higher baseline glucose:insulin ratios and reduced glucose-stimulated insulin secretion. Moreover, hindlimb glucose oxidation was impaired independent of glucose uptake. Skeletal muscle specific glucose uptake and oxidation was reduced in MI-IUGR …

Variation In The Genome And Transcriptome Associated With Beef Cattle Production And Investigation Of The Metabolic Consequences Of Beta-Adrenergic Agonist Supplementation, Renae L. Sieck

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

Beta-adrenergic agonists (β-AA) are widely used supplements in livestock production to improve feed efficiency and increase lean muscle mass. Heat stress is one of the largest economic burdens to the livestock industry due to production efficiency losses and morbidity and mortality of animals. Both β-AA and catecholamines released in response to heat stress bind to β-adrenoceptors on the skeletal muscle cell surface to activate downstream signaling pathways. The purpose of this study was to determine if β-AA supplementation and heat stress have an additive effect on the skeletal muscle transcriptome. 3’ RNA sequencing of samples of the longissimus dorsiwas …

Beef Production Systems In The Nebraska Sandhills, Mckay Erickson

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

Four studies were conducted to determine the effectiveness of improving production systems of beef cattle in the Sandhills region of Nebraska. These studies were to determine impacts of modified estrus synchronization protocols, genomic testing heifer calves for longevity, and evaluation of 2 differing calving systems (March or May) for improving biological outcome and improved production. Experiment 1 utilized 180 yearling heifers to determine the effectiveness of a second dose of prostaglandin F_2α(PGF) with those females not expressing estrus after an initial 14 d MGA-PG estrus synchronization protocol. The treatment of PGF did increase estrus expression, but did not …

Genome-Wide Association Study For The Relationship Between Temperature And Feed Intake In Beef Cattle, Robel Ghebrewold

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

The interaction of livestock with the environment they live in is complex and plays a significant role in their production performance, which also depends on location and management practices. Climate change is projected to increase temperature globally. As a result, climate change will most likely aggravate the pressure from different sources of stressors on the current agricultural production system in general and in livestock specifically. Environmental conditions, such as changes in ambient temperature, can cause changes in animal behavior and performance. In general, it is believed that as ambient temperature increases, dry matter intake (DMI) of beef cattle decreases. However, …

Genetic Parameter Estimates And Breed Effects For Calving Difficulty And Birth Weight In A Multi-Breed Population, Cashley Ahlberg

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

There are multiple breeds of beef cattle available to utilize in breeding systems to maximize production and economics. Calving difficulty (dystocia) is a significant cost to beef production and is more prevalent in first-calf heifers. The objectives of this study were to estimate genetic parameters and breed differences for calving difficulty and birth weight as a first step towards the development of across-breed adjustment factors for calving difficulty.

Two models were employed to analyze birth weight (BWT) and calving difficulty (CD) recorded on 4,579 first parity females from the Germplasm Evaluation program at the U.S. Meat Animal Research Center (USMARC). …

Lifecycle Efficiency Of Mice Divergently Selected For Heat Loss, Adrienne Bhatnagar

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

Divergent selection for heat loss as an indication of maintenance energy requirements in mice resulted in a low (ML) and high maintenance line (MH), and an intermediate control line (MC). Improved feed efficiency has been observed in ML mice, which would be economically beneficial in livestock species. However, previous work showed evidence of unfavorable correlated responses to selection in ML mice compared to MH mice. Therefore, the objective of this study was to model a lifecycle similar to a livestock production system using these lines and determine if these correlated responses diminish the benefit of improved feed efficiency by calculating …

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 …