Theses and Dissertations at Montana State University (MSU)
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Item A comparative approach to refine molecular mechanisms impacting meat quality and carcass characteristics(Montana State University - Bozeman, College of Agriculture, 2021) Schumacher, Madison Lee; Chairperson, Graduate Committee: Jennifer Thomson and Jane A. Boles (co-chair)Fat deposition is important to both producers and consumers. Producers decide when to harvest animals based on a fat endpoint while consumers equate marbling to tenderness. USDA quality grade is determined by physiological age and marbling. While quality grades help provide insight about product palatability, there is too often variation within the same quality grade. The control of fat deposition is important to determination of carcass endpoint and efficiency of production. The purpose of this study was to increase our understanding of the regulation of fat deposition and muscle growth in relation to USDA quality grade, and to utilize a species comparison to highlight genes and pathways regulating these tissues in multiple meat producing species. Fifteen wethers and fifteen steers from the Red Bluff Research Center were fed to end points that represented Standard, Select, and Choice quality grades endpoints for steers while sheep were fed to fat thicknesses typical to industry endpoints. Subcutaneous adipose tissue and muscle samples were collected for gene expression analysis. Loin were removed from each animal for shear force analysis. Shear force analysis showed a significant reduction in shear force values as quality increased in beef (p < 0.05). RNA extracted from the adipose and muscle tissue was sent to Novogene for RNAseq analysis. The largest difference observed in this study was found within the ovine muscle tissue. Comparing Class 3 to Class 1 muscle tissue resulted in 723 genes down regulated and 1,853 genes up regulated. Class 3 to Class 2 showed 1,127 genes down regulated and 2,272 genes up regulated. When comparing bovine samples, there was an equal distribution of up and down regulated genes. Differentially expressed genes were associated with fat metabolism, cellular signaling, and inflammation in beef. Poor annotation limited the functional analysis of differentially expressed genes in sheep. This study emphasized the need for additional studies evaluating the relationship between gene expression and fat deposition.Item Evaluation of molecular mechanisms impacting beef quality and carcass characteristics(Montana State University - Bozeman, College of Agriculture, 2018) Blatter, Sarah Anne; Chairperson, Graduate Committee: Jennifer ThomsonTenderness has been stated as being one of the most important traits for consumers with regards to purchasing steak. However, too often there is much variation in tenderness in steaks that grade the same quality. Research in the past has done little to expand on the impact that genetics has on meat tenderness. This study was designed to attempt to illuminate this question by looking at the genes being differentially expressed between quality grades, and the pathways they impact. Angus crossbred steers (15) were fed to the end points of Standard, Select and Choice. Intermuscular and subcutaneous adipose tissue and muscle samples were snap frozen for gene expression analysis, as well as a loin kept from each animal for shear force analysis. Shear force analysis showed a significant difference between Choice and Standard graded animals (P<0.05), showing that the Choice animals in this study were more tender than Standard. RNA extracted from the adipose and muscle samples were sent to Novogene for RNAseq analysis. The results of the gene expression analysis showed 4 genes down regulated and 29 up regulated in the comparison of Select to Standard adipose tissue, with 8 genes down regulated and 15 up regulated with Select to Choice adipose tissue. The largest difference occurred between Standard to Choice adipose tissue with 49 genes down regulated and 113 up regulated. With regards to the muscle, 15 genes were down regulated while 20 were up regulated in the Standard to Choice. In the Select to Choice, 1 gene was down regulated with 4 up regulated. When comparing Select to Standard, there was not a large enough difference in genes being expressed. This study emphasized the need for additional functional studies on the impacts of gene expression on marbling deposition.Item The Evaluation of paternal half-sib heritabilities and genetic, environmental and phenotypic correlation estimates for randomly selected Hereford cattle(Montana State University - Bozeman, College of Agriculture, 1990) Veseth, Dale AllenItem Factors affecting survival of range sheep in the U.S. and characterization of sheep in Indonesia(Montana State University - Bozeman, College of Agriculture, 1984) SubandriyoItem Direct and correlated responses to selection for reproductive rate in Rambouillet sheep(Montana State University - Bozeman, College of Agriculture, 1988) Schoenian, Susan GailItem Time trends, sex and age of dam correction factors, and genetic parameters for production traits in Angus and Hereford cattle(Montana State University - Bozeman, College of Agriculture, 1976) Nelsen, Terry C.Item Sire by region interaction for production traits in beef cattle(Montana State University - Bozeman, College of Agriculture, 1974) Nunn, Thomas RobertItem Estimation of maternal effects on birth and weaning weight of Hereford cattle(Montana State University - Bozeman, College of Agriculture, 1984) Cantet, Rodolfo Juan CarlosItem A comprehensive analysis of pelvic measurements in beef cattle(Montana State University - Bozeman, College of Agriculture, 1991) Cook, Barry RogerItem Major aspects of Appaloosa horse coat color genetics(Montana State University - Bozeman, College of Agriculture, 1974) Montgomery, Sandra Sowerwine