Theses and Dissertations at Montana State University (MSU)
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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 Economic determinants of the variation in average carcass weight for United States slaughter cattle(Montana State University - Bozeman, College of Agriculture, 2016) Vogstad, Amanda Rae; Chairperson, Graduate Committee: Randal R. RuckerOver the past century, average carcass weights of slaughter cattle have demonstrated a substantial upward trend, as well as year-to-year volatility. Since the mid-1970s however, increasing average carcass weights have coincided with high levels of beef production but with diminishing beef cow herds. Increased beef production with fewer cow numbers is likely explained by technological advancements throughout the beef industry. Annual variability in average carcass weight, on the other hand, is hypothesized to arise because of the dynamics of fed cattle production arising from changes in input and output prices. To identify the economic factors responsible for the variation in average carcass weight theoretical and empirical models are developed. Based on the theoretical model, cattle feeders choose the levels of corn and labor that yield optimal carcass weights by equating each factor's value marginal product to the marginal cost. Theoretical predictions are then tested using 85 years of aggregate annual data in a distributed lag model. Overall, we find coefficient estimates on the input and output prices consistent in sign with our theoretical predictions. Of importance is the finding that the manufacturing wage accounts for an estimated 61 percent of the total input and output price induced variation in average carcass weight. A trend for technological change in the beef industry accounts for a yearly increase in average carcass weight of 3.6 pounds.Item Genetic evaluation of carcass traits in Simmental cattle(Montana State University - Bozeman, College of Agriculture, 1999) Shanks, Bruce CameronItem 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 A study of the relationship between growth traits and carcass characteristics in beef cattle(Montana State University - Bozeman, College of Agriculture, 1968) Henderson, Richard ArchieItem The economic value of carcass traits, and their differences across bull sales(Montana State University - Bozeman, College of Agriculture, 2007) Vanek, Joseph Keith; Chairperson, Graduate Committee: Myles Watts.Higher quality beef can only be distinguished from lower quality beef in the final stages of production when animals are slaughter. Because of quality measurement issues it is difficult to determine and value higher quality animals at the individual levels of beef production. Cow-calf producers are the primary supply of cattle into the beef marketing chain. The genetics introduced at this level follow through to the slaughter stage. Cow-calf producers use expected progeny differences (EPDs) provided at seed stock bull sales to make selective breeding decisions. The introduction of carcass EPDs has technologically advanced a cow-calf producer's ability to select bulls based on carcass quality traits. A cow-calf producer will increase profits by reacting to market conditions and selectively choosing breeding livestock.