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A Quantitative And Molecular Evaluation Of Bovine Respiratory Disease, Growth Traits, And Carcass Traits In Crossbred Steers, Samantha Lidia Miller
A Quantitative And Molecular Evaluation Of Bovine Respiratory Disease, Growth Traits, And Carcass Traits In Crossbred Steers, Samantha Lidia Miller
LSU Master's Theses
The first objective of the two studies presented herein evaluated on farm sources of variation and correlated effects contributing to BRD incidence in a population of crossbred steers sent to the feedlot from 2010-2013. Analyses revealed that incidence of BRD was lowly positively correlated to birth weight (BW) and lowly negatively correlated to weaning weight (WW), hip height (HH), sire breed, site, and birth year. These results indicate that the traits analyzed herein are not precursors for BRD in the current population. However, since little is still known about the correlation between genetic predisposition to BRD and animal performance, further …
A Genomic And Quantitative Evaluation Of Modern Charolais Sired Calves Versus Multigenerational Angus Sired Calves For Growth And Carcass Quality And Compostion Traits, Jennifer Lynn Bailey
A Genomic And Quantitative Evaluation Of Modern Charolais Sired Calves Versus Multigenerational Angus Sired Calves For Growth And Carcass Quality And Compostion Traits, Jennifer Lynn Bailey
LSU Master's Theses
The objective of this study is to evaluate the association of single nucleotide polymorphisms with growth, performance, and carcass quality and composition characteristics in a population of cattle consisting of multigenerational Angus sired calves and modern characteristic Charolais sired calves. A total of 132 calves were evaluated. Due to a limited sample population statistical difference was set at p ˂ 0.05 and statistical trends were set at p ˂ 0.1. Mean birth weights were significantly higher for Charolais sired calves as compared to Angus sired calves. Significant differences were observed between the two breed types for mean weaning weights with …
Evaluation Of 54 Years Of Louisiana Bull Testing, And Snp Affecting Growth And Performance Of Yearling Bulls On A Forage Performance Bull Test, Tabitha Howard
Evaluation Of 54 Years Of Louisiana Bull Testing, And Snp Affecting Growth And Performance Of Yearling Bulls On A Forage Performance Bull Test, Tabitha Howard
LSU Master's Theses
The first objective of these two studies was to evaluate genetic trends for bulls that have comprised the LSU AgCenter Dean Lee performance bull test for the past 55 years. Data included birth weight (BW), initial weight, 112-day weight, average daily gain (ADG), adjusted yearling weight, and scrotal circumference (SC), on 7,488 yearling bulls of 34 breeds on 112d of test for the last 55 years. The top 4 represented bull breeds with greater than 500 animals (Angus, Charolais, Hereford, and Simmental) were included in this analysis. Analyses revealed that growth traits for all bulls regardless of breed demonstrated a …
Evaluation Of Single Nucleotide Polymorphisms Associated With Fertility And Production Traits In Holstein And Multi-Generational Angus Females, Rebecca Ann Hill
Evaluation Of Single Nucleotide Polymorphisms Associated With Fertility And Production Traits In Holstein And Multi-Generational Angus Females, Rebecca Ann Hill
LSU Master's Theses
The objective of this study was to test the association of single nucleotide polymorphisms (SNPs) with fertility in two populations consisting of Holstein cows and multi-generational Angus cows. The candidate gene approach was utilized and previously described SNPs were tested for possible associations with fertility. Single nucleotide polymorphisms on three genes were evaluated including leptin receptor LEPR, calpastatin CAST, and DGAT1. Fertility traits were evaluated in conjunction with production traits for Holstein females and growth traits for Angus females. One SNP was significantly associated with birth weight (P < 0.05) in Angus females while a trend (P < 0.10) was observed for two markers influencing birth weight performance and three markers influencing weaning weight performance. An association of two SNP for birth weight and back fat thickness in Angus females was identified.!A trend (P < 0.10) was observed for one marker within LEPR influencing average services to conception, two markers within CAST influencing average days open, two markers within CAST and one marker within DGAT1 influencing average protein production, and one marker within CAST and one marker within DGAT1 influencing average milk production. One SNP within LEPR was significantly associated with average milk production (P < 0.05) in Holstein females. An association of one SNP within CAST and one SNP within DGAT1 for average protein production and average milk production in Holstein females was identified. An association of one SNP within CAST for average days open and average protein production in Holstein females was also identified. The association of these markers indicates that the evaluated quantitative trait loci (QTL) region may harbor causative mutations responsible for the variation observed in fertility and production traits. Further evaluation of SNP in these regions is necessary in order to identify mutations accounting for the largest degree of variation for fertility and production traits.
Distributions And Associations Of Single Nucleotide Polymorphisms In The Leptin Gene Of Bos Taurus And Bos Indicus Cattle, Douglas Henry Fischer, Jr
Distributions And Associations Of Single Nucleotide Polymorphisms In The Leptin Gene Of Bos Taurus And Bos Indicus Cattle, Douglas Henry Fischer, Jr
LSU Master's Theses
In recent years, the use of genetic markers has become more and more prevalent in beef breeding programs. This research focused on four previously identified single nucleotide polymorphisms in a leptin gene on chromosome 4 of beef cows. The SNP were E2FB, T945M, UA1, and UA2. Beef cows used in this research were maintained at the Louisiana State University AgCenter Central Research Station. Cows consisted of purebred Bos tauras and Bos indicus cattle as well as crossbreds. The objectives were to estimate genotypic and allelic frequencies for each SNP and to determine the influence of cow breed type, cow age, …