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A Study Evaluating Genetic Trends And Molecular Predisposition To Improved Carcass Quality Of Brahman And Brahman Influenced Cattle, Amanda M. Royer
A Study Evaluating Genetic Trends And Molecular Predisposition To Improved Carcass Quality Of Brahman And Brahman Influenced Cattle, Amanda M. Royer
LSU Master's Theses
The first objective of the current study was to evaluate genetic trends from 10 years of the American Brahman Breeders Association Carcass Evaluation Program from 2004 to 2013. Changes of performance in growth, carcass composition, and carcass quality traits were evaluated. Overall means were calculated to report the total average for each trait along with an average rate of change per year. Growth traits evaluated included feedlot entrance weight (INWT), harvest weight (HRVWT), and average daily gain (ADG). Carcass composition and quality traits evaluated included hot carcass weight (HCW), rib eye area (REA), marbling score (MARB), dressing percent (DP), quality …
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.