Fine mapping quantitative trait loci for feed intake and feed efficiency in beef cattle

Area of Science:

• Animal Genetics
• Quantitative Genetics
• Livestock Production

Background:

• Feed intake and feed efficiency are critical economic traits in beef cattle production.
• Feed efficiency is commonly measured by feed conversion ratio (FCR) or residual feed intake (RFI).
• Identifying genetic markers for these traits can improve breeding strategies and reduce production costs.

Purpose of the Study:

• To fine map quantitative trait loci (QTL) associated with feed intake and feed efficiency in beef cattle.
• To utilize a high-density marker panel and statistical models to pinpoint genomic regions influencing these economically important traits.

Main Methods:

• Genomic analysis of 2,194 markers across 24 autosomes in 20 half-sib families of Angus, Charolais, and hybrid bulls.
• A mixed-effects model incorporating sire and QTL effects was used for QTL mapping.
• Chromosome- and genome-wide significance thresholds were established using 20,000 permutations.

Main Results:

• Several QTL for RFI, FCR, and dry matter intake (DMI) were identified, with varying significance levels.
• The most significant QTL for RFI was on BTA 3, for FCR on BTA 24, and for DMI on BTA 7.
• QTL for RFI were detected on 19 chromosomes, with some overlap and differences compared to RFI(bf), FCR, and DMI QTL.

Conclusions:

• The identified QTL provide valuable genetic markers for marker-assisted selection in beef cattle breeding programs.
• These findings contribute to understanding the genetic architecture of feed efficiency and intake.
• Further research can focus on identifying specific genes within these QTL regions to enhance feed utilization and reduce costs.