Genetic mechanisms underlying feed utilization and implementation of genomic selection for improved feed efficiency in dairy cattle

Abstract

The economic importance of genetically improving feed efficiency has been recognized by cattle producers worldwide. It has the potential to considerably reduce costs, minimize environmental impact, optimize land and resource use efficiency, and improve the overall cattle industry’s profitability. Feed efficiency is a genetically complex trait that can be described as units of product output (e.g. milk yield) per unit of feed input. The main objective of this review paper is to present an overview of the main genetic and physiological mechanisms underlying feed utilization in ruminants and the process towards implementation of genomic selection for feed efficiency in dairy cattle. In summary, feed efficiency can be improved via numerous metabolic pathways and biological mechanisms through genetic selection. Various studies have indicated that feed efficiency is heritable and genomic selection can be successfully implemented in dairy cattle with a large enough training population. In this context, some organizations have worked collaboratively to do research and develop training populations for successful implementation of joint international genomic evaluations. The integration of “-omics” technologies, further investments in high-throughput phenotyping, and identification of novel indicator traits will also be paramount in maximizing the rates of genetic progress for feed efficiency in dairy cattle worldwide.

Effects of Incorporating Dry Matter Intake and Residual Feed Intake into a Selection Index for Dairy Cattle Using Deterministic Modeling

“…Direct selection on FE occurs when the selection pressure is placed directly on the trait, RFI for this study, and indirect selection for FE occurs when the components of FE are included in the selection index. The components of FE are traditionally considered to be feed intake, milk production, and body maintenance [ 21 , 22 ]. In this study, the traits that were considered as the components of FE are DMI, FY, and PY (production) and BCS and STAT (body maintenance).…”

“…In this study, the traits that were considered as the components of FE are DMI, FY, and PY (production) and BCS and STAT (body maintenance). Other traits that could replace those used in this study are energy-corrected milk and metabolic body weight, which would represent the production and body maintenance components, respectively [ 21 , 22 , 45 ]. It is important to note that FE in this study is a residual trait (RFI), meaning it is the residual of a linear regression of DMI on the energy sink traits.…”

“…The lack of practical methods for measuring feed intake on a large number of animals has hindered the incorporation of FE into breeding programs. Using technologies such as milk mid-infrared spectroscopy [ 19 ] and 3D cameras [ 20 ] to estimate feed intake could enable more large-scale phenotyping, allowing for easier implementation of FE into breeding programs [ 21 , 22 ]. With many aspects of including FE in breeding programs still unknown, the purpose of this research was to estimate preliminary genetic and phenotypic correlations for dry matter intake and residual feed intake with eight currently evaluated traits and to simulate the impact of including FE through direct and indirect selection in a selection index.…”

Phytogenic Additives Can Modulate Rumen Microbiome to Mediate Fermentation Kinetics and Methanogenesis Through Exploiting Diet–Microbe Interaction

“…The host diet has a major influence on the relative abundance and diversity of the rumen microbiome. However, genetic manipulation of rumen microbiota is also possible through different techniques as host genetics influences some heritable microbial traits (81)(82)(83). In this regard, recent biological techniques such as transgenesis are getting attention for improving the efficiency of animal production and reducing environmental impacts (84).…”

Associations between feed efficiency and aspects of lactation curves in primiparous Holstein dairy cattle

“…Ruminants, such as dairy cattle, are well positioned to fill this nutrient deficit through the ability to utilize cellulose as an energy source, allowing them to convert plant material into high-quality protein sources suited for inclusion in the human food chain, such as milk (Morgavi et al, 2010). These factors have stimulated a renewed interest in feed efficiency research in dairy cattle, with an emphasis on the potential for using selective breeding and advances in genetics to improve this trait (as reviewed by VandeHaar et al, 2016;Miglior et al, 2017;Brito et al, 2020).…”