LINCOLN, Neb. 鈥 Nebraska scientists have begun a federally funded study to deepen the understanding of links between genetics and cattle growth efficiency. The project has significant potential to expand the range of genetic tools used by breeders.
The study will focus on cattle鈥檚 mitochondria, cell components whose biochemical activity produces most of the body鈥檚 energy for cell function, according to a University of Nebraska news release.
Breeders use a variety of genetic data for their operations, but information from the mitochondrial genome of an animal is largely ignored. In this project, a five-person team of University of Nebraska-Lincoln faculty and graduate students will aim to determine how variation in cattle鈥檚 mitochondrial genomes affects overall efficiency in animal growth.
As a result, said Jessica Petersen, associate professor of animal science, 鈥淚nformation on mitochondrial genotype will serve as a new tool for the selection of the most energy-efficient cows.鈥 Those cows, in turn, 鈥渨ill produce calves with the same desirable mitochondrial genotype.鈥
An increase in feed efficiency of just 1% would save the U.S. cattle sector more than $11 million a year, the researchers wrote in their grant application.
The other members of the research team are Dustin Yates, associate professor of animal science; Kristi Montooth, professor of biological sciences; and graduate students Mackenzie Batt and Lauren Seier.
鈥淭his project benefits the feedlot sector, where efficiency of growth is of critical importance, as well as cow-calf operations, where feed represents the greatest expense for each cow,鈥 the team wrote in describing the project to the USDA, which is providing a three-year, $650,000 research grant.
People are also reading…
Breeding has focused primarily on selecting the best bulls and their genetic characteristics, but this project points to the benefits of also understanding key genomic information from cows. Mitochondrial DNA is inherited exclusively from the mother, so cows 鈥渁re the ones passing on this mitochondria that鈥檚 so important for energy production,鈥 Petersen said.
An animal鈥檚 mitochondrial genomic data can be collected alongside genetic data gathered through commercial genotyping of cattle.
鈥淲e鈥檙e hoping to show that this information can be collected and used without much additional expense鈥 to bolster genomic evaluations for breeding selection, Petersen said.
The researchers plan to analyze the genomic data using skeletal muscle samples from about 1,500 steers from the university鈥檚 West Central Research, Extension and Education Center in North Platte and the Eastern Nebraska Research, Extension and Education Center near Mead.
An advantage of using the university鈥檚 cattle, Petersen said, 鈥渋s that they all have a genetic sample that鈥檚 taken when they鈥檙e born or when they鈥檙e received. So we鈥檙e already doing some genetic analyses of these animals. When they go through a feedlot, many have individual intake measures showing exactly how much they eat. We can then track how much weight they gained to get measures of efficiency.鈥
This USDA-funded mitochondrial study has a logical and promising follow-up, Petersen said.
鈥淭he next step is figuring out how the mitochondrial genome interacts with proteins with the nuclear genome鈥 also located inside cattle cells, she says.
Once those findings are complete, 鈥淭hat gives us a whole other tool to select for animals that have those better symbiotic genomes.鈥
Those improved genomes, she said, will work together to make the animal even better.