What’s your cattle’s genotype?

How genetic information can assist beef production decisions

What’s your cattle’s genotype?

Genomics can be tricky. But in today’s marketplace, cattle producers need to do all they can to maintain their competitive edge, and this can be one of the keys.

Fortunately, there are people out there like Steven James, director of research development at Quantum Genetix, whose job it is to simplify these matters for farmers.

Back in July, James was part of the livestock and forage speaker series at the Ag in Motion Discovery Plus virtual farm show, where he discussed the importance of knowing the genetic variation between animals.

James’ company provides digital DNA testing solutions for the agriculture industry.

“Genomics can be complicated,” said James. “So our goal is to simplify genomics with digital technology to make genomic information easier to use and apply to ag production.”

The company works with producers in both the crops and livestock sectors, but James’ presentation focused on genomics in beef production.

He began with a basic overview.

“DNA is information. It’s the blueprints of an organism. How to make things like cells, proteins and enzymes and how to turn things on and off in response to environmental stimulus,” he said.

He went on to explain the difference between a phenotype and a genotype. A phenotype is an observed trait (such as weaning weight and marbling) while genotypes are differences in the DNA code that may or may not result in observable traits on the animal, depending on whether they are dominant or recessive traits. A dominant trait is one that will be passed down to the bull’s offspring. A recessive trait will only be passed down if the cow he breeds with also has that trait.

If using only phenotyping for breeding selection, explains James, you can’t be certain to get the results you want. For instance, mating a black bull with a black cow doesn’t always produce offspring with a black coat.

“It depends on the genotypes,” he said. “The bull and female could appear black, but have heterozygous black genotypes.”

That is, they possess one copy of the dominant variant for a black coat and one copy of the recessive variant for a red coat, so the calf could end up black or red. If the black coat variant is passed on from one of the parents, then the calf will appear black and have a heterozygous black genotype. If the black coat variant is passed on from both parents, then the calf will have a black coat and a homozygous black genotype. If the red coat variant is passed on from both parents, then the calf will be red, with a homozygous red genotype.

“If you knew the bull and female actually had heterozygous genotypes, then you could avoid pairing them together if you didn’t want a red calf,” James said.

He then described how to use genotypes to improve beef productivity.

“Basically cow-calf operations make money by the number of sale animals and the quality of sale animals,” James said.

That means the value of a herd bull can be distilled down to the ability to impregnate females and the ability to pass on quality traits. Likewise, the value of replacement heifers can be distilled down to the ability to be bred, and the ability to pass on quality traits.

“So when you’re deciding which bull to buy or keep or cull and which heifers to keep or cull or buy, you’re probably already doing a phenotype appraisal,” James suggests. “How does the animal look? Is it the right colour? The right breed? Is it from a good lineage? And so on. Without DNA information, this might be where the decision tree stops.”

But this method would not answer the question of whether the animal possesses the genotypes to pass on the desired traits.

“The animal looks good, but what is the likelihood that the calves are going to possess the same traits?” he said.

This is where James and Quantum Genetix step in. Q-Select is a product they offer that provides the genotypes for genetic variants that impact some important performance traits.

“Knowing whether an animal has a homozygous or a heterozygous genotype for desired trait allows you to know if the trait will be passed on,” James said. “This genotype information can improve decisions on which breeding animals to keep, sell or buy and which are the optimal mate-pairings to have.”

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