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Advancing connections between genomics and fertility

Mandy Brazil for Progressive Dairyman Published on 24 February 2017

“I now say that the world has the technology – either available or well advanced in the research pipeline – to feed on a sustainable basis a population of 10 billion people.

The more pertinent question today is whether farmers and ranchers will be permitted to use this new technology?”
—Norman Borlaug, 1970 Peace Prize winner

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While Borlaug was known for his work with plants in sparking the Green Revolution, his insight is aligned with fears we should have in the dairy industry. We have refined dairy cattle reproductive programs into a precise science using hormone therapy.

What happens if the ability to use hormone treatments, to the extent we do today, is ended by consumerism?

Impact of genomics for fertility

The USDA-NIFA AFRI put forward a grant dedicated to researching dairy cattle fertility through translational genomics. The grant is specifically committed to unlocking tools that will help producers on a day-to-day herd management level.

While genomics is literally analysis of the genome, genetics is actually a focus on traits passed from one generation to the next. We can observe the impact of genetics in animals based on the phenotypes. A phenotype is an observable characteristic, such as milk yield, stature and fertility.

Daughter Pregnancy Rate (DPR) is a Predicted Transmitting Ability genetic trait used to estimate the phenotype for female fertility. An increase of +1.0 DPR Predicted Transmitting Ability corresponds to 1 percent higher pregnancy rate and four fewer days open. A portion of the phenotypic variation (hard versus easy breeders) in your breeding pens can be attributed to genetic variation for DPR.

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The Holstein breed has made tremendous progress for milk yield as a result of genetic selection. The fertility of Holsteins has correspondingly decreased. It was historically believed you can select for production or DPR, but you cannot get both.

New research suggests some genetic packages may exist where an animal can pass down traits for both increased production and fertility. The work of this grant is helping to further define how you can select for this.

Genomic testing options

The bovine genome was sequenced for the first time in 2009. The genomic testing tool has quickly and powerfully impacted our entire industry for male and female genetic selection.

The types of genomic tests available and speed to get results have both greatly increased. Neogen, one of two main genomic test providers in the U.S., offers a wide portfolio of options. In addition to the traditional test, producers can choose to add on tests such as BVD testing, Y SNP testing for increased reproductive efficiency and traits for specific health and longevity screening.

Uniquely, they offer simplified, lower-cost options than the industry standard. These tests are popular for commercial dairies wanting a more cost-effective way to make genetic decisions. They also offer the only test for crossbred cattle.

The introduction of disease-resistant health traits has been the latest evolution. The other major genomic test provider, Zoetis, offers the ability to genomic test for “wellness traits” such as displaced abomasums, retained placenta and lameness. Their geneticists recommend ranking heifers on a single index number, such as their Wellness Trait Index and Dairy Wellness Profit Index, rather than sorting heifers on individual disease traits.

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Dairy Wellness Profit Index places emphasis on multiple wellness traits and industry Predicted Transmitting Ability traits depending on the amount of economic benefit and impact per generation each trait has. It predicts the potential lifetime profitability which will be passed down to the next generation. Using a multi-trait index instead of pointed single-trait selection allows for more consistent herd progress.

Return on investment

About 10 percent of today’s female U.S. dairy cattle population is being genomic-tested. Most producers are testing their females at 1 to 2 months and the second-largest group is at 4 to 5 months. With these timelines, calves are old enough to be past early calfhood loss.

However, they are young enough where a producer can use the data in his genetic management plan, starting with young heifers.

Dr. Albert De Vries of the University of Florida said while genomic testing predicts future performance, “producers must have a plan. The plan may be profitable.”

De Vries identified the following as ways to get value back from genomic testing:

  • Avoiding inbreeding associated with parentage misidentification; estimated performance loss is $25 per 1 percent increase in inbreeding over the animal’s lifetime.

  • Selling surplus heifers strategically

  • Segment females and delegate sorted semen or beef semen

  • Faster genetic progress through culling low-end genetics

  • Better reproduction through fertility trait identification

The general goal with making a female genomic plan is doing a better job identifying the top animals and a better job identifying the low animals. If a dairy has a surplus of animals, they will do a better job finding the worst animals to cull through genomic testing.

To truly justify the cost of the test, producers need to pencil out how the animals which are kept will pay for the genomic test over their lifetimes. For example, if you sell the low 10 percent of your genetics, these cattle will pay for the test in opportunity cost savings of not having to waste resources raising them. The top 90 percent, which you keep, must somehow generate enough additional income during their lifetime to return the initial genomic test investment.

Some dairies, especially those which have a lot of reliable pedigree information, might gain more value using higher-genetic-level sires each generation instead.

Professional consultants are available to help create your genetic plan. The bottom line is to determine your profit per milking cow per year and how genomic testing will impact this. Some of the factors which should be considered include:

  • Genetic variation and genetic trend by age group in your herd

  • Expense of testing, feed costs and milk pricing

  • Reproduction performance, stillbirth rates and culling trends

  • Quality of parentage data existing in the herd  end mark

This article is based on coverage of Dairy Genomics Workshop at the UC – Davis Veterinary Medicine Teaching and Research Center, featuring Drs. Joe Dalton, University of Idaho; Dale Moore, Washington State University; Pablo Pinedo, Colorado State University; Ricardo Chebel, Jose Santos and Albert De Vries from University of Florida.

Workshops were funded by USDA-NIFA AFRI grant award 2013-68004-20365 titled “Improving Fertility of Dairy Cattle Using Translational Genomics.” Recordings of the presentations can be found on the Washington State University Veterinary Medicine Extension website (Dairy cow fertility).

Mandy Brazil
  • Mandy Brazil

  • Freelance Writer
  • based in northern California

 

 

 

 

5 ways to get value back from genomic testing

  • Avoiding inbreeding associated with parentage misidentification; estimated performance loss is $25 per 1 percent increase in inbreeding over the animal’s lifetime.

  • Selling surplus heifers strategically

  • Segment females and delegate sorted semen or beef semen

  • Faster genetic progress through culling low-end genetics

  • Better reproduction through fertility trait identification

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