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Category Archives: Dairy News

Haplotypes vs. genetic mutations

With August proofs, we saw a new and unique situation with two Alta sires: newly released sexed-only 11HO12240 AltaMILESTONE and G-STAR sire, 11HO11740 AltaFACET.

AltaMILESTONE’s initial genomic test told us he was free from the HH5 haplotype. However, the more extensive gene test for the causative mutation told us he is, in fact, an HH5-carrier. Similarly, AltaFACET was initially coded as free from the HH3 haplotype, but a later gene test revealed he is an HH3-carrier.

Traditionally, haplotypes are identified when animals have the same extended sequence of about 100 SNPs. Because we know there is more to this than the currently identified haplotypes, researchers are working to identify the exact causative mutations that cause early embryonic death1,2. This causative mutation is located in between two of the 100 SNPs used in the haplotype identification, but prior to finding the true causative mutation the exact location was unknown.

Over time, crossover events that occur in the DNA during sperm and egg creation can breakup and reassemble parts of an animal’s genome. That’s why we often see so much diversity in the progeny from a single mating pair.

These crossover events can also breakup that sequence of the 100 SNPs that we traditionally use to identify the haplotypes. If this happens, an animal could still have the causative mutation, but only have 40 of the 100 SNPs that would identify them as a haplotype carrier.

As researchers continue to identify the causative mutations for negative haplotypes, the specific gene tests will eventually replace the current haplotype tests used by the CDCB.

Although crossover events frequently happen in gamete formation, this process rarely occurs within the lethal haplotypes. In fact, these are the first instances of inconsistent haplotype results for Alta marketed sires.

For full disclosure, it’s important to remember that AltaMILESTONE (HH5) and AltaFACET (HH3) both have the causative mutation for their respective haplotypes and will therefore be labeled as carriers on Alta’s proof materials and website.

 

1Shutz et al. 2016. The Holstein Friesian Lethal Haplotype 5 (HH5) Results from a Complete Deletion of TBF1M and Cholesterol Deficiency (CDH) from an ERV-(LTR) Insertion into the Coding Region of APOB. PLoS ONE 11:e0154602.

2McClure et al. 2014. Bovine Exome Sequence Analysis and Targeted SNP Genotyping of Recessive Fertility Defects BH1, HH2, and HH3 Reveal a Putative Causative Mutation in SMC2 for HH3. PLoS One 9(3):e92769.

 

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A Q&A on DWP$ and WT$ – Dairy Wellness Profit $ / Wellness Trait $

Dairy Wellness Profit $ and Wellness Trait $ indexes

The Dairy Wellness Profit $ and Wellness Trait $ indexes may have you wondering whether you should adjust your genetic plan to include this information. We want to help you decide what’s best for your dairy. So we answer a few questions about DWP$ and WT$ to help you better understand these indexes.

What is Dairy Wellness Profit $ (DWP$)?

Dairy Wellness Profit $ (DWP$) is a genetic selection index. It equates to a genetic plan of 34% production–56% health–10% conformation. This differs from TPI (46-28-26) and the overall NM$ index (43-41-16).

The breakdown of the weight on health is different as well. DWP$ puts 30% of the health trait weight on WT$. This leaves 26% for the CDCB evaluated health traits of PL, DPR, SCS, DSB, DCE, CCR, HCR.

What is Wellness Trait $ (WT$?)

WT$ is a combination of the Wellness Traits (ketosis, displaced abomasum, retained placenta, metritis, mastitis and lameness). This means it is an index analogous to a 0-100-0 index, with 100% weight on health traits. However, those weights are divided between the various Wellness traits that Zoetis calculates.

Do each of the Wellness Traits get their own evaluation?

Yes. They are then combined into a Wellness Trait $ index to combine the expected impact.

Does Alta test all bulls for DWP$ and WT$?

No, but we test the sires that we predict will do well on the respective indexes. We test our bulls that have favorable health trait values and rank well on a 34% Production-56% Health-10% Conformation index. We list the top ten DWP$ sires and top five WT$ bulls in each of three categories: G-STARS, FUTURE STARS and daughter-proven sires.

What is Alta’s testing plan going forward?

This will be dependent on the feedback from the customers and the demand for this information. In the short-term we will continue to test those sires that rank well on a traditional 34-56-10 index.

How can we predict which sires will do well on these indexes?

Because the correlation between DWP$ and a traditional 34% production – 56% health – 10% conformation index is very high, we can predict quite well which sires will rank well on the DWP$ index.

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The genetic guide to healthier cows

Industry buzz has been booming about new genetic programs that promise to create healthier cows.

That means it’s the perfect time to revisit the impact that selection for Productive Life within your genetic plan can have on the overall health and longevity of your cows.

 

The Productive Life (PL) number that appears for any given sire on your proof sheet is defined as the number of months longer (or shorter) that his daughters will be productive in your herd as compared to herdmates. If a bull is 7.0 for PL, his daughters within a given herd are predicted to live seven months longer than the average cow in that herd. If a bull is -2.0 for PL, his daughters are predicted to live about two months less than the average cow in that given herd.

PL is often associated with old cows. However, if you think about which cows live longest in your herd, it would be those that have no troubles calving, fewer incidences of mastitis, no respiratory issues, fewer hoof problems, and so on.

Four-event cows

In reality, genetic selection for PL doesn’t just mean more old cows; it predicts which cows are toughest, healthiest and easiest to manage. We call those the four-event cows. If you look at a cow card on your herd management software program, a four-event cow has only four events listed throughout her lactation: 1-fresh; 2-bred; 3-confirmed pregnant; and 4-dry.

If those four events are the only major things a cow experiences throughout her lactation, chances are she’s trouble-free, making you money, and will stick around for several lactations.

Any time an event takes place, such as milk fever, a displaced abomasum, retained placenta, mastitis, pneumonia, or any other disruption to the normal progression of a cow’s lactation, milk is lost. In addition to lost milk production, vet and treatment costs add to the dollars lost.

The proof is in the numbers

Selection for Productive Life propels you toward the goal of a herd full of four-event cows. Since the actual measure of PL is not calculated until after a cow leaves the herd, we can use other ways to see if higher PL bulls actually create healthier and more trouble-free cows.

# of cowsSire PLAborts‘Do Not Breed’SoldDiedMastitisRPDAKetosisPneumoniaMetritisInjuryLame
Top 50%: High PL478>3.515121136331155118
Bottom 50%: Low PL502<3.6709024152309612153762930

Table 1 breaks down the events within a real 2,400-cow Holstein herd on all first lactation animals with known sire ID’s. Based only on the animal’s parent average or Productive Life, this shows the extreme difference in health events between cows with a high PL pedigree versus those with a low PL pedigree

These are real numbers, recorded on this farm’s herd management software program. Keep in mind, management is consistent throughout the herd, and no preferential treatment is provided for any given cows.

As the table clearly illustrates, far fewer of the high PL cows had issues after calving and throughout their lactation. Fewer cows from high PL group were coded as ‘do not breeds’ (DNB) and therefore, fewer of the high PL cows died or were sold. This means more cows from within that high PL group claimed the title of trouble-free, four-event cows.

On your dairy, how much does a displaced abomasum decrease a cow’s profitability over her lactation? How much of your milk check is sacrificed with every case of mastitis? How many dollars are lost for every lame cow or case of pneumonia? If you put a dollar value to the lost production and treatment cost associated with each extra health event experienced by the group of low PL cows it adds up significantly.

Want healthier cows? Let Productive Life get you there

While environment, cow comfort and overall management practices all play an integral role in the health of any given herd, genetic selection can also aid your quest for a herd of healthy, trouble-free cows. To do that, keep these points in mind.

  1. Genetic selection for PL will help you create longer living cows.
  2. Despite new genetic programs promising added immunity or greater health during a cow’s transition period, PL remains the standard for breeding tougher, healthier cows with fewer issues throughout their lactations.
  3. Include selection for PL as part of your customized genetic plan in order to build your herd of the profitable, four-event cows.
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