Taking DNA samples

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Dr. Kevin DeHaan, technical services director, Igenity, offers tips about collecting DNA samples to ensure the best possible results.

Q: How important is it that producers submit good DNA samples?
A:
The process for DNA profiling begins with the collection of good DNA samples. How those samples are collected can make a big difference in accuracy of the results and how quickly they are received. Submitting adequate, quality samples is the first step to ensuring accurate results in a timely fashion.

Q: What happens if a sample isn't clean or high enough quality?
A:
When a poor sample with a visible issue — such as manure in a hair sample or a too-small sample size — is received at the lab, the customer will be contacted to send in a new sample. In some cases, microscopic contaminants decrease the quality of a sample; therefore, the DNA cannot be read and will show a no result (NR) on the results certificate.

Q: How important is organization of the samples?
A:
Quality samples begin with organization. Because one of the most common mistakes seen is misidentification, it's best to gather all materials needed before the sample is taken, then correctly label all cards, collectors, etc., and double-check that the animal identification matches the labels after taking the sample. It's also important to obtain the correct sample for the requested analysis.

Q: Do you have any advice for producers who are collecting tissue samples with an ear punch?
A:
Yes. First, make sure you order the tags in a timely fashion to ensure you will have all the necessary tools on hand when you are working cattle. Here are a few other tips to follow:

  • Make sure the applicator gun is loaded correctly, with the sample container sealed under the retainer clip.
  • Make sure the animal's ear is dry, and clean of dirt and debris.
  • Avoid punching through tattoos. The ink leaves a residue, which may interfere with results.
  • Place the applicator gun between the ribs in the ear, making sure you get a tissue sample and not cartilage.

Q: Do you have any advice for producers when collecting hair samples?
A:
Yes. Here are a few things to remember when collecting hair samples:

  • Some of the most common sampling problems are related to hair. Because DNA is in the hair follicle (or root bulb), and not the hair itself, the hair follicle must be present on hair samples.
  • Approximately 20 to 30 hair follicles are needed for animals 90 days or older. Collect 40 to 60 hair follicles for calves younger than 90 days because of their smaller follicle size.
  • Hair should be obtained from the switch of the tail.
  • Hair should be free of manure.
  • Using pliers to pull hairs is an effective method, but be sure to remove all hairs from the pliers before sampling another animal.
  • Only use hair collector cards for Igenity, as plastic bags can cause mold to grow and other collector cards can leave residue on the hair, which will result in a NR.
  • Cut hair is not an acceptable sample, as it is the hair follicle (root bulb) that contains DNA.


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