Stories of life on our farm in Northwest Georgia where every day is an adventure in this beautiful spot that God has entrusted to our stewardship.

Monday, November 25, 2013

How to Do Genetic Testing for Your Dexter at UCDavis Lab

As of this summer, the Veterinary Genetics Lab at UCDavis has been added as an officially approved lab for ADCA owners to use for their genetic testing.  (It was possible to use them before, but now a streamlined process, along with special rates, has been developed.)  You can access VGL through a link on the ADCA website.

The first step is to create a MyVGL account.  Easy instructions are here on the ADCA website.  Once your new account is created, be sure to follow the instructions to add the ADCA code:  ADCA2024.  This will entitle you to the special ADCA pricing.  If you do this, your Sample ID number will begin with DEX$.  If it begins with NC$ you have not registered yourself as an ADCA member.

Once you have your My VGL account, on the Home page you will select the next option, "Order Tests."

Click on "Cattle Tests" and this page will appear with the ADCA Cattle Test Form.  Fill in the animal's name, sex, date of birth, etc.  Here are a few tips:

  • If your animal is not already registered, leave the "Registration #" blank.  Do not write "Pending."  (This comes straight from VGL personnel.)
  • You are not required to enter a color.  If your animal might carry red and dun, you will need the testing to determine its color classification.  
  • "Alt ID" is where you may include an alternate ID.  You may put a tattoo number, the number from a metal ear tag, a  number from a group like Legacy, or even a barn name.  
  • You may also upload a photo of your animal, but it must be 2MB or less.  I encourage you to do this.  I previously posted instructions on how to take good photos and resize them. 
Next, under "Selected Tests" you will choose the tests you want to order.  

Here is the pricing for the tests.  If you are registering an animal, you obviously want to select "Genotype for Permanent Record" or "Genotype and Parentage Verification" as discussed in this post.  You will note that "A2 Genotyping" costs $20.  VGL has this advisory:  "Note: In compliance with the A2 Genotyping Test license agreement, a copy of all A2 test reports will be sent to the A2 Corporation Ltd."  I encourage you to consider adding A2 to your testing even though it can not be currently displayed on the ADCA website.  I believe that A2 status is becoming increasingly important to many people who are looking for a family milk cow, one niche that Dexters do a great job of fulfilling.  You may choose as many of the other tests as you wish; note that after the first test, each other one costs only $10.  Here are some thoughts on testing:
  • Dun is only necessary if your animal has dun in its ancestry.  If it carries a dun gene, this can potentially attract buyers.  You might also choose "Dun" to eliminate it as a possibility in your animal.
  • Extension (Red/Black) is only necessary if your animal has one red parent.  Again, this can potentially attract buyers if they are looking for red.
  • Bulldog Dwarfism (Chondrodysplasia) should always be selected if your animal has a Chondro-positive parent.  It is important to have this information in order to make wise breeding choices for your animal, either for yourself or a buyer.  For those of us who breed Chondro-positive animals, I believe it is incumbent on us to clearly identify every carrier animal that we sell.  You can only do this if you have tested!  Even experienced breeders can not always tell an animal's Chondro status by looking.
  • Dexter Pulmonary Hypoplasia with Anasarca (PHA) should always be selected if your animal has a PHA-positive parent.  The ADCA website has this to say about breeding PHA-positive animals:  "Every time a PHA carrier bull is bred to a PHA carrier cow there is a 25% probability of producing a dead PHA-affected calf, a 50% probability of producing a live calf that carries the PHA gene, and a 25% probability of producing a live calf that is a non-carrier of the PHA gene.  Every time a PHA carrier is bred to a PHA non-carrier there is a 50% probability of producing a PHA carrier calf and a 50% probability of producing a PHA non-carrier calf."  In addition to having a dead calf, delivering a PHA-positive calf can put the cow's life at risk, too.  It is incumbent on Dexter breeders to clearly identify every PHA carrier that they sell.  They can only do this if they have tested, as there is NO way to visually identify PHA carriers.
  • Polled vs. Horned seems obvious, even in a fairly young calf, so why would you test?  This test is useful in a calf with two polled parents, one of which has a horned parent, to find out if it is heterozygous or homozygous for polled.  If your animal is horned, it is homozygous and you can skip this test unless you want it for clarification in a de-horned animal.
  • Obligate status means that your animal has two homozygous parents for a particular test.  This is the case for two Chondro-negative animals, two PHA-negative animals or two homozygous A2 animals.  At this time, only Legacy offers Obligate Reports ($2 each).  Some breeders who test directly through VGL (or TAMU) choose to test animals they know are obligate in order to have the status reflected on their registration page.  I generally run all the tests even though this adds $30 to my testing.  It eliminates any doubt for future buyers.
Next you have the option to select "Sire (or Dam) Parent Verification Info."

  • For both sire and dam, you can select "Search My Account" if you have previously tested them at VGL and have them in your My VGL account.  
  • Or you may select "Enter Name + VGL Case #." For instance, if you bred your cow to someone else's bull or used AI, you can use this option.  Check with the bull's owner to see if he is on file at VGL and if he is, ask for his VGL number.   (If he is not on file at VGL, it is my understanding that you will need to have the calf "Sire Qualified" at TAMU where he is most likely on file.)
  • There is a third option, explained below.  You may select "New Dam" or "New Sire."

If you fill out the information in this section, adding $25 to your total bill, you will be able to print out an additional test form with which to send in tail hairs to genotype the sire and/or dam.  Parent verification will then be done automatically at the time your calf is tested.

This third option saves you doing what I did, which is to test the dam, wait for the results to come back with her VGL number, and then test the calf!

When you are done filling in everything, click on "Save Test."  Woo-hoo!  You're half-way there!

Once you have saved your test, a screen will appear with three pages on it.  This is the first page, which is for you to keep.  It is a record of the tests you have ordered.  I print it and stick it in my animal's file folder.  If a question arises about your testing, you will need the "Sample ID" number.  You can see that my cow's tests cost me $95 because she does not have dun in her ancestry so I did not order that test.

This is the second page which you must send with in the envelope to VGL as proof of payment.

This is the third page--the nitty-gritty part!  There are clear instructions at the top.  Follow them carefully, and you can't go wrong!

This is a close-up of the bottom of the page where you will attach your animal's tail hairs.

Here I am set up on a clean countertop ready to finish the testing process.  I have assembled:

  • The "Payment Information" page I must send to VGL.
  • The "Cattle Sample Submission Form," herein referred to as the "test page."
  • A stamped envelope addressed to VGL.
  • Scotch tape.
  • My plastic bag of tail hairs.  Notice that I do not take the test page out to the barn to tape tail hairs directly on it.  I'm usually doing this by myself, and it is much easier for me to come back and do this on a nice, clean, flat work surface!

Make your first fold along the dotted line as instructed.  You'll see that you are going to form a handy packet that keeps the tail hairs safely inside.

Make the second fold as instructed.  Now you have your instructions on top.

If you flip your page over, you will see all your and your animal's identifying information.

When you peek inside your little packet you can see where the tail hairs are going to be.  It's just SO much easier to fold it without the tail hairs attached!

If you haven't already, go wash your hands!  Then pull your tail hairs out of your plastic bag.

Oops!  What if you don't already have your tail hairs?  Kim Newswanger has a helpful how-to post on her blog.  Or here are some quick tips:

  • Halter and tie your animal.  You will need to be able to handle the tail switch, the long hair at the end of the tail.
  • If the tail is dirty, wash it in clean water and dry it with a clean towel.  You can use a bit of rubbing alcohol to help speed drying.
  • Wash your own hands or use hand sanitizer.
  • Lay an open zip-loc baggie where you can reach it.
  • If you are doing more than one animal, write the name on the baggie!
  • I've found a way to do this by myself, although it helps to have an extra set of hands.  I apply the end of a roll of clear packing tape to something and stretch out about 6" of packing tape, letting the weight of the dispenser hold the tape stretched out.  Alternatively, you can just lay the hairs on a clean paper towel.
  • Grasp 10-15 tail hairs about an inch from their roots, wrap once or twice around your finger, and yank the hairs out of the tail.
  • With calves, whose hair is short and fine, it may be helpful to use a needle nose pliers whose tip you have sterilized with rubbing alcohol.
  • Without touching the bulb end of the hairs (the part you have just pulled out of the tail) lay them on the tape around the middle of the hairs with the bulb end clear of the tape and not touching anything else.
  • Repeat this until you have 30-50 (the higher number is for calves, who have smaller hairs with less DNA matter).  Be sure to align the hairs with the bulbs all together!
  • Either fold up the towel around the hairs or tear your tape loose from the dispenser and fold it around the middle of the hairs.
  • Stick the hairs into the plastic baggy.
  • Pet and praise your animal and let it go.  Head into the house with your precious loot! 

Here are Siobhan's tail hairs laid out on the test page.  You can see the packing tape at the right-hand edge of the hairs.  You can also see that no matter how careful you are to try to line up the bulbs together, a few stray hairs always stick out every which-way.

So I put on a pair of clean, disposable gloves.  I've tried using pliers, but this is just the easiest way to be sure my test results don't come back saying that I own a cow-human hybrid!  I pull any stray hairs out and reposition them aligned with the others.

Then I lay the hairs down on the test page, tape them down with Scotch tape, and cut off the excess, including the packing tape.

The hair sample is now ready to be folded back up inside the handy packet.  You do not need to secure it with tape or staples.

Here is a close-up of the bulb end of the tail hairs of another animal, ready to send off.

Lay the folded up packet containing the hairs on top of the "Payment Information" sheet.

Fold the payment page around the test page and stick them in the envelope.  All that's left is to put the envelope in the mail and wait for your test results to be emailed to you.

This may seem complicated, but don't worry--it's all very straightforward.  It will most likely take you longer to read through this tutorial than it will to do the actual process!


  1. Replies
    1. Ouch as in a lot of work or ouch as in pulling tail hairs? It's not as complicated as it looks; if you ever want help we can get on VGL together and I can talk you through it. I'd be glad to! You'll have to pull your own tail hairs, though! ;)


I LOVE comments so please take a minute and let me know you were here! Sorry I have to use Captcha, but I hope you'll comment anyway! Comments make my day! :)