DNA Sampling

Genomic testing of sheep is most commonly conducted using Allflex Tissue Sampling Units, or TSUs.

TSUs are a fast, simple method of collecting DNA.

These units use an ear punch to take a small tissue sample, placing it directly into a sealed vial for processing. This replaces the more complex tasks of collecting hair, blood, semen or other sample types used for DNA testing.

A single-squeeze motion collects a sample in seconds with minimum need for restraint or distress to the animal.

The genetic material is sealed in a specially designed vial to prevent contamination. Tissue samples contain a large quantity of high-quality DNA for genetic analysis, yielding excellent lab results, maximising sample integrity, and ensuring you have confidence in the results you receive for each animal.

The TSU is fully sealed and positively identified with both a 2D barcode and ID panel.

TSUs can be purchased from Neogen Australasia.

Allflex TSUs can be purchased from Neogen Australasia. Applicators and TSU racks are available too. For more information or to order a sample collection kit, contact customer service or your local territory manager.

  • Quick, simple, and clean process.
  • Sample at any age, even day-old lambs.
  • Receive more data from one sample. 
  • Positively identified with both a 2D barcode and ID panel.

  • Be sure that if the animal has been freshly tattooed that all ink is avoided in the sample.
  • If sampling a newborn lamb, be sure to wipe the ear clean so that no DNA is transferred from the ewe.
  • Be sure that there is tissue within the TSU before releasing the animal, and that the tissue is submerged in the buffer.
  • TSUs can be stored for up to one year at room temperature.
  • Be sure to note which sample belongs to which animal.

The Do’s

  • Sample lambs as soon as possible for the earliest results
  • Wipe off any excess dirt with water and towel
  • Position cutter approximately 1 – 2cm from the edge of the ear, avoiding veins
  • Squeeze handles together in one swift, fluid, motion with enough force to pierce the ear
  • Check to ensure sample is present and submerged in buffer and that excess hair isn’t protruding from the top
  • Remove cutter by pulling handles apart
  • Store samples in dark, temperature controlled room for up to 12 months
  • For long term storage (over 12 months), place samples in deep freezer without auto-defrost capability

The Don’ts

  • Sample “wet” lambs – the placenta and fluid could cause a failed sample
  • Use chemicals to clean off the ear – bleach degrades DNA
  • Position cutter over any tattoo ink
  • Squeeze handles together with excess force (shouldn’t take as much as ear tagging) that would damage the TSU
  • Place TSU in box without ensuring sample is present
  • Use pliers to remove cutter
  • Place samples in direct sunlight or heat
  • Store samples in auto-defrost freezers – such as the one in your kitchen

  • General Issues
    1. Biological contamination
    2. Cross contamination between samples/animals
    3. Fecal matter or dirt in sample
  • Chemical contamination
    1. Dye/pigment from animal markers
    2. Insect repellant
    3. Cleaning agents
  • Improper storage
    1. Heat exposure including leaving the samples in vehicle or in hot sun
    2. Exposure to foreign material including mold
    3. Improper frozen storage- the freeze/thaw cycle of a self-defrosting unit can degrade DNA
    4. Extended sample storage- DNA degrades over time
  • Insufficient sample
  • Improper shipping

Semen straws, pellets or blood cards can also be submitted for genotyping, however these sample types attract a surcharge due to the additional steps required to process them within the DNA laboratory, and are not preferred.

Tissue Sampling Instructions: How to load the applicator & take the sample

For detailed instructions, refer to the kit manual provided with your TSU order. This guide has been designed to help ensure that you get the best possible result out of what has become the most accepted tissue sampling system.

TSU’s should be stored at room temperature prior to use (for a maximum period of 12 months). Care should be taken not to expose the unused product to extremes of heat or cold prior to sampling.
Step 1:
 Take an assembled TSU i.e the cutter, connection piece and collection tube.		 Step 2:
 Squeeze the two spring loaded retainer clips together.		 Step 3:
 And insert the TSU as shown in the picture.		 Step 4:
 After insertion of the TSU, release the spring loaded clips to lock in the tube.		 Step 5:
 Carefully squeeze the plier handles until the large piston comes to a stop against the red connection piece.		 Step 6:
 You have now completely grabbed the cutter. After the cutter is inserted into the piston you can release the handles.

Step 7:
 You can now easily remove the red connection piece while holding the two red tabs and pushing sideways.

 
 Step 8:
 Slide the charged pliers over the ear and position the cutter about 1cm to 2cm from the edge of the ear.
Step 9:
 Try to avoid large veins and ridges. The sample should be taken in a very swift, fluid motion.		 Step 10:
 Remove the TSU tube from the piers by squeezing the two spring loaded clips together, then slide out the tube.		 Step 11:
 A tissue sample should be clearly visible inside the tube.		 Step 12:
 Remove the used cutter from the pliers by pushing the handles apart. This will loosen the cutter and make it easy to remove.
You CANNOT reuse the needle as it has no red plunger.		 Step 13:
 The TSU is for SINGLE USE only, both the tubes and the cutter can’t be re-used! See the difference between an unused and a used TSU.		 Step 14:
 In the used TSU a clear RED plunger will be visible indicating the tube already contains a sample and can’t be used again.		 CAUTION: The cutter is very sharp. Mind your fingers!