There are several different sample types that you can collect on your animals for SNP DNA testing purposes. While you should choose the most convenient for your individual circumstances, be aware that some sample types can only be collected once an animal reaches a certain age. In general:
- Tissue sampling units (TSUs) can be used from birth onwards. TSUs allow beef producers to collect an ear plug sample from their animals using a specialised applicator gun. TSUs are often collected in conjunction with calf tagging and have a unique barcode system that can be linked to the animal ID tags (including NLIS tags). This barcoding system, along with machine processing, means that sample mix-ups are less likely than for other sample types. TSUs can be shipped at room temperature; however, once the tissue samples have been collected, TSUs are not suitable for long term storage in a home environment.
- Hair samples can be collected once animals are aged 60 days or older. Hair samples are collected by pulling approximately 40 hairs from the tail switch of an animal. These hairs should be clean (i.e. free from any foreign matter such as manure) and dry. As the DNA is contained in the root bulb, it is important that hair samples are pulled rather than cut. Collecting hair samples from calves younger than 60 days of age is not recommended as the hair roots are still developing. Instead, hair samples are commonly collected at marking and/or weaning. Hair samples are also suitable for long term storage at room temperature.
- Semen samples can be collected from mature bulls. While other sample types can be collected when bulls are still immature, one advantage of a semen sample is that it can be used to procure DNA when the physical animal is not readily available (e.g. overseas and/or deceased sires). Semen straws should be thawed prior to postage; however, they should not be left to sit at room temperature for prolonged periods of time. Semen straws should also be protected to prevent damage while in transit; placing each straw inside an empty pen is a good option. If sending multiple straws, each should be placed into a separate sealed plastic bag to prevent contamination of all straws should one break in the post. Please note that only unopened semen straws can be processed.
No matter the sample type you decide to use for DNA testing, remember that it will take time for the samples to be processed by the genotype service provider and for results (i.e. parentage and/or genetic conditions) to be returned for you. Single-Step BREEDPLAN results will take some additional time as they must wait to go through the next scheduled BREEDPLAN analysis. For those wanting Single-Step BREEDPLAN results for sale catalogues, it is recommended that genotypes are sent in at least six months in advance of the analysis for which you plan to extract sale catalogue information. This gives you some leeway in case resampling is required.