Some genetic conditions have been proven to be detrimental to economic production and need to be managed carefully through DNA testing and the use of tools such as GeneProb to estimate carrier status. The gene probability analysis includes all known DNA information for animals recorded on the relevant breed society database. Genetic condition status results are based on DNA samples provided by breeders to their relevant breed society*. Genetic condition status results are only displayed for animals that have been DNA tested for a particular genetic condition or in circumstances where sufficient DNA testing has been conducted on animals within the pedigree to make some assertions as to genetic condition status. In cases where the genetic condition status of an animal is unknown, no genetic condition status will be displayed for the animal.
_ _ F
Indicates that the sample submitted for this animal has been tested and found to be free of the causative mutation responsible for the indicated genetic condition. This animal is homozygous free, meaning that it has two copies of the normal variant (or allele) of the gene.
Indicates that, this animal has not been tested for the causative mutation but that both the recorded sire and dam have either been tested and found to be free, or have a status of _ _FU and are expected to be free of the causative mutation responsible for the genetic condition. DeSireBull gives no guarantee as to the animal's genetic condition status.
_ _ %
Chance of carrier
Indicates that, based on pedigree information supplied by the breeder of the animal, the animal has a chance to be a carrier of the mutation responsible for the genetic condition but has not been tested. The higher the indicated percentage, the larger the chance the animal may be a carrier. To verify the status of this animal, DeSireBull recommends that testing be undertaken prior to using this animal for breeding purposes.
_ _ A
Indicates that the sample submitted for this animal has been tested and found to possess two copies of the mutant variant of the gene. This animal is homozygous for the mutation responsible for the genetic condition and may be affected by the genetic condition. Even if the animal appears normal it will pass the mutation to 100% of its progeny.
_ _ C
Indicates that the sample submitted for this animal has been tested and found to be a carrier of the causative mutation responsible for the indicated genetic condition. This animal is heterozygous for the mutation, meaning that it has one mutant allele and one normal allele. This animal could pass the mutation to approximately half of its progeny.
*DeSireBull makes no statements, representations or warranties about the accuracy or completeness of any information relating to the status of a particular animal: and disclaims all responsibility for information and all liability (including without limitation, liability in negligence) for all expenses, losses, damages, and costs you may incur as a result of information being inaccurate or incomplete in any way for any reason.
What happens when carriers are mated to other animals?
A carrier will, on average, pass the undesirable gene form to a random half (50 %) of their progeny.
When a carrier bull and carrier cow are mated:
- There is a 25% chance that the progeny produced will have two normal genes and so will never pass on the undesirable gene.
- There is a 50% chance that the mating will produce a carrier.
- There is a 25% chance that the progeny will inherit two copies of the undesirable gene and hence be affected by the genetic condition.
When a carrier animal is mated to an animal tested free of the genetic condition:
- All progeny will appear normal and will be unaffected by the condition.
- There is a 50% chance that the mating will produce a carrier.
- There is a 50% chance that the progeny produced will have two normal genes and so will never pass on the undesirable gene.
Note that an animal that is tested free by DNA test of the genetic condition will not pass the genetic condition to its descendants, even if it has carriers in its own ancestry. Therefore, DNA-tested free animals can be used in your breeding program with confidence that they are not transmitting the unfavourable gene to subsequent generations.
How should genetic conditions be managed?
An informative presentation on the management of genetic conditions was delivered as part of the “Know Your Genes” webinar course conducted by Southern Beef Technology Services (SBTS). This presentation can be viewed on the SBTS website.
Breed Genetic conditions
Understanding EBV subgroups
Download the Beefclass Structural Assessment.
What is a selection index?
Selection indexes are created using the BreedObject software that has been developed by the Animal Genetics and Breeding Unit (AGBU) at the University of New England (UNE). BreedObject combines an animals BREEDPLAN estimated breeding values (EBVs) with economic weightings for each trait (based on net profit [production returns – cost of production] in a commercial production system) to produce a single selection index value, in the currency units which are under consideration, e.g. $AU for Australian indexes. This value describes how much an animal will impact on commercial profitability if selecting for breeding. Selection indexes enable cattle producers to make “balanced” selection decisions to improve profitability, by taking into account the growth, carcase, birth, fertility and efficiency potential of an animal, to identify the animal that is most profitable for a particular commercial production system and market endpoint.
What is an EBV?
An EBV (estimated breeding value) is an estimate of an animal’s genetic merit for a given trait. BREEDPLAN EBVs are routinely estimated using the BREEDPLAN software by the Agricultural Business Research (ABRI) at UNE. EBVs are reported in the units of the trait (e.g. kilograms for weight EBVs). EBVs are used to compare individuals within a breed. If the EBVs of two bulls were: Bull A = 100kg and Bull B = 120kg, we would expect 1) the progeny of Bull B to have higher performance on average and 2) the difference in average performance of the progeny of these bulls to be 10kg ([120-100]/2) because half the genes are contributed by the while the other half of the genes are contributed by the dam.
What is EBV Subgrouping within an index?
Subgrouping of EBVs is when a group of EBVs (e.g. 200/400/600 day weight and mature cow weight) which impact a certain production characteristic (e.g. Growth) are combined to demonstrate their combined effect on profit as described by the index of interest. These subgroups have been created in a way that is envisaged, will assist producers select animals based on specific focus areas, e.g. fertility without needs to simultaneously consider all relevant EBVs. Currently there are 2 subgroups, depending on the EBVs available for each breed: Birth & Calving, Carcass, Efficiency, Fertility, Growth and Temperament & Structure.
How does the Subgroup Rating work?
The subgroup rating provides an indication of the animal’s genetic merit for a particular subgroup compared to the rest of the breed based on a percentile rankings. For example, an animal with a score of 20%, sits in the top 20% of the breed for that particular subgroup. The sliding bars for each subgroup can be used to filter animals that do or do not match your needs based on percentile rankings.
Why are my results changing when I move the sliding bars?
The filtering of animals is displayed in real time, meaning that as you adjust the sliding bars, those animals that do not match your criteria are filtered out.
Why do other sliding bars move when I have only adjusted 1 bar?
The sliding bars are designed to be dynamic. Once you restrict one subgroup within a certain percentile range, the other bars adjust to illustrate the percentile range the remaining animals are in for the other subgroups. This provides you with an indication of the compromises you will needs to make concerning production characteristics as represented by the subgroups in order to find bulls that match your specific needs, while still accounting for the underlying economical and biological implications of your decision.
What is the Index Rating?
The Index rating is a representation of the percentile band using star ratings an animals is contained in for the index of interest. Each half start is equivalent to 10% of the breed such that an animal with a 5 star rating is considered to be in the top 10% of the breed for that index while an animal with a 2.5 star rating is in the top 50% of the breed.
What is Subgroup Merit?
The Index Subgroup Merit graph displays the genetic merit, or rating, of an animal for the respective subgroups.
What are the EBV Components?
The EBV Components graph displays the percentile band for individual EBVs that are used within each subgroup. Each EBV is only used in one sub-group.
What’s the difference between Horn Status and Poll Gene Test?
Horn status is the visually observed on the animal. The poll gene test provides the result from gene testing as either polled or horned, so you can be certain that a polled animal is a true poll or heterozygous for that trait. A heterozygous animal will pass on the horned gene to 50% of their offspring.
What does Traits Observed mean?
The traits observed are those that have been recorded for an animal. These raw measurements are used by BREEDPLAN in the estimation of that animal’s EBVs and directly impact the level of accuracy for each trait.