Who’s your daddy?

May 22, 2018 10:38 am

Registering Calves from Multiple Sire Joinings

There has been an increasing number of Angus Australia members utilising multiple sire joining, where several bulls are joined to a mob of females at the same time, followed by the utilisation of DNA technology to assign the individual sire of calves.

While this has a number of management advantages, there are a few key considerations that members must be aware of when registering calves arising from a multiple sire joining.

In particular, some members have elected to assign an individual sire from the multiple sire group when registering calves, and then amend the sire later following a DNA parentage verification test.  In the long run, this might work, but short term, registering calves with a potentially incorrect sire, causes serious complications.

Implications of guessing and fixing it later.

Angus Australia runs specific analyses that provide our members and the broader public with valuable information about each registered animal.  These include the Angus TACE analysis which produces estimates of the genetic merit of each animal, and GeneProb which calculates the percentage chance that each animal carries specific genetic abnormalities such as AM, NH, CA and DD.

Both Angus TACE and GeneProb rely on pedigree integrity to calculate their respective estimations and probabilities.  Obviously, no matter how many checks and balances are put in place, there is always the possibility that an animal may have an incorrect assignment somewhere in the pedigree. However, the more animals that have pedigree integrity issues, the harder it is for both TACE and GeneProb to calculate accurate results.

GeneProb Calculations

An example is provided below as to what can happen within the GeneProb analysis when the wrong sire is listed in a calf’s pedigree.

The calf, ABCN1, has been tested and has been identified as a carrier of DD (i.e. DDC). The calf’s dam, ABCF2, has not been tested for DD, but is expected to be free (i.e. DDFU) based on the tests that have been undertaken on animal’s in her pedigree.

In scenario 1, the calf has been registered with an incorrect sire, ABCG12, who has previously been identified as being free of DD (i.e. DDF). As the sire has been tested free, and the calf is a carrier, GeneProb assumes that the calf’s dam (who is untested) must actually be a carrier of DD.

GeneProb consequently assigns the dam with a 99% chance of being a DD carrier, and assigns each of her relatives (both pedigree and progeny) a probability of being a DD carrier based on their relationship to her.

In scenario 2, the correct sire ABCG17 has been assigned. By contrast to the incorrect sire in scenario 1, ABCG17 has previously been identified as being a carrier of DD. As the sire is a confirmed carrier, GeneProb has no reason to doubt the DDFU status of the calf’s dam, and the GeneProb probability for her and all her relatives remains unchanged.

This simple example demonstrates the potential issues that can be caused when incorrect sire details are provided when registering calves, even if the intention is to amend the sire details as soon as the DNA sire verification is conducted.


TACE EBV Calculations

Likewise, assigning the incorrect sire when registering calves from multiple sire joining can have significant impacts on the Estimated Breeding Values (EBVs) calculated in Angus TACE.
The EBVs that are initially generated for ABCN1 may potentially be quite different, subject to how different the EBVs are for the different sires in scenario 1 and scenario 2, and in the case of scenario 1 where the calf was registered with the incorrect sire, the EBVs may be quite misleading.

While some members may argue that this is not a problem, as they are aware that the animal is likely registered with the incorrect parentage and won’t take note of the EBVs until the DNA sire verification has been conducted, what is often overlooked is the impact that the calf’s performance can have on its relatives EBVs.

For example, the calf will more than likely have had birth weight, calving difficulty and gestation length information submitted in association with its registration. TACE will attribute this information to the sire that is recorded, and if the incorrect sire has been assigned, will incorrectly attribute the information to the wrong animal. As a result, the sire’s EBV may be misleading this may have a flow on affect to animals in his pedigree and his progeny, similar to GeneProb.

Best Practice: Registering calves arising out of multiple sire joining

To make sure these problems are avoided, and the GeneProb and TACE information is as accurate as possible, the following process should be undertaken when registering calves arising from multiple sire joining:

Step 1: Provide Angus Australia with details of the multiple sire groups.

This involves provision of a multi-sire group ID. (e.g “MULTABCM1” or “MULTABCM2”) and the Angus Australia ident of the sires joined.

The multi-sire group ID should be allocated with:

•    The letters e.g. “MULT”
•    The Angus Australia Member Id e.g. “ABC”
•     the joining year e.g. “M”
•    A number, beginning at 1, that corresponds to the multi-sire group e.g. “1”

Step 2: Submit your calf registration details as per usual, but with the multi-sire group ID specified as being the sire of the animal. The calves will be recorded with Angus Australia with a registration status of “pending”.

Step 3: Obtain hair samples for the calves arising from the multi sire joining and send them to Angus Australia for DNA parent verification. When completing the DNA test request form, only the multiple sire group ID needs to be specified, rather than all sires within the joining group.

Step 4: Once the results of the DNA parent verification test are available, Angus Australia staff will update the sire details with the correct sire, and register the calf in the appropriate register.

Obtaining Advice

Should you require any assistance, or have any questions regarding how to register calves from multiple sire joinings, please contact staff at Angus Australia.