Basically the GeneSTAR® test included a suite of 12 markers: 4 markers for Marbling, 4 markers for Tenderness and 4 markers for Feed Efficiency. Results were reported in both the 2008 and 2009 Hartebeestloop Auction Catalogues as a star result for each individual marker, and also as a combined star rating for each trait.
There is a maximum of 8 stars available for any one of these traits. Results for each marker within a trait are additive, which means the more stars, the better. An animal with 8 stars has the best possible result on the current scale of tests and will on average have a higher score than an animal with a lower GeneSTAR® star result.
During 2010 we moved from “Stars” to Molecular Value Predictions (MVP’s) and the MVP’s were reported in the 2010 Hartebeesloop 2010 Auction Catalogue (5 MB). There were a number of reasons why we decided on MVP’s:
- MVP is an estimate of the genetic potential of an animal calculated from the sum of all genetic effects at specific genome locations and these include both additive and non-additive effects.
- The MVP calculates the effect that each DNA marker contributes to the result by assessing both the size of the effect (small or large) and the direction of the effect (positive or negative) and then combines it into a single value that can be used as an overall indicator of genetic potential.
- MVP’s can be used to rank animals based on their genetic potential to express the trait. (Animal can then be compared against others, within or across breed).
- The animal’s actual DNA genotype expressed as a MVP can be used to make early and accurate breeding decisions increasing the accuracy of selection and decreasing the age at which animals can be selected.
The main reason why we moved from GeneSTAR to Molecular Value Predictions in 2010 and once again in 2011 from Molecular Value Predictions to Igenity Genome Selection is to apply the most powerful genetic technology available to increase the reliability of the breeding value predictions for young animals.
At Hartebeestloop we completely understand the limitations in reliability and accuracy of the estimated breeding values (EBV’s) of young animals – it basically represents mid-parent values. For instance, milk production and the maternal values for bulls are not directly measured and EBV’s will change as own recordings and the recordings of progeny become available. These traits of high economic importance have a low heritability. This is a shortcoming of EBV’s and a major problem for us to breed the best bulls for our partner herds, fellow stud breeders and commercial farmers. We are tired of explaining the change in EBV’s (mostly negative changes because those are the farmers that phone you) that happens over time. Any technology that will enhance the reliability of the EBV’s for young animals, especially bulls, will contribute to a greater breeding success rate at Hartebeestloop.
- Igenity Genome Selection
This technology will eventually lead to a Genomic Estimated Breeding Value (GEBV). The genomic values will be “linked” with the BLUP EBV’s and the reliability of the GEBV’s for a young (not yet performance tested) beef bull may be as high as when 10 daughters of a dairy bull were recorded.
We like the concept of a GBEV as it will combine all the trusted and proven concepts of BLUP with the direct genomic value of the animal. There is still a lot of work to be done by the Bonsmara Cattle Breeding Societies worldwide to establish reference populations and to join hands with each other and also international organisations like Interbull. At Hartebeestloop we have the Illumina 50K SNP data available for all our stud bulls used in the herd and also all our auction bulls.
We would not like to start with genome selection when it becomes the standard in beef cattle production. We would like to be the pace-setter and front-runner herd in Africa with genome selection already in place.
- Some more information on DNA and genetic testing
We hardly ever use DNA and genetic testing to monitor genetic defects and conditions – currently the Bonsmara breed are almost free of any genetic disorders. As a matter of fact we have never experienced any genetic disorder in all our years of Bonsmara breeding. We are contemplating testing for Freemartinism because of the number of twins (different genders) born over the last couple of years. With twins from different genders we would like to identify the sub-fertile bull calves and non fertile heifers at a much earlier age. It makes economic sense to channel them into a production system outside the stud.
DNA profile analysis is the backbone of breeding confirmation and this forms part of the guarantee that all stock bred at Hartebeesloop has the correct selected lineage.
- The current Hartebeestloop philosophy with regard to DNA and Genetic Testing, GeneSTAR, Molecular Value Predictions and Igenity Genome Selection.
We have realized very early that there are few Bonsmara breeders that are involved with DNA genetic testing. Furthermore, we have noted that very few stud breeders of all breeds in Africa are participating in this technology. Comparison of Hartebeestloop animals with other animals, other herds, other breeds and across farms and countries became very difficult.
At Hartebeestloop we resorted to cross-referencing to determine the rankings of individual animals on the farm for specific traits.
I will use a simple example to illustrate:
Cross-referencing bull HART 02-0011 for potential as a parent to enhance Average Daily Gain (ADG) and Feed Conversion Rate/Feed Efficiency and Residual Feed Intake in the herd. For the purpose of this simple exercise I will combine Feed Conversion Rate/Feed Efficiency and Residual Feed Intake into the term Hartebeestloop Bull Feed Needs. I have taken ADG and Hartebeesloop Bull Feed Needs as the 2 traits are highly correlated.
- We determine the mid parent values for both ADG and Hartebeestloop Bull Feed Needs for all his male progeny. Easily obtain with BeefPro software.
Beefpro will refer to Feed Conversion Rate.
- The performance measurement of all his bull calves for ADG and Hartebeestloop Bull Feed Needs are calculated during the Phase D on the farm and Phase C Intensive growth tests. We will put more emphasis on how the progeny compares to the average of the groups tested than to the minimum breed standards.
- HART 02-0011 has bull calves that where tested using GeneSTAR, Molecular Value Predictions and Igenity Genome Selection. A bull would only be tested for one of the 3 genetic testing systems depending on the year the bull was auctioned.
We can now cross-reference any paternal stud sire genetic line on direct performance where a number of progeny took part in performance testing for a specific trait (indicated as an EBV as part of the BLUP analysis) and the information we received from genome selection technology.
If the majority of the progeny are average or above for a specific trait like Hartebeestloop Bull Feed Needs during the GeneSTAR, Molecular Value Predictions and Igenity Genome selection, we rate the bull high on his potential as a parent to enhance this trait in the herd.
We do the same for meat tenderness combining the results from Real Time Ultrasound scanning and DNA genetic testing. Calving ease (Igenity Genome Selection) are correlated with pelvic measurements and a hands-on point system for calving ease recording at calving.
The value of DNA genetic testing at Hartebeestloop is currently used for cross-referencing animals and determining the genetic lines that constantly perform well on specific traits.