TransTasman Cattle Evaluation is a modern genetic evaluation programme for beef cattle breeders. It compares cattle on the basis of their breeding values.
TransTasman Cattle Evaluation (TACE) is formerly known as BreedPlan.
TACE provides predictions of the genetic merit of individual animals called Estimated Breeding Values (EBVs). These EBVs are used by Angus breeders and bull buyers to assist in selection decisions and purchase of breeding stock. EBVs are now accepted by most beef producers as an essential tool in the breeding and marketing of seedstock.
EBVs are based on all available pedigree and performance records provided by breeders in New Zealand and Australia, along with available overseas genetic information. EBVs provide the best means for comparison of the relative genetic merit of animals across the breed for those traits included in the analysis. EBVs obviously cannot be used in isolation in any selection or purchase decision. Visual assessment is still necessary for those characteristics not adequately described by EBVs.
GROUP TACE EBVs have been proven to be more accurate than raw performance measurements for assisting in the selection of breeding stock. Research results and industry experience has shown that that more rapid genetic gains can be achieved in herds which make use of EBVs in their selection decisions. In the calculation of EBVs all available pedigree and performance information on each animal and its relatives (parents, ancestors, siblings, progeny, etc.) is combined to provide a single best estimate of an individual’s genetic merit for each trait. In addition, allowance is made for environmental differences between properties, seasons and management groups on each animal’s performance. Differences in heritabilities between traits and genetic associations between traits are also accounted for in the calculation of EBVs.
The service is run by the Agricultural Business Research Institute (ABRI) at the University of New England, Armidale, NSW., Australia. TACE research and development is carried out by the Animal Genetics and Breeding Unit (AGBU), also at the University of New England.
An overview of TACE.
What you see in an animal is the effect of genes they inherit from their parents modified by the effect of non-genetic (environmental) factors such as feeding and parasite control, sex, age of dam etc.
To improve your herd by selection, you need to evaluate the genetic merit of cattle – that is the proportion of the animals performance which is controlled by its genes, and not its overall performance which has been influenced by environmental and other non-genetic effects.
Early approaches to performance recording used the ratio system. The animals performance was corrected for sex, age of calf and age of dam, and then compared as a percentage to other animals within the same management group. Comparison of animals across management groups, herds or years was not possible using this system.
TACE represents a major improvement over the more traditional methods of performance recording. It uses all the records available on the animal and its relatives to disentangle genetic and environmental factors, giving the best estimate of the animals breeding value that is possible from the available information.
To allow comparison of animals from between management groups or even different properties genetic links between contemporary groups are essential. A genetic link is achieved where animals in one group/herd have a parent in common with an animals in another group/herd. For sires, this cross linkage is usually achieved through AI but could also be through common dams.
TACE uses “multiple trait” evaluation which further increases the accuracy of the EBVs
Because there is usually a genetic association between different traits (which may be positive or negative and vary from weak to strong) this information can be used enhance measurements of recorded traits or estimate an animal’s breeding value for traits that have not been directly measured.
For example, 200 day weight has a positive association with 400 day weight – that is, as 200 day weight increases so does 400 day weight.
The multiple trait analysis also helps to reduce the “bias” which can be introduced by a previous selection decision, say selective joining or dis-proportional culling. For example, culling of lighter calves at weaning will give higher group average 400 day weight. The fact that the remaining animals have a higher group average as a result of previous culling is accounted for in TACE as long as the records of the previously culled animals are included in the evaluation.
EBVs are expressed in the same units as they were measured (eg, kg) and are estimated relative to the breed benchmark of zero, which was established at the time of the first analysis.
What does TACE do?
TACE adjusts field measurements (raw data) submitted by the breeder to calculate an estimate of the animals breeding value (EBV). It uses information from the performance of the individual animal as well as its relatives, and allows for differences in environment and chance that animals have been exposed to and that would otherwise bias our selection decisions.
It provides the best estimate of an animal’s breeding value from the information available.
TACE is a useful aid to selection, not because you are a poor judge of cattle but because when it comes to long term memory recall or making simultaneous adjustments for known environmental effects over a number of traits, human brain power is no match for a computer.
Why use TACE to analyse performance records?
What we see or measure in an animal is influenced by both environmental and genetic factors.
Environmental factors influence the way an animal may look or perform within a given environment but not the way his progeny will look or perform within a different environment. Environmental influences include nutrition (differences between paddocks or properties, supplementary feeding, or trace mineral capsules), management such as castration and drenching, grooming and clipping, gut-fill, ill-health, and parasites.
Observed differences of performance between animals resulting from differences in environment can be large, but are not inherited by their progeny, and as such can lead our selection decision astray.
Genetic factors are the result of genes inherited from the parents and are the blueprint for future performance, both of the individual and its progeny.
You buy a bull not for what he looks like but how his progeny will perform. It is only when environment factors are either standardised or adjusted for that real genetic differences become apparent.
TACE uses sophisticated computing technology to adjust for known environmental effects over a number of selection traits.
What are the key features of the TACE analysis?
Key features of TACE include:
- Calculating breeding values for all animals and all traits simultaneously, hence its description as a “Multiple Trait Animal Model”.
- Using performance information from relatives and progeny, as well as the individual animal.
- Using the known correlation between traits to increase the accuracy of measured traits and to calculate EBVs for non-measured traits such as birth weight or weight at later ages.
- The use of “country of origin” performance information of imported (introduced) animals.
- Adjusting for the effects of differences of nutrition, age of dam, age of calf and management group treatments. These are non-genetic differences that will affect the observed performance of the individual but are not passed onto its progeny.
- Adjusting for the effects of preferential mating of a sire to selected cows, unequal and selective culling, and competition between comparison groups.
Removing these biases and taking into account the performance of other animals makes TACE predictions more accurate than predictions on visual assessment.
As well as giving you EBVs for your animals, TACE also plots the genetic trend for your herd. This trend shows you the genetic direction of your herd for individual traits from year to year, and also lets you see the effect of environmental changes such as pasture improvement on your overall herd production.
Visit Beef + Lamb New Zealand Genetics for further information.