Group Breedplan calculates predictions of genetic merit called EBVs for a range of traits on a national across-herd basis. The EBVs are calculated using information of the animal’s own performance, the performance of all known relatives, the relationships between the traits and the pedigree links between animals and between herds.
EBVs are expressed as plus(+) or minus(-) the given measure (eg. + or – cm for scrotal size). Animals are ranked in comparison to a breed base of 0.
The following EBVs are reported in this catalogue:
200 Day Milk (kg) is an estimate of an animal’s milking ability. For sires, this EBV is indicative of their daughter’s milking ability as it affects the 200 day weight of their calves.
200 Day Growth (kg) estimates the genetic differences between animals in live weight at weaning, adjusted to 200 days of age. It is independent of the influence of milk.
400 & 600 Day Weight (kg) estimate the genetic differences between animals in live weight at 400 and 600 days of age respectively.
Mature Weight (kg) is based on cow weight when her calf is weaned, adjusted to 5 years of age. It estimates the genetic differences between animals in live weight at this age and is an indicator of growth at later ages and potential feed maintenance requirements of the females in the breeding herd.mSince recording mature weights, we believe the maturity patterns of our cattle are being more accurately mapped and hence all growth EBVs have become more accurate.
Scrotal Size (cm) estimates the genetic differences between animals in scrotal circumference at 400 days of age and gives an indication of sexual maturity as a yearling.
Eye Muscle Area (cm2) estimates the genetic differences between animals for EMA at the 12/13th rib in a 300kg dressed carcase.
Rib & Rump Fat (mm) estimate the genetic differences between animals for fat depth at the 12/13th rib and P8 sites respectively, in a 300kg dressed carcase. More positive EBVs indicate more subcutaneous fat and earlier maturity.
Intra-Muscular Fat Percentage (%) is an estimate of the genetic differences between animals for percent intra-muscular fat (marbling), in a 300kg carcase.
An accuracy is presented with every EBV and gives an indication of the amount of information that has been used in the calculation of that EBV. The higher the accuracy the lower the likelihood of change in the animal’s EBV as more information is analysed for that animal and it’s relatives.
Accuracies are calculated by taking into account the following points:
- The heritability of the trait
- The size of the groups in which the animal is compared
- Genetic associations with other observed traits
- The accuracy of the parents’ EBVs for that trait
- The amount of performance information available