Estimated Breed Values (EBVs)
Half of an animal’s genetic merit is passed on to their offspring. Although we can never accurately forecast an animal’s breeding value, we can make accurate estimates for certain desirable performance traits. An Estimated Breed Value is the best estimate of an animal’s genetic merit for that trait.
In the calculation of EBVs, the performance of individual animals within a contemporary group is directly compared to the average of other animals in that group. A contemporary group consists of animals of the same sex and age class within a herd, run under the same management conditions and treated equally. Indirect comparisons are made between animals reared in different contemporary groups, through the use of pedigree links between the groups.
New Zealand Simmental Breedplan
An accuracy is presented with every EBV and is 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 or it’s relatives. Accuracy below 75% should be considered low, however young bulls with performance data but no progeny will all have similarly low accuracy rates.
Birth Weight EBV (kg)
Birth weight is based on the measured birth weight of animals, adjusted for dam age. The lower the value the lighter the calf at birth and the lower the likelihood of a difficult birth. This is particularly important when selecting sires for use over heifers.
200-day Milk EBV (kg)
This estimated breed value 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 EBV (kg)
Growth EBV is calculated from the weight of animals taken between 80 and 300 days of age. Values are adjusted to 200 days and for dam age. This EBV is the best single estimate of an animal’s genetic merit for growth to weaning.
400-day Weight EBV (kg)
The 400-day estimated breed value is calculated from the weight of progeny taken between 301 and 500 days of age, adjusted to 400 days and for dam age. This EBV is the best single estimate of an animal’s genetic merit for yearling weight.
600-day Weight EBV (kg)
This Weight EBV is calculated from the weight of progeny taken between 501 and 900 days of age, adjusted to 600 days and for dam age. This EBV is the best single estimate of an animal’s genetic merit for growth beyond yearling age.
Carcase Weight EBV (kg)
Carcase weight EBV estimates the genetic difference in carcase weight at a standard age of 650 days. More positive EBVs indicate heavier carcases at 650 days of age.
Scrotal Size EBV (cm)
Scrotal size is an indicator of male fertility as expressed in semen quality and quantity. Higher (positive) EBVs indicate higher fertility. SS is also positively associated with female fertility.
Eye Muscle Area EBV (sq cm)
The eye muscle area estimated breed value is calculated from measurements from live animal ultrasound scans and from abattoir carcase data, adjusted to a standard 300 kg carcase. This EBV estimates genetic differences in eye muscle area at the 12/13th rib site of a 300 kg dressed carcase. More positive EBVs indicate better muscling on animals. Sires with relatively higher Eye Muscle Area EBVs are expected to produce better muscled
and higher percentage yielding progeny at the same carcase weight than will sires with lower Eye Muscle Area EBVs.
Rib fat and Rump fat EBVs (mm)
These are calculated from measurements of subcutaneous fat depth at the 12/13 rib site and the P8 rump site (from live animal ultrasound
scans and from abattoir carcases) and are adjusted to a standard 300 kg carcase. These EBVs are indicators of the genetic differences in fat distribution on a standard 300 kg carcase. Sires with low, or negative, fat EBVs are expected to produce leaner progeny at any particular carcase weight than will sires with higher EBVs.
Retail beef Yield Percent EBV (%)
This is a genetic estimate of the meat yield as a percentage of a 300kg dressed carcase. A more positive EBV indicates a higher percentage
yield for a 300kg carcase.
Intramuscular Fat EBV (%)
This is an estimate of the genetic difference in the percentage of intramuscular fat (marbling) at the 12/13th rib site in a 300 kg carcase. Depending on market targets, larger more positive values are generally more favourable