Page 17 - Totaranui Angus Catalogue ebook

of puberty in female progeny and therefore selection for increased Accuracy values range from 0-99%.
scrotal size will result in reduced age at calving of female progeny. As a rule, animals should be compared on EBVs regardless of
Days to Calving accuracy. However, where two animals have similar EBVs the one
with higher accuracy could be the safer choice, assuming other
Days to Calving EBV (days) indicates the fertility of the daughters factors are equal. For further information please contact NZ Angus
of the sire. It is the time interval between the day when the or TransTasman Angus Cattle Evaluation.
female is first exposed to a bull in a paddock mating to the day
when she subsequently calves. A negative EBV for days to calving
indicates a shorter interval from bull-in date to calving and SELECTION
therefore higher fertility.
Carcase Weight INDEXES
Carcase Weight EBV (kg) is based on abattoir carcase records and
is an indicator of the genetic differences in carcase weight at the
standard age of 750 days. There are currently three different selection indexes calculated for
New Zealand Angus animals. These are Self-Replacing, AngusPure
Eye Muscle Area and Heifer/Dairy Terminal. Each selection index describes a different
Eye Muscle Area EBV (sq cm) is calculated from measurements production/market scenario and relates to a typical commercial herd
from live animal ultrasound scans and from abattoir carcase data, in New Zealand that is targeting the following specifications.
adjusted to a standard 400 kg carcase. This EBV estimates genetic
differences in eye muscle area at the 12/13th rib site of a 400 kg Index values are reported as EBVs, in units of relative earning
dressed carcase. More positive EBVs indicate better muscling on capacity ($’s) for a given market. They reflect both the short-term
animals. Sires with relatively higher EMA EBVs are expected to profit generated by a sire through the sale of his progeny, and the
produce better-muscled and higher percentage yielding progeny at longer-term profit generated by his daughters in a self-replacing
the same carcase weight than will sires with lower EMA EBVs. cow herd. More information is available on selecting animals using a
selection index.
Rib Fat and Rump Fat The Index values are derived using BreedObject technology. More
Rib Fat and Rump Fat EBVs (mm) are calculated from measurements information is available from the BreedObject web site.
of subcutaneous fat depth at the 12/13-rib site and the P8 rump
site (from live animal ultrasound scans and from abattoir carcases) Self-Replacing Index ($)
and are adjusted to a standard 400 kg carcase. These EBVs are Self-Replacing Index ($) - Estimates genetic differences between
indicators of the genetic differences in fat distribution on a standard animals in net profitability per cow joined for a self-replacing
400 kg carcase. Sires with low, or negative, fat EBVs are expected commercial herd, targeting the production of grass finished steers.
to produce leaner progeny at any particular carcase weight than Steers are assumed marketed at 525 kg live weight (280 kg carcase
will sires with higher EBVs. weight and 10 mm fat depth) at 16 months of age.
Retail Beef Yield AngusPure Index ($)
Retail Beef Yield EBV (%) indicates genetic differences between AngusPure Index ($) – Estimates genetic differences between
animals for retail yield percentage in a standard 400 kg carcase. animals in net profitability per cow joined for a self-replacing
Sires with larger EBVs are expected to produce progeny with higher commercial Angus herd, targeting the production of grass finished
yielding carcases. steers for the AngusPure programme. Steers are assumed marketed
at 525 kg live weight (280 kg carcase weight and 10 mm fat depth)
Intramuscular Fat at 18 months of age with a significant premium paid for marbling.
Intramuscular Fat EBV (%) is an estimate of the genetic difference
in the percentage of intramuscular fat at the 12/13th rib site in a Heifer/Dairy Terminal Index ($)
400 kg carcase. Depending on market targets, larger more positive Heifer/Dairy Terminal Index ($) – Estimates the genetic differences
values are generally more favourable. between animals in net profitability per female joined in an example
Docility herd where all progeny are marketed. All progeny are marketed at
approximately 510 kg live weight (280 kg carcase weight and 7 mm
Docility EBV (%) is an estimate of the genetic differences between fat depth) at approximately 24 months of age.
animals in temperament. Docility EBVs are expressed as differences
in the percentage of progeny that will be scored with acceptable Note that $Index values for individual animals are sensitive to the
temperament (ie. either “docile” or “restless”). assumptions used in the BreedObject analysis to calculate the
selection index. More information is available on the weightings
Accuracy used in the New Zealand Angus Selection Indexes.
Accuracy (%) is based on the amount of performance information
available on the animal and its close relatives - particularly the
number of progeny analysed. Accuracy is also based on the
heritability of the trait and the genetic correlations with other
recorded traits. Hence accuracy indicates the “confidence level”
of the EBV. The higher the accuracy value the lower the likelihood
of change in the animal’s EBV as more information is analysed for
that animal or its relatives. Even though an EBV with a low accuracy
may change in the future, it is still the best estimate of an animal’s
genetic merit for that trait. As more information becomes available,
an EBV is just as likely to increase in value, as it is to decrease.

TOTARANUI 2YR OLD BULL SALE 15