Page 50 - Shian Angus Sale Catalogue eBook.pdf

Days to Calving EBV (days) indicates the fertility of the daughters of the sire. It is the time interval between the day when the 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 indicated a shorter interval from bull-in date to
calving and therefore higher fertility.
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.
Eye Muscle Area EBV (sq cm) is calculated from measurements from live animal ultrasound scans and from abattoir carcase data, adjusted to a standard 400kg
carcase. This EBV estimates genetic differences in eye muscle area at the 12/13th rib site of a 400kg dressed carcase. More
positive EBVs indicate better muscling on animals. Sires with relatively higher EMA EBVs are expected to produce better-muscled and higher
percentage yielding progeny at the same carcase weight than will sires with lower EMA EBVs.
Rib Fat and Rump Fat EBVs (mm) are calculated from measurements of subcutaneous fat depth at the 12/13th rib site and the P8 rump site (from live animal
ultrasound scans and from abattoir carcases) and are adjusted to a standard 400kg carcase. These EBVs are indicators of the genetic differences in fat distribution
on a standard 400kg 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 EBV (%) indicates genetic differences between animals for retail yield percentage in standard 400kg carcase. Sires with larger EBVs are ex-
pected to produce progeny with higher yielding carcases.
Intramuscular Fat EBV (%) is an estimate of the genetic difference in the percentage of intramuscular fat at the 12/13th rib site in a 400kg
carcase. Depending on market targets, larger more positive values are generally more favourable.
Selection Indices
There are currently three different selection indexes calculated for New Zealand Angus animals. These are Self Replacing Index, AngusPure Index and Heifer/Dairy
Terminal Index. Each selection index describes a different production/market scenario and relates to a typical commercial herd using Angus bulls. Producers are
advised to use the selection index that most closely aligns to their production system. Each selection indexes is focused on efficient beef production, including ma-
ternal traits where appropriate. In addition, each selection index targets the following specifications.
Self Replacing Index (SRI) - Estimates the genetic differences between animals in net profitability per cow joined in an example self-replacing commercial herd
that targets the production of grass finished steers. Steers are assumed marketed at approximately 480 kg live weight (265 kg carcase weight and 7 mm fat depth) at
approximately 16 months of age. Selected heifers are retained for breeding and the balance marketed at approximately 16 months weighing 415 kg (230 kg carcase
weight and 8 mm fat depth). As some daughters are retained, maternal traits are also of importance.
AngusPure Index (API) - Estimates the genetic differences between animals in net profitability per cow joined in an example self-replacing commercial Angus
herd that targets the production of grass finished steers for the AngusPure programme. Steers are assumed marketed at approximately 530 kg live weight (290 kg
carcase weight and 10 mm fat depth) at approximately 20 months of age. Selected heifers are retained for breeding and the balance marketed at approximately 20
months weighing 450 kg (240 kg carcase weight and 10 mm fat depth). A significant premium for carcase quality was assumed and, as some daughters are retained,
maternal traits are also of importance.
Heifer/Dairy Terminal Index (HDT) - Estimates the genetic differences between animals in net profitability per female joined in an example herd where all proge-
ny are marketed. All progeny are marketed at approximately 510 kg live weight (280 kg carcase weight and 7 mm fat depth) at approximately 24 months of age.
All selection indexes are reported as an EBV, in units of net profit per cow mated ($) for a given production/market scenario. They reflect both the short term profit
generated by a sire through the sale of his progeny, and the longer term profit generated by his daughters in a self-replacing cow herd (where applicable).
The index values are derived using BreedObject technology. More information is available from the BreedObject Website.
A full explanation of EBV’s will be on display on sale day.