Page 9 - Kaingaroa Simmentals Catalogue ebook

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) 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 EBV (%) indicates genetic differences between animals for retail yield
percentage in a standard 300 kg carcase. Sires with larger EBVs are expected to produce
progeny with higher yielding carcases.
Intramuscular Fat EBV (%) 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.

Selection Indexes
New Zealand Simmental selection indexes are calculated for two market specifications,
namely, Maternal (Self Replacing) and Terminal. These Indexes relate to typical
commercial herds in temperate New Zealand targeting these specifications.
Indexes are reported as an EBV, in units of relative earning capacity ($’s) for a given
market. 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 sustainable cow herd,
if a proportion of heifers are retained for breeding.
The Indexes are derived using BreedObject technology. More information on this
technology is available from the BreedObject web site.

Maternal (Self Replacing) Index ($) Estimates the genetic differences between animals
in net profitability per cow joined for an example self replacing commercial herd (run in
a temperate environment) producing steers. This Index assumes that the joinings are to
British breed cows where there is only a modest concern about calving difficulty. The
steer progeny are pasture grown and finished and marketed to produce a 300 kg carcase
at 16 months. Daughters are retained for breeding.
More information is available on the EBV weightings and profit drivers for the Maternal
(Self Replacing) Index.
Terminal Index ($) Estimates the genetic differences between animals in net profitability
per cow joined for an example commercial crossbred herd (run in a temperate
environment) targeting grass-finished production. This Index assumes that the joinings
are to British breed cows where there is only a modest concern about calving difficulty.
Both heifer and steer progeny are pasture grown and finished and are then slaughtered to
produce a 300 kg carcase at 15 months. All progeny are slaughtered. More information is
available on the EBV weightings and profit drivers for the Terminal Index.
Kaingaroa Simmentals • 7