Page 57 - Woodbank Matariki 2021 Catalogue ebook

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 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 Herefords currently report three different selection indexes. These are the
Hereford Prime Index, Beef Heifer Index and the Dairy Beef Index. These Indices relate to
typical commercial herds in New Zealand targeting these specifications.
Index values are reported as EBVs, in units of relative earning capacity ($) 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 self-replacing cow herd. A selection
index combines the EBVs with economic information (costs and returns) for specific market and
production systems to rank animals based on relative profit values. Note that different types
of animals can give similar profit values, so consideration should be given to both the index
and the component EBVs when selecting animals for a particular production system. More
information is available on selecting animals using a selection index.
The Index values are derived using BreedObject technology.
HEREFORD PRIME INDEX - Estimates the genetic differences between animals in net
profitability per mixed age cow joined for a typical self-replacing commercial herd where
Hereford bulls are joined to either Hereford or other British breed females and targeting the
production of grass finished steers for the Hereford Prime program. Selected heifers are
retained for breeding and so maternal traits are of importance. Steers target 550 kg live weight
(300 kg carcase weight & 7 mm P8 fat) at 20 months of age, and heifers 475 kg (260 kg carcase
weight & 8 mm fat depth), at 22 months of age.
BEEF HEIFER INDEX - Estimates the genetic differences between animals in net profitability
per yearling heifer joined for a typical self-replacing commercial herd where Hereford bulls
are joined to either Hereford or other British breed heifers. Selected heifers are retained for
breeding and so maternal traits are of importance. Steers target 510 kg live weight (280 kg
HSCW and 7 mm P8 fat depth) and heifers 450 kg ( 250 kg HSCW and 8 mm P8 fat depth) at
20 months of age.
DAIRY BEEF INDEX - Estimates the genetic differences between animals in net profitability
per mixed age dairy cow joined with all progeny destined for slaughter. Steers and heifer
progeny target 550 kg live weight (300 kg carcase weight and 6 mm fat depth) at 24 months
of age and at 475 kg live weight (260 kg carcase weight and 7 mm fat depth) at 22 months,
respectively.
2021 HEREFORD BREEDPLAN AVERAGES

DIR GL BW 200 400 600 MCW MILK SS
+1.1 -0.3 +4.4 +33 +54 +77 +68 +16 +2.0

EMA RIB RUMP RBY IMF HP B/H D/B
+3.3 +0.5 +0.6 +0.8 +0.4 +$102 +$104 +$100

ACCURACY
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.

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