Page 66 - Otapawa Bull Sale 2021 ebook

SCROTAL CIRCUMFERENCE
No bull sold with a circumference of less than 34cm. Although bulls with 35-40 cm achieve
no higher conception rate than bulls with 30 -34 cm testicles, their daughters will as heifers,
cycle earlier in the breeding season and more will conceive. But don’t show any preference
for bulls with 37 - 40+ cm testicles over bulls with testicles of average size of 34 -37 cm,
because their daughters cycle no earlier in the breeding season.

UNDERSTANDING GROUP BREEDPLAN EBVS
What are EBVs: Estimated breeding values are best estimates of an animals genetic quality
of various traits. EBVs are rankings for an animals performance. It’s simple, if bred to similar
cows, a sire with bigger kilogram live weight EBV for 400 Day Weight, for example, can be
expected to leave calves that are on average heavier at 400 days than the progeny of a sire
with a smaller 400 Day weight EBV.
How are they calculated: EBVs are calculated using all the information that has been
recorded with the Hereford Association on an animal’s own performance for a trait, that is it’s
relatives and performance recorded “related traits”. The analysis uses data from all Hereford
Herds over the years of recording. The more information there is on an animal and it’s relations
for a trait that better the estimate (EBV).
What are they used for: Use EBVs as a tool to help you select a bull for it’s breeding
strengths relative to your needs. However don’t select on figures alone - there are many
other important traits that have no EBVs! Group EBVs can be used to compare animals
on performance from one Hereford to another Hereford. EBVs are calculated with a breed
nationally. You cannot compare animals on EBVs from one breed to another.
How accurate are EBVs? An accuracy percentage score is presented below each EBV
in the catalogue. The accuracy indicates how much information has been used to calculate
EBVs - higher the percentage the less likelihood of the EBV changing when more information
is recorded.
THE FIGURES EXPLAINED
Calving Ease EBVs: Are based on calving difficulty scores, birth weights and gestation
length information. More positive EBVs are favourable and indicate easier calving.
CE Direct = Direct Calving Ease - The EBV for direct calving ease indicates the
influence of the sire on calving ease in purebred females calving at two years of age.
CE Daughters = Daughters’ Calving Ease - The EBV for daughters’ calving ease
indicates how easily that sire’s daughters will calve at two years of age.
Gestation Length: Is based on AI records. Lower (negative) Gest EBVs indicate easier
calving and increased growth after birth.
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.

OTAPAWA 64