Understanding the EBVs

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 % Dir = 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 = Daughter's Calving Ease - The EBV for daughters' calving ease indicates how easily that sire's daughters will calve at two years of age.

Gestation Length (days) is an estimate of the time from conception to the birth of the calf and is based on AI records. Lower (negative) GL EBVs indicate shorter gestation length and therefore easier calving and increased growth after birth.

Birth Weight EBV (kg) is based on the measured birth weight of progeny, adjusted for dam age. The lower the value the lighter the calf at birth and the lower the likelihood of a difficult birth. This is particularly important when selecting sires for use over heifers.

200 Day Growth EBV (kg) is calculated from the weight of progeny taken between 80 and 300 days of age. Values are adjusted to 200 days and for age of dam. This EBV is the best single estimate of an animal's genetic merit for growth to early ages.

400-Day Weight EBV (kg) is calculated from the weight of progeny taken between 301 and 500 days of age, adjusted to 400 days and for age of dam. This EBV is the best single estimate of an animal's genetic merit for yearling weight.

600-Day Weight EBV (kg) is calculated from the weight of progeny taken between 501 and 900 days of age, adjusted to 600 days and for age of dam. This EBV is the best single estimate of an animal's genetic merit for growth beyond yearling age.

Mature Cow Weight EBV (kg) is based on the cow weight when the calf is weighed for weaning, adjusted to 5 years of age. This EBV is an estimate of the genetic difference in cow weight at 5 years of age and is an indicator of growth at later ages and potential feed maintenance requirements of the females in the breeding herd. Smaller, or more moderate EBVs are generally more favourable.
The Mature Cow Weight EBV may also be used by steer breeders wishing to grow animals out to a larger weight.

Milk EBV (kg) is an estimate of an animal's milking ability. For sires, this EBV indicates the effect of the daughter's milking ability, inherited from the sire, on the 200 and 400 day weights of her calves. For dams, it indicates her own milking ability.

Scrotal Size EBV (cm) is calculated from the circumference of the scrotum, measured in centimetres and adjusted to 400 days of age. This EBV is an estimate of a sire's genetic merit for scrotal size and is positively correlated to age of puberty in female progeny.

Days to Calving (days) - This EBV indicates the fertility of the daughters of the sire. It is the time interval between the date 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 indicates 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 650 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 300 kg carcase. This EBV estimates genetic differences in eye muscle area at the 12/13th rib site of a 300 kg 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 12/13 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 intra-muscular fat at the 12/13th rib site in a 300kg carcase. Depending on market targets, larger more positive values are generally more favourable.

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. Accuracy ranges from 0-99% and indicates the probability of an EBV changing with the addition of more progeny data. The magnitude of possible change decreases as accuracy increases. Accuracy below 75% should be regarded as low, between 76-90% as medium and above 90% as high.

An accuracy value is reported with every EBV.