Resources

Learn about the importance of Estimated Breeding Values (EBVs) and how we use them to enhance our breeding program.

We are big believers in using performance recording to improve genetic gain. This need to be a combination of both Phenotypic (Physical measurement) Genomic (DNA) and Objective (Human Observation)

EBV’s when used correctly are a very powerful tool for animal selection. We just need to respect how powerful they are and like anything understand how connected everything is.

Calving Ease (CE Dir): We look at calving ease EBV’s of sires. However, in our herd if we have to put a hand on a cow while calving, it is out of our herd. We don’t see how that variation in calving ease can be so big, either you produce a live calf at weaning or you don’t. In our herd there is no middle ground.

Calving Ease Daughters (CE Dtrs): The same as CE Dir, we don’t have a problem in our herd with calving, and we don’t pay much attention to it.  The accuracy of this EBV is being eroded with the number of ET calves sired, where this data is not counted towards the EBV.

Days to Calving: EBVs are estimates of genetic differences between animals in the time from the start of the joining period (i.e. when the female is introduced to a bull) until subsequent calving.
Days to Calving EBVs are calculated from the joining records submitted for both heifers and cows who have been mated naturally in a paddock situation, and are expressed in day units.
Lower Days to Calving EBVs indicate an animal is expected to produce progeny that conceive earlier in the joining period. Females with lower Days to Calving EBVs also tend to show earlier puberty as heifers and earlier return to oestrous after calving.

Gestation length (GL):  GL is an important trait. It is calculated from the joining date and date of birth records for calves conceived by either artificial insemination (AI) or hand mating, and/or genomic information, and are expressed in day units.

Lower Gestation Length EBVs indicate an animal is expected to produce calves that are born with a shorter gestation length. Our Herd average GL is 10 days shorter than the 282 days for the Angus breed. This has a big impact on ensuring that cows can calve within a 365 day period.

Birth Weight (BW) Birth weight is an important trait and highly heritable. Every calf ever born in our stud herd has been weighed within 24 hours of birth. If anything, we need to increase our birth weight a little. In a self-replacing herd, the concept of using “heifer bull” needs to be challenged. Every bull should be able to produce replacements.

200, 400 600 Day weight. Estimate of the genetic difference among animals in weight at 200, 400 and 600 days respectively. As the animal gets older the accuracy of this EBV increases from 12%, 23 % and 35 %. Growth is important, but we need animals that stop growing at 400 days, otherwise our Mature cow weight blows out. Overall, in our opinion, the angus cows are too big. We are really focusing on reducing mature cow size, and therefore reducing our growth EBV’s.

Milk “Milk EBVs are estimates of genetic differences between animals in live weight at 200 days of age due to the maternal contribution of its dam.” How is this calculated?  We don’t look at Milk EBV’s, as we just think it’s confusing.

Mature Cow Weight (MCW) Highly Heritable (40%) and unfortunately across the Angus breed, is the least of the growth traits measured. At OMC we weigh every cow every year at weaning and that data is submitted to form the basic of the MCW EBV. We also use this data to create our own Weaning Percentage.  Our ideal MCW is 500-560 Kg.

Weaning Percentage. This is the cow’s weight divided by the calf weight on the day of weaning, displayed as a percentage. We have also weighed average back to a 3 score condition using 70 kg per condition score to account for changes in cow body condition at weaning.

Our goal is to have our herd average above 55%.”

Scrotal Size (SS): These are estimates of the genetic differences among animals in Scrotal circumference at 400 days. The trait is highly heritable at 39%. It also is highly correlated with heifer puberty, an important fertility trait. As our bulls are raised on a 100% grass only diet, our SS measurement is very accurate and is 100% scrotal; no fat at all. The physical measurement in CM is displayed in our catalogue.

Carcass Weight (CWT) Carcass Weight EBVs are estimates of genetic differences between animals in hot standard carcass weight at 750 days of age. It is highly heritable at 42 %

Carcass Weight EBVs are calculated from the hot standard carcass weight of animals between 300 and 1000 days of age, and/or genomic information, and are expressed in kilogram units.

Higher Carcass Weight EBVs indicate the animal is expected to produce progeny with heavier carcass weights. While it is important, as our overall growth profile is lower, because our focus is on reducing MCW, our animals don’t rank high on CWT EBV’s. This is a compromise between having bragging rights (per head performance) or profitability (per Hectare performance). We will take profitability every time.

Eye Muscle Area (EMA) EBVs are estimates of genetic differences between animals in eye muscle area at the 12/13th rib site in a 400 kg carcass. 20 % Heritable. It is a trait we have to pay attention to, but we don’t want extremes. If our EMA becomes too big, we had better get used to eating thin 500-gram scotch fillets that are hard to fit on a plate.

Docility EBV’s are an Estimate in the genetic difference in Animal temperament.

Our animals are measured for docility using the crush test at weaning at approx. 200 days of age, which objectively assesses the animals temperament as it leaves the crush.  They are independently assessed at the time of structural assessment. These two pieces of data combine to predict the EBV. Higher Docility EBVs indicate an animal is expected to produce a higher percentage. Our animals are very good to handle. We pride ourselves on handling our animals so they handle be put into a stressful situation and recover from it.

Rib Fat (RIB) EBVs are estimates of genetic differences between animals in fat depth at the 12/13th rib site in a 400 kg carcass. Heritability 45%

Rump Fat (P8) EBVs are estimates of genetic differences between animals in fat depth at the P8 rump site in a 400 kg carcass. Heritability is 32 %

Intramuscular Fat (IMF) EBVs are estimates of genetic differences between animals in intramuscular fat (marbling) at the 12/13th rib site in a 400 kg carcass. Heritability of 37 % and is of great importance to fleshing ability,

Positive Fat is highly desirable, and has a high correlation to fleshing ability, and being “low maintenance”. An animal will only lay down fat after all other requirements have been met, so we want to breed animals that do that easily.

Selection Indices: We have developed our own OMC selection index with the help of the team at NextGen Agri. We have place a heavier weighting on the fertility and maternal traits then the Angus index and also placed a higher weighting on our most limiting resource grass

Estimated Frame Score:  As we are selling our bulls as yearlings, we don’t get to see them fully grown out. We have estimated the Mature Frame score by using the yearling Hip Height measurement taken on 29 July 2021, and running it through the conversion table that we received from Kit Pharo and Beef Improvment.

This have proven to be accurate over the past several years.

We measure hip Hight in CM as a yearling and run through the Hip Height/Frame.