B66 Heritability, EPDs & Performance Data

Infovets Educational Resources – www.infovets.com – Slide 2

Heritability

Heritability is the measurement of how much of a trait is passed on to its offspring by genes.

Those traits that are more highly heritable can be used by the producer in selecting breeding stock.


Heritability Estimates


Heritability

Low: Reproductive traits Medium: Growth Traits (birth weight, wean weight, yearly weight,

rate of gain) High: Carcass traits


A producer currently has ewes that wean 70 lb. lambs. They want to raise weaning wt. to 110 lbs. They select a ram with a wean wt. of 110 lbs. The heritability of weaning wt. is 30%. What can the producer expect the new lamb crop to weigh at

weaning?

Calculating Genetic ImprovementUsing Heritability Estimates


Heritability

What is the difference in current weaning wt. and that of the new ram?

110 - 70 = 40 lbs. Heritability % x difference

30% x 40 = 12 lbs. Can expect a gain in weaning wt of 12 lbs. 70 lbs + 12 lbs = 82 lbs.


Heritability

Activity: Do the Heritability problems


Expected progeny differences predict the expected difference in performance of a sire’s or dam’s progeny when compared to the average for that breed.

Breed Specific (can’t compare EPDs of different breeds) Performance data is researched, collected, and computer analyzed to

provide the predicted outcome or genetic merit.

EPDs Expected Progeny Differences


Expressed as + or - Birth weight in pounds Weaning weight in pounds at 205 days Yearling weight in pounds at 365 days Gestation length in days Yearling height in inches Scrotal circumference in centimeters

EPDs & Units of measurement


EPDs & Units of measurement

Carcass weight in pounds Marbling in USDA marbling degrees Ribeye area in square inches Fat thickness in inches


Performance Data

Data is collected in three important areas: Ancestry Individual performance Progeny


Ancestry

If you were breeding race horses, what information would you want to see to help you select the right stallion?

The performance records of ancestors are a valuable tool and should be considered in the selection process.

The performance records on ancestors are analyzed in the equation and they offer a good indication what the EPD of the animal might be.


If the animals in a herd are raised under similar environmental conditions, the top producing animals must have had a genetic advantage over the average or poor producing animals.

Records on the individuals performance provide a way to ensure that the genetics of the ancestors were passed on to the individual and are used to calculate EPDs.

Individual Performance


Progeny records are the best indication of the three genetic merits of the sire.

This is especially true if the progeny are distributed in different herds and under different environmental conditions, but still constantly out produce the animals in the contemporary group.

Progeny Records


Accuracy

Accuracy value reflects the amount of and distribution of information included in the evaluation.


Accuracy

0102030405060708090

100

Accuracy

Pedigree Estimate(1/ 2 Dam & 1/ 2Sire)

Pedigree estimate+IndividualsPerfomance Data

Pedigree estimate+ PerformanceData + 1st yearsProgeny recordsWide spreadprogeny records


What an EPD Looks Like


Birth Weight(BW)

Unit of Change

ImpactEPD

Pounds (lbs) Fewer lbs = Fewer Calving Problems

Weaning Weight(WW) Pounds (lbs)

More lbs = faster calf growthMore lbs = Heavier Feeder Calves

Milk - maternal(MILK)

Pounds (lbs) More lbs = More Cow Milk Production

Yearling Weight(YW) Pounds (lbs)

More lbs = faster steer growthMore lbs = Reach market fasterMore lbs = greater mature size

Rib Eye AreaREA

Inches2 More in2 = heavier muscled calves

Marbling(MARB)

Percent%

Higher % = more intramuscular fatHigher % = higher quality grade

Important EPDs for Beef Cattle


Which bull would be the best choice to breed to heifers?

A 0.0 +20 +15 +40 -0.3 +0.05

B -1.6 +16 +22 +32 +0.8 -0.02

C +2.1 +42 +21 +55 +0.4 +0.08

D -0.2 +35 +30 +44 -0.7 +0.12

Bull B - He has the lowest birth weight (BW) EPD.

Birth Weight(BW)

Weaning Weight (WW)

Milk (MILK)

Yearling Weight(YW)

Rib Eye Area(REA)

Marbling(MARB)

Bull

Question 1


Which bull would produce the lightest feeder calves?

A 0.0 +20 +15 +40 -0.3 +0.05

B -1.6 +16 +22 +32 +0.8 - 0.02

C +2.1 +42 +21 +55 +0.4 +0.08

D -0.2 +35 +30 +44 -0.7 +0.12

Bull B - He has the lowest weaning weight (WW) EPD birth weight (BW) EPD.

Birth Weight(BW)

Weaning Weight (WW)

Milk (MILK)

Yearling Weight(YW)

Rib Eye Area(REA)

Marbling(MARB)

Bull

Question 2


Which bull will produce calves with the highest quality grade?

A 0.0 +20 +15 +40 -0.3 +0.05

B -1.6 +16 +22 +32 +0.8 - 0.02

C +2.1 +42 +21 +55 +0.4 +0.08

D -0.2 +35 +30 +44 -0.7 +0.12

Bull D - He has the highest marbling (MARB) EPD.

Birth Weight(BW)

Weaning Weight (WW)

Milk (MILK)

Yearling Weight(YW)

Rib Eye Area(REA)

Marbling(MARB)

Bull

Question 3


Which bull will sire steers that reach market weight the quickest?

A 0.0 +20 +15 +40 -0.3 +0.05

B -1.6 +16 +22 +32 +0.8 - 0.02

C +2.1 +42 +21 +55 +0.4 +0.08

D -0.2 +35 +30 +44 -0.7 +0.12

Bull C - He has the highest yearling weight (YW) EPD.

Birth Weight(BW)

Weaning Weight (WW)

Milk (MILK)

Yearling Weight(YW)

Rib Eye Area(REA)

Marbling(MARB)

Bull

Question 4


Which bull will sire the poorest milk-producing daughters?

A 0.0 +20 +15 +40 -0.3 +0.05

B -1.6 +16 +22 +32 +0.8 - 0.02

C +2.1 +42 +21 +55 +0.4 +0.08

D -0.2 +35 +30 +44 -0.7 +0.12

Bull A - He has the lowest milk (MILK) EPD.

Birth Weight(BW)

Weaning Weight (WW)

Milk (MILK)

Yearling Weight(YW)

Rib Eye Area(REA)

Marbling(MARB)

Bull

Question 5


Which bull will produce the heaviest muscled calves?

A 0.0 +20 +15 +40 -0.3 +0.05

B -1.6 +16 +22 +32 +0.8 - 0.02

C +2.1 +42 +21 +55 +0.4 +0.08

D -0.2 +35 +30 +44 -0.7 +0.12

Bull B - He has the highest rib eye area (REA) EPD.

Birth Weight(BW)

Weaning Weight (WW)

Milk (MILK)

Yearling Weight(YW)

Rib Eye Area(REA)

Marbling(MARB)

Bull

Question 6


Which bull’s calves will be the oldest when sold as feeder calves weighing 500 pounds?

A 0.0 +20 +15 +40 -0.3 +0.05

B -1.6 +16 +22 +32 +0.8 - 0.02

C +2.1 +42 +21 +55 +0.4 +0.08

D -0.2 +35 +30 +44 -0.7 +0.12

Bull B - He has the lowest weaning weight (WW) EPD.

Birth Weight(BW)

Weaning Weight (WW)

Milk (MILK)

Yearling Weight(YW)

Rib Eye Area(REA)

Marbling(MARB)

Bull

Question 7


Which bull will sire the heaviest calves at birth?

A 0.0 +20 +15 +40 -0.3 +0.05

B -1.6 +16 +22 +32 +0.8 - 0.02

C +2.1 +42 +21 +55 +0.4 +0.08

D -0.2 +35 +30 +44 -0.7 +0.12

Bull C - He has the highest birth weight (BW) EPD.

Birth Weight(BW)

Weaning Weight (WW)

Milk (MILK)

Yearling Weight(YW)

Rib Eye Area(REA)

Marbling(MARB)

Bull

Question 8


Which bull will make the most improvement in milking ability?

A 0.0 +20 +15 +40 -0.3 +0.05

B -1.6 +16 +22 +32 +0.8 - 0.02

C +2.1 +42 +21 +55 +0.4 +0.08

D -0.2 +35 +30 +44 -0.7 +0.12

Bull D - He has the highest milk (MILK) EPD.

Birth Weight(BW)

Weaning Weight (WW)

Milk (MILK)

Yearling Weight(YW)

Rib Eye Area(REA)

Marbling(MARB)

Bull

Question 9


Which bull will sire the most growth?

A 0.0 +20 +15 +40 -0.3 +0.05

B -1.6 +16 +22 +32 +0.8 - 0.02

C +2.1 +42 +21 +55 +0.4 +0.08

D -0.2 +35 +30 +44 -0.7 +0.12

Birth Weight(BW)

Weaning Weight (WW)

Milk (MILK)

Yearling Weight(YW)

Rib Eye Area(REA)

Marbling(MARB)

Bull

Bull C - He has the highest weaning weight (WW) and yearling weight EPDs.

Question 10


Additional Scenarios

The situation or environment that these cattle (bulls or heifers) are going to placed into once the selection process is complete should always be considered, so you can determine what traits to emphasize when evaluating the EPD and the phenotype.

Here are some examples:


Scenario 1

1. All offspring are sold at weaning. This indicates that the weaning weight EPD should be emphasized

heavily.


Scenario 2

2. These bulls will be mated to first calf heifers and their offspring will be kept as replacements.

This indicates that birth weight EPD should be strongly evaluated and that weaning and yearling EPDs should be considered as well. Moreover, since the scenario says that all replacements are being kept, then the milk EPD is important also.


Scenario 3

3. Forage is low quality for the heifers. This should indicate that moderate milking ability should be

emphasized. Thus, a high milk EPD should be discouraged in the decision making process.


Scenario 4

4. Forage and feed are high in quality and abundant. This signals that a high milk EPD should be emphasized.


Scenario 5

5. The producer is retaining ownership through the feedlot. This indicates that the owner does not sell the castrated bull calf

(steer) or heifer until after they are fed in the feedlot and go to harvest. Growth data (weaning and yearling EPD ) are important. Specifically, the yearling weight EPD is by far the most important trait to evaluate in this scenario.


Scenario 6

6. The ranch labor is limited. This means that there is no one there to pull calves if cows or

heifers are having trouble calving. Thus, a low birth weight EPD in potential sires is a much more desirable economic trait.

B66 Heritability, EPDs & Performance Data

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