B66 Heritability, EPDs & Performance Data

Infovets Educational Resources – – 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.

Infovets Educational Resources – – Slide 3 Heritability Estimates

Infovets Educational Resources – – Slide 4 Heritability  Low: Reproductive traits  Medium: Growth Traits (birth weight, wean weight, yearly weight, rate of gain)  High: Carcass traits

Infovets Educational Resources – – Slide 5  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 Improvement Using Heritability Estimates

Infovets Educational Resources – – Slide 6 Heritability  What is the difference in current weaning wt. and that of the new ram? = 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.

Infovets Educational Resources – – Slide 7 Heritability  Activity: Do the Heritability problems

Infovets Educational Resources – – Slide 8  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

Infovets Educational Resources – – Slide 9  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

Infovets Educational Resources – – Slide 10 EPDs & Units of measurement  Carcass weight in pounds  Marbling in USDA marbling degrees  Ribeye area in square inches  Fat thickness in inches

Infovets Educational Resources – – Slide 11 Performance Data  Data is collected in three important areas:  Ancestry  Individual performance  Progeny

Infovets Educational Resources – – Slide 12 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.

Infovets Educational Resources – – Slide 13  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

Infovets Educational Resources – – Slide 14  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

Infovets Educational Resources – – Slide 15 Accuracy  Accuracy value reflects the amount of and distribution of information included in the evaluation.

Infovets Educational Resources – – Slide 16 Accuracy

Infovets Educational Resources – – Slide 17 What an EPD Looks Like

Infovets Educational Resources – – Slide 18 Birth Weight (BW) Unit of Change ImpactEPD Pounds (lbs) Fewer lbs = Fewer Calving Problems Weaning Weight (WW) Pounds (lbs) More lbs = faster calf growth More lbs = Heavier Feeder Calves Milk - maternal (MILK) Pounds (lbs)More lbs = More Cow Milk Production Yearling Weight (YW) Pounds (lbs) More lbs = faster steer growth More lbs = Reach market faster More lbs = greater mature size Rib Eye Area REA Inches 2 More in 2 = heavier muscled calves Marbling (MARB) Percent % Higher % = more intramuscular fat Higher % = higher quality grade Important EPDs for Beef Cattle

Infovets Educational Resources – – Slide 19 Which bull would be the best choice to breed to heifers? A B C D 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

Infovets Educational Resources – – Slide 20 Which bull would produce the lightest feeder calves? A B C D 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

Infovets Educational Resources – – Slide 21 Which bull will produce calves with the highest quality grade? A B C D 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

Infovets Educational Resources – – Slide 22 Which bull will sire steers that reach market weight the quickest? A B C D 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

Infovets Educational Resources – – Slide 23 Which bull will sire the poorest milk-producing daughters? A B C D 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

Infovets Educational Resources – – Slide 24 Which bull will produce the heaviest muscled calves? A B C D 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

Infovets Educational Resources – – Slide 25 Which bull’s calves will be the oldest when sold as feeder calves weighing 500 pounds? A B C D 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

Infovets Educational Resources – – Slide 26 Which bull will sire the heaviest calves at birth? A B C D 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

Infovets Educational Resources – – Slide 27 Which bull will make the most improvement in milking ability? A B C D 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

Infovets Educational Resources – – Slide 28 Which bull will sire the most growth? A B C D 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

Infovets Educational Resources – – Slide 29 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:

Infovets Educational Resources – – Slide 30 Scenario 1  1. All offspring are sold at weaning.  This indicates that the weaning weight EPD should be emphasized heavily.

Infovets Educational Resources – – Slide 31 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.

Infovets Educational Resources – – Slide 32 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.

Infovets Educational Resources – – Slide 33 Scenario 4  4. Forage and feed are high in quality and abundant.  This signals that a high milk EPD should be emphasized.

Infovets Educational Resources – – Slide 34 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.

Infovets Educational Resources – – Slide 35 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.