1. Principles of Agricultural Science – Animal 1

2. 2 Expected Progeny Differences Principles of Agricultural Science – Animal Unit 7 – Lesson 7.2 Predicting Genetic Inheritance

3. Expected Progeny Differences (EPDs) Use performance data from an animal and all relatives (living and dead) More accurate than ratios Expressed in pounds, inches, or days Used to compare animals to each other or to a breed average 3

4. Common Beef EPDs BW = Birth Weight –Listed in pounds –Lower numbers indicate the offspring from that animal should be smaller at birth and have less birthing difficulty –Producers prefer lower birth weights WW = Weaning Weight –Listed in pounds –Higher numbers indicate the offspring of the animal should be heavier at weaning time –Producers prefer heavier weaning weights because calves are usually sold on a cents-per-pound basis

5. YW = Yearling Weight –Listed in pounds –Higher numbers indicate the offspring of the animal should be heavier at one year of age –Producers prefer heavier yearling weights because yearling cattle are usually sold on a cents-per-pound basis Common Beef EPDs Continued

6. MM = Maternal Milk –Listed in pounds of calf weaned by the daughters of the animal resulting from the daughter’s milk production. –In general, high milk EPDs are preferred for the same reasons high weaning weight EPDs are preferred. –However, if daughters will live on poor range conditions with minimal feed resources, high milk EPDs should be avoided. –When feed resources are low, excessive milk production can cause cows to become thin and fail to rebreed. Common Beef EPDs Continued

7. Common Swine EPDs NBA = Number Born Alive –Listed in number of pigs per litter –Higher numbers indicate that female offspring should give birth to more pigs in each litter –Producers prefer sows have larger litters more piglets to sell, resulting in higher revenue

8. Common Swine EPDs Continued LW21 = 21-day Litter Weight –Listed in total pounds of litter weight –Combines milk production with number of piglets in the litter Sows with litters weighing more when the baby pigs are 21 days of age are better milking sows with more pigs per litter –Higher numbers are preferred

9. BF = Back Fat –Listed in inches of back fat –Paid more money for leaner pigs, so lower EPDs are preferred for this trait Days = Days to 250 Pounds –Listed in days –Need to grow as quickly as possible and take fewer days to reach 250 pounds –Therefore lower numerical EPDs are preferred for this trait Common Swine EPDs Continued

10. EPD Example Cattle – Birth weight EPD (Note: Low birth weights are preferred) –Bull A Birth weight EPD = +0.8 –Bull B Birth weight EPD = +3.6 Expect – Calves from bull B to weigh an average of 2.8 pounds more at birth than those of bull A. 10

11. EPD Examples Swine – Days to 250 EPD (Note: Fewer days to 250 are preferred) –Boar A EPD = +2.5 –Boar B EPD = -1.1 Expect – Offspring of boar B to reach 250 pounds 3.6 days faster than those of boar A. 11

12. References Trickett, S. (2008). Genomics sets new standard for livestock breeding. Farmers Weekly Interactive. Retrieved December 15, 2008 from http://www.fwi.co.uk/Articles/2008/11/30/113295/ genomics-sets-new-standard-for-livestock- breeding.html. http://www.fwi.co.uk/Articles/2008/11/30/113295/ genomics-sets-new-standard-for-livestock- breeding.html American Angus Association. (2008). How to read the report. Retrieved December 15, 2008 from http://www.angus.org/sireeval/howto.html. http://www.angus.org/sireeval/howto.html 12