Beef Cattle Genetics

Question 1

Phenotype

Answer 1

physical appearance from genotype and environment

Question 2

Breeding Value

Answer 2

portion of genetic make up passed down from generation to generation
–> total off all independent genetic effects on given trait of an individual

Question 3

Heritability

Answer 3

percent of total phenotypic variation due to breeding value

Question 4

High Heritability Traits (40%)

Answer 4

-carcass/end product
-skeletal measures
-mature weight

Question 5

Moderate Heritability Traits (20-40%)

Answer 5

-growth rate
-birth/weaning/yearling weight

Question 6

Low Heritability Traits (<20%)

Answer 6

-maternal ability
-reproduction
-health
-cow longevity
-cow productivity

Question 7

EPD

Answer 7

Expected Progeny Difference

Question 8

EPD- maternal traits

Answer 8

-milk
-maternal weaning weight

Question 9

EPD- reproduction traits

Answer 9

-calving ease
-scrotal circumference

Question 10

EPD- carcass traits

Answer 10

-marbling
-ribeye area

Question 11

EPD- growth traits

Answer 11

-weaning weight
-yearling weight

Question 12

EPD- management

Answer 12

-docility
-claw
-hair shedding
-pulmonary artery pressure
-stayability

Question 13

Replacement Heifer Selection

Answer 13

-conceive early
-calve easily
-milk
-wean heavy calves
-calves have high post wean weight

Question 14

Cow Selection

Answer 14

-calve productivity
-early pregnancy
-eyes, mouth, skeleton, teeth

Question 15

What do crossbreeding programs take advantage of?

Answer 15

heterosis or hybrid vigor
–>improvement of a trait from parent to offspring

Question 16

Composite Breeds

Answer 16

range of new breeds or new lines to improve heterosis
ex: beefmaster and brangus