selection methods

Question 1

composite scores

Answer 1

(multiple relatives records used)

Question 2

EPD

Answer 2

expected progeny difference (beef)

Question 3

ETA

Answer 3

expected transmitting ability (dairy)

Question 4

EBV

Answer 4

expected breeding value (swine)

Question 5

BLUP

Answer 5

best linear unbiased prediction (name for the mathematical method)

Question 6

recurrent selection

Answer 6

-specialized form of progeny selection
-e.g goal: develop a boar line that is useful in crossbreeding
-“general combining ability”-boar produces good piglets with any line of sow

Question 7

reciprocal recurrent selection

Answer 7

-specialized form of progeny selection
-example goal: develop a poultry lines for crossbreeding
-“specific combining ability”-male works well when mated to a specific line of females

Question 8

companion animal selection-horses

Answer 8

-genetic improvement is slow
-long generation
-few offspring
-late mating
-“training” is a confounding factor
-emphasis on “famous names not in pedigree… not ideal”

Question 9

companion animal selection- dogs (and cats)

Answer 9

-obedience test:
-(training is also a cofounding factor)
-1st, 2nd, 3rd+competition
-little selection benefit but good advertising

-ancestor selection
-ask about parents or interact with them

-progeny/sib selection
-ask fr previous litter “success”
-breeder should maintain contact and follow up

Question 10

pros and cons to individual selection

Answer 10

pros: accurate if h2 is high, milk yield, etc
cons: cant always measure

Question 11

pros and cons to pedigree selection

Answer 11

pros: useful for some traits that arent measurable in individuals, cheap
cons: low accuracy

Question 12

pros and cons to sibling selection

Answer 12

pros: relatively accurate if h2 low, quicker then progeny
cons: expensive

Question 13

pros and cons to progeny selection

Answer 13

pros: very accurate feasible for litter bearers & males
cons: time consuming and expensive

Question 14

selection and traits

Answer 14

-typically need to select for more then one trait
-improvement goals that include more than 3-5 traits are very difficult to implement
-pos (r>0) inc milk yield, inc protein yield
-neg (r<0) inc broiler size, dec fertility
-negative does not mean detrimental
-positive doest mean beneficial

Question 15

correlated responses for dairy

Answer 15

milk yield : fat yield +.8
milk yield : protein yield +.9

Question 16

correlated responses for pigs

Answer 16

growth rate : feed conversion -.8
growth rate : backfat -.25

Question 17

correlated responses for chickens

Answer 17

eggs : BW -.2
eggs : egg size-.3
body weight : egg size +.4

Question 18

correlates responses for beef

Answer 18

calving ease : birthweigh -.3
birthweigh : yearling weigh +.4

Question 19

genetic correlations of meat quality

Answer 19

-marbling score and back fat thickness + .3
-marbeling score and lean yield -.56
-marbling score and shear force -.47