Systems of Mating

Question 1

alternative strategies for the mating of animals selected to be parents

Answer 1

systems of mating or mating systems

Question 2

generally something to be avoided in animal breeding

Answer 2

inbreeding

Question 3

what is inbreeding?

Answer 3

mating of related animals

Question 4

True or false:
outbreeding increases the probability that more of the alleles at each gene in offspring or proogeny will be identical

Answer 4

false, inbreeding

Question 5

the level of inbreeding is measured by what?

Answer 5

inbreeding coefficient

Question 6

the inbreeding coefficient measures level of inbreeding

what is the inbreeding coefficient?

Answer 6

measure of the probability that alleles carried by that individual will be identical

Question 7

consequences of increased inbreeding

Answer 7

• reductions in fertility
• reductions in litter size
• inbreeding depression (reduction in genera viability)
• increased incidence of genetic abnormalities
• loss of genetic variation (hence no genetic progress)

Question 8

define line breeding

Answer 8

mating of animals in the same genetic line or selected groups which are not highly related

Question 9

during the history of creating each breed, __________ is used; if used with care, can help estabilsh particular characteristics

clue: one of the reasons that pure breeds of livestock looks the same is due to a low level of inbreeding

Answer 9

line breeding

Question 10

mating of animals in the same genetic line or selected groups which are not highly related

Answer 10

line breeding

Question 11

mating of unrelated animals

Answer 11

outbreeding

Question 12

define outbreeding

Answer 12

mating of unrelated animals

Question 13

primary forms of outbreeding

Answer 13

• crossbreeding
• outcrossing
• linecrossing
• grading-up
• species hybridization

Question 14

what does outbreeding take advantage of in livestock production?

Answer 14

heterosis and complementarity

Question 15

aka hybrid vigor

Answer 15

heterosis

Question 16

occurs when genetic merit (hence performance) of the cross[breeding] is greater than the average of parents

Answer 16

hybrid vigor / heterosis

Question 17

commercial sows are often crossbreds of large white and landrace pigs because they exhibit _________ for all aspects of reproduction

bonus: if higher ______ for crossbred sows, then?

Answer 17

heterosis

bonus: higher heterosis for crossbred sows produce more litters with more piglets per liter

Question 18

what are dam lines and terminal sire lines?

Answer 18

dam lines
- specialized female parents
- selected for a combination of goof female reproductive and growth performance

terminal sire lines
- specialized male parents
- selected for growth performance

Question 19

what is breed complementarity?

Answer 19

using breeds as dam lines and other breeds as terminal sire lines