Outbreeding

Question 1

Outbreeding

Answer 1

Mating of individuals less closely related genetically than the average of the population
Within a breed
Opposite of inbreeding

Question 2

Poultry

Answer 2

Big in this industry
Several lines combined together for desirable traits

Question 3

Grading up

Answer 3

“top crossing”
Mating purebred males with non-purebred females
Goal: to make a purebred population
[Takes generations]

Question 4

Crossbreeding

Answer 4

crossing different breeds to combine desired traits

Question 5

Species crosses

Answer 5

Closely related species
Ex: horse x donkey = mule

Question 6

Genetic affect

Answer 6

increase heterozygosity
keeps more deleterious recessives in heterozygous form, which means they are present but not expressed in phenotype

Question 7

Phenotypic affect

Answer 7

Heterosis
Hybrid vigor
[Opposite of inbreeding depression]

Question 8

Effects of Outbreeding

Answer 8

The degree of superiority of the outbred offspring for a particular trait as compared to the average of the parental line/breed

Question 9

Meat Animal Production

Answer 9

crossbreeding used by most commercial producers (ex: beef, sheep, hogs)

Often, crossbreeds will not exceed the purebred parent for individual traits such as survival, growth rate, feed efficiency, and carcass merit

Question 10

Heterosis

Answer 10

For all the traits contributing to the overall production efficiency will cumulate and result in crossbreds with greater net economic merit that the best average straightbred

Question 11

Breed complementation

Answer 11

Combining the desirable traits of 2 or more breeds into same offspring

Question 12

The degree of heterosis and complementarity

Answer 12

Depends on Genetic relationship of parents and Trait heritability

Question 13

Trait heritability

Answer 13

Measures the strength of the relationship between performance (phenotypic value) and breeding values (genotypic) for a trait in a population

Question 14

Genetic Relationship of Parents

Answer 14

The more genetically diverse the parents are, the greater the expression of heterosis and complementation

Question 15

Heritability vs Heterosis

Answer 15

Has an inverse relationship
Ex: When one is high, the other is low

Question 16

Major uses of outbreeding in livestock industry

Answer 16

General - maximum production of offspring
Specific - Commercial cow/calf, Swine, Poultry, and Sheep

Question 17

Outbreeding in Commercial cow/calf

Answer 17

Almost all commercial cows are crossbreds
Ex: black baldy

Question 18

Outbreeding in Swine

Answer 18

Extensive crossing of inbred lines and breeds to maximize reproduction and ground from maternal lines

Question 19

Reciprocal recurrent selection

Answer 19

system of selection for increasing the combining ability of two lines that have demonstrated past crosses that have combined well

Question 20

Net result

Answer 20

Development of genetically diverse inbred lines
better performing crossed lines would express greater heterosis

Question 21

Outbreeding in Poultry

Answer 21

meat breeds use crossbreeding for growth advantages
EX: male selected for growth and meat, female selected for maternal characteristics

Question 22

Outbreeding in Sheep

Answer 22

Meat breeds
[Prices favorable in the spring, when winter lambs are ready for market]

Question 23

Limited Outbreeding in Dairy

Answer 23

Outcrossing within breeds, but rarely between breeds (Not cost effective or efficient)