exam 4

Question 1

berkshire

Answer 1

• paternal
• black with 6 white points
• erect ears
• known for fast and efficient growth and high quality carcasses

Question 2

chester white

Answer 2

• maternal
• all white
• droopy ears
• known for mothering ability, durability, and soundness

Question 3

duroc

Answer 3

• paternal
• solid red
• droopy ears
• known for fast growing and having excellent meat quality

Question 4

hampshire

Answer 4

• paternal
• black with white belt
• erect ears
• known for lean muscle and good carcass quality

Question 5

hereford

Answer 5

• paternal
• red body, white face and legs
• droopy ears
• known for distinct color markings, being good feeders, and fatten readily

Question 6

landrace

Answer 6

• maternal
• white
• droopy ears
• known for ability to farrow and raise large litters

Question 7

poland china

Answer 7

• paternal
• black with 6 white points
• droopy ears
• known for being big framed, long bodied, lean, muscular

Question 8

spot

Answer 8

• paternal
• black and white spotted body
• droopy ears
• known for porcine stress syndrome (PSS)

Question 9

tamworth

Answer 9

• paternal
• red
• erect ears
• known for producing high quality bacon

Question 10

yorkshire

Answer 10

• maternal
• all white
• erect ears
• known as the “mother breed” because they excel in litter size, birth and weaning weight, rebreeding interval, durability, and longevity

Question 11

mating systems definition

Answer 11

responsible for controlling the recombination of genes in a population by assignment of mate

Question 12

Inbreeding can be done within a line/family to increase ____.

Answer 12

homozygosity

Question 13

Outbreeding can be done across populations to increase ____

Answer 13

heterozygosity

Question 14

what is positive assortative mating? how does it affect variance?

Answer 14

with purebreds, mating like to like, the best to the best or worst to the worst; will increase the phenotypic and genetic variance

Question 15

what is negative assortative mating? how does it affect variance?

Answer 15

with purebreds, mating the best to the worst animal; decreases phenotypic and genetic variance

Question 16

what does positive assortative mating do to the population curve?

Answer 16

increases the spread resulting in a wide, flat curve

Question 17

what does negative assortative mating do to the population curve?

Answer 17

squishes it together around the mean creating a tall narrow curve

Question 18

what is a complimentarity crossbreeding strategy?

Answer 18

matching strengths of one breed with the strengths of another in a synergistic manner

Question 19

what is corrective mating?

Answer 19

matching strengths in one mate to offset a weakness in another

Question 20

the ____ different two animals are, the ____ you’re able to maximize heterosis

Answer 20

more; more

Question 21

what happens in an F1 cross? what heterosis does it cause?

Answer 21

• purebred females are mated to a sire of another breed
• results in heterosis for traits such as growth, improved carcass, feed efficiency, and vigor
• no maternal heterosis from the dam

Question 22

____ = beginning of breed rotation

Answer 22

backcross

Question 23

what is a backcross?

Answer 23

crossing F1 back to one of its parent breeds

Question 24

what does a 3-breed terminal cross maximize/maintain?

Answer 24

100% heterosis in both the sows and market animals (maternal hybrid vigor and direct hybrid vigor)

Question 25

what percent heterosis is maintained in a 3-breed rotational cross?

Answer 25

86% in offspring and sows

Question 26

what percent heterosis is maintained in a rotaterminal cross?

Answer 26

- 86% in sows - 100% in market hogs

Question 27

draw/explain a mating system that would yield a 5/8 and 3/8 breed combination, starting with purebred parents

Question 28

what is the process of making a composite breed?

Answer 28

crossbred animal x crossbred animal until you reach desired breed proportions

Question 29

if a production system is more vertically integrated, it will have ____ genetic lag.

Answer 29

less

Question 30

to be a good seed stock producer, data needs to be ____, ____, and ____.

Answer 30

detailed, accurate, and unbiased

Question 31

what are some of the ways in which data can be biased?

Answer 31

- failure to correctly identify parentage - inaccurate collection of performance data (ex: birth weights) - breeders choose not to report poor performance offspring - poor contemporary groups

Question 32

what are contemporary groups?

Answer 32

individuals of the same relative age and sex that are managed together (and often sold together)

Question 33

what is a single-sire bias?

Answer 33

when a single sire is used on a group of females or when data is only collected on one sire

Question 34

what is a single-animal bias?

Answer 34

when a producer weighs each calf at certain days of age rather than as a group

Question 35

what are ranch-to-rail programs?

Answer 35

programs that allow producers to obtain feedlot performance information and carcass data

Question 36

what is the purpose of data adjustments?

Answer 36

so that the comparison is “apples to apples” (ex: same age)

Question 37

so that you are comparing “apples to apples” regarding weaning weight, you adjust back to a ___ day weaning weight.

Answer 37

205

Question 38

in what ways are producers responsible for managing the environment? (6)

Answer 38

- temperature and humidity - housing conditions - nutrition - management practices (vaccinations, deworming, handling) - adaptability of breed/herd (crossbred vs purebred) - consistent environment

Question 39

what is the 1st step for breeding

Answer 39

describe the production system - mating systems, G x E, breed effects, evaluation programs - need to know resources and market

Question 40

what is the 2nd step for breeding?

Answer 40

develop goals / figure out your selection objective - noting where you want to go - need to recognize role w/i the industry - what is your market plan?

Question 41

what is the 3rd step for breeding?

Answer 41

choosing breeding system and breeds (that are applicable to your environment) - not only what best fits today, but what is the potential for a change of breeding system to match your goal? (breed effects, heterosis, and complementary)

Question 42

what is the 4th step for breeding?

Answer 42

estimate genetic parameters and economic values - determining what you want to focus on, specific to your breed(s) and conditions (G*E)

Question 43

what is the 5th step for breeding?

Answer 43

design evaluation system - what are you going to measure, on whom and when (may utilize multi stage approach)

Question 44

what is the 6th step for breeding?

Answer 44

develop selection criteria - take into consideration how you are going to pick parents of the next generation - target your goal, utilize information available, ensure accuracy - probably multi-trait and multi-stage

Question 45

what is the 7th step for breeding?

Answer 45

design mating system - must maintain breeding system - must provide for genetic improvement - produce saleable product

Question 46

what is the 8th step for breeding?

Answer 46

multiplication system - do you want to grow your operation? if not, can you still compete?

Question 47

what is the 9th step for breeding?

Answer 47

method of evaluating alternatives - comparing your operation to others - systems analysis

Question 48

what is outcrossing?

Answer 48

the mating of unrelated animals within a breed

Question 49

what does MPV stand for?

Answer 49

mid-parent value

Question 50

what is crossbreeding?

Answer 50

the mating of animals of two or more different breeds

Question 51

what is heterosis/hybrid vigor?

Answer 51

increased performance (vigor) of the offspring over the average performance of the parents when unrelated individuals are mated