Sheep Selection

Question 1

What are the types of sheep industry?

Answer 1

purebred, commercial, and dairy

Question 2

Is the sheep industry large in the US?

Answer 2

no, it’s small

Question 3

What does Purebred industry include?

Answer 3

• seedstock for commercial producers

- show sheep (4-H)

Question 4

What are show sheep (4-H)?

Answer 4

• club lambs

- “collectors”

Question 5

What are “collectors”?

Answer 5

purebred breeders that trade among themselves

Question 6

What is part of Commercial sheep industry?

Answer 6

lamb/meat and wool

Question 7

Where does the majority of income for commercial industry come from?

Answer 7

lamb/meat

Question 8

What is dairy industry for?

Answer 8

cheese

Question 9

What are traits of economic importance for sheep?

Answer 9

• meat production
• wool production
• milk

Question 10

What are traits under meat production?

Answer 10

• number of lambs born/weaned

- growth rate

Question 11

What are traits under wool production?

Answer 11

• fiber diameter

- fleece weight

Question 12

What are traits under milk?

Answer 12

-pounds/lactation

Question 13

How heritable are reproductive traits?

Answer 13

lowly heritable

Question 14

Dressing % formula?

Answer 14

(carcass weight/live weight) x 100

Question 15

What is the formula for carcass weight?

Answer 15

live weight - eviscerated weight

Question 16

What is eviscerated weight?

Answer 16

weight of carcass without internal organs

Question 17

Is fleece lowly or highly heritable?

Answer 17

highly

Question 18

How many breeds of sheep are there worldwide?

Answer 18

425

Question 19

How many sheep breeds are in the US?

Answer 19

47

Question 20

Does the sheep industry use inbreeding?

Answer 20

some in purebreds, especially breeds with smaller numbers or imported breeds with limited numbers

Question 21

Does the sheep industry use crossbreeding?

Answer 21

used extensively in commercial production

Question 22

What does the National Sheep Improvement Program do?

Answer 22

calculates cross flock EPDs for sheep

Question 23

What sheep does the National Sheep Improvement Program apply to?

Answer 23

• Targhee
• Suffolk
• Polypay
• Dorset
• Hampshire
• Columbia
• Katahdin
• Romney

Question 24

Is National Sheep Improvement Program used in most breeds?

Answer 24

no

Question 25

What are Central Ram Tests most effective for?

Answer 25

traits of moderate to high heritability which can be measured in a young growing ram

Question 26

What is a danger of Central Ram Tests?

Answer 26

danger of emphasis on easily measured traits at the expense of other traits

Question 27

What are some major genes for important traits sheep can get?

Answer 27

- Spider Syndrome - Scrapie - Callipyge - Booroola

Question 28

What is Spider Syndrome?

Answer 28

a lethal or semi-lethal skeletal abnormality

Question 29

What breeds has Spider Syndrome been found in?

Answer 29

Suffolk, Hampshire, Shropshire, Southdown, and Oxford breeds

Question 30

What kind of disease is Spider Syndrome?

Answer 30

single gene, recessive

Question 31

What gene is defected that causes Spider Syndrome?

Answer 31

fibroblast growth factor receptor

Question 32

Can Spider Syndrome be genetic tested for?

Answer 32

yes

Question 33

What is Scarpie?

Answer 33

a central nervous system disease, scrape off their wool

Question 34

What is Scrapie similar to?

Answer 34

- mad cow disease - chronic wasting disease - Creutzfeldt-Jakob disease

Question 35

What is the consumer perception of Scrapie?

Answer 35

- some negative impact | - has never been transmitted to humans

Question 36

Why does Scrapie cost the US sheep industry millions?

Answer 36

- lost export opportunities - increased offal disposal costs - reduced productivity

Question 37

How is Scrapie diagnosed in dead animals?

Answer 37

examine brain and lymph nodes for lesions of scrapie and presence of abnormal prions

Question 38

How is Scrapie diagnosed in live animals?

Answer 38

examination of 3rd eyelid for abnormal prion protein

Question 39

Is there a treatment of Scrapie?

Answer 39

no

Question 40

What is Scrapie Susceptibility in codon 136?

Answer 40

AA low susceptibility, AV or VV high suscpetibility

Question 41

What is Scrapie susceptibility in codon 154?

Answer 41

RR or no effect, HR or HH overides Q171 in some cases

Question 42

What is Scrapie susceptibility to codon 171?

Answer 42

QR or RR low susceptibility, QQ high susceptibility

Question 43

What good does Booroola do?

Answer 43

increase ovulation rate, results in higher litter size

Question 44

What bad does Booroola do?

Answer 44

poor lamb survival, lamb growth, and ewe conception

Question 45

What is Booroola mapped to?

Answer 45

chromosome 6

Question 46

What is Booroola also called?

Answer 46

Fec or fecundancy allele

Question 47

What is Callipyge?

Answer 47

muscle hypertrophy, "big butt gene"

Question 48

What chromosome is Callipyge mapped to?

Answer 48

chromosome 18

Question 49

How is meat affected by Callipyge?

Answer 49

extremely tough meat

Question 50

What is Callipyge the result of?

Answer 50

polar overdominance

Question 51

What does Callipyge increase?

Answer 51

- higher dressing percentage | - larger loin eye

Question 52

How can polar overdominance occur?

Answer 52

- one copy from sire express trait (Parent of origin effect) - One copy from dam normal appearing - Two copies normal appearing

Question 53

When does muscle hypertrophy manifest in offspring?

Answer 53

one month after birth

Question 54

What is muscle hypertrophy accompanied by?

Answer 54

a decrease in all measures of fatness

Question 55

What do animals affected by muscle hypertrophy have improved?

Answer 55

feed efficiency and dressing percentage