Selection of Breeding Stock

Question 1

Producers need to evaluate several breeding stock factors.

Answer 1

Genetics
Expected Genetic Potential
Phenotype

Question 2

When 1 or both testicles are retained in body cavity

-When both retained, boar is sterile

Answer 2

Cryptorchidism

Question 3

Mostly seen in Yorkshire and Landrace, occasionally occurs in large litters as a result of uterine crowding

• Most are genetic female
• Portions of male sex organs and tipped vulvas

Answer 3

Hermaphrodites

Question 4

• Failure of nipples to protrude from udder surface
• Milk flow is prevented
• Should look at boar teats too, can genetically pass on to daughters

Answer 4

Inverted nipples

Question 5

• Result of weakness of musculature surrounding inguinal canal
• Intestines to drop into the scrotum

Answer 5

Scrotal hernia

Question 6

• Weakened muscle in the naval area causes intestines to protrude through belly wall
• Some pigs die during growth due to strangulation of the intestine

Answer 6

Umbilical hernia

Question 7

• Most common leg disorder
• Mainly affects rear legs
• Incomplete development of muscle fibers in front and rear legs
• Affected pigs can be treated somewhat successfully

Answer 7

Splay leg/Spraddle legs

Question 8

• Carrier of this dominant gene
  
  • lower muscle pH
  • pale meat color
  • lower water holding capacity
  • greater cooking loss
• Seen in hampshires and hampshire x’s
• Dominant have elevated glycogen storage in muscles, ^ lactate prod., reduces ultimate pH at harvest

Answer 8

Napole Gene (RN)

Question 9

Best estimate/indicator of a sire or dam’s genetic potential

• It is actual difference a producer could expect from future offspring
• # can be (+) or (-)

Answer 9

Expected Progeny Difference (EPD)

Question 10

6 common terminal traits evaluated (what we want)

Answer 10

1. ) Backfat (low)
2. ) LEA (high)
3. ) Days to 250 (low)
4. ) Lbs of lean (high)
5. ) Avg. daily gain (high)
6. ) Feed efficiency - lb feed/ lb gain (low)

Question 11

4 common maternal traits evaluated (what we want)

Answer 11

1.) # born alive (high)
2.) # weaned (high)
3.) Litter weaning weight (high)
4.) Wean-to-estrus interval (low)
-How many days from weaning for a sow to go
back into heat

Question 12

Allow for simultaneous selection of multiple traits

• Weighs EPDs relative to their economic value
• 3 types

Answer 12

Swine Indexes

- Terminal Sire Index
- Maternal Line Index
- Sow Productivity Index

Question 13

Terminal Sire Index

Answer 13

Designed to select boars to be used as sires in crossbreeding programs

Question 14

The TSI combines (3):

Answer 14

Days to 250
lb of lean
Backfat

Question 15

Average for TSI is…

Answer 15

100

> 100 is most desirable

Question 16

Maternal Line Index

Answer 16

Indicates economic value of the progeny produced

Question 17

With MLI, there is 2X as much emphasis on _____ traits as on _____ traits.

Answer 17

Reproductive… Post-weaning

Question 18

The MLI combines (5):

Answer 18

Backfat
Days to 250
Lb of lean
# born alive
Litter wt

Question 19

MLIs will be used for…

Answer 19

Boars to be used for breeding

Question 20

Sow Productivity Index

Answer 20

Indicator for a sow’s reproductive traits

Question 21

The SPI combines (3):

Answer 21

born alive
Litter weaning wt
-Also includes, lifetime # born alive and litter weaning weight

Question 22

Female selection underline:

Answer 22

Minimum of 6 or more functional teats

Question 23

Reproductive soundness (5)

Answer 23

Feet and legs
Growth
Muscle
Capacity (depth of body)
Leanness

Question 24

Leanness is visually evaluated on gilt’s fat depots (6)

Answer 24

1. ) Jowl
2. ) Blades
3. ) Elbow pocket
4. ) Belly
5. ) Loin edge
6. ) Seam of ham