Pig Repro 1 Flashcards
Breed complementation - definition?
using breeds or lines to take max. advantage of their genetic type.
Heterosis aka ___. Definition?
hybrid vigor. Tendency for crossbred progeny to perform differently than avg of their parents
Guidelines for selecting replacements:
2.
3.
4.
- structural soundness
- External Genitalia
- Internal genitalia
- Mammary system
Structural soundness involves examination of what?
general structural soundess including signs of injuries, hoof cracks, sole bruises, foot rot, etc
Guidelines for Selecting Replacements:
External Genitalia - examine what?
1.
2.
3.
4.
- Infantalism - small repro tract
- Dorsally tipped vulva - difficulty with mating
- Male psuedohermaphroditism - “fishhook” or “sky-tipped” vulva
- mammary gland abnormalities
Guidelines for Selecting Replacements:
Internal Genitalia: Look for what abrnormalities:
1.
2.
3.
4.
- Hydrosalpinx or Pyosalpinx = obstruction of oviducts
- Segmental aplasia - complete or partial infertility
- Blind or missing cervix
- Oviductal Adhesions
Guidelines for Selecting Replacements:
Mammary System: Look for…
1. 2. 3. 4. 5.
- Six functional teats on each side
- Three cranial to umbilicus
- blind teats (not fully developed), pin nipples, or inverted nipples
- Sows at least 10 functional teats
- Abscesses, injuries
Factors affecting puberty:
- 2.
3.
- Age
- Weight
- Breed
Factors affecting puberty:
- Age range?
- Weight Range?
- Breeds that have unique factors?
- 5-8 months
- 200-250 lbs
- Meishan, Landrace, Crossbred, Duroc
Factors affecting puberty: Breed related differences:
- Meishan -
- Landrace -
- Crossbred -
- Duroc -
- Reaches puberty as early as 67 d
- 173 d of age
- reach puberty earlier than purbred
- latest to reach puberty (224 days)
Goals to Managing the Gilt Pool:
1.
2.
3.
4.
- Keep a large enough gilt pool to meet weekly breeding targets
- Daily boar exposure will stimulate puberty
- Gilt in heat - use sterile boar 1st heat and fertile boar 2nd heat.
- Aim for large litter size and good nursing ability in gilts
Factors that would hasten onset of puberty:
1.
2.
3.
- movement/mixing of females
- length of day - long
- boar effect
Factors that would delay onset of puberty
1.
2.
- confinement housing
2. season (photoperiod not temp.)
Owner management techniques to hasten onset of puberty:
1.
2.
3.
4.
- crossbreeding - crossbred females reach puberty earlier
- Lighting - long day length reduces age at puberty BUT is detrimental to cycling females
- mixing of gilts and sows
- boar effect
What is the most common method used to hasten puberty onset?
Boar effect
Boar effect:
- (single/continuous) exposure to the boar?
- Best to use a (young/old) boar?
- begin at what age?
- (direct/indirect) contact?
- continuous
- old smelly boar
- 160-170 days of age
- direct
Estrous Cycle type?
non-seasonal polyestrous
Estrous Cycle:
- Length?
- Main difference in cycle from cattle?
- 21 days
2. no series of follicular waves as seen in cattle
Estrus:
- Gilts in estrus for how long?
- Sows in estrus for how long?
- 36-48 hours
2. 48-72 hours
Ovulation occurs ___ of the way through estrus:
A) 1/4
B) 1/2
C) 3/4
C
Ovulation in sows occurs how long after LH peak?
24 hours
Estrus:
- Multiple follicles will rupture over how long?
1-4 hours
Estrus:
Ovulation rate is (smallest/largest) over the first 3 parities?
Largest