Swine Flashcards
when does farrowing occur with periodic farrowing?
twice yearly
how old is a finisher pig?
up to 6 months
how large are piglets when they are weaned?
12-15 lbs
what type of breeders are sows?
nonseasonal polyestrous
how prevalent is artificial insemination?
90% of USA swine farms
how long does pregnancy last?
113-115 days
do nursing sows experience lactation anestrus?
yes
what is the weaning to estrus interval?
4-6 days
how many oocytes do sows ovulate each estrus?
15-30 oocytes
do swine have follicular waves?
no
how large are follicles in estrus?
7-12 mm
what happens during the follicular phase?
number of small and medium follicles decreases: leave roughly 20 follicles 7-10 mm in diameter which will go on to ovulate
what can be seen when a sow is in estrus?
standing heat: reflex immobility
redness of vulva with production of thick/whitish mucus
how long does the estrous cycle last?
18-24 days
mean 21 days
how long does estrus last?
depends on presence of boar
40-60 hours
can vary <24 hours and >96 hours
what is estrus duration affected by?
intensity of boar contact during estrus detection
stress
parity
weaning to estrus interval
when does the corpus lutea reach their final diameter?
one week after ovulation
how long is development of the corpus luteum and production of progesterone independent from luteinizing hormone production?
10-12 days after ovulation
when does PGF2alpha cause luteolysis?
day 15
does the corpus luteum last for the entire pregnancy?
yes
why does lactational anestrus occur?
luteinizing hormone suppression
what is the degree of luteinizing hormone suppression related to?
suckling intensity
negative energy balance
stress
what is the common boar to sow ratio for group/pen mating?
1:8
when should you mate sows with hand mating/observed mating?
24-hour intervals
how can you make sure to not over-use boars in hand mating/observed mating?
not more than once or twice a day
rest at least 24 hours after 5 consecutive breedings at 12 to 24 hour intervals
how often are boars collected for artificial insemination?
1-2x per week
what is the typical dose of semen for artificial insemination?
1.5-5 billion sperm diluted to a total volume of 80-100 ml
sows that don’t conceive after _______________ are usually culled
3 cycles
what is the expected conception rates from artificial insemination?
90%
when is the first insemination for artificial insemination?
12 hours after sow comes into standing heat
what is the classic approach to artificial insemination?
intra-cervical
___________________ rotating locks the catheter into the cervix
counterclockwise
which female swine are not cycling for estrus synchronization?
prepubertal gilts
lactating sows
what is used to induce/advance estrus in non-cycling gilts?
boar exposure
what will affect timing of onset of puberty?
boar exposure
number of animals in group: larger group makes sooner
when should gilts be exposed to boars?
150-170 days
how long should gilts be exposed to boars?
5-30 minutes each day
boar exposure will result in _________ gilts in heat in the next 28 days
> 70%
what does boar exposure result in an increase in (hormone)?
GnRH and therefore luteinizing hormone and estrogen