Swine Repro Flashcards
What is a gilt?
a female pig that has not had any offspring
What is a sow?
a female pig that has had offspring
When does puberty typically occur in a female pig?
150-220 days: producers want 180 days
What are factors that affect when puberty begins?
boar contact and the housing environment
What type of breeders are female pigs?
non-seasonal, polyestrous, polytocous: 21 day estrous cycle (18-24 days)
What are the phases of the pig estrous cycle?
pre-follicular phase, follicular phase, luteal phase, lactational anestrous
When does the pre-follicular phase occur in pigs?
4-6 days prior to the follicular phase
What occurs to the follicle in the pre-follicular phase?
follicular development is largely suppressed
When does the follicular phase occur?
4-6 days following the luteal phase or lactation
How many follicles typically ovulate during the follicular phase?
15-30
What is the size of the dominant follicles?
2-4 mm are predestined to be dominant and they turn into 7-8 mm follicles
When does the luteal phase occur?
immediately after ovulation
What hormone levels rise during the luteal phase?
progesterone
What happens in lactational anestrous?
LH pulsatility is suppressed from suckling inhibition on GnRH
What phase is the number of follicles that will ovulate dependent on?
the pre-follicular phase
What is the BPT and how does it work?
it is the back pressure test, if a pig is in standing estrus and you put pressure on their back they will not lay down, they will stay standing
How long are pigs typically in standing estrus?
40-60 hours (24-90 hours)
When does ovulation typically occur in pigs?
two thirds of the way into standing estrus
When do we typically breed gilts after standing estrus has been detected?
twice/day detection: 12 hours for the first breeding and then 12 hours after that for the second
once/day detection: 4 hours for the first breeding and then 12 hours after that for the second breeding
When do we typically breed sows when twice/day estrus detection is done?
24 hours for the first breeding and then 24 hours after that for the second breeding
When do we typically breed sows when once/day heat detection is done?
12 hours for the first breeding and then 24 hours after that for the second breeding
What happens to follicles during anestrous?
the follicular pool increases during lactation and at the end of it they synchronize and follicle diameter increases
When does estrus occur post-weaning?
4-7 days
What signaling molecule is used to signal pregnancy in pigs?
estrogen
What is estrogen produced by during pregnancy?
conceptus
What does estrogen do during pregnancy?
alters direction of PF2 alpha, increases PGE2 secretion by the uterus and maintains LH-R on the CL
What does PGE2 do during pregnancy?
it protects PGF 2 alpha luteolytic effects on the CL
How many conceptuses are needed ‘turn on’ the maternal recognition molecule?
4
When must estrogen be present during pregnancy?
at days 11-12 and 15-18
Why must estrogen be present on days 11-12?
to extend diestrus
Why must estrogen be present on days 15-18?
for reinforcement to carry to term
If we want to eliminate pregnancy, when must we do it and how?
at day 12 of the cycle and by introducing PGF 2 alpha
What supploes progesterone during pregnancy?
the CL
How long is gestation in the pig?
114 days
When can pregnancy be diagnosed by abdominal ultrasound?
21-25 days
What type of placenta does the pig have?
epithelialchorial diffuse
When does progesterone decline during pregnancy?
10-14 days prior to parturition
What is relaxins role during pregnancy?
relaxin rises and inhibits oxytocin until 12-15 hours prior to parturition
When does puberty occur in the male?
5-9 months
What creates the submaxillary salivary glands and when do they typically grow?
5 alpha androstenone and 3 alpha androstenol (testosterone derivatives) at 10-11 months
How long is the spermatogenic cycle in the male?
47 days
How long does spermatogenesis occur?
35 days
How long does epididymal transit take?
12 days
What is the swine penis shaped like and why?
a spiral with a big sigmoid flexure to fit into the cervix of the female
What is the make up of the first fraction of ejaculate and where does it come from?
clear with some gel from the vesicular gland
What is the make up of the second fraction of ejaculate?
sperm rich with gel
What is the make up of the third fraction of ejaculate and where does it come from?
mostly gel from the bulbourethral gland
How often is sperm collected from the boar?
every 5 days
Describe natrual copulation in the boar.
thrusting until the penis is engaged in the cervix, ejaculation happens after thrusting
How many days are between weaning and servicing?
4-7 days
How long does a gilt need to be in contact with a boar to induce cyclicity?
40 days
What exogenous drugs can be used to induce cyclicity if a gilt is not cycling by by the 180 day point?
PG600 - acts like FSH, and HCG - acts like LH
