EXAM 2: Breeding Flashcards
what is critical to successful breeding
estrus detection
how often are heat checks performed
2x a day ( after morning feed and afternoon)
what are the conditions heat checks are performed under
in the presence of a mature boar
rub flanks and underline to stimulate sow for a standing response
_________ is defined as a period of sexual excitement and ovulation, during which a sow will accept the male and is capable of conceiving
estrus
estrus to estrus is how many days
21
length of estrus in mature sows compared to gilts
mature sows: ~55 hours
gilts: 40 hours
two to three days before the onset of estrus, increasing estrogen levels from developing ovarian follicles stimulate increase ___________________ and _______________ in repro tract
blood flow
fluid retention
the increase in blood flow before the onset of estrus causes what to happen to the vulva
swell
turn red
is red, swollen vulvas more common in gilts or sows
gilts
only seen in sows if parted to examine the interior
**sows in estrus raise tail and quiver when vulva is examined
signs of estrus include
reddening/swelling of vulva
mucus discharge
riding
seeking of the boar
back pressure test
____________ may drip and hang from the vulva in response to increasing levels of estrogen
clear, sticky mucus
more sticky= closer to ovulation
how do we check if the mucus is indicating closer to ovulation
thumb test
sample smeared on thumb and pressed/stretched to determine stickiness
gilts and sows coming into heat or going out of estrus often _________ pen mates when group-housed, even though themselves are not in heat
ride/mount
**volcalize and move= not in estrus
** stand still= in estrus
females that have been ridden can develop
rough hair
rub marks
signs of a female seeking the boar
in the presence of boar: pop ears, arch back, brace legs
sow makes effort
some will exhibit standing responses without direct contact
sows in heat when under the back pressure test will
arch back
brace legs
immobile
females not in heat= run away
__________________ represents one of the most critical factors affecting the reproductive performance of a sow herd
gilt development and management
Reproductive performance and longevity are optimized when gilts are bred at approx. _______ pounds and near ___________ days of age and one their ________ estrus cycle
300 pounds
230 days
second or third
first service at a heavier initial weight increases _______________ to maintain body weight and may have a negative effect on ______________
feed cost
structure
what happens on day 0 of gilt puberty
select gilts to keep based on genetics
what happens on day 120 of gilt puberty
gilts kept as replacements are switched to a replacement gilt diet
diet is higher in calcium & phosphorus
diet also has trace minerals and additional vitamin E and biotin
what happens on day 160 of gilt puberty
cull replacement gilts that dont meet physical attributes
cull gilts go to finishing
gilts kept start puberty induction
what happens on day 230 of gilt puberty
cull replacement gilts that failed to reach puberty and those with unacceptable physical attributes as market hogs
what does high calcium and phosphorus help with
bone mineralization
strucutre
why do we add vitamin E and biotin to gilt diet
vit E= immune function
biotin= hoof strength/development
on day 120 what happens to replacement gilts and market hogs
they are seperated
when does fertility and longevity problems occur in regard to the puberty timeline
breeding outside of target
underweight or overweight gilts
replacement gilts= more culling
behavior expression of estrus coincides with the occurrence of ovulation
puberty
the age of puberty is heritable up to ___% of the variation attributed to genetics
40%
T/F the start of puberty varies among breeds, herds, genetics
true
in swine the average age of puberty ranges from
190-230 days
is there a way to internally measure when a gilt has hit puberty
NO
depend of weight and age
puberty induction in gilts can be managed starting at __________ weeks of age
24 wks (160-180 days)
during puberty induction, how are gilts housed
group housing of 10-12 gilts
increased floor space
ad lib access to feed and water
Examples of how we can induce puberty
boar exposure
transportation stress
outdoor housing
group size
photoperiod/lighting
PG600
boar exposure
greatest impact/ MOST CRITICAL on age of puberty in gilts
daily direct physical, fence line exposure
minimum 10 min, no more than 30 min
transportation stress
combination with boar exposure is the most potent stimuli to bring prepubertal gilts into puberty
including moving gilts, regrouping, relocating
outdoor housing
gilts indoor experience more silent estrus than outdoor raised gilts
group size
less than 3 or more than 50 can cause delayed estrus
photoperiod/lighting
outdoor fall born gilts mature in spring
outdoor spring-born gilts mature in fall, pubertal age delayed 15 days
wild, feral females reach peak repro activity in spring
total darkness delays puberty
need at least 10-18 hours of light
PG600
used to induce estrus in swine and contains combo of two hormones
each dose contains hCG (human chorionic gonadotropin) and PMSG (preg mare serum gonadotropin) that mimic FSH and LH
what does PG600 stimulate
stimulates the follicle on the ovary to grow and produce estrogen
for PG600 to work effectively, what needs to occur
gilts must be near age and weight of natural puberty but not reached it
females should be treated 2-3 weeks before expected onset of pubertal estrus
provide 10 min of boar exposure
breed on second or thrid estrus
why do we do estrus synchronization
better idea of farrowing
better estimate of pig flow
synchronization of estrus in prepubertal gilts
possible by having gilts go through puberty induction together
Boar exposure, transport stress and PG600 produce most synchronization
ability to precisely control the onset of estrus is called
synchronization
once females reach puberty and begin to exhibit estrous cycles, what two things can not be used
boar exposure and PG600
orally active, synthetic progesterone-like compound can be used for synchronizing estrus in mature sows and gilts
matrix
how long is matrix fed
14 days
matrix produced estrus on average ______ days after removal from the feed
4-9
T/F females can be at any stage of estrous cycle at the onset of feeding matrix
true
early estrous cycle and PG600
~2 days
works with progesterone being produced by CL
mid estrous cycle and PG600
~13 days
prevents resumption of follicular growth
late estrous cycle and PG600
~18-19 days
halts follicular growth of Medium to large and ovulation
sync estrus in mature sows/gilts natural estrus
bred and abort (uncommon)
between 15-40 days of gestation, inject 10-15mg lutalyse (PGF2-alpha)–> abortion withing 24 hours
display estrus 4-8 days after abortion
synchronization of estrus in weaned sows
MOST COMMON
mostly natural
lactation inhibits the release of GnRH= low LH and FSH
weaning stimulated the release of GnRH= LH and FSH released
weaning groups of sows on the same day is an effective method of estrus sync
the single most important factor affecting the fertilization rate and overall success of AI
timing of insemenation
if the female is inseminated too early or too late, the result will be
poor litter size
reduced farrowing rates
The most critical factor in AI is ensuring that insemination occurs with fertile semen 12 to 18 hours before
ovulation
when do you inseminate a gilt who is check once a day for estrus
1st= 0 hours
2nd= 24 hours
when do you inseminate a gilt who is check twice a day for estrus
1st= 12 hours
2nd= 24 hours
when do you inseminate a sow who is check once a day for estrus
1st= 0 hours
2nd= 24 hours
when do you inseminate a sow who is check twice a day for estrus
1st= 24 hours
2nd= 36 hours
insemination process
determine if female is in estrus
clean vulva
apply lub to AI rod
insert AI rod
how do you insert AI rod
lube tip and angle rod upward
rod should lock in cervix
remove tip of semen bottle and insert end into rod
semen starts to flow if properly stimulated
how to stimulate sow/gilt for insemenation
nose to nose with boar
rub flanks, apply weight to back
how in semen taken in by the sow during AI
semen is not injected BUT is pulled into female by uterine contractions
without stimulation, what will occur
decreased conception rates
longer to breed
types of AI rod
foam
spirette
when using a spirette is it turned clockwise or counterclockwise
counterclockwise
once all semen is deposited, what happens
AI rod is removed and trashed
female shouldn’t move for 20-30 min
