Swine breeding management Flashcards
Main goals of swine reproduction
- Maximize the number of weaned pigs per sow per year
(pigs/sow/yr) - Be sure that the sows in the gestation barn are pregnant
> Minimize non-productive sow days (NPD) - Consistent flow of pigs
> Economics of predictable flow
pig gesttion length
- Gestation days fixed biologically (114-116d)
pig lactation length
- Lactation days is “fixed” based on herd management (21-28d)
metrics that inpact how many gestation-lactation cycles we have in a year. why do we want to max this?
- Want to ‘fit’ as many gestation-lactation cycles per
year, to maximize number of litters/sow/yr - Gestation days fixed biologically (114-116d)
- Lactation days is “fixed” based on herd management (21-28d)
Weaning prior to 14 days (or 16 days) will:
- reduce ovulation
- cause longer wean-breed interval
- cause cystic ovaries
- lower farrowing rate
- reduce the number of pigs born alive
what is a productive sow vs non-productive
- Productive sow: pregnant or lactating
- Non-productive sow: open and not lactating
Non-productive sow days = what? what influences this?
Non-productive sow days =
The number of days a sow is neither lactating nor pregnant/year
Influenced by:
* Weaning to conception /breeding interval
* Unrecognized pregnancy loss or NIP
what is the wean-to-estrus interval and why is it important?
As wean-to-estrous interval (WEI) increases, NPD increases
* Textbook WEI is 4-5 days
* Fertility is lower for sows bred at >5 days
how long from wean to estrus is normal, and how long would require investigating?
normal <7
investigate >7
what proportion of sows should be bred by 6d after weaning? what proportion requires investigating?
normal >90
investigate <85
- Risk factors for long WEI/anestrus
- Young sows
- Inadequate lactation nutrition (poor body condition)
issue for pen introduction of piglets
mixing aggression
how long after weaning does a sow come into heat
In heat 3–5 days later
Observable signs of estrus; primary sign
Primary signs:
* Standing while another sow or boar mounts
* Back pressure test
Observable signs of estrus; secondary signs
- Bar biting, climbing
- Vocalization
- Restlessness
- Seeking boar, solicitation
- Swollen, deep red vulva
- Malelikebehaviour
- Off feed
- Ears pricked
- Elevated rectal temperature
- Quiver
- Tail twitch, held up
- Evidence of viscous, sticky vaginal mucous
- In general, the stickier the mucous, the stronger the heat (use the “thumb test”)
“Hand Breeding” what is this
natural breeding, Stay in pen with sow and boar
Semen Collection steps
- Boar mounts the dummy. Exteriorize the penis
- Gloved-hand technique
- Collect sperm rich fraction into a warm thermos
Semen Storage; how do we do it, special considerations
- Boar semen is extremely sensitive to temperature change
- Sperm damage if < 15 or >20oC for 40 minutes
– Store between 15 and 20oC
– Fluctuations < 2oC - 36% of farm storage units in Ontario did not meet this criteria
- Most semen is purchased from boar stud and may be stored (in special coolers) on-farm for 3–5 days
Artificial insemination: How to
- Identify sows in heat
- Lubricate catheter tip with water soluble lubricant
- Wipe vulva if required, part lips
- Angle catheter 30-45 degrees craniodorsally
- Insert catheter 10-15 cm (4-6”)
- Reposition catheter horizontally
- Push forward gently, until resistance is felt
- If a spiral tipped catheter is used, rotate counter- clockwise
- When the catheter feels tight, it is “locked” in the cervix
- Connect semen (bottle, tube, flat pack)
- Raise catheter dorsally into a near vertical position
- If required, initiate semen flow by gently squeezing bottle.
- Female will continue to “draw” semen, do not squeeze bottle.
- Remove catheter when complete
Summary:
-Insert AI catheter into sow
-Attach semen tube to catheter
-Hook semen bottle onto “hands free device”
-Allow sow to “draw” semen into her reproductive tract
catheter characteristics for sow AI
- Reusable or disposable
- Spiral or sponge tip (sized for gilts & sows)
- Cervical or post-cervical (deep or intra-uterine)
– Personal preference
Belt around sow mimics
pressure of boar’s legs
what do we see in a case of failure of conception? what is this due to? what are normal rates and concerning rates?
bred and then fail to conceive. Results in them coming back into heat 21d later (or 42d).
- Efficiency of estrous detection
- Sows not getting pregnant, or lost pregnancy very early (before maternal recognition of pregnancy)
Normal: ≤8%
Investigate: >10%
what do we see in a case of failure of pregnancy? what is this due to? what are normal rates and concerning rates?
bred, maternal recognition of pregnancy, then return to estrous at an irregular period, not pregnant.
- Return to estrous > 25d post breeding
- Why are sows losing pregnancy?
Normal: ≤3%
Investigate: >4%
Pregnancy Detection methods for sow
- Stimulate with boar at 18–25d post breeding
- Ultrasound at 24–28d post breeding
- Recheck at 36–50d for repeat sows (2nd regular estrus post breeding) – part of our goal!
Why induce sows to farrow?
– Management
– Batch farrowing
What can we use to induce sows to farrow?
Prostaglandin
how do we administer prostaglandin to induce farrowing? what is the schedule?
- Causes agitation, sweating, panting
- 1⁄2 dose in vulva vs full dose IM
- Administer: 2 d before normal gestation length of the herd (~113-114d gestation)
what happens if we administer prostaglandin too early for induction?
- Increase stillbirths
- Weakborn & splayleg pigs
Farrowing Rate
The proportion of the sows that are bred that go to term (farrow)
– (# farrow / # bred) x 100
normal farrowing rate? when should we investigate?
normal >87
investigate <82
Adjusted farrowing rate; what does this account for? how different will it be from non-adjusted rate?
accounts for sows not farrowing due to non-reproductive reasons
– (# farrow / {# bred - # non-repro culls}) x 100 *Normal vs adjusted
should not differ by more than 2 or 3%
what should we do if the farrowing rate is too low?
investigate:
– Bred sows are not becoming pregnant
OR
– Pregnant sows are becoming non-pregnant
how are gilts housed?
- Sufficient space (16ft2 or 1.5m2)
- Housed in pens
breeding protocol for gilts
- Daily exposure to mature boars (15 min/day)
- Relocate gilt, estrous 5-7d later
- Identify first estrus
- Breed at 2nd estrus*
- Re-mix anestrus gilts
- Breed every 12 h while in heat*
*Shorter duration of estrus than sows
when do we select gilts?
Select gilts at 150d of age or ~100kg
how to induce estrus in gilt
- May use ‘‘PG 600” to induce estrus
- Human chorionic gonadotropin & pregnant mare serum gonadotropin
- Mimics LH and FSH
- Will induce a fertile estrus in gilts that have not had a first estrus
what is regumate and what do we use it for in gilts?
- Oral progesterone (Regumate)
- Used to synchronize females
- Feed for 8 days in a row
litters/female/year
2.2
Non-productive days/sow/yr
70
Pigs weaned/litter
8.8
Born alive/litter
10
Total born/litter
11
Born dead/litter
0.9
Pre-weaning mortality
<8-10%
