The timing of inseminslion is the single most important factor affecting fertilisation rate and the overall success of At. If the sow/gilt is inseminated too early (24 hours before ovulation) or too late (after ovulation), the result will be poorer litter sizes and reduced farrowing rates. An Al strategy has to be developed to optimise insemination timing.
Time of weaning must be consistent so all sows can be sorted and bunched according to size and condition
Weaning-to-oestrus interval varies between sows
Sows showing early oestrus, say four days after weaning, tend to be in oestrus longer (3 days) than sows which come on heat on day 6-7 (2 days)
The weaning to oestrus interval varies with season arid length of lactation
Body condition of sows at weaning has a major influence
on the weaning-to-oestrus interval. Lean sows tend to
exhibit later oestrus Q The best farrowing rates and numbers born alive are
associated with longer duration of oestrus
High feed intake during lactation improves weaning-to-oestrus interval, and consequently improves farrowing rate
and numbers of piglets born alive
Ovulation occurs during the last ⅓ of the standing
Never inseminate a sow/gilt that is not in standing oestrus
90% of sows weaned on the same day will ovulate in a
Average standing to oestrus time can change 12 hours
between good/poor breeding times. Typically, oestrus
January to May will tend tooccur earlier than oestrus
September to January
Unfertilised ova degenerate after approximately 8 hours of
waiting following ovulation
Sperm can live within the uterine tract for approximately
Long-life extenders help prolong sperm life up to the point
Treat each sow as an individual. KEY POINTST FOR SUCCESSFUL TIMING OF INSEMINATION
Accurate twice-per-day standing oestrous detection is
Twice/day oestrous identification allows more accurate heat
detection and thus timing of insemination.
If twice/day oestrous detection is operated, an example insemination programme is shown in Table 1.
Therefore from Table 1:
Sows found in oestrus on day 4 am are left until day 5 am to be served
Sows found in oestrus on day 4 pm are served day 5 pm
Sows found in oestrus on day 5 pm are served day 6 am
Sows found in oestrus on day 6 are inseminated immediately.
Table 1 is a guide and will need to be modified according to when standing oestrus is first identified.