When to skip-a-heat in sows and gilts

Skip-a-heat can help avoid a second litter performance drop and improve performance and longevity of the sow. This information covers equipment, checks and best practice.

Skip-a-heat is a practice that is most used in first parity sows, to avoid a second litter performance drop; it can, however, be adapted and used for older sows.

Skipping a heat will increase the farm’s number of non-productive days, but there is some reported evidence of payback in terms of improved performance and longevity of the sow.

Skip-a-heat can also be used for older sows that come out of the farrowing house in a poor body condition (BCS S <2.5), having lost a significant amount of protein mass and fat during lactation. Skipping a heat gives the sow extra time to improve body condition before the next cycle.

Equipment

You will need the following equipment:

• Recording sheets/performance data
• An additional 21 days of dry herd weaned sows
• Pig boards

Initial checks

Assess the performance of the farm’s first parity sows and their performance in the second litter. Does there appear to be a drop-in conception rate and numbers born? Consider if any managerial aspect is contributing to this.

If nothing is identified, it may be beneficial to adopt skip-a-heat.

• Monitor body condition of the first parity sows/sows entering the farrowing house, and throughout lactation
• Record body condition scores a few days prior to weaning
• Decide if any sows will benefit from skipping a heat
• Ensure an additional 21 days dry sow accommodation is available
• Practically, it is better to retain the same number of sows each week/batch to feed back into service 3 weeks later

Outline of work

Assuming skip-a-heat is only first parity sows:

• Wean piglets and move sows as normal
• Keep the first parity sows separate from the other sows
• Heat detect as normal, record dates of first heat post-weaning, but do not serve or mate the first parity sows
• Keep the first parity sows in separate pens for the next 21 days
• Feed a standard lactation diet ad lib for the 21-day period
• Provide at least daily boar contact (fence line) for heat detection throughout the 21-day period

Three weeks after weaning, it may be necessary to mix sows back in with the small weaned sows, or, depending on number, the ‘skipped’ group may need to be housed as a stable group in the service area.

• At second heat post-weaning, serve as normal and record as skip-a-heat for future analysis
• Move the served sows to permanent dry sow accommodation (avoid mixing), and manage as normal
• Review second litter performance and compare the before and after skip-a-heat performance

Skip-a-heat in gilts 

• In gilts, skip-a-heat has been found to improve follicular development, ovulation rate and embryo survivability (an extra 2.3 embryos compared with not skipping a heat) at day 30 of gestation
• Research and farm data suggest that an extra 1–2 piglets will be produced the following litter.