Problem Solving - Litters Per Sow Per Year

Target = 2.40**

Rationale for Target:

Given a gestation length of 114-115 days for most herds & lactation length is approximately 28 days, when the target of 10 Non Productive Days (NPDs)/litter is added this gives us a minimum of 152 days to produce a litter. 365/152 = 2.4 litters/sow/year.

** Assumes gilts are counted in the herd only from the day of first breeding

Focus Areas

It is inevitable that a few sows will be truly anoestrus after weaning as a result of abnormal hormonal or tissue changes. In addition, other sows will appear anoestrus but will actually be cycling females whose heats have been poorly shown or poorly detected. Once the latter issue has been dealt with it is reasonable to expect very few truly anoestrous sows to be present, hence the target of less than 1 in 25.
Causes Solutions
Low lactation feed intake
  1. Check lactation feeding of sows
  2. Increase feeding frequency
  3. Ensure water flow rate of at least 2L/min.
  4. Keep farrowing house temperature below 24°C
Low post-weaning feeding
  1. Ensure weaned sows are fed at least 40 MJ of DE/day of a lactation sow diet
Large litter size suckled
  1. Use expert cross-fostering 24 hours after birth
  2. Give parity 1 & thin sows fewer piglets to suckle than other sows
  3. For lactating sows clearly losing condition consider split-weaning the heaviest 3 piglets in the litter (leaving at least 7) 5-7 days early. Split weaned piglets can enter the nursery flow or be placed on a nurse sow
  4. If this is a significant problem consider treating with PG600 on the day of weaning
High proportion of parity 1 sows
  1. Consider split-weaning 5-7 days early the heaviest 3 piglets in a litter (leaving at least 7) 5-7 days early. Split weaned piglets can enter the nursery flow or be placed on a nurse sow
Lactation heats in sows
  1. Be aware up to 15% of sows may come on heat in the farrowing house
  2. Ensure every sow suckles at least 10 piglets
  3. Check lactating sows for heat daily in their last week in the farrowing house. You can breed any on heat
Failure to stimulate weaned sows
  1. Ensure weaned sows are given daily boar contact for 5 min. to both stimulate & detect heat starting on the day after weaning.
  2. Where possible group-house weaned sows
Poor heat detection post-weaning
  1. Check heat detection procedures
Seasonal problems
  1. Only give boar contact in cool times of day
  2. If anoestrus rate increases in Summer/early Autumn give boar contact for 5 min. twice a day
  3. If all else fails treat sows at weaning with PG600
Most sows should return to heat 4-5 days after weaning. Any earlier means they were already preparing to come on heat during lactation. A few sows, particularly after weaning the first litter or where lactation feed intake was inadequate, will take a day or two longer.
Causes Solutions
Low lactation feed intake
  1. Check lactation feeding of sows
  2. Increase feeding frequency
  3. Ensure water flow rate of at least 2L/min.
  4. Keep farrowing house temperature below 24°C
Low post-weaning feeding
  1. Ensure weaned sows are fed at least 40 MJ of DE/day of a lactation sow diet
Large litter size suckled
  1. Use expert cross-fostering 24 hours after birth
  2. Give parity 1 & thin sows fewer piglets to suckle than other sows
  3. For lactating sows clearly losing condition consider split-weaning the heaviest 3 piglets in the litter (leaving at least 7) 5-7 days early. Split weaned piglets can enter the nursery flow or be placed on a nurse sow
  4. If this is a significant problem consider treating with PG600 on the day of weaning
Poor heat detection post-weaning
  1. Check heat detection procedures
Seasonal problems
  1. Check sow feed intake in lactation & post-weaning
  2. Only give boar contact in cool times of day
  3. If anoestrus rate increases in Summer/early Autumn give boar contact for 5 min. twice a day
  4. If all else fails treat sows at weaning with PG600
High proportion of parity 1 sows
  1. Aim for a parity distribution of approximately 20% gilts, 17% parity 1 sows, 15% parity 2 sows, 14% parity 3 sows, 13% parity 4 sows, 11% parity 5 sows & 10% parity 6 sows if culling on age after 6 parities. Adjust these proportions appropriately if culling after 7 or 8 parities.
  2. Consider split-weaning the heaviest 3 piglets in a litter (leaving at least 7) 5-7 days early. Split weaned piglets can enter the nursery flow or be placed on a nurse sow
Lactation heats in sows
  1. Be aware up to 15% of sows may come on heat in the farrowing house
  2. Ensure every sow suckles at least 10 piglets
  3. Check lactating sows for heat daily in their last week in the farrowing house. You can breed any on heat
This target reflects a targeted 3-week return rate of no more than 6%, irregular return rate of 2%, 6-week return rate of 1% & a further 1% of sows failing to farrow due to abortion or being a NIP. Each of these causes of a sow failing to farrow is dealt with separately in this application. Note that the adjusted farrowing rate targeted here omits sow deaths which should be no more than 1-2% of all pregnant females.
Vulval discharge normally results from ‘unclean' mating or insemination. In reality this is mainly due to mating or inseminating the sow late in her heat period when she has already ovulated & her signs of heat are rapidly waning. As it is easily avoided a very low target is given here.
Causes Solutions
Non-hygienic farrowing assistance
  1. Ensure any manual farrowing interventions are done cleanly & that the sow is treated with an antibiotic at completion of farrowing & a prostaglandin 24 hours later.
Non-hygienic service
  1. Conduct mating/insemination in a clean pen
  2. Ensure breeding technician wears non- powdered gloves
  3. Review natural mating & artificial insemination protocols.
Mating/insemination late in heat
  1. Review heat detection procedure
  2. Do not mate/inseminate a sow late in her heat period (usually day 3 or later) if she is not showing a good standing heat.
Poor housing
  1. Ensure pens are dry & faeces is regularly removed.
  2. Avoid solid back panels if using sow stalls.
  3. Ensure a water supply with a flow rate of 2L/min. If water intake is low consider raising dietary salt level (but to no more than 1% of diet).
In good herds it is standard practice to target a farrowing rate of 90%+, the losses consisting of a ratio of 3-week returns to irregular returns (days 25-38 post-breeding) of at least 3:1 & a ration of at least 4:1 of 3-week to 6-week returns. Allowing for up to 1% of pregnancy failures as abortions & NIPs (not-in-pig sows) this translates as approximately 6% 3-week returns, 2% irregular returns & 1% 6-week returns.
Causes Solutions
Poor gilt management
  1. Check that gilts are not being bred at their first (pubertal) heat, which normally gives a lower conception/farrowing rate
  2. Consider mating gilts at puberty with a vasectomised boar. This normally raises conception/farrowing rate by about 6% & litter size by 0.5-2.0 piglets/litter to a fertile breeding at second heat
Poor sow body condition
  1. Check lactation feeding of sows
  2. Ensure weaned sows are fed at least 40 MJ of DE/day of a lactation sow diet
Poor timing of mating/insemination
  1. Review heat detection procedure
  2. Review natural mating / artificial insemination procedure
Poor mating/insemination technique
  1. Review natural mating / artificial insemination procedure
In good herds it is standard practice to target a farrowing rate of 90%+, the losses consisting of a ratio of 3-week returns to irregular returns (days 25-38 post-breeding) of at least 3:1 & a ration of at least 4:1 of 3-week to 6-week returns. Allowing for up to 1% of pregnancy failures as abortions & NIPs (not-in-pig sows) this translates as approximately % 3-week returns, 2% irregular returns & 1% 6-week returns.
Causes Solutions
Poor mating/insemination technique
  1. Review natural mating/ artificial insemination procedure
  2. Check sows for vulval discharge
Stress in early pregnancy
  1. Wherever possibly avoid mixing sows during the first 2 weeks post-breeding
  2. If the problem persists consult your veterinarian.
Seasonal problems
  1. Be aware that irregular return rates tend to rise in the Summer & early Autumn
In good herds it is standard practice to target a farrowing rate of 90%+, the losses consisting of a ratio of 3-week returns to irregular returns (days 25-38 post-breeding) of at least 3:1 & a ration of at least 4:1 of 3-week to 6-week returns. Allowing for up to 1% of pregnancy failures as abortions & NIPs (not-in-pig sows) this translates as approximately % 3-week returns, 2% irregular returns & 1% 6-week returns.
Causes Solutions
Missed 3-week returns
  1. Improve heat detection in sows from days 17- 24 post-breeding
  2. Implement a good pregnancy detection program at 28-35 days post-breeding
Stress in early pregnancy
  1. Wherever possibly avoid mixing sows during the first 2 weeks post-breeding
  2. If the problem persists consult your veterinarian.
Seasonal problems
  1. Be aware that irregular return rates tend to rise in the Summer & early Autumn
A few abortions tend to happen apparently randomly on all breeding units & can be tolerated. Occasionally abortion rate rises suddenly at which time veterinary advice should be sought.
Causes Solutions
Mouldy feed
  1. Avoid obviously mouldy feed & ensure feed build-up in feeders & feed equipment is minimised
Environmental issues
  1. Avoid stressing pregnant sows
  2. Avoid extremes of temperature & sunburn
  3. Avoid build-up of pit effluent gases
A NIP is usually a sow that is pseudo-pregnant. This means that she has detected the embryonic signals in the first 3 weeks post-breeding that tell her she is pregnant but she has then lost the pregnancy. As no further signals will be given she continues to think she is pregnant & enters a pseudo-pregnant state. Alternatively, she may simply be a sow that has returned to service but this heat has not been detected.
Causes Solutions
Pseudopregnancy
  1. Avoid stressing the sow in the period up to 5 weeks post-breeding
Poor heat detection
  1. Improve heat detection in sows from days 17- 24 post-breeding
  2. Implement a good pregnancy detection program at 28-35 days post-breeding & repeat it 3-4 weeks later
Mycotoxins or infection
  1. Avoid obviously mouldy feed & ensure feed build-up in feeders & feed equipment is minimised
  2. Feed a mycotoxin binder in the sow's diet
  3. Maintain strict biosecurity protocols
  4. Maintain herd vaccination programs
Housing & feed
  1. Ensure hygienic housing for pregnant sows
  2. Ensure gestation diet has adequate vitamin & trace element levels

NPDs represent those days in the production of a litter that the sow is neither pregnant nor lactating. Hence, it is made up of:

  1. the weaning-to-mating interval
  2. those weaned sows that go anoestrus & are culled,
  3. conception failures
  4. pregnancy failures
  5. any sow deaths that occur between weaning & farrowing.

It would also be logical to include gilt time in herd from selection/arrival until breeding & also gilts that were selected/arrived but were culled without being bred. However, in virtually all recording systems this is not done & is therefore not done here.

Given targets of 5 days for the weaning-to-remating interval, 6% regular (3-week) returns, 2% irregular returns, 1% 6-week returns, 1% abortions/NIPs & 2% sow deaths, this gives a target figure for NPDs of 9-10 days. The likely causes & solutions to the individual components of NPDs, as given above, should be followed to minimise NPDs.