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Management of farrowing objectives to achieve optimal piglet weight at weaning (I): weekly batches

Wouldn’t it be great if all the sows on a farm (weaned sows, gilts, repeat breeders…) could be mated on the same day?! And if we were able to choose, on Mondays?

Wouldn’t it be great if all the sows on a farm (weaned sows, gilts, repeat breeders…) could be mated on the same day?! And if we were able to choose, on Mondays? In this case, with just one weaning per week, for example, on Thursday:

- There would be no mating on the weekends.
- Farrowings would be concentrated on Wednesdays –Thursdays – Fridays (without affecting the weekend).
- Sows would wean at 3 weeks for a minimum of 22 – 21 – 20 days, but no less.

In this ideal world, a farm with 400 farrowing places spread between 4 rooms (100 sows/room), with an objective of 100 farrowings per week, will consistently wean piglets at approximately 21 days (as long as the target of 100 farrowings per week is not exceeded).

However, unfortunately, in the real world, this isn’t possible. In farms with good estrus timing and, even when the mating of gilts is programmed with altrenogest (avoiding weekend cycles), we will usually have mating distributions such as these:

- Monday: 60% entry into estrus (some weaned even go into estrus on Sunday).
- Tuesday: 20% entry into estrus
- Wednesday: 7% entry into estrus
- Thursday - Saturday: 13% entry into estrus

With a gestation length of 114 days and a single weaning on Thursdays:

- Mating on Mondays translates into Wednesday farrowings → Weaning at 22 days, after 3 weeks.
- Mating on Tuesdays → Thursday farrowings → Weaning at 21 days, after 3 weeks.
- Mating on Wednesdays → Friday farrowings → Weaning at 20 days, after 3 weeks.
- Mating on Thursdays – Sundays → farrowings from Saturday - Tuesday → Weaning at 19, 18, 17 and 16 days. Normally these sows with anticipated farrowing on Monday and Tuesday would enter the next batch, meaning they would be the first to farrow in that batch, and they would wean at 23 – 24 days.

In this case, on our farm with 4 rooms and 100 farrowing pens, we would be weaning approximately 10% of sows and piglets at less than 20 days, as long as we continue achieving the objective of 100 farrowings per week. If on occasion we exceed the objective due to carelessness, the number of premature weanings will increase even more.

If we add small piglets, premature piglets, and those who experienced a late farrowings, to the piglets weaned before 21 days, we can easily find ourselves with a 20-30% rate of ‘conflictive’ piglets upon weaning. We also must take into consideration the piglets born to first farrowing sows. If the estrus cycles of the first farrowing sows are not synchronized, it is probable that these sows will mate between Thursday and Sunday, and this means that the majority of small piglets, premature piglets, and those with a late farrowing, will be a result of these first farrowing sows.

This is what usually happens on farms that try to squeeze the farrowing pen to the maximum, imposing rotations every 4 weeks and rushing the farrowing target.

Obviously, we aren’t stating anything new. This practice is surely being applied by many farmers intuitively. What they probably haven’t realized is that by reducing farrowing objectives by just 5% they will in turn attain 10 to 20% more space per batch in order to lengthen the lactation period of the sows that were mated between batches.

Other advantages of this system:

This extra space can also be used for the following:

- Since a large part of displaced sows are primiparous, we would be lengthening the lactation period of the sows that need it most.

- To lengthen the lactation period of small piglet litters. If we take care to enter the second and third farrowing sows in the last room of the batch, we can place the small piglets with them without having to move them later.

- When nurse sows are used, allowing the piglets one extra week of weaning, we will end up weaning them at the same age if we have the foresight to put them in “extra” rooms where they can remain for another week.

- In the case that farrowing objectives are occasionally exceeded, we have more leeway.

- All-in/all-out management is not compromised.

Special precautions:

It is essential to enter the sows into farrowing pens in a certain order. Ideally, they will enter perfectly ordered by mating day. The problem we will have is with the gestation stalls; it is difficult to order sows by mating date if they are mixed in the same stall (above all if the ear tags are dirty). For this reason, a good option is to order them as they pass from the pens to the stalls, and at least separating those mated on Mondays, Tuesdays, and Wednesdays from those mated on Thursdays, Fridays and Saturdays. The ones mated on Sunday can mix with those of the following Monday.

In the case of a farm with very prolific sows, where a larger quantity of small piglets tend to be born and the need to create nurse sows obliges us to advance the weaning age of many piglets, we can use the same method but adjust it by increasing the margin of “extra” places, and reducing the farrowing objectives, for example, by 10%.

Another option is, instead of reducing the farrowing objectives, increase space in the farrowing pens. (In the case of our example we could build an extra room with 20 places). In this way we can carry out the same management strategy, but with a farrowing objective of 100 farrowings / batch.


Many small rooms are necessary in order to put this into practice, otherwise we compromise the all-in / all-out management. Therefore it is easier to apply this to larger farms (they tend to have more rooms) as opposed to on smaller farms.


Logically it is not easy to accept census reductions, but the advantage of gaining quality weaned piglets and lengthening the lactation periods of sows that would have been weaned at very few days (with more problems in estrus and less prolificacy in their next farrow) it is easy to compensate, above all in times of economic crisis such as the current situation.

This management style can also make us reconsider what the ideal room size is. Large rooms are more comfortable when working and cheap to construct (one thermal regulator and ventilation system for a larger number of sows, a larger pit, fewer intermediate walls…). However, as we can see, they offer less flexibility when determining farrowing objectives and managing sows to be weaned in batches.

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This area is not intended to be a place to consult authors about their articles, but rather a place for open discussion among pig333.com users.
12-Nov-2012ray croteauray croteauI have a young gilt whose farrowing date was 6 days ago. She seems healthy and has been developing all the signs that she will be ready but her two siblings had very early farrowing times and also had problems. Is there anything I need to do except wait & see.
Thanks for any advice
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