Advantages

The main benefits of batch farrowing and all-in all-out systems result from improved health, leading to faster growth, improved feed efficiency, lower mortality and reduced medication costs. Batch systems have one extremely important feature from the health viewpoint.

They help to contain any flare up of circulating disease or specific health problem in one batch from spreading to other batches. Not only does this provide a valuable "insurance policy" against disease, but it also enables treatment to be carried out specifically on the affected pigs only. Treated animals are therefore clearly identified, giving food safety benefits, while treatment costs are kept to a minimum.

Some herds that have gone over from continuous to all-in/all-out systems with cleaning between batches are commonly experiencing growth rate increases of 100-150 grams/day. Neville Kingston reported on the success of a batch farrowing system in 2 herds farrowing every 3 weeks. Using the same facilities, a change from weekly to 3 weekly batch production resulted in overall savings of 8.5p/kg dead weight, or £6.00/pig.

Performance of Feeding Herds
Weaning Weekly as Compared to Weaning Every Third Week
(2 Units - 590 Sows)

Two-weekly or three-weekly batch farrowing

Breeding herd management has to be of a very high standard to maintain an even pig flow. A batch system on every third week fits in easiest with the breeding programme as any returns from one batch in 80% of (based on the normal herd) returns are on a 3 week cycle and should fit in to the subsequent batch. Other options include two-weekly or four-weekly batch farrowing. Extra farrowing crates are required for batch farrowing but this does allow more time for cleaning, disinfection and a rest between batches. From research in France an increased rest between batches was one factor that appears to be associated with reduced risk of PMWS. It may also be possible to wean pigs later.

How batch farrowing works on a 225 sow herd

How many females will I need?

The object of dry sow management is to provide group of sows that farrow within a specific time interval and provide a batch of pigs large enough to fill the weaning accommodation. The first steps are to decide on the number of sows per batch and the frequency of farrowing. The number of sows per batch will be determined by the average litter size weaned and the number of weaners required to fill the weaner facilities. It is more efficient to increase farrowing facilities than to under utilise weaner accommodation.

Three weekly batch farrowing requirements

Each group should contain enough sows and gilts to fill the farrowing accommodation, with an appropriate buffer to allow for returns to service, or unexpected cullings. Multiply the number of groups by the number of crates, add ten percent to allow for cullings (reproductive failure, lameness etc.) and you have your number of female breeders.

However, before deciding the size of the breeding herd, you should identify the area most likely to limit, or "bottleneck" the farm's animal movement. For example, you shouldn't use every farrowing crate if your weaner (or grower or finisher) accommodation is not big enough for a full group's worth of weaners (or growers or finishers) arriving at once.

When considering the move to batch farrowing, it is useful to draw a simple pig-flow diagram such as the one below, in order to recognise any physical limitation imposed by your accommodation. This is particularly important if the herd is moving to an all-in/all-out system.

Three weekly batch farrowing requirements

In this example, two grower rooms are filled alternately every four weeks, to ensure that each batch of growers has eight weeks of growth without other batches entering or leaving the same room. Where separate rooms are unavailable, the use of relatively cheap partitioning to keep batches apart has proven to be worthwhile.

Even if weaner and grower batches cannot move into empty rooms, the period between arrivals of new batches (ie 4 weeks) may be great enough to significantly reduce the numbers of pathogenic organisms passed from older to younger batches, thereby reducing the effect of disease.

An example is outlined below of how 3 week batch farrowing would work where sows are brought into the farrowing rooms 7 days before farrowing, pigs are weaned at 28 days of age, there is an average weaning to service interval of 5 days and the average pregnancy length of the herd is 114 days. These could be adjusted to the average intervals in any specific herd.

How 3 week batch farrowing would work

How do I get sows cycling together?

Initially, each group of females must be carefully managed to ensure synchronous farrowing. There are several ways of achieving this and you should seek management and veterinary advice when planning to change your system.

1. Your veterinary surgeon can advise on the use of different treatments to synchronise heat in sows and gilts.
   
   
2. Progressively weaning sows together, over a range of litter ages.
   
   For example, If you normally wean at four weeks, the first weaning would involve all litters between the ages of three and five weeks. If a fortnight's weanings are done on the same day then a month's weanings result in two batches of breeder females cycling a fortnight apart. Once pregnant, they will then farrow two weeks apart. If you wish to move to four-weekly batching the pigs could be weaned together when the earlier group of litters is 5 weeks old and the later is 3 weeks old.
   
   One disadvantage of weaning 3 to 5 week old pigs is that it will result in size unevenness throughout the growing period. Many farms will not have sufficient farrowing crates to allow a delay in weaning. As an alternative temporary farrowing pens can be made. Sows nursing 2- or 3- week old piglets can be moved with their litters to temporary pens and nursing can continue until an appropriate time to wean. You will still need to to synchronise incoming gilts.
   
   
3. Careful use of prostaglandins to induce farrowing 2-3 days early will help shorten the time range of a batch farrowing, as well as help avoid weekend farrowings.
   
   
4. Changing your system to batch farrowing may also be an opportunity to do a partial depopulation and progressively replace breeding stock. Ideally these should be mated and housed off site until the last group of sows have been weaned and removed.

A Tight Farrowing Period is Essential

In a batch farrowing system it is essential that all farrowings are completed within a few days. Sows not farrowing within this time period may need to be treated with prostaglandins to advance the time of farrowing so that their piglets reach the required weaning weight when older litters are weaned.

Delayed return to heat after weaning can disrupt batch farrowing programmes. It is more common in gilts weaning their first litter, in sows that are in poor body condition and in the mid-late summer months. It may be useful to wean these sows slightly earlier than the main batch.

Using AI in conjunction with batch farrowing is important as it will reduce the number of boars required. Heat detection also needs to be improved as missed heats will result in females that may be out of synchrony with the system.

Pregnancy testing sows as early as practical and removing non-pregnant animals from the group is also important to control non-productive days. Testing as early as 18 to 20 days is possible with modern ultrasound equipment.

Maintaining Batch Size

Batch management is focussed on having full batches all the time and staff are much more aware of the importance of batch size on profitability. Achieving maximum output depends on achieving constant production, which requires output targets to be met. The key output targets are :

• Number of productive sows and gilts
• Gilt pool size
• Number of matings per batch
• Number of farrowings per batch

Gilt management

Gilt management must be of the highest standard. The most important aspect of management is to ensure that enough gilts are available and on heat in the service weeks to replace sows that will eventually be culled. This is achieved by :

• Ensuring that delivery dates coincide with the week of weaning
• Following a predictable management routine with correct integration, feeding and boar exposure.
• Using synchronisation treatments to bring out of step gilts in heat for the required service week

Will batch farrowing suit me?

Batch farrowing will not suit everyone. It is important to keep groups separately to minimise the opportunity for disease to spread from older to younger pigs. It is not necessary to run a batch farrowing herd as an all-in/all-out operation between weaning and marketing, but to do so would help maximise the advantages of the batch farrowing system.

Some additional investment is likely to be required. Existing buildings may not fit the requirements of a batch farrowing system but it may be possible to adapt these for example by moving internal partitions. It is likely that in most cases additional farrowing facilities will be required. Extra weaning places may also be required. Weaning age is also likely to be increased.

Batch farrowing allows you to limit the number of times that pigs are moved, which reduces growth setbacks associated with stress and fighting. Ideally, pigs would only move twice; once from the farrowing house into weaner accommodation, and once more into finisher pens. If you are worried that weaners going into finisher pens will be too cold during the cooler months, consider leaving some pens empty and increase the stocking rate in the others for a fortnight or so. Where the weather permits, weaners should occupy finisher pens at the rate of 0.65 m2 per pig, which is the recommended stocking rate for pigs over 85kg.

In units where PRRS is a problem the onset ,may be delayed in batch farrowing systems. This can result in pigs getting the virus at a later stage and pneumonia problems for older finisher pigs Batch production, focuses management effort on achieving the correct batch size, giving constant (maximum) output, which maximises profit. However, batch farrowing requires consistently high standards of management and works best where staff have been fully involved in planning the changeover and are fully committed to ensuring its success.

Advantages of batch farrowing

1. The main benefits of the system result from improved health, leading to faster growth, improved feed efficiency, lower mortality and reduced medication costs.
2. Management of breeders, weaners and finishers in groups results in more efficient use of time (eg. preg testing, litterwork), materials (eg. iron dextrose, vaccines, with-holding period medications) and feed.
3. Room environments can be finely adjusted to suit particular age groups without disadvantaging older or younger pigs.
4. With pigs managed in distinct age ranges, the opportunity exists to progressively adjust diets through the grower/finisher period ("phase feeding"), knowing that feed can be specifically formulated for entire grower and finisher populations.
5. Split sex feeding is possible on larger units where the number of pigs justifies splitting each group into two batches and feeding boars and gilts separate diets.
6. Pig movements and management practices can be more easily planned and predicted. Busy weeks (mating, farrowing, weaning) alternate with less active times allowing more economical use of casual labour and better management of time. Weekly activities are fixed making it easier to plan ahead.
7. Batch production makes it possible to monitor feed and water consumption on a continuous basis so that you can respond to changes in the pattern of consumption, that may indicate a health problem.
8. There is more incentive to meet mating targets, as failed matings result in empty crates.
9. The use of AI fits well in a batch farrowing system. AI will introduce genetic improvement and helpsafeguard herd health. It is generally quicker than natural mating, and a further saving can be made through the reduction of boar numbers.
10. Possible to market larger groups of uniform animals.
11. Cross fostering is easier, with more foster mothers to choose from, especially when colostrum is needed.
12. A variation in activities from week to week provides more varied and interesting routines for staff and as a result improves motivation. Batch production also enables skills and effort to be concentrated at critical times such as service and farrowing.
13. Regularly emptied farrowing rooms can be more thoroughly cleaned and maintained.
14. The extra time between farrowings can be used for bigger maintenance or refitting jobs.

Disadvantages of batch farrowing

1. Gilts and "stale" sows can fail to cycle within the required period, meaning that extra females need to be mated to avoid empty crates. Mating targets must be met.
2. This in turn could lead to an oversupply of pregnant females.
3. If you choose not to use AI, boar demand would alternate between heavy and light.
4. Unpredictably late and early farrowings within a group will extend the age and weight ranges of weaner groups.
5. Mid week matings are likely to lead to weekend farrowings.
6. If changing over from a continuous flow system, there may be an initial period of low production, although this income will soon be recovered through increased growth rates, reduced medication and so on.

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