Batch farrowing

Batch farrowing involves grouping 3 weeks' sows into one batch, so that every third week one large batch of sows farrow. This batch is weaned 4 weeks later and served during the following week. This means that only farrowing, weaning or service takes place on the farm each week, allowing the producer to concentrate and specialise on each of these activities.

The change from weekly to 3-weekly production must be planned well in advance, otherwise the process will descend into chaos. This can only begin when aspects such as the availability of replacement gilts and adjustments to housing have been addressed.

Usually each batch of sows is created by weaning 3 weeks' sows on the one day. For example, on a 100 sow unit, 4 sows are weaned as normal when the pigs are 4 weeks of age. A further 4 sows have been kept with their pigs until 5 weeks after farrowing and a third group are weaned at 3 weeks. The result is that 12 sows are weaned at the one time. This process is repeated every 3 weeks until all sows have been grouped into batches of 12.

Sows are served as normal the week after weaning. As there are now no sows farrowing or being weaned this week, full attention can be given to heat detection and service. As a larger batch of sows is served every third week, natural service does not work well with 3-week production. Although some boars are necessary for heat detection and stimulation, the service routine relies mainly on AI. Results from units which operate 3 week production and rely on AI, show conception rates and litter sizes to be at least as good as those from units operating weekly production with natural service.

As sows naturally cycle every 3 weeks, sows that repeat at 3-weeks, or even 6 or 9 weeks, fall into a service week. Sows with irregular repeats are either culled out of the herd or are served out of sequence and weaning age adjusted to bring them back into the batch. This has worked well in practice, with replacement rate being similar to that on weekly run systems.

Performance in the farrowing house is often improved with 3-week production, due to more time being available to concentrate on farrowing sows and young piglets. Also the larger numbers of sows farrowing makes fostering easier. As a maximum of two batches of sows are in the farrowing area at any time, it can be divided into two rooms. However, some additional farrowing accommodation is necessary. Typically a 100-sow herd will require four extra farrowing pens

There is always a break of at least one week between sows being weaned and a new batch entering the farrowing house. This all in - all out process allows for complete cleaning and resting, which gives improved disease control.

Undoubtedly the success of batch farrowing relies on gilts being available and on heat when required. Indeed herds that have adopted the 3-week system have successfully improved gilt management. This has involved stimulating gilts into first heat 6 weeks before they are needed to replace a cull sow. Stimulating gilts before they cycle naturally, ensures that they fit in with the 3-week system. If synchronising gilts proves to be a problem, hormones can be used to delay heat. With weekly production usually one or two gilts are required at any time, whereas in the batch system 3 times as many gilts are needed. This allows gilts to be bought or selected in batches and stimulated as a batch.

As a large number of pigs are weaned, sizing of pigs is much easier. In many cases this allows a batch of smaller pigs to be grouped together to receive additional care. Also these pigs can be fed creep feed for a longer period. If the feeding system allows, this can also be applied to the link and grower feed.

As pigs are transferred through the feeding herd in large batches, there is more opportunity for the accommodation to be washed and rested between batches. This all in - all out policy in the feeding herd has undoubtedly given improved performance on units.

A further benefit of the system is that labour can be used more efficiently. For example, additional help can be used at peak times such as farrowing. Similarly at other times, like the end of the service week, less labour is required and this has allowed some producers to take up work of the farm.