A recent survey by UK pharmaceutical company Janssen Animal Health suggests that more than half of producers in the country farrow batches of sows every 2-5 weeks rather than farrowing each week. The survey covered 48,500 sows or 11.5 per cent of the UK breeding herd and showed that 53 per cent of respondents batch farrowed. Of these 85 per cent operated a three-week system, 9 per cent farrowed every two weeks and 6 per cent ran a five-week system.
Of those producers that did not batch farrow, 71 per cent said that they had considered making the change and half of these said they were likely to make the change.
Batch farrowing has a number of benefits in controlling disease and the UK producers’ move to the system was primarily in response to the ravages of PRRS combined with circovirus, which caused devastating losses before the advent of vaccines. Even without these diseases, health is improved by batching in continuous flow farrow-to-finish units. The reason is that pigs of different ages can be segregated in separate rooms within the barn and also separated by time, similar in some ways to the principles of three-site production.
Pigs become infected with many diseases, especially respiratory diseases, either from the sow during the suckling period or from other pigs in the nursery. These rarely cause a problem prior to weaning provided the piglets received plenty of colostrum, but immediately after weaning, when immunity is low, they tend to flare up and the pigs show signs of clinical disease. The peak of infection is about 7-10 days after weaning and that is when they are shedding large numbers of bacteria or viruses. It is also around the time the next group of pigs is weaned in weekly farrowing systems with the nursery on the same site. Just as pigs are weaned, they are faced with a massive pathogen challenge from the previous week’s pigs and this effect compounds as time goes on, leading to high levels of disease.
The principle of segregated three-site production is that pigs are moved onto a separate site at weaning, ideally with one week’s weaned pigs on a single site, in order to reduce pig-to-pig contact. However, this is only possible in large-scale production systems. Batch farrowing achieves some of the benefits due to the time separation. After the pigs enter the nursery room, they still encounter the disease challenge but are better able to deal with it because the level of environmental pathogens is lower. This is because the previous batch of pigs, weaned maybe three weeks ago, have already overcome their own disease challenge, have developed immunity and are therefore shedding very few pathogenic organisms.
Farrowing every three weeks is most common because the sow cycles every 18-24 days, making it easier to fit the sows that return into the following batch. However, most farms that batch farrow make use of an oral progestagen such as Matrix (Intervet) to manage the timing of estrus in sows that fall out of line and also to ensure that gilts are bred at the same time as a batch of weaned sows. Daily treatment with Matrix delays the onset of estrus and when it is withdrawn the sow will show estrus 4-5 days later. This is an essential tool when batch farrowing, otherwise tight batching cannot be achieved.
In addition to the health benefits, there are operational advantages to batch farrowing. The most important of these is that each week, the management focus is on one area: Week 1, weaning; week 2, breeding and week 3 farrowing. For example, over the period that farrowing takes place staff has to work as a team and can concentrate their efforts on maximizing piglet survival. Because they have to work in all departments rather than specialize in one, this produces stockpersons with better all-round ability and increases motivation. Also, a clear focus on key tasks leads to improved performance. Experience in Europe suggests that labour costs are significantly reduced, sometimes by up to 25 per cent, because of the improvement in labour efficiency due to the way work is organized.
Converting from weekly to batch production may cause some initial problems. In order to create a group of sows, some of them have to have their estrus delayed after weaning, using Matrix, while others have to be weaned one week earlier than normal.
Also, depending on the age at weaning and batch timing (2, 3, 4 or 5 weeks) additional farrowing pens may be required. While 3-week batching seems the most logical, it also has the highest need for additional farrowing space, which adds cost. Depending on how the existing nursery and finishing facilities are organized, they may need alteration so that room capacity is matched to batch size and that full all in – all out management is possible.
The UK survey asked producers who were batch farrowing which benefits they thought were most important. Number one was a tighter spread of farrowings, second was improved pigs/sow/year, third was larger batches of more uniform weaners and finishers and fourth was better working practices, improved staff morale and better herd health. Also cited as advantages were improved growth rate in finishers and lower medication costs. Batch farrowing has some significant benefits for small-to medium-sized farrow to finish units, especially where disease levels are causing loss of performance. In addition, the management advantages make it a technique worth considering as a means of reducing production cost.