NADIS surveillance Veterinary Surgeons collect data from farms visited on a quarterly basis and over a two-year period the trend in farrowing rates has been collated (graph 1).

Somewhat surprisingly, given that the last 12 months has seen PCV2 vaccines widely introduced and that claims that vaccination can improve breeding herd performance have been made (and on some farms have been seen), the data collected, if anything, shows a small reduction in successful farrowings with a dip seen at the end of both 2007 and 2008 (representing sows served in late summer/autumn). However, it is important to remember that small differences like this can be within the scope of normal variation and may not be statistically significant.

More concerning is the reduction of approximately 1.5 per cent through the spring of 2009 compared to the previous year. It will be interesting to see how the figures progress through the rest of 2009.

For 2009 data, the pattern seen 12 months ago across systems has not only been repeated but the differences, if anything, have widened (graph 2). Thus, indoor herds have outperformed outdoor herds by one percentage point and continuous flow systems have seen a comparable benefit compared to batch farrowing. As last year, there is little difference in fertility between sows kept on slats and straw.

In terms of fertility by herd type, there has been a complete change from last year (graph 3). Whereas 12 months ago breeding only and breeder/weaner farms out-performed breeder/feeders, over the last 12 months breeder/feeders have recorded farrowing rates four percentage points higher than breeder/weaners (84.5 versus 80.5) with the small number of breeder only units in between.

Similarly, the pattern of farrowing rates against herd size has altered over the last 12 months. In August 2008 small herds were the poorest performers with farrowing rates below 81 per cent. These have improved substantially in the last year (now 84 per cent) whilst there has been a small drop in the fertility of the largest herds (graph 4).

Whilst graph 5 appears to show marked regional variations in farrowing rates, with herds in the Midlands particularly fertile, the figures must be viewed in the context of a small number of farms outside the pig dense areas of North East England and East Anglia . Even so, the latter has produced higher farrowing rates in the last year than the former.

Further Reading

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