According to the latest figures from Nadis reports 38 percent of grower pigs are finished on sites separate from their breeding herd of origin. However only 15 percent of weaners (from weaning to ~35kg) are reared on a site separate to their breeding herd origin.

So has this helped with disease control? With respect to growing pigs, two specific disease syndromes can be studied.

1. RESPIRATORY DISEASE

Of 380,000 growing pigs on breeder feeder farms (35kg – finishing) respiratory disease was reported as a clinical entity in 22,500 pigs representing a prevalence of 5.9 percent.

Conversely on separate finishing or nursery/finishing sites 230,000 pigs were seen with respiratory disease evident in 16,700 – a prevalence of 7.25 percent.

(Within this latter group, pigs on finishing-only sites had a prevalence of respiratory disease of 6.6 percent and whereas finishing pigs on nursery finisher sites showed a prevalence of 8.5 percent).

2. COLITIS/GROWER SCOUR

Pigs retained on their farm of origin for finishing showed a prevalence of 2.5 percent colitis whereas those grown on separate sites showed a prevalence of 3.3 percent.

This data has not been analysed statistically but it can be seen that there is no obvious benefit from growing pigs to finish on a separate site.

The figures must, however, be treated with caution. They represent just what is evident at clinical inspection and make no allowance for other variables - vaccination patterns, system used (straw v slats; continuous flow v batch; single or multiple source), or control measures in place.

To be able to study these variables will require a much larger data set collected over a longer period. However, the message seems to be, unsurprisingly, that simply separating growers from the breeding herd gives little direct benefit in terms of respiratory or gut health. April 2007.