• (495) The objective of a routine programme is to maintain infection at negligible levels. It is impossible to maintain a herd completely free of all parasites because the risk of re-introduction is high and always present. The medicines used to treat parasites are called anthelmintics or parasecticides.
• Most are broad acting. Some of the common generic compounds available are shown in Fig.11-8.

This list is repeated again in Fig.11-9 to show the medicines that are active against different parasites and a comparison of approximate cost ratios. If the herd is free from mange and lungworm then less costly anthelmintics can be used. The most effective time to treat outdoor sows and particularly sows remaining in permanent paddocks or yards is seven days prior to farrowing to break the cycle of infection to the piglet. However this may not be easy and the alternate is to treat the complete herd by in-feed medication every three to six months.

The following methods of treatment can be adopted:-

• Inject sows with either ivermectin or levamisole seven days prior to farrowing or two days before entering the farrowing crate.
• Mix the wormer in the feed according to the manufacturers instructions either:
• - As a single dose given on one day.
• - Continuously for 7 days.
• - Continuously for 14 days.
• Top dress the sow or boars feed individually with the anthelmintic in pellets or use a small amount of the premix.