Prevention and control of Dictyocaulus infections
Non-chemical prevention
Reducing pasture contamination with infective larvae is a key preventative measure that can be achieved to a large extent with adequate management measures.
Rotational grazing with a change interval of 4 days and keeping the paddocks empty for at least 40 days significantly reduces pasture contamination. This is due to the fact that larvae are susceptible to dryness and won't survive more than 4 or 5 weeks on pasture if they do not find an adequate host. Obviously, by very moist weather or where pastures are almost permanently moist survival may be longer.
Alternate grazing with sheep and/or horses may be considered, since Dictyocaulus species are quite host-specific (for cattle, sheep & goats, horses). The longer the absence of the specific host, the higher will be the reduction of its specific lungworm. However, this may not be advisable in places infected with gastrointestinal roundworms that are simultaneously parasitic of cattle and sheep or horses.
For their first grazing season it is highly advisable that young stock does not share the pastures with older stock that has been exposed earlier to infected grounds and can therefore shed larvae. It must also be avoided that young stock uses pastures already used by older stock during the same season.
It must also be considered that heavy rains and flooding can disseminate infective larvae inside a property or from one property to neighboring ones.
Keeping the pastures as dry as possible and keeping livestock away from places excessively humid are additional key measures to reduce the exposure of livestock to infective larvae.
Since livestock and horses can become infected indoors, strict hygiene and sanitation of the facilities are essential: frequent manure removal and bedding replacement, keeping everything as dry as possible, etc. It is safer not to harvested hay from contaminated paddocks, or it must be thoroughly dried before usage.
Dictyocaulus species that infect livestock and horses can also infect numerous wild animals (deer, antelopes, etc.). If feasible, they should be kept off the pastures used by livestock.
Other preventative measures are similar than those against gastrointestinal roundworms and explained in a specific article in this site (click here).
Biological control of Dictyocaulus worms (i.e. using its natural enemies) is so far not feasible. Learn more about biological control of worms.
You may be interested in an article in this site on medicinal plants against external and internal parasites.