Gut worms

Gut worms cause parasitic gastroenteritis which leads to diarrhoea and weight loss in cattle. The risk of exposure varies between stock type, however.

It is very rare for adult cattle to show clinical signs of gut worm infestation.

However, one consideration should be heifers that calved at two years of age. Added pressure on the body at a younger age may increase susceptibility.

While these animals are probably going to be put with the main cow herd for the grazing season, it is important to monitor them closely for scour or loss of condition which may suggest a worm burden.

Heifers that calved at two years of age should be monitored closely.

Second-season grazers will have some, but not a full level of immunity. Immunity will be even lower in those born late in the first year, or those who were under an intensive anthelmintic treatment regime in their first grazing season.

These animals should be monitored for lose dung and poor performance and treated if necessary.

Calves, ie first-season grazers, should be categorised into suckler calves or dairy calves.

Suckler calves are at low risk early in the season as they are grazing with their mothers and have a low herbage intake. The greatest risk periods are only after weaning in the autumn. To monitor, growth rates should be measured and faecal samples should be tested.

Dairy calves are exposed to infection as soon as they are let to grass and it is common for significant infection to be evident after only a few months grazing.

Proactive management will include grazing calves on the cleanest possible pasture and treating within the first three weeks of grazing.

This should be repeated throughout the grazing season at appropriate intervals depending on the drug used.

Alternatively, calves should be monitored by weighing and faecal-sampling and treated when ADG drops below 0.6kg or when samples return over 200 epg.

Lungworm

Signs of lungworm include coughing, hoosing and, in extreme cases, difficulty breathing. Furthermore, infected cattle have increased susceptibility to viral and bacterial pneumonia.

Immunity to lungworm develops quickly but only lasts for approximately six months in the absence of further infection.

Therefore, at the start of each grazing season, cattle have little or no immunity to lungworm, with the main risk period then being late-summer and autumn.

Ideally, to manage infection, calves should be turned out onto pasture where there was no cattle previously. Also, if turnout is staggered, the later calves should be put on to different clean pasture than the early ones.

That said, lungworm is unpredictable and has a rapid development, so control through management alone is difficult.

Therefore, it is essential that all ages of cattle are monitored closely over the grazing season and treatment of the whole group should be performed if signs appear to avoid lung damage.