Field evaluation of a method for the chemoprophylaxis of parasitic bronchitis in calves
Jacobs, D.E.; Fox, M.T.; Koyo, F.A.
Veterinary Record 116(18): 492-496
1985
ISSN/ISBN: 0042-4900 PMID: 3160156 Document Number: 258275
Adult lungworms present in calves around the sixth week after turnout play an important role in determining the subsequent pattern of disease. A trial was designed to test whether prophylactic treatment at this time would control disease in calves under British conditions. Thirty autumn-born Friesian or Friesian-cross bull calves were allowed to graze the whole of a 5 hectare field for six weeks after turnout. The field was then divided into two and the calves split into matching groups, one group being put into each of the paddocks. One group was treated with levamisole at this time and again two weeks later while the other was kept as an untreated control. Anthelmintic treatment resulted in a great reduction in larval excretion and considerably delayed the build-up of infection on pasture. This in turn delayed the onset and reduced the severity of clinical signs in the treated group. However, as disease was not eliminated completely, this prophylactic programme cannot be recommended in its present form.