The study of the transmission of the cattle lungworm (Dictyocaulus viviparus) in relation to pasture conditions

1. A series of experiments is described in which the transmission of cattle lung-worm infection has been investigated in relation to four different pasture conditions—long grass, short grass produced by gangmowing, grazing by sheep and grazing by resistant cattle. 2. The methods of study of value in this type of field investigation are discussed. It is suggested that the results can be usefully expressed as a series of coefficients which summarize the factors involved in the process of transmission. The methods of calculation of these coefficients are described.