an epidemiological study of listeriosis in dairy cattle

found between the duration of feeding maize silage, hay, straw or root crops and clinical
Listeriosis.
Table 3. 4. The relationship between listeriosis and duration of feeding grass silage
Duration of feeding Grass silage Maize silage
Y N OR P Value X Y N OR P Value X
6 months 52 288 1.78 11 28 1.51
All year 14 70 1.97 0.03 4 10 1.53 0.3
R reference category, X X 2 for trend, OR odds ratio
(iii) Making forage crops:
a) Type of harvesters: Using a mower conditioner in the process of making grass silage
increased risk of reporting disease (OR 2.02, CL 1.21-3.37). This relationship was
statistically significant (Table 3. 3).
b) Number of cuts made for grass silage and hay: Although the relationship between
number of cuts made for grass silage and Listeriosis was not statistically significant
there was an increasing risk of disease as the number of cuts were increased (Table 3.
5).
Table 3. 5. The univariate relationship between number of grass cuts and disease
77