an epidemiological study of listeriosis in dairy cattle

listeriosis. Maize silage feeding also increased the risk of disease in dairy cattle and the
Odds Ratio for this variable was 2.4 (95% CL 1.50-3.85). There was also a statistically
significant association between feeding straw when animals were housed and a
decreased risk of reporting disease in dairy cattle (OR 0.38, 95% CL 0.18-0.78). (Table
3. 3).
When the individual types of straw (barley, wheat, wheat and barley and the
combination of wheat, barley, oat and pea) or root crops (beet type, potatoes, brassica
type, kale and others) were taken into consideration there was no association between
these and the occurrence of listeriosis in dairy cattle.
b) Sources of forage: Farmers were given three alternative sources of forage; purchased,
home made and any other sources. There was a statistically significant association
between purchased grass silage (OR 2.91, CL 1.22-6.8) and increased risk of reporting
Listeriosis (Table 3. 3).
c) Methods of feeding forages:
1) outdoor feeding: Feeding maize silage (OR 1.35, CL 1.59-13.04), hay (OR 2.98, CL
1.12-8.23) and straw (OR 3.72, CL 1.25-11.88) in ring feeders when animals were out
were associated with an increased risk of disease (Table 3. 3).
2) indoor feeding: Two methods (feeding forages in ring feeders and on the floor) were
associated with disease. Feeding grass silage (OR 1.93, CL 1.21-3.07), maize silage
(OR 4.96, CL 2.17-11.46) and hay (OR 4.17, CL 1.83-9.61) in ring feeders was
positively associated with disease whereas feeding grass silage (OR 0.23, CL 0.04-0.97)
and hay (OR 0.0, CL 0.0-0.85) on the floor was negatively associated with disease
(Table 3. 3).
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