an epidemiological study of listeriosis in dairy cattle

Sheep 8 27 3.94 1.55-9.71 0.001
Vaccine use
Leptospirosis 25 216 1.77 1.01-3.10 0.04
Mole hills
mole hill 35 362 1.80 1.01-3.23 0.05
Y number of farmers reporting cases, N number of farmers not reporting cases, OR (95% CL) Odds Ratio
with 95% confidence limit.
3. 3. 5. The univariate relationship between farming practices and nervous signs of
Listeriosis (meningo-encephalitis).
Only 26 farms reported having had cases with nervous signs of Listeriosis and
10 of the predictor variables were associated with reporting this form of the disease.
(i) Herd size:
There was a statistically significant association with herd sizes in all age groups
(milking cows, replacement heifers and dairy calves). As the herd sizes increased the
risk of reporting Listeriosis with nervous signs increased (Table 3. 19).
Table 3. 19. The univariate relationship between herd sizes and nervous form of
listeriosis
June 1995 July 1994
Herd sizes Y N OR P value Y N OR P value
Milking cows 100 12 204 5.78 0.005 X 11 201 4.78 0.009 X
Replacement