an epidemiological study of listeriosis in dairy cattle

was made by a veterinarian or V.I.C. The frequency of clinical signs seen in milking cows,
replacement heifers and dairy calves is also given in Table 2. 5.
Table 2. 4. Frequency of clinical signs in cases reported between June 1994 and June
1995
all diagnosis diagnosed by vet. Or VIC
Clinical signs n=405 (%) n=222 (%)
silage eye 339 (83.7) 177 (79.7)
silage eye and nervous signs 29 (7.2) 12 (5.4)
nervous signs 20 (4.9) 20 (9)
abortion 10 (2.5) 9 (4.1)
mastitis 4 (1) 1 (0.5)
Sudden death 1 (0.2) 1 (0.5)
Diarrhoea 1 (0.2) 1 (0.5)
silage eye and sudden death 1 (0.2) 1 (0.5)
n number of cases
When re-estimated for the three age groups of dairy cattle the distribution of silage
eye was similar in all groups but no cases of Listeriosis showing nervous signs were
reported in dairy calves (Table 2. 5).
Table 2. 5. The frequency of clinical signs for the cases reported in three groups of
dairy cattle between July 1994 and June 1995
56