Comparative and Veterinary Pharmacology

by multilevel logistic regression. The quarters treated with the cloxacillin and the
internal sealant were significantly more likely to be bacteriologically negative in
the immediate period after calving and were significantly less likely to suffer
clinical mastitis, with an odds ratio of 0.47 (95% credibility interval 0.26–0.82),
than the quarters treated with cloxacillin alone (Table 6 ). It was also observed that
there was more variation between farms, than between cows within farm, in the
probability of clinical mastitis. This finding indicates that farm characteristics such
as management, nutrition and prevalence of concurrent diseases are important
determining factors for the occurrence of clinical mastitis.

4 Control of Respiratory Disease in Cattle and Swine

Pneumonia is a cause of major economic loss for the cattle and swine industries,
due to decreased production, high levels of mortality and increased veterinary and
labour costs. It is estimated that the costs of an outbreak of calf pneumonia range

Table 5Frequency of isolation of different pathogens from cases of clinical mastitis in quarters
treated with cloxacillin alone or with cloxacillin plus teat sealant and the (numbers of quarters
affected) (from Newton et al. 2008 )
Cloxacillin alone CloxacillinþTeat Sealant
Streptococcus uberis
Escherichia coli
Bacillusspecies
Citerobacterspecies
Coagulase positive staphylococci
Corynebacteriumspecies
Escherichiaspecies
OtherStreptococcusspecies
Mixed growth
No growth
Total

15 (14a)*

5 (4)*

1(1)

1 (1)

7(7a)

1 (1)

1 (1)

3 (3)

16 (16)

50 (48)c

4(4b)

4 (4)

1(1b)

1 (1)

3 (3)
10 (10)
23 (23)
a, bRows with different superscripts are significantly different (P<0.05)
*Some quarters were infected by different pathogens at different times

Table 6Logistic regression model for the outcome of clinical mastitis: comparison between
cloxacillin and cloxacillinþteat sealant (from Newton et al. 2008 )
Coefficient Odds ratio 95% credibility interval
Intercept –3.47 –5.07, –2.19
Reference cloxacillin alone
Cloxacillinþteat sealant 0.47 0.26, 0.82
Reference quarter right fore
Left fore 1.25 0.56, 2.80
Left hind 0.93 0.41, 2.17
Right hind 1.84 0.87, 4.03
Between cow variance 1.37 0.19, 3.14
Between farm variance 2.93 0.36, 11.7

Population Medicine and Control of Epidemics 127