Abstract:
A cross-sectional study was conducted in large and small dairy farms
in Khartoum state from April to October 2012. The objectives were to
estimate the overall prevalence of bovine mastitis (clinical and sub clinical),
elucidate the association of potential risk factors and to isolate and identify t
bacteria associate with mastitis from milk samples. A total of 646 lactating
dairy cow comprising 51 local, 590 cross and 5 pure breed cows were
randomly selected and screened using Calinfornia Mastitis Test (CMT) for
subclinical mastitis and clinically examined for clinical mastitis. The overall
prevalence rate was found to 51% (6.3% clinical and 44.7% subclinical).
The prevalence in different localities was 99 (67.7%) in Ombada, 104
VIII
(45.2%) in Omdorman, 308 (50%) in Eastnile and 153 (45.1%) in Khartoum.
The overall herd prevalence was 66.2% (27% clinical and 63.5 subclincal).
The percentage of mastitis within quarters was 24% (4% clinical and 20%
subclincal, 50% hind quarters and 48.7% front quarters). Risk factors such as,
locality (p-value = .003), health score (p-value = .000), stage of lactation
(p-value = .004), parity (p-value = .009), previous exposure to mastitis
(p-value = .000), teat injuries (p-value = .06), presence of ticks (p-value =
.001), yielding milk (p-value = .000), herd size (p-value = .10), floor
disinfectant (p-value =.21), water scarcity (p-value = .03), drainage system
(p-value = .006), dung removing (p-value = .21), farm fencing (p-value = .05)
and education level (p-value = .09) showed statistically significant association
( p-value < 0.25) with the occurrence of mastitis in the univariate analysis.
The results of this study also showed that locality (p-value = .02), stage of
lactation (p-value = .004), parity (p-value = .02), previous exposure to
mastitis (p-value = .007) and yielding milk (p-value = .000) had statistical
significant association of mastitis (p-value ≤ 0.05) in the multivariate analysis.
Twenty five subclinically positive milk samples and 25 milk samples from
clinically affected cows were subjected to bacteriological examination. All
samples were cultured positive. In addition, mixed infection was found.
Among these cultured positive samples, the prevalent mastitis causing agents
isolated were: 61.1% Staphylococcus spp, 15% Streptococcus spp, 6%
Corynobactirum spp, 3% Aerococcus spp, 2% Micrococcus spp and 2%
Bacillus spp.
