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 subclinical), elucidate the association of potential risk factors and to isolate and identify the bacteria associated 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 California Mastitis Test (CMT) for subclinical mastitis and clinical examination for clinical mastitis. The overall individual animal prevalence was found to be 51% (6.3% clinical and 44.7% subclinical). The prevalence in different localities was 67.7% in Ombadda, 45.2% in Omdurman, 50% in East Nile and 45.1% in Khartoum. The overall herd prevalence was 90.5% (27% clinical and 63.5% subclinical). The percentage of mastitis within quarters was 24% (4% clinical and 20% subclinical, 50% in the hind quarters and 48.7% in the front quarters). Risk factors such as, locality, health score, stage of lactation, parity, previous exposure to mastitis, teat injuries, presence of ticks, yielding milk, herd size, floor disinfectant, water scarcity, drainage system, dung removing, farm fencing and education level showed statistically significant association with the occurrence of mastitis in the univariate analysis (p-value ? 0.25). The results of the present study also showed that locality, stage of lactation, parity, previous exposure to mastitis and yielding milk had statistically significant association with mastitis in the multivariate analysis (p-value ? 0.05). Twenty five subclinically positive milk samples and 25 milk samples from clinically affected cows were subjected to bacteriological examination. All 50 samples yielded growth. Among these cultured positive samples, the prevalent mastitis causing agents isolated were: 61.1% Staphylococcus spp., 15% Streptococcus spp., 6% Corynebacterium spp., 3% Aerococcus spp., 2% Micrococcus spp. and 2% Bacillus spp.
