aThis study was carried out to determine the prevalence of intra-mammary bacterial infections in healthy dairy goats in the central Kenyan highlands, where the highest density of dairy goats in Kenya occurs, in order to formulate mastitis control measures in the flocks.The investigation was carried out in 7 dairy goat farmer groups. All the does that were in different stages of lactation from all the dairy goat groups were sampled once a month for 3 months. The number of does sampled were 130 in the 1st month, 108 in the 2nd month and 77 in the 3rd month. The decrease in the number of does sampled in the 2nd and 3rd months was due to drying off of some of the does. The does were mainly German Alpine crosses with a few Toggenberg, Saanen and Galla crosses. The mammary glands of the does were examined visually for any injuries or swellings and by palpation for consistency and warmth. The first streams of milk from each mammary gland half were macroscopically examined. After discarding the first 3 streams of the fore milk, a 20 ml milk sample was collected aseptically from each mammary gland half into sterile Bijoux bottles. The milk samples were kept at 4°C until bacteriologically processed in the laboratory between 3 and 6 h after collection. In the laboratory the milk samples were streaked onto sheep blood and MacConkey agar plates and incubated aerobically at 37°C for 48 h. Significant bacterial colonies at 24 and 48 h were selected and sub-cultured for 24 h after which they were Gramstained and biochemically tested and classified according to standard methods 5 . With a few exceptions, most organisms were identified to genus level. The data were analysed using Statistix (SX v. 4.0) (Analytical Software, St Paul).Visual evaluation and palpation of the mammary gland halves and the macroscopic examination of the milk revealed no abnormalities. The prevalence of bacteria in the 630 clinically normal milk samples cultured was 28.7 % ( Table 1). The prevalence of bacteria isolated from normal caprine milk varies among studies undertaken in different countries 3 . This has been attributed to the influence of factors such as differences in the time of sampling, the diagnostic criteria used, breed differences, different hygiene and management practices followed on each farm, age and parity of the animals, and the milking method [2][3][4]11 . The goats used in this study were mainly stall-fed and were washed with warm water before being hand-milked. The does were milked twice a day, with no teat dipping after milking. Hand-milked goats have been found to have a lower prevalence of bacteria than machine-milked goats 10 . Hand milking of the does in this study may therefore have influenced the prevalence of bacteria. There were significantly (P < 0.05) more bacterial organisms isolated from the left mammary gland halves (55.8 %) than from the right mammary gland halves (44.2 %). This was similar to observations by Boscos et al. 2 , who suggested that this was possibly related to the milking process. They observed t...

California mastitis test (CMT), direct leukocytes counts and bacteriological examination were performed on 630 milk samples from apparently healthy mammary glands of dairy goats comprising a mixed population of German Alpine, Toggenberg, Saanen and Galla crosses to find the prevalence of subclinical mastitis. The prevalence of subclinical mastitis was 9.8 %according to CMT, 9.7 %according to direct leukocyte counts and 28.7 %by bacterial isolation during a 3-month period. The proportion of the bacteriologically positive milk samples was significantly (P &lt; 0.01) higher than that positive for CMTand direct leukocyte counts. There was a significant (P &lt; 0.01) correlation between CMT and direct leukocyte counts. There was no significant direct relationship between bacterial isolation and CMT. Bacterial organisms were isolated in 22.5 % of the 568 CMT-negative milk samples. The results suggest that bacterial organisms isolated from the CMT-negative milk samples were either latent infections or did not stimulate any significant increase in somatic cell counts that could be detected by either the CMT or direct leukocyte counts. The observations of this study indicate that the mere presence of bacteria in goat's milk does not mean that the udder is infected and so does not warrant antibiotic therapy

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