Milk samples (n = 160) from 7 clinically healthy bactrian camels were cultured to detect subclinical udder infection. The samples were assessed by the Californian mastitis test (CMT) and somatic cell count (SCC). Bacteria were recovered from 36 (22.5%) of the milk samples. Staphylococcus aureus and coagulase-negative staphylococci (CNS) were the main organisms found. Infected quarters had significantly higher mean values for the SCC (p < 0.01) and CMT (p < 0.001) than non-infected quarters. All 7 camels were infected with CNS but only 4 with S. aureus. CMT values for S. aureus-infected camels were significantly higher than for those only infected with CNS. The values for SCC and CMT were significantly influenced by the stage of lactation (p < 0.05). No significant difference was found from the effect of the quarters. Both SCC and CMT were of value in predicting the infection status of the udder.

Summary NAGase activity (NAGase) and serum albumin concentrations were determined in milk from 101 traditionally managed camels in the Sudan. NAGase, a lysosomal enzyme released from damaged epithelial cells as well as other somatic cells in milk, was recorded for quarter milk samples from camels (n = 353) using the fluoroscan method. NAGase activity in major pathogen‐infected quarters was significantly (P < 0.05) higher than in minor pathogen‐infected and non‐infected quarters. Means for minor pathogen‐infected quarters were also significantly higher than non‐infected quarters. Concentrations of serum albumin, resulting from increased vascular permeability, in quarter milk samples (n = 320) were measured by the radial immunodiffusion test. Serum albumin content in milk was not affected by infection status of the quarter. There were, however, large variations in serum albumin levels and, to a lesser extent, NAGase values between samples in both infected and non‐infected quarters. NAGase was more effective in predicting bacteriological status of the quarter than serum albumin.

Peripheral blood was obtained from four lactating camels (Camelus bactrianus) and flow cytometry was used to characterize cell populations. The ability of the granulocytes to engulf fluorescent bacteria was studied in vitro using fluorescence microscopy.Three clusters of blood cells (mononuclear cells, neutrophils and eosinophils) were identified by flow cytometry and fluorescent microscopy. Milk, on the other hand, was dominated by cell fragments and no distinct cluster formation was found. The mean yield of blood granulocytes and monocytes isolated on Ficoll gradient was 92.2 5 5.4 % and 7.9 f 5.7 YO, respectively. Cell viability was 95 %. The mean percentage of phagocytic cells was 71.8 f 5.9 % at 10 min and increased to 97.3 2 0.5 '70 at 60 min when observation was terminated. The average number of bacteria per phagocyte was 8.7 * 2.1 and 13.1 k 0.9 at 10 and 60 min incubation time. BUSCHMANN, 1987b) and flow cytometry (SAAD and HAGELTORN, 1985; FOERSTER and WOLF, 1990; JENSEN-WAERN et al., 1994). T h e cells in mammary gland secretions and their relationships with various physiological and pathological states of the udder have been recognized in many animal species (see JAIN, 1976). Unlike other dairy animals, little is known regarding physiological and pathological states of the mammary gland of the camel. The aim of U.S. Copyright Clearance Center Code Statement: 0931 -184X/96/4302-0111$11.50/0 112 ABDURAHMAN and SAADthe present s t u d y was to characterize leukocyte populations from peripheral blood and milk of camels by means of flow cytometry and to evaluate phagocytic activity of granulocytes from blood using fluorescence microscopy. Materials and Methods AnimalsFour clinically healthy camels at Kilmirden park were used. The camels were of different ages and at different stages of lactation.