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Abstract
7.1. Milk samples:
A total of 200 random goat’s milk were samples collected from different place in Alexandria province. Samples were transferred to laboratory with a minimum of delay where they were examined physicaly, chemicaly and microbiologically. The obtained results could be summarized as follows:
7.1. Physical examination of goat’s milk:
1- Specific gravity values of goat’s milk ranged from 1.0293 to 1.0328 with average values 1.030 ± 0.01.
2- The viscosity values were 2.46 (minimum) and 2.54 (maximum) with an average values of 2.50 ± 0.03.
7.2. Keeping quality testes:
1- pH value in goat’s milk ranged from 6.40 to 6.99 during the lactation period with mean values of 6.69 ± 0.01.
2- Titratable acidity values of goat’s milk ranged from 0.10 to 0.24 with mean values of
0.18 ± 0.02.
7.3 Chemical examination:
1- Fat content in goat’s milk ranged from 1.40% (minimum) to 7.40% (maximum with a mean valueof 4.88 ± 0.11%.
2- Total solids content in goat’s milk ranged from 10.58% to 18.50 % with an average of
14.41 ± 0.14%.
3- Solids not fat of goat’s milk ranged from 6.00% (minimum) to 7.00 % (maximum) with a mean value of 6.76 ± 0.0 1%.
4- Protein values of goat’s milk ranged from 2.30% to 5.30% with an average of 3.57 ±
0.05%.
5- Casein content of goat’s milk ranged from 2.6% to 3.4% with a mean value of 1 ±
0.04%.
6- Albumin content varied through different stage of lactation from 279.9 to 471.4 with an average of 392.5 ± 35.6%.
7- Lactose content of goat’s milk was related to the stage of lactation. Lactose content ranged from 2.60% (minimum) to 6.60% (maximum with a mean value of 4.14 ± 0.07%.
7.4. Detection of sunclinical mastitis:
1- Chloride content of milk ranged from 0.08% to 0.18% with a mean value of 0.14 ±
0.07%.
2- Somatic cell count (SCC) of goat’s milk was related to degree of infection by pathogenic microorganisms from 6.3 x104 /ml to 1.2 x l0 /ml with an average of 2.0 x 106 ±5.3xl05/ml.
7.5. Microbiological examination of 2oat’s milk:
The microbiological analysis of the examined goat’s milk samples revealed that:
1- The total bacterial count ranged from 6.0 x l0 to 1.8 x i05 Iml with a mean value of
1.4 x l0 ± 2.5 x io /ml. The number of positive samples were 112 out of 200, which represent 56% and considered infected with subclinical mastitis.
2- Staphylococcus aureus counts in the examined goat’s milk samples ranged from 4.0 x
102 to 6.3 x /ml with a mean value of 2.6 x ± 0.5 x 102 /ml. The number of positive samples were 38 out of 200, which represent (19%) of total samples and represent (3 8%) of total positive goat’s milk samples.
3- Streptococcal count ranged from 3.0 x 102 to 6.0 x i03 /ml with a mean value of 1.95
i0 ± 0.4 x io /ml. The number of positive samples were 56 out of 200, which
represent (28%) of total samples, but represent (56%) of positive samples divided to
28.6% Str. agalactiae, 18% Str. dysagaiactiae and 6% Str. uberis.
4- Total coliform count (MPN/g) in goat’s milk samples ranged from 2.5 x 102 to 5.2 x /ml with a mean value of 2.9 x i0 0.3x The positive samples were 17 (14.4%) out of total positive samples . The incidence of identified coliform species, (E. coil, Kieb. Pneumoniae , Citrobacter diversus and Enterobacter aerogens) were 6 (4.5%), 5 (4.5%), 3 (2.7%) and 3 (2.7%), respectively.
5- Yeast count in goat’s milk samples was 1 (0.9%) of total positive samples.
6- Molds: not detected in all goat’s milk samples.
7- Identifecation for Str. agaiactiae by using primers Vl and V2, specific to rRNA and early diagnosis of subclinical mastitis by using,(PCR)technique.
7.6. Correlation coefficient among different parameters:
7.6.1. Correlation coefficient between pH value and bacteriological examination:
103 out of 200 milk samples contained pH less than 6.7 (negative result) out of them
37 samples were positive bacteriology. So, using of pH in detecting subclinical mastitis was unreliable with accuracy true positive 70.50%.
7.6.2. Correlation coefficient between chloride test and bacteriological examination:
120 out of 200 milk samples showed a level less than 0.14 (negative results), out of them 44 samples were positive bacteriologicaly. In this study, the using of chloride test in detecting subclinical mastitis was unreliable, with accuracy true +ve 72%.
7.6.3. Correlation coefficient between (SCC) and bacteriological
examination:
70 out of 200 milk samples contained (SCC) less than (106) /ml, out of them 14 samples were ositive bacteriologicaly. On the other hand, 130 samples showed acount more than (10 ) out of them 98 samples were bacteriologically positive and 32 samples were false positive, with high accuracy true +ve 77%.
7.6.4. Correlation coefficient between bacterial cell counts and chemical analysis:
- Correlation coefficient (r) between bacterial cell counts and (SCC) was not significant.
- However, correlation between percent of protein and SCC was significant.
- Among relations between bacterial cell counts, the only significant relation was between TBC and coliform counts. The relation between protein and Staph viococcus count also were significant.
- The relation between SCC and Staphylococcus counts was significant. Also, the relation between fat and protein was significant.