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Bovine milk hydrophobic fraction of proteose-peptone was prepared by hydrophobic interaction fast protein liquid chromatography. This method has several advantages such as high rapidity, simple good reproducibility and less denaturation. The proteose-peptone was eluted from a TSK-Phenyl-5PW column with a 1 M-0 M ionic strength gradient of NaH 2 PO 4 , pH 6-8, using a 6 ml/min flow rate for 56 min. The quantity of protein injected was 62-5 mg; however, it could be increased up to 100 mg. The elution order was /J-CN-4P

The chemical composition and nitrogen distribution of milk from two ewe's breed (Ouled-Djellal and Rumbi) (n = 20 each) reared in Algerian area steppe, were studied. The ewes were balanced for age and weight. All were in middle period of lactation. Individual milk samples were taken from each ewe third time from lactating period during spring season. Rumbi ewe's milk gave the highest values (p≤0.01) for lactose (4.89±0.61%), solid non-fat (11.19±0.87%) and density (1037.57±3.78) than Ouled-Djellal ewes (4.38±0.45%, 10.24±0.77% 1033.82±2.59, respectively) and lowest values (p≤0.01) for freezing point (-0.57±0.05°C vs -0.53±0.02°C). No significant difference was observed between the two breeds on fat, protein, total solids. The mean percentages were 6.26±1.38%, 5.54±0.76 and 16.51±1.44%, respectively for Ouled-Djellal ewes, while those of Rumbi's were 5.66±3.52%, 5.91±1.10% and 16.85±3.32%, respectively. No statistical differences related to the breed were found in the milk for all nitrogen fractions. Rumbi ewe's milk contains about 1.01% nitrogen however Ouled-Djellal's hold about 0.96%. Total nitrogen content is distributed between non-protein nitrogen (0.09% in all breeds) and protein nitrogen (0.93 vs 0.87% for Rumbi and Ouled -Djellal ewes respectively). The protein nitrogen includes casein nitrogen (0.76 vs 0.71) and whey protein nitrogen (0.20 vs 0.19%) from Rumbi and Ouled-Djellal ewes, respectively. Algerian sheep breeds were not actually selected for their milk production; selection program should be implemented to improve milk production and increase fat and protein contents. Thus further studies should carry out on milk ability and milk yield of these breeds.

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Characterization of breeding dairy cattle systems from the Mediterranean basin was conducted on 16 farms in the north center region of Algeria through a survey. Results are highly variable both structurally and in techno- economic management terms. The principal component analysis and clusters analysis have identified four groups of farms that differ in feeding strategies. The first group contains four farms that promote the use of forages (61.8% of the total dry matter (DM) intake). The costs are above the general averages (cost of production: 38.4 DA / liter ? 0.34 ? and cost of food in total production costs = 71.8%). The average annual productivity is about 4328.6 kg. Five farms of group 2 are characterized by milk yields below average (4146.5 kg). The concentrates represent only 39.3% of total DM intake. The cost of production (37.1 DA ? 0.33 ?/ liter of milk) and food costs are the lowest (65.17% of total production costs). The third group contains 5 farms dominated by profitable farms (4833.4 kg) and the lower cost of production (35.2 DA ? 0.31 ?). A relatively high proportion of DM is provided by forages (53.6%). Food accounts for 69.2% of the total production cost. The fourth group consists of two farms whose main characteristic is the total absence of forage production. This is associated with a significant contribution of concentrates in the global feed balance (48.8% of total DM intake). These concentrated foods were poorly converted into milk as recorded yields are the lowest (3561.2 kg). Production costs are highest (45.1 DA ? 0.40 ?) and relation price of food/total cost of production is very high (79.3%). So there are areas for improvement via land restructuring and the adoption of healthy feeding practices in order to ensure the profitability and sustainability of farms identified in this study.