The influence of some non-genetic factors on the production and quality of East Friesian sheep milk in Croatia

The aim of the study was to determine the influence of the herd (A and B), stage of lactation (0-60th day; 61st-150th day and 151st - drying off) and number of lactation (I., II. III. IV. and other) on daily milk yield, physicalchemical properties and the hygienic quality of East Friesian sheep milk. The study was conducted during 2004 and 2005 years on a 100 sheep sample. The milk samples were taken during morning and evening milking after weaning, every 30 days during lactation. The physical-chemical properties and the hygienic quality of milk were determined by reference and standard methods. The collected data were statistically analysed by the PROC ANOVA, SAS programme. The East Friesian sheep in the lactation of 217 days, produced in average 1040 mL milk/day. A significant effect (P < 0,001) of the herd was determined on the daily milk yield, dry matter non fat, freezing point, protein content (P < 0,01) and pH value (P < 0,01). The stage of lactation had a significant effect (P < 0,001) on all analyzed parameters except on somatic cell count. The highest content of fat (6.53 %), proteins (5.44 %), dry matter (17.45 %) and dry matter non fat (10.98 %) were determined at the end of lactation, while the content of lactose (4.61 %) was the lowest. Significant coefficient of correlations (P<0,05) were also determined between daily milk yield and: the content of dry matter (-0,46), milk fat (-0,51), proteins (-0,39), lactose (0,51), dry matter non fat (-0,28), pH value (0,14). From the results, it can be concluded that the herd, stage and number of lactation have significant influence on the most analyzed parameters.