Changes in ewe milk composition depending on lactation stage and feeding season

Ewe milk contains relatively a high amount of total solids, fats and protei ns but milk composition changes depending on breed, stage of lactation, cli matic conditions, feeding, health and herd. The aim of these investigations was to find out the impact of lactation stage and feeding season on ewe mi lk composition during the lamb sucking period. Biological investigations we re carried out with 15 ewes of Wurtemberg breed till the 60th lactation day (all ewes were in the fourth and fifth lactation). The investigations comp rised two feeding seasons (winter and summer). The winter feeding period st arted on 1 October whereas the summer one started on I May, i.e. in the thi rd month of ewe pregnancy. It finished by their dryness. The ewes were hous ed in stable boxes and fed grains mixture (300 g daily) containing 60% of o ats, 30% of maize and 10% of soybean meal as well as meadow hay (ad libitum ). The ewes grazed in the summer feeding period. The stage of lactation and feeding season (winter and summer) considerably affected ewe milk composit ion in the lamb sucking period (2nd to 60th day). The highest concentration s of basic constituents of ewe milk (fats, proteins, total solids and solid s non-fat) were in colostrum (2nd day), except lactose, followed by their d ecrease on 10th and 30th lactation day and increase on 60th lactation day. The content of macro (Ca, P, K, Na and Mg) and microelements (Fe, Zn and Cu ) was also highest in colostrum (2nd day) followed by their milk concentrat ion decreasing and increasing on the 60th lactation day. Ca and Mg concentr ations considerably differed depending on the feeding season. In general, h igher K and Fe concentrations were determined in the summer whereas P and N a in the winter feeding season. Significant variations were also determined for Zn and Cu concentrations.