| Popis: |
During two successive lactations in 2009 and 2010 the aim of the study was to determine and evaluate chosen milk quality and quantity parameters in the flock of purebred East Friesian (EF) ewes. Experiment occurred during two lactation periods and 35 ewes were included in experiment in 2009 and 45 ewes in 2010. Milk records and samplings were carried out five times during milking period from May to September. Individual milk samples were analyzed for: total solids (TS), fat (F), protein (P), casein (CN), whey protein (WP), lactose (L). In addition the samples from 20 ewes were analyzed for: pH, titratable acidity (TA), rennet clotting time (RCT), rennet curd quality (RCQ), somatic cell count (SCC) and urea (U). In the study the effects of lactation stage, parity, litter size and month of lambing on chosen parameters were evaluated, as well as their interactions with LS. In 2009 the lactation stage had a significant effect on daily milk yield (DMY), milk composition, pH and titratable acidity. The parity had a significant effect on P, WP, L and RCT. However the litter size had a significant effect on DMY, L, TA and U. The month of lambing had a significant effect on DMY, TS, P, CN, L and TA. In 2010 the lactation stage had a significant effect on on DMY, milk composition, pH, TA, SCC and RCT. The parity had a significant effect on TS, F, L and U. Nevertheless the litter size had a significant effect on L and the month of lambing had a significant effect on L and SCC. In 2010 the part aim of the study was to evaluate the influence of lactation stage on fatty acids composition. The LS had a significant effect on contents of all chosen fatty acids and their sums. |
