DOJIVOST, SLOŽENÍ A KVALITA EKOLOGICKÉHO MLÉKA KŘÍŽENEK OVCÍ PLEMEN LACAUNE, VÝCHODOFRÍSKÁ OVCE A ZUŠLECHTĚNÁ VALAŠKA V PRŮBĚHU LAKTACE

Abstract

Evaluation of milk yield, composition and quality of organic milk of crossbreeds of Lacaune (L), East Friesian (EF) and Improved Wallachian (IW), (n = 10, L 50 EF 43.75 IW 6.25) during lactation was carried out on organic farm in Valašská Bystřice in 2007. All sheep were on the third lactation and during study they were reared on permanent pasture. The stage of lactation (SL) had a highly significant effect on milk yield (MY) and contents of total solids (TS), fat (F), protein (P), casein (C), lactose (L) and urea (U). The SL had also a highly significant effect on pH and titrable acidity (TA), whereas on rennet clotting time (RCT) the SL had a significant effect. On the other hand the SL had not a significant effect on somatic cell counts (SCC) and rennet curd quality (RCQ). The highest contents of TS, F and C were found at the end of the lactation, whereas their lowest contents were found on the 120th day. Between the second and the last sampling the lactose content decreased. The content of U and RCT were the most variable indicators whithin the frame of our study. On the other hand SCCs were, during the whole lactation, very well-balanced and relatively low. Between pH and SCC was found positive correlation. TA gradually increased and RCT gradually prolonged with advanced lactation.