The morphology of the udder and milk quantity and quality in the milking hybrid ewes F_1 East Friesian X Polish Merino

摘要

Research was carried out on 40 one- to three-year-old (the 1st to 3rd lactation) F_1 crossbreeds of East Friesian and Polish Merino on the Experimental Station at Koluda Wielka situated in the lowlands of central Poland. The ewes were milked mechanically twice a day during a period of 4 months (May -September 1997) after the weaning of 8-week-old lambs. The measurements of the udders, the milk yield, the chemical composition and the somatic cell number were taken during the milking period, in the10th, 16th and 22nd weeks of lactation. The udder sizes of the older ewes were larger than those of the primigravidae (by 4 - 7 percent) and their milk yields were also larger, by 13 percent in two-year-old ewes and by 8 percent in three-year-old ones. The udders shrank by 4 - 28 percent between the 10th and 22nd week of lactation (especially in width, length and circumference), and the daily milk yield dropped by 57 percent at the same time. Along with the lactation development, the contents of protein, fat and dry matter in the milk increased, and the lactose content, the SFA : NSFA ratio and the somatic cells count became smaller. The miik yield was statistically significant when correlated with the udder measurements: the circumference (r = 0.53),width (r = 0.52) and depth (r = 0.39).