A nyers juh- és kecsketej minőségét befolyásoló főbb tényezők
Absztrakt
SUMMARY
Based on large number of publications in scientific literature, the author provide
information on the factors affecting the quality of raw sheep and goat milk. She
presents the effect of the variety within species, the impact of stage of lacta tion and seasons, the influence of milking and changes in somatic cell count in
milk composition. In sheep milk the amount of milk fat, milk protein and casein
in the final stage of the lactation rises compared to the first stage. In goat
milk the concentration of milk fat decreases in the middle stage of lactation
compared to the first stage and it increases in the final stage and the amount
of milk protein and casein constantly increases during the lactation. High milk
yield is usually combined with a long lactation period, normally 8-10 months,
but the dairy sheep maintain lactation for 2 years without more calving. A high
somatic cell count milk have a higher proteolytic activity, and they contain larger
quantities of fat and casein and lower concentration of whey proteins, especially
serum albumin and immunoglobulin. The proteolytic enzymes in the somatic
cells attack the αs2- and β-casein. Just like the goats, the sheep also respond to
changes in the environment, they have developed a genetic multiplication pace
that follows the seasons change and the better food endowments. If the lacta tion period begins before the spring or the rainy season, lactation period will be
longer because of the better feed. There is 80-90% correspondence between
the udder size and the milk yield, and the milk yield depends on the surface size
of alveoli, too. Increasing the number of milking ordinarily increases the amount
of the expressed milk, but in this case there are significant differences between
individual animals.